Witness: add pidl output

[wireshark-wip.git] / epan / tvbuff.c

/* tvbuff.c
 *
 * Testy, Virtual(-izable) Buffer of guint8*'s
 *
 * "Testy" -- the buffer gets mad when an attempt to access data
 *              beyond the bounds of the buffer. An exception is thrown.
 *
 * "Virtual" -- the buffer can have its own data, can use a subset of
 *              the data of a backing tvbuff, or can be a composite of
 *              other tvbuffs.
 *
 * $Id$
 *
 * Copyright (c) 2000 by Gilbert Ramirez <gram@alumni.rice.edu>
 *
 * Code to convert IEEE floating point formats to native floating point
 * derived from code Copyright (c) Ashok Narayanan, 2000
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <string.h>

#ifdef HAVE_LIBZ
#include <zlib.h>
#endif

#include "wsutil/pint.h"
#include "tvbuff.h"
#include "tvbuff-int.h"
#include "strutil.h"
#include "to_str.h"
#include "charsets.h"
#include "proto.h"      /* XXX - only used for DISSECTOR_ASSERT, probably a new header file? */
#include "exceptions.h"

static guint64
_tvb_get_bits64(tvbuff_t *tvb, guint bit_offset, const gint total_no_of_bits);

tvbuff_t *
tvb_new(const struct tvb_ops *ops)
{
        tvbuff_t *tvb;
        gsize     size = ops->tvb_size;

        g_assert(size >= sizeof(*tvb));

        tvb = (tvbuff_t *) g_slice_alloc(size);

        tvb->next            = NULL;
        tvb->ops             = ops;
        tvb->initialized     = FALSE;
        tvb->flags           = 0;
        tvb->length          = 0;
        tvb->reported_length = 0;
        tvb->real_data       = NULL;
        tvb->raw_offset      = -1;
        tvb->ds_tvb          = NULL;

        return tvb;
}

static void
tvb_free_internal(tvbuff_t *tvb)
{
        gsize     size;

        DISSECTOR_ASSERT(tvb);

        if (tvb->ops->tvb_free)
                tvb->ops->tvb_free(tvb);

        size = tvb->ops->tvb_size;

        g_slice_free1(size, tvb);
}

/* XXX: just call tvb_free_chain();
 *      Not removed so that existing dissectors using tvb_free() need not be changed.
 *      I'd argue that existing calls to tvb_free() should have actually beeen
 *      calls to tvb_free_chain() although the calls were OK as long as no
 *      subsets, etc had been created on the tvb. */
void
tvb_free(tvbuff_t *tvb)
{
        tvb_free_chain(tvb);
}

void
tvb_free_chain(tvbuff_t  *tvb)
{
        tvbuff_t *next_tvb;
        DISSECTOR_ASSERT(tvb);
        while (tvb) {
                next_tvb=tvb->next;
                tvb_free_internal(tvb);
                tvb  = next_tvb;
        }
}

tvbuff_t *
tvb_new_chain(tvbuff_t *parent, tvbuff_t *backing)
{
        tvbuff_t *tvb = tvb_new_proxy(backing);

        tvb_add_to_chain(parent, tvb);
        return tvb;
}

void
tvb_add_to_chain(tvbuff_t *parent, tvbuff_t *child)
{
        tvbuff_t *tmp = child;

        DISSECTOR_ASSERT(parent);
        DISSECTOR_ASSERT(child);

        while (child) {
                tmp   = child;
                child = child->next;

                tmp->next    = parent->next;
                parent->next = tmp;
        }
}

/*
 * Check whether that offset goes more than one byte past the
 * end of the buffer.
 *
 * If not, return 0; otherwise, return exception
 */
static inline int
validate_offset(const tvbuff_t *tvb, const guint abs_offset)
{
        if (G_LIKELY(abs_offset <= tvb->length))
                return 0;
        else if (abs_offset <= tvb->reported_length)
                return BoundsError;
        else if (tvb->flags & TVBUFF_FRAGMENT)
                return FragmentBoundsError;
        else
                return ReportedBoundsError;
}

static int
compute_offset(const tvbuff_t *tvb, const gint offset, guint *offset_ptr)
{
        if (offset >= 0) {
                /* Positive offset - relative to the beginning of the packet. */
                if ((guint) offset <= tvb->length) {
                        *offset_ptr = offset;
                } else if ((guint) offset <= tvb->reported_length) {
                        return BoundsError;
                } else if (tvb->flags & TVBUFF_FRAGMENT) {
                        return FragmentBoundsError;
                } else {
                        return ReportedBoundsError;
                }
        }
        else {
                /* Negative offset - relative to the end of the packet. */
                if ((guint) -offset <= tvb->length) {
                        *offset_ptr = tvb->length + offset;
                } else if ((guint) -offset <= tvb->reported_length) {
                        return BoundsError;
                } else if (tvb->flags & TVBUFF_FRAGMENT) {
                        return FragmentBoundsError;
                } else {
                        return ReportedBoundsError;
                }
        }

        return 0;
}

static int
compute_offset_and_remaining(const tvbuff_t *tvb, const gint offset, guint *offset_ptr, guint *rem_len)
{
        int exception;

        exception = compute_offset(tvb, offset, offset_ptr);
        if (!exception)
                *rem_len = tvb->length - *offset_ptr;

        return exception;
}

/* Computes the absolute offset and length based on a possibly-negative offset
 * and a length that is possible -1 (which means "to the end of the data").
 * Returns integer indicating whether the offset is in bounds (0) or
 * not (exception number). The integer ptrs are modified with the new offset and length.
 * No exception is thrown.
 *
 * XXX - we return success (0), if the offset is positive and right
 * after the end of the tvbuff (i.e., equal to the length).  We do this
 * so that a dissector constructing a subset tvbuff for the next protocol
 * will get a zero-length tvbuff, not an exception, if there's no data
 * left for the next protocol - we want the next protocol to be the one
 * that gets an exception, so the error is reported as an error in that
 * protocol rather than the containing protocol.  */
static int
check_offset_length_no_exception(const tvbuff_t *tvb,
                                 const gint offset, gint const length_val,
                                 guint *offset_ptr, guint *length_ptr)
{
        guint end_offset;
        int exception;

        DISSECTOR_ASSERT(offset_ptr);
        DISSECTOR_ASSERT(length_ptr);

        /* Compute the offset */
        exception = compute_offset(tvb, offset, offset_ptr);
        if (exception)
                return exception;

        if (length_val < -1) {
                /* XXX - ReportedBoundsError? */
                return BoundsError;
        }

        /* Compute the length */
        if (length_val == -1)
                *length_ptr = tvb->length - *offset_ptr;
        else
                *length_ptr = length_val;

        /*
         * Compute the offset of the first byte past the length.
         */
        end_offset = *offset_ptr + *length_ptr;

        /*
         * Check for an overflow
         */
        if (end_offset < *offset_ptr)
                return BoundsError;

        return validate_offset(tvb, end_offset);
}

/* Checks (+/-) offset and length and throws an exception if
 * either is out of bounds. Sets integer ptrs to the new offset
 * and length. */
static void
check_offset_length(const tvbuff_t *tvb,
                    const gint offset, gint const length_val,
                    guint *offset_ptr, guint *length_ptr)
{
        int exception;

        exception = check_offset_length_no_exception(tvb, offset, length_val, offset_ptr, length_ptr);
        if (exception)
                THROW(exception);
}

void
tvb_check_offset_length(const tvbuff_t *tvb,
                        const gint offset, gint const length_val,
                        guint *offset_ptr, guint *length_ptr)
{
        check_offset_length(tvb, offset, length_val, offset_ptr, length_ptr);
}

static const unsigned char left_aligned_bitmask[] = {
        0xff,
        0x80,
        0xc0,
        0xe0,
        0xf0,
        0xf8,
        0xfc,
        0xfe
};

tvbuff_t *
tvb_new_octet_aligned(tvbuff_t *tvb, guint32 bit_offset, gint32 no_of_bits)
{
        tvbuff_t     *sub_tvb = NULL;
        guint32       byte_offset;
        gint32        datalen, i;
        guint8        left, right, remaining_bits, *buf;
        const guint8 *data;

        byte_offset = bit_offset >> 3;
        left = bit_offset % 8; /* for left-shifting */
        right = 8 - left; /* for right-shifting */

        if (no_of_bits == -1) {
                datalen = tvb_length_remaining(tvb, byte_offset);
                remaining_bits = 0;
        } else {
                datalen = no_of_bits >> 3;
                remaining_bits = no_of_bits % 8;
                if (remaining_bits) {
                        datalen++;
                }
        }

        /* already aligned -> shortcut */
        if ((left == 0) && (remaining_bits == 0)) {
                return tvb_new_subset(tvb, byte_offset, datalen, -1);
        }

        DISSECTOR_ASSERT(datalen>0);

        /* if at least one trailing byte is available, we must use the content
        * of that byte for the last shift (i.e. tvb_get_ptr() must use datalen + 1
        * if non extra byte is available, the last shifted byte requires
        * special treatment
        */
        if (tvb_length_remaining(tvb, byte_offset) > datalen) {
                data = tvb_get_ptr(tvb, byte_offset, datalen + 1);

                /* Do this allocation AFTER tvb_get_ptr() (which could throw an exception) */
                buf = (guint8 *)g_malloc(datalen);

                /* shift tvb data bit_offset bits to the left */
                for (i = 0; i < datalen; i++)
                        buf[i] = (data[i] << left) | (data[i+1] >> right);
        } else {
                data = tvb_get_ptr(tvb, byte_offset, datalen);

                /* Do this allocation AFTER tvb_get_ptr() (which could throw an exception) */
                buf = (guint8 *)g_malloc(datalen);

                /* shift tvb data bit_offset bits to the left */
                for (i = 0; i < (datalen-1); i++)
                        buf[i] = (data[i] << left) | (data[i+1] >> right);
                buf[datalen-1] = data[datalen-1] << left; /* set last octet */
        }
        buf[datalen-1] &= left_aligned_bitmask[remaining_bits];

        sub_tvb = tvb_new_child_real_data(tvb, buf, datalen, datalen);
        tvb_set_free_cb(sub_tvb, g_free);

        return sub_tvb;
}

static tvbuff_t *
tvb_generic_clone_offset_len(tvbuff_t *tvb, guint offset, guint len)
{
        tvbuff_t *cloned_tvb;

        guint8 *data = (guint8 *) g_malloc(len);

        tvb_memcpy(tvb, data, offset, len);

        cloned_tvb = tvb_new_real_data(data, len, len);
        tvb_set_free_cb(cloned_tvb, g_free);

        return cloned_tvb;
}

tvbuff_t *
tvb_clone_offset_len(tvbuff_t *tvb, guint offset, guint len)
{
        if (tvb->ops->tvb_clone) {
                tvbuff_t *cloned_tvb;

                cloned_tvb = tvb->ops->tvb_clone(tvb, offset, len);
                if (cloned_tvb)
                        return cloned_tvb;
        }

        return tvb_generic_clone_offset_len(tvb, offset, len);
}

tvbuff_t *
tvb_clone(tvbuff_t *tvb)
{
        return tvb_clone_offset_len(tvb, 0, tvb->length);
}

guint
tvb_length(const tvbuff_t *tvb)
{
        DISSECTOR_ASSERT(tvb && tvb->initialized);

        return tvb->length;
}

gint
tvb_length_remaining(const tvbuff_t *tvb, const gint offset)
{
        guint abs_offset, rem_length;
        int exception;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        exception = compute_offset_and_remaining(tvb, offset, &abs_offset, &rem_length);
        if (exception)
                return 0;

        return rem_length;
}

guint
tvb_ensure_length_remaining(const tvbuff_t *tvb, const gint offset)
{
        guint abs_offset, rem_length;
        int   exception;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        exception = compute_offset_and_remaining(tvb, offset, &abs_offset, &rem_length);
        if (exception)
                THROW(exception);

        if (rem_length == 0) {
                /*
                 * This routine ensures there's at least one byte available.
                 * There aren't any bytes available, so throw the appropriate
                 * exception.
                 */
                if (abs_offset >= tvb->reported_length) {
                        if (tvb->flags & TVBUFF_FRAGMENT) {
                                THROW(FragmentBoundsError);
                        } else {
                                THROW(ReportedBoundsError);
                        }
                } else
                        THROW(BoundsError);
        }
        return rem_length;
}




/* Validates that 'length' bytes are available starting from
 * offset (pos/neg). Does not throw an exception. */
gboolean
tvb_bytes_exist(const tvbuff_t *tvb, const gint offset, const gint length)
{
        guint abs_offset, abs_length;
        int exception;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        exception = check_offset_length_no_exception(tvb, offset, length, &abs_offset, &abs_length);
        if (exception)
                return FALSE;

        return TRUE;
}

/* Validates that 'length' bytes are available starting from
 * offset (pos/neg). Throws an exception if they aren't. */
void
tvb_ensure_bytes_exist(const tvbuff_t *tvb, const gint offset, const gint length)
{
        guint real_offset, end_offset;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        /*
         * -1 doesn't mean "until end of buffer", as that's pointless
         * for this routine.  We must treat it as a Really Large Positive
         * Number, so that we throw an exception; we throw
         * ReportedBoundsError, as if it were past even the end of a
         * reassembled packet, and past the end of even the data we
         * didn't capture.
         *
         * We do the same with other negative lengths.
         */
        if (length < 0) {
                THROW(ReportedBoundsError);
        }

        /* XXX: Below this point could be replaced with a call to
         * check_offset_length with no functional change, however this is a
         * *very* hot path and check_offset_length is not well-optimized for
         * this case, so we eat some code duplication for a lot of speedup. */

        if (offset >= 0) {
                /* Positive offset - relative to the beginning of the packet. */
                if ((guint) offset <= tvb->length) {
                        real_offset = offset;
                } else if ((guint) offset <= tvb->reported_length) {
                        THROW(BoundsError);
                } else if (tvb->flags & TVBUFF_FRAGMENT) {
                        THROW(FragmentBoundsError);
                } else {
                        THROW(ReportedBoundsError);
                }
        }
        else {
                /* Negative offset - relative to the end of the packet. */
                if ((guint) -offset <= tvb->length) {
                        real_offset = tvb->length + offset;
                } else if ((guint) -offset <= tvb->reported_length) {
                        THROW(BoundsError);
                } else if (tvb->flags & TVBUFF_FRAGMENT) {
                        THROW(FragmentBoundsError);
                } else {
                        THROW(ReportedBoundsError);
                }
        }

        /*
         * Compute the offset of the first byte past the length.
         */
        end_offset = real_offset + length;

        /*
         * Check for an overflow
         */
        if (end_offset < real_offset)
                THROW(BoundsError);

        if (G_LIKELY(end_offset <= tvb->length))
                return;
        else if (end_offset <= tvb->reported_length)
                THROW(BoundsError);
        else if (tvb->flags & TVBUFF_FRAGMENT)
                THROW(FragmentBoundsError);
        else
                THROW(ReportedBoundsError);
}

gboolean
tvb_offset_exists(const tvbuff_t *tvb, const gint offset)
{
        guint abs_offset;
        int exception;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        exception = compute_offset(tvb, offset, &abs_offset);
        if (exception)
                return FALSE;

        /* compute_offset only throws an exception on >, not >= because of the
         * comment above check_offset_length_no_exception, but here we want the
         * opposite behaviour so we check ourselves... */
        if (abs_offset < tvb->length) {
                return TRUE;
        }
        else {
                return FALSE;
        }
}

guint
tvb_reported_length(const tvbuff_t *tvb)
{
        DISSECTOR_ASSERT(tvb && tvb->initialized);

        return tvb->reported_length;
}

gint
tvb_reported_length_remaining(const tvbuff_t *tvb, const gint offset)
{
        guint abs_offset;
        int exception;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        exception = compute_offset(tvb, offset, &abs_offset);
        if (exception)
                return 0;

        if (tvb->reported_length >= abs_offset)
                return tvb->reported_length - abs_offset;
        else
                return 0;
}

/* Set the reported length of a tvbuff to a given value; used for protocols
 * whose headers contain an explicit length and where the calling
 * dissector's payload may include padding as well as the packet for
 * this protocol.
 * Also adjusts the data length. */
void
tvb_set_reported_length(tvbuff_t *tvb, const guint reported_length)
{
        DISSECTOR_ASSERT(tvb && tvb->initialized);

        if (reported_length > tvb->reported_length)
                THROW(ReportedBoundsError);

        tvb->reported_length = reported_length;
        if (reported_length < tvb->length)
                tvb->length = reported_length;
}

guint
tvb_offset_from_real_beginning_counter(const tvbuff_t *tvb, const guint counter)
{
        if (tvb->ops->tvb_offset)
                return tvb->ops->tvb_offset(tvb, counter);

        DISSECTOR_ASSERT_NOT_REACHED();
        return 0;
}

guint
tvb_offset_from_real_beginning(const tvbuff_t *tvb)
{
        return tvb_offset_from_real_beginning_counter(tvb, 0);
}

static const guint8*
ensure_contiguous_no_exception(tvbuff_t *tvb, const gint offset, const gint length, int *pexception)
{
        guint abs_offset, abs_length;
        int exception;

        exception = check_offset_length_no_exception(tvb, offset, length, &abs_offset, &abs_length);
        if (exception) {
                if (pexception)
                        *pexception = exception;
                return NULL;
        }

        /*
         * We know that all the data is present in the tvbuff, so
         * no exceptions should be thrown.
         */
        if (tvb->real_data)
                return tvb->real_data + abs_offset;

        if (tvb->ops->tvb_get_ptr)
                return tvb->ops->tvb_get_ptr(tvb, abs_offset, abs_length);

        DISSECTOR_ASSERT_NOT_REACHED();
        return NULL;
}

static const guint8*
ensure_contiguous(tvbuff_t *tvb, const gint offset, const gint length)
{
        int           exception = 0;
        const guint8 *p;

        p = ensure_contiguous_no_exception(tvb, offset, length, &exception);
        if (p == NULL) {
                DISSECTOR_ASSERT(exception > 0);
                THROW(exception);
        }
        return p;
}

static const guint8*
fast_ensure_contiguous(tvbuff_t *tvb, const gint offset, const guint length)
{
        guint end_offset;
        guint u_offset;

        DISSECTOR_ASSERT(tvb && tvb->initialized);
        /* We don't check for overflow in this fast path so we only handle simple types */
        DISSECTOR_ASSERT(length <= 8);

        if (offset < 0 || !tvb->real_data) {
                return ensure_contiguous(tvb, offset, length);
        }

        u_offset = offset;
        end_offset = u_offset + length;

        if (end_offset <= tvb->length) {
                return tvb->real_data + u_offset;
        }

        if (end_offset > tvb->reported_length) {
                if (tvb->flags & TVBUFF_FRAGMENT) {
                        THROW(FragmentBoundsError);
                } else {
                        THROW(ReportedBoundsError);
                }
                /* not reached */
        }
        THROW(BoundsError);
        /* not reached */
        return NULL;
}

static const guint8*
guint8_pbrk(const guint8* haystack, size_t haystacklen, const guint8 *needles, guchar *found_needle)
{
        gchar         tmp[256] = { 0 };
        const guint8 *haystack_end;

        while (*needles)
                tmp[*needles++] = 1;

        haystack_end = haystack + haystacklen;
        while (haystack < haystack_end) {
                if (tmp[*haystack]) {
                        if (found_needle)
                                *found_needle = *haystack;
                        return haystack;
                }
                haystack++;
        }

        return NULL;
}



/************** ACCESSORS **************/

void *
tvb_memcpy(tvbuff_t *tvb, void *target, const gint offset, size_t length)
{
        guint   abs_offset, abs_length;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        /*
         * XXX - we should eliminate the "length = -1 means 'to the end
         * of the tvbuff'" convention, and use other means to achieve
         * that; this would let us eliminate a bunch of checks for
         * negative lengths in cases where the protocol has a 32-bit
         * length field.
         *
         * Allowing -1 but throwing an assertion on other negative
         * lengths is a bit more work with the length being a size_t;
         * instead, we check for a length <= 2^31-1.
         */
        DISSECTOR_ASSERT(length <= 0x7FFFFFFF);
        check_offset_length(tvb, offset, (gint) length, &abs_offset, &abs_length);

        if (tvb->real_data) {
                return memcpy(target, tvb->real_data + abs_offset, abs_length);
        }

        if (tvb->ops->tvb_memcpy)
                return tvb->ops->tvb_memcpy(tvb, target, abs_offset, abs_length);

        /* XXX, fallback to slower method */

        DISSECTOR_ASSERT_NOT_REACHED();
        return NULL;
}


/*
 * XXX - this doesn't treat a length of -1 as an error.
 * If it did, this could replace some code that calls
 * "tvb_ensure_bytes_exist()" and then allocates a buffer and copies
 * data to it.
 *
 * "composite_get_ptr()" depends on -1 not being
 * an error; does anything else depend on this routine treating -1 as
 * meaning "to the end of the buffer"?
 *
 * If scope is NULL, memory is allocated with g_malloc() and user must
 * explicitely free it with g_free().
 * If scope is not NULL, memory is allocated with the corresponding pool
 * lifetime.
 */
void *
tvb_memdup(wmem_allocator_t *scope, tvbuff_t *tvb, const gint offset, size_t length)
{
        guint   abs_offset, abs_length;
        void    *duped;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        check_offset_length(tvb, offset, (gint) length, &abs_offset, &abs_length);

        duped = wmem_alloc(scope, abs_length);
        return tvb_memcpy(tvb, duped, abs_offset, abs_length);
}



const guint8*
tvb_get_ptr(tvbuff_t *tvb, const gint offset, const gint length)
{
        return ensure_contiguous(tvb, offset, length);
}

/* ---------------- */
guint8
tvb_get_guint8(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, sizeof(guint8));
        return *ptr;
}

guint16
tvb_get_ntohs(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, sizeof(guint16));
        return pntohs(ptr);
}

guint32
tvb_get_ntoh24(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, 3);
        return pntoh24(ptr);
}

guint32
tvb_get_ntohl(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, sizeof(guint32));
        return pntohl(ptr);
}

guint64
tvb_get_ntoh40(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, 5);
        return pntoh40(ptr);
}

guint64
tvb_get_ntoh48(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, 6);
        return pntoh48(ptr);
}

guint64
tvb_get_ntoh56(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, 7);
        return pntoh56(ptr);
}

guint64
tvb_get_ntoh64(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, sizeof(guint64));
        return pntoh64(ptr);
}

/*
 * Stuff for IEEE float handling on platforms that don't have IEEE
 * format as the native floating-point format.
 *
 * For now, we treat only the VAX as such a platform.
 *
 * XXX - other non-IEEE boxes that can run UNIX include some Crays,
 * and possibly other machines.
 *
 * It appears that the official Linux port to System/390 and
 * zArchitecture uses IEEE format floating point (not a
 * huge surprise).
 *
 * I don't know whether there are any other machines that
 * could run Wireshark and that don't use IEEE format.
 * As far as I know, all of the main commercial microprocessor
 * families on which OSes that support Wireshark can run
 * use IEEE format (x86, 68k, SPARC, MIPS, PA-RISC, Alpha,
 * IA-64, and so on).
 */

#if defined(vax)

#include <math.h>

/*
 * Single-precision.
 */
#define IEEE_SP_NUMBER_WIDTH    32      /* bits in number */
#define IEEE_SP_EXP_WIDTH       8       /* bits in exponent */
#define IEEE_SP_MANTISSA_WIDTH  23      /* IEEE_SP_NUMBER_WIDTH - 1 - IEEE_SP_EXP_WIDTH */

#define IEEE_SP_SIGN_MASK       0x80000000
#define IEEE_SP_EXPONENT_MASK   0x7F800000
#define IEEE_SP_MANTISSA_MASK   0x007FFFFF
#define IEEE_SP_INFINITY        IEEE_SP_EXPONENT_MASK

#define IEEE_SP_IMPLIED_BIT (1 << IEEE_SP_MANTISSA_WIDTH)
#define IEEE_SP_INFINITE ((1 << IEEE_SP_EXP_WIDTH) - 1)
#define IEEE_SP_BIAS ((1 << (IEEE_SP_EXP_WIDTH - 1)) - 1)

static int
ieee_float_is_zero(const guint32 w)
{
        return ((w & ~IEEE_SP_SIGN_MASK) == 0);
}

static gfloat
get_ieee_float(const guint32 w)
{
        long sign;
        long exponent;
        long mantissa;

        sign = w & IEEE_SP_SIGN_MASK;
        exponent = w & IEEE_SP_EXPONENT_MASK;
        mantissa = w & IEEE_SP_MANTISSA_MASK;

        if (ieee_float_is_zero(w)) {
                /* number is zero, unnormalized, or not-a-number */
                return 0.0;
        }
#if 0
        /*
         * XXX - how to handle this?
         */
        if (IEEE_SP_INFINITY == exponent) {
                /*
                 * number is positive or negative infinity, or a special value
                 */
                return (sign? MINUS_INFINITY: PLUS_INFINITY);
        }
#endif

        exponent = ((exponent >> IEEE_SP_MANTISSA_WIDTH) - IEEE_SP_BIAS) -
                IEEE_SP_MANTISSA_WIDTH;
        mantissa |= IEEE_SP_IMPLIED_BIT;

        if (sign)
                return -mantissa * pow(2, exponent);
        else
                return mantissa * pow(2, exponent);
}

/*
 * Double-precision.
 * We assume that if you don't have IEEE floating-point, you have a
 * compiler that understands 64-bit integral quantities.
 */
#define IEEE_DP_NUMBER_WIDTH    64      /* bits in number */
#define IEEE_DP_EXP_WIDTH       11      /* bits in exponent */
#define IEEE_DP_MANTISSA_WIDTH  52      /* IEEE_DP_NUMBER_WIDTH - 1 - IEEE_DP_EXP_WIDTH */

#define IEEE_DP_SIGN_MASK       0x8000000000000000LL
#define IEEE_DP_EXPONENT_MASK   0x7FF0000000000000LL
#define IEEE_DP_MANTISSA_MASK   0x000FFFFFFFFFFFFFLL
#define IEEE_DP_INFINITY        IEEE_DP_EXPONENT_MASK

#define IEEE_DP_IMPLIED_BIT (1LL << IEEE_DP_MANTISSA_WIDTH)
#define IEEE_DP_INFINITE ((1 << IEEE_DP_EXP_WIDTH) - 1)
#define IEEE_DP_BIAS ((1 << (IEEE_DP_EXP_WIDTH - 1)) - 1)

static int
ieee_double_is_zero(const guint64 w)
{
        return ((w & ~IEEE_SP_SIGN_MASK) == 0);
}

static gdouble
get_ieee_double(const guint64 w)
{
        gint64 sign;
        gint64 exponent;
        gint64 mantissa;

        sign = w & IEEE_DP_SIGN_MASK;
        exponent = w & IEEE_DP_EXPONENT_MASK;
        mantissa = w & IEEE_DP_MANTISSA_MASK;

        if (ieee_double_is_zero(w)) {
                /* number is zero, unnormalized, or not-a-number */
                return 0.0;
        }
#if 0
        /*
         * XXX - how to handle this?
         */
        if (IEEE_DP_INFINITY == exponent) {
                /*
                 * number is positive or negative infinity, or a special value
                 */
                return (sign? MINUS_INFINITY: PLUS_INFINITY);
        }
#endif

        exponent = ((exponent >> IEEE_DP_MANTISSA_WIDTH) - IEEE_DP_BIAS) -
                IEEE_DP_MANTISSA_WIDTH;
        mantissa |= IEEE_DP_IMPLIED_BIT;

        if (sign)
                return -mantissa * pow(2, exponent);
        else
                return mantissa * pow(2, exponent);
}
#endif

/*
 * Fetches an IEEE single-precision floating-point number, in
 * big-endian form, and returns a "float".
 *
 * XXX - should this be "double", in case there are IEEE single-
 * precision numbers that won't fit in some platform's native
 * "float" format?
 */
gfloat
tvb_get_ntohieee_float(tvbuff_t *tvb, const int offset)
{
#if defined(vax)
        return get_ieee_float(tvb_get_ntohl(tvb, offset));
#else
        union {
                gfloat f;
                guint32 w;
        } ieee_fp_union;

        ieee_fp_union.w = tvb_get_ntohl(tvb, offset);
        return ieee_fp_union.f;
#endif
}

/*
 * Fetches an IEEE double-precision floating-point number, in
 * big-endian form, and returns a "double".
 */
gdouble
tvb_get_ntohieee_double(tvbuff_t *tvb, const int offset)
{
#if defined(vax)
        union {
                guint32 w[2];
                guint64 dw;
        } ieee_fp_union;
#else
        union {
                gdouble d;
                guint32 w[2];
        } ieee_fp_union;
#endif

#ifdef WORDS_BIGENDIAN
        ieee_fp_union.w[0] = tvb_get_ntohl(tvb, offset);
        ieee_fp_union.w[1] = tvb_get_ntohl(tvb, offset+4);
#else
        ieee_fp_union.w[0] = tvb_get_ntohl(tvb, offset+4);
        ieee_fp_union.w[1] = tvb_get_ntohl(tvb, offset);
#endif
#if defined(vax)
        return get_ieee_double(ieee_fp_union.dw);
#else
        return ieee_fp_union.d;
#endif
}

guint16
tvb_get_letohs(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, sizeof(guint16));
        return pletohs(ptr);
}

guint32
tvb_get_letoh24(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, 3);
        return pletoh24(ptr);
}

guint32
tvb_get_letohl(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, sizeof(guint32));
        return pletohl(ptr);
}

guint64
tvb_get_letoh40(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, 5);
        return pletoh40(ptr);
}

guint64
tvb_get_letoh48(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, 6);
        return pletoh48(ptr);
}

guint64
tvb_get_letoh56(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, 7);
        return pletoh56(ptr);
}

guint64
tvb_get_letoh64(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;

        ptr = fast_ensure_contiguous(tvb, offset, sizeof(guint64));
        return pletoh64(ptr);
}

/*
 * Fetches an IEEE single-precision floating-point number, in
 * little-endian form, and returns a "float".
 *
 * XXX - should this be "double", in case there are IEEE single-
 * precision numbers that won't fit in some platform's native
 * "float" format?
 */
gfloat
tvb_get_letohieee_float(tvbuff_t *tvb, const int offset)
{
#if defined(vax)
        return get_ieee_float(tvb_get_letohl(tvb, offset));
#else
        union {
                gfloat f;
                guint32 w;
        } ieee_fp_union;

        ieee_fp_union.w = tvb_get_letohl(tvb, offset);
        return ieee_fp_union.f;
#endif
}

/*
 * Fetches an IEEE double-precision floating-point number, in
 * little-endian form, and returns a "double".
 */
gdouble
tvb_get_letohieee_double(tvbuff_t *tvb, const int offset)
{
#if defined(vax)
        union {
                guint32 w[2];
                guint64 dw;
        } ieee_fp_union;
#else
        union {
                gdouble d;
                guint32 w[2];
        } ieee_fp_union;
#endif

#ifdef WORDS_BIGENDIAN
        ieee_fp_union.w[0] = tvb_get_letohl(tvb, offset+4);
        ieee_fp_union.w[1] = tvb_get_letohl(tvb, offset);
#else
        ieee_fp_union.w[0] = tvb_get_letohl(tvb, offset);
        ieee_fp_union.w[1] = tvb_get_letohl(tvb, offset+4);
#endif
#if defined(vax)
        return get_ieee_double(ieee_fp_union.dw);
#else
        return ieee_fp_union.d;
#endif
}

/* Fetch an IPv4 address, in network byte order.
 * We do *not* convert them to host byte order; we leave them in
 * network byte order. */
guint32
tvb_get_ipv4(tvbuff_t *tvb, const gint offset)
{
        const guint8 *ptr;
        guint32       addr;

        ptr = fast_ensure_contiguous(tvb, offset, sizeof(guint32));
        memcpy(&addr, ptr, sizeof addr);
        return addr;
}

/* Fetch an IPv6 address. */
void
tvb_get_ipv6(tvbuff_t *tvb, const gint offset, struct e_in6_addr *addr)
{
        const guint8 *ptr;

        ptr = ensure_contiguous(tvb, offset, sizeof(*addr));
        memcpy(addr, ptr, sizeof *addr);
}

/* Fetch a GUID. */
void
tvb_get_ntohguid(tvbuff_t *tvb, const gint offset, e_guid_t *guid)
{
        const guint8 *ptr = ensure_contiguous(tvb, offset, GUID_LEN);

        guid->data1 = pntohl(ptr + 0);
        guid->data2 = pntohs(ptr + 4);
        guid->data3 = pntohs(ptr + 6);
        memcpy(guid->data4, ptr + 8, sizeof guid->data4);
}

void
tvb_get_letohguid(tvbuff_t *tvb, const gint offset, e_guid_t *guid)
{
        const guint8 *ptr = ensure_contiguous(tvb, offset, GUID_LEN);

        guid->data1 = pletohl(ptr + 0);
        guid->data2 = pletohs(ptr + 4);
        guid->data3 = pletohs(ptr + 6);
        memcpy(guid->data4, ptr + 8, sizeof guid->data4);
}

/*
 * NOTE: to support code written when proto_tree_add_item() took a
 * gboolean as its last argument, with FALSE meaning "big-endian"
 * and TRUE meaning "little-endian", we treat any non-zero value of
 * "representation" as meaning "little-endian".
 */
void
tvb_get_guid(tvbuff_t *tvb, const gint offset, e_guid_t *guid, const guint representation)
{
        if (representation) {
                tvb_get_letohguid(tvb, offset, guid);
        } else {
                tvb_get_ntohguid(tvb, offset, guid);
        }
}

static const guint8 inverse_bit_mask8[] = {
        0xff,
        0x7f,
        0x3f,
        0x1f,
        0x0f,
        0x07,
        0x03,
        0x01
};

static const guint8 bit_mask8[] = {
        0x00,
        0x01,
        0x03,
        0x07,
        0x0f,
        0x1f,
        0x3f,
        0x7f,
        0xff
};

/* Get 1 - 8 bits */
guint8
tvb_get_bits8(tvbuff_t *tvb, guint bit_offset, const gint no_of_bits)
{
        return (guint8)_tvb_get_bits64(tvb, bit_offset, no_of_bits);
}

/* Get 9 - 16 bits */
guint16
tvb_get_bits16(tvbuff_t *tvb, guint bit_offset, const gint no_of_bits,const guint encoding _U_)
{
        /* note that encoding has no meaning here, as the tvb is considered to contain an octet array */
        return (guint16)_tvb_get_bits64(tvb, bit_offset, no_of_bits);
}

/* Get 1 - 32 bits */
guint32
tvb_get_bits32(tvbuff_t *tvb, guint bit_offset, const gint no_of_bits, const guint encoding _U_)
{
        /* note that encoding has no meaning here, as the tvb is considered to contain an octet array */
        return (guint32)_tvb_get_bits64(tvb, bit_offset, no_of_bits);
}

/* Get 1 - 64 bits */
guint64
tvb_get_bits64(tvbuff_t *tvb, guint bit_offset, const gint no_of_bits, const guint encoding _U_)
{
        /* note that encoding has no meaning here, as the tvb is considered to contain an octet array */
        return _tvb_get_bits64(tvb, bit_offset, no_of_bits);
}
/*
 * This function will dissect a sequence of bits that does not need to be byte aligned; the bits
 * set will be shown in the tree as ..10 10.. and the integer value returned if return_value is set.
 * Offset should be given in bits from the start of the tvb.
 * The function tolerates requests for more than 64 bits, but will only return the least significant 64 bits.
 */
static guint64
_tvb_get_bits64(tvbuff_t *tvb, guint bit_offset, const gint total_no_of_bits)
{
        guint64 value;
        guint octet_offset = bit_offset >> 3;
        guint8 required_bits_in_first_octet = 8 - (bit_offset % 8);

        if(required_bits_in_first_octet > total_no_of_bits)
        {
                /* the required bits don't extend to the end of the first octet */
                guint8 right_shift = required_bits_in_first_octet - total_no_of_bits;
                value = (tvb_get_guint8(tvb, octet_offset) >> right_shift) & bit_mask8[total_no_of_bits % 8];
        }
        else
        {
                guint8 remaining_bit_length = total_no_of_bits;

                /* get the bits up to the first octet boundary */
                value = 0;
                required_bits_in_first_octet %= 8;
                if(required_bits_in_first_octet != 0)
                {
                        value = tvb_get_guint8(tvb, octet_offset) & bit_mask8[required_bits_in_first_octet];
                        remaining_bit_length -= required_bits_in_first_octet;
                        octet_offset ++;
                }
                /* take the biggest words, shorts or octets that we can */
                while (remaining_bit_length > 7)
                {
                        switch (remaining_bit_length >> 4)
                        {
                        case 0:
                                /* 8 - 15 bits. (note that 0 - 7 would have dropped out of the while() loop) */
                                value <<= 8;
                                value += tvb_get_guint8(tvb, octet_offset);
                                remaining_bit_length -= 8;
                                octet_offset ++;
                                break;

                        case 1:
                                /* 16 - 31 bits */
                                value <<= 16;
                                value += tvb_get_ntohs(tvb, octet_offset);
                                remaining_bit_length -= 16;
                                octet_offset += 2;
                                break;

                        case 2:
                        case 3:
                                /* 32 - 63 bits */
                                value <<= 32;
                                value += tvb_get_ntohl(tvb, octet_offset);
                                remaining_bit_length -= 32;
                                octet_offset += 4;
                                break;

                        default:
                                /* 64 bits (or more???) */
                                value = tvb_get_ntoh64(tvb, octet_offset);
                                remaining_bit_length -= 64;
                                octet_offset += 8;
                                break;
                        }
                }
                /* get bits from any partial octet at the tail */
                if(remaining_bit_length)
                {
                        value <<= remaining_bit_length;
                        value += (tvb_get_guint8(tvb, octet_offset) >> (8 - remaining_bit_length));
                }
        }
        return value;
}
/* Get 1 - 32 bits (should be deprecated as same as tvb_get_bits32??) */
guint32
tvb_get_bits(tvbuff_t *tvb, const guint bit_offset, const gint no_of_bits, const guint encoding _U_)
{
        /* note that encoding has no meaning here, as the tvb is considered to contain an octet array */
        return (guint32)_tvb_get_bits64(tvb, bit_offset, no_of_bits);
}

static gint
tvb_find_guint8_generic(tvbuff_t *tvb, guint abs_offset, guint limit, guint8 needle)
{
        const guint8 *ptr;
        const guint8 *result;

        ptr = tvb_get_ptr(tvb, abs_offset, limit);

        result = (const guint8 *) memchr(ptr, needle, limit);
        if (!result)
                return -1;

        return (gint) ((result - ptr) + abs_offset);
}

/* Find first occurrence of needle in tvbuff, starting at offset. Searches
 * at most maxlength number of bytes; if maxlength is -1, searches to
 * end of tvbuff.
 * Returns the offset of the found needle, or -1 if not found.
 * Will not throw an exception, even if maxlength exceeds boundary of tvbuff;
 * in that case, -1 will be returned if the boundary is reached before
 * finding needle. */
gint
tvb_find_guint8(tvbuff_t *tvb, const gint offset, const gint maxlength, const guint8 needle)
{
        const guint8 *result;
        guint         abs_offset;
        guint         tvbufflen;
        guint         limit;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        check_offset_length(tvb, offset, -1, &abs_offset, &tvbufflen);

        /* Only search to end of tvbuff, w/o throwing exception. */
        if (maxlength == -1) {
                /* No maximum length specified; search to end of tvbuff. */
                limit = tvbufflen;
        }
        else if (tvbufflen < (guint) maxlength) {
                /* Maximum length goes past end of tvbuff; search to end
                   of tvbuff. */
                limit = tvbufflen;
        }
        else {
                /* Maximum length doesn't go past end of tvbuff; search
                   to that value. */
                limit = maxlength;
        }

        /* If we have real data, perform our search now. */
        if (tvb->real_data) {
                result = (const guint8 *)memchr(tvb->real_data + abs_offset, needle, limit);
                if (result == NULL) {
                        return -1;
                }
                else {
                        return (gint) (result - tvb->real_data);
                }
        }

        if (tvb->ops->tvb_find_guint8)
                return tvb->ops->tvb_find_guint8(tvb, abs_offset, limit, needle);

        return tvb_find_guint8_generic(tvb, offset, limit, needle);
}

static gint
tvb_pbrk_guint8_generic(tvbuff_t *tvb, guint abs_offset, guint limit, const guint8 *needles, guchar *found_needle)
{
        const guint8 *ptr;
        const guint8 *result;

        ptr = tvb_get_ptr(tvb, abs_offset, limit);

        result = guint8_pbrk(ptr, limit, needles, found_needle);
        if (!result)
                return -1;

        return (gint) ((result - ptr) + abs_offset);
}

/* Find first occurrence of any of the needles in tvbuff, starting at offset.
 * Searches at most maxlength number of bytes; if maxlength is -1, searches
 * to end of tvbuff.
 * Returns the offset of the found needle, or -1 if not found.
 * Will not throw an exception, even if maxlength exceeds boundary of tvbuff;
 * in that case, -1 will be returned if the boundary is reached before
 * finding needle. */
gint
tvb_pbrk_guint8(tvbuff_t *tvb, const gint offset, const gint maxlength, const guint8 *needles, guchar *found_needle)
{
        const guint8 *result;
        guint         abs_offset;
        guint         tvbufflen;
        guint         limit;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        check_offset_length(tvb, offset, -1, &abs_offset, &tvbufflen);

        /* Only search to end of tvbuff, w/o throwing exception. */
        if (maxlength == -1) {
                /* No maximum length specified; search to end of tvbuff. */
                limit = tvbufflen;
        }
        else if (tvbufflen < (guint) maxlength) {
                /* Maximum length goes past end of tvbuff; search to end
                   of tvbuff. */
                limit = tvbufflen;
        }
        else {
                /* Maximum length doesn't go past end of tvbuff; search
                   to that value. */
                limit = maxlength;
        }

        /* If we have real data, perform our search now. */
        if (tvb->real_data) {
                result = guint8_pbrk(tvb->real_data + abs_offset, limit, needles, found_needle);
                if (result == NULL) {
                        return -1;
                }
                else {
                        return (gint) (result - tvb->real_data);
                }
        }

        if (tvb->ops->tvb_pbrk_guint8)
                return tvb->ops->tvb_pbrk_guint8(tvb, abs_offset, limit, needles, found_needle);

        return tvb_pbrk_guint8_generic(tvb, abs_offset, limit, needles, found_needle);
}

/* Find size of stringz (NUL-terminated string) by looking for terminating
 * NUL.  The size of the string includes the terminating NUL.
 *
 * If the NUL isn't found, it throws the appropriate exception.
 */
guint
tvb_strsize(tvbuff_t *tvb, const gint offset)
{
        guint abs_offset, junk_length;
        gint  nul_offset;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        check_offset_length(tvb, offset, 0, &abs_offset, &junk_length);
        nul_offset = tvb_find_guint8(tvb, abs_offset, -1, 0);
        if (nul_offset == -1) {
                /*
                 * OK, we hit the end of the tvbuff, so we should throw
                 * an exception.
                 *
                 * Did we hit the end of the captured data, or the end
                 * of the actual data?  If there's less captured data
                 * than actual data, we presumably hit the end of the
                 * captured data, otherwise we hit the end of the actual
                 * data.
                 */
                if (tvb->length < tvb->reported_length) {
                        THROW(BoundsError);
                } else {
                        if (tvb->flags & TVBUFF_FRAGMENT) {
                                THROW(FragmentBoundsError);
                        } else {
                                THROW(ReportedBoundsError);
                        }
                }
        }
        return (nul_offset - abs_offset) + 1;
}

/* UTF-16/UCS-2 version of tvb_strsize */
/* Returns number of bytes including the (two-bytes) null terminator */
guint
tvb_unicode_strsize(tvbuff_t *tvb, const gint offset)
{
        guint     i = 0;
        gunichar2 uchar;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        do {
                /* Endianness doesn't matter when looking for null */
                uchar = tvb_get_ntohs(tvb, offset + i);
                i += 2;
        } while(uchar != 0);

        return i;
}

/* Find length of string by looking for end of string ('\0'), up to
 * 'maxlength' characters'; if 'maxlength' is -1, searches to end
 * of tvbuff.
 * Returns -1 if 'maxlength' reached before finding EOS. */
gint
tvb_strnlen(tvbuff_t *tvb, const gint offset, const guint maxlength)
{
        gint  result_offset;
        guint abs_offset, junk_length;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        check_offset_length(tvb, offset, 0, &abs_offset, &junk_length);

        result_offset = tvb_find_guint8(tvb, abs_offset, maxlength, 0);

        if (result_offset == -1) {
                return -1;
        }
        else {
                return result_offset - abs_offset;
        }
}

/*
 * Implement strneql etc
 */

/*
 * Call strncmp after checking if enough chars left, returning 0 if
 * it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
 */
gint
tvb_strneql(tvbuff_t *tvb, const gint offset, const gchar *str, const size_t size)
{
        const guint8 *ptr;

        ptr = ensure_contiguous_no_exception(tvb, offset, (gint)size, NULL);

        if (ptr) {
                int cmp = strncmp((const char *)ptr, str, size);

                /*
                 * Return 0 if equal, -1 otherwise.
                 */
                return (cmp == 0 ? 0 : -1);
        } else {
                /*
                 * Not enough characters in the tvbuff to match the
                 * string.
                 */
                return -1;
        }
}

/*
 * Call g_ascii_strncasecmp after checking if enough chars left, returning
 * 0 if it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
 */
gint
tvb_strncaseeql(tvbuff_t *tvb, const gint offset, const gchar *str, const size_t size)
{
        const guint8 *ptr;

        ptr = ensure_contiguous_no_exception(tvb, offset, (gint)size, NULL);

        if (ptr) {
                int cmp = g_ascii_strncasecmp((const char *)ptr, str, size);

                /*
                 * Return 0 if equal, -1 otherwise.
                 */
                return (cmp == 0 ? 0 : -1);
        } else {
                /*
                 * Not enough characters in the tvbuff to match the
                 * string.
                 */
                return -1;
        }
}

/*
 * Call memcmp after checking if enough chars left, returning 0 if
 * it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
 */
gint
tvb_memeql(tvbuff_t *tvb, const gint offset, const guint8 *str, size_t size)
{
        const guint8 *ptr;

        ptr = ensure_contiguous_no_exception(tvb, offset, (gint) size, NULL);

        if (ptr) {
                int cmp = memcmp(ptr, str, size);

                /*
                 * Return 0 if equal, -1 otherwise.
                 */
                return (cmp == 0 ? 0 : -1);
        } else {
                /*
                 * Not enough characters in the tvbuff to match the
                 * string.
                 */
                return -1;
        }
}

/* Convert a string from Unicode to ASCII.      At the moment we fake it by
 * replacing all non-ASCII characters with a '.' )-:   The len parameter is
 * the number of guint16's to convert from Unicode.
 *
 * If scope is set to NULL, returned buffer is allocated by g_malloc()
 * and must be g_free by the caller. Otherwise memory is automatically
 * freed when the scope lifetime is reached.
 */
/* XXX: This has been replaced by tvb_get_string() */
char *
tvb_get_faked_unicode(wmem_allocator_t *scope, tvbuff_t *tvb, int offset,
                      const int len, const gboolean little_endian)
{
        char    *buffer;
        int      i;
        guint16  character;

        /* Make sure we have enough data before allocating the buffer,
           so we don't blow up if the length is huge. */
        tvb_ensure_bytes_exist(tvb, offset, 2*len);

        /* We know we won't throw an exception, so we don't have to worry
           about leaking this buffer. */
        buffer = (char *)wmem_alloc(scope, len + 1);

        for (i = 0; i < len; i++) {
                character = little_endian ? tvb_get_letohs(tvb, offset)
                                          : tvb_get_ntohs(tvb, offset);
                buffer[i] = character < 256 ? character : '.';
                offset += 2;
        }

        buffer[len] = 0;

        return buffer;
}

/*
 * Format the data in the tvb from offset for length ...
 */
gchar *
tvb_format_text(tvbuff_t *tvb, const gint offset, const gint size)
{
        const guint8 *ptr;
        gint          len;

        len = (size > 0) ? size : 0;

        ptr = ensure_contiguous(tvb, offset, size);
        return format_text(ptr, len);
}

/*
 * Format the data in the tvb from offset for length ...
 */
gchar *
tvb_format_text_wsp(tvbuff_t *tvb, const gint offset, const gint size)
{
        const guint8 *ptr;
        gint          len;

        len = (size > 0) ? size : 0;

        ptr = ensure_contiguous(tvb, offset, size);
        return format_text_wsp(ptr, len);
}

/*
 * Like "tvb_format_text()", but for null-padded strings; don't show
 * the null padding characters as "\000".
 */
gchar *
tvb_format_stringzpad(tvbuff_t *tvb, const gint offset, const gint size)
{
        const guint8 *ptr, *p;
        gint          len;
        gint          stringlen;

        len = (size > 0) ? size : 0;

        ptr = ensure_contiguous(tvb, offset, size);
        for (p = ptr, stringlen = 0; stringlen < len && *p != '\0'; p++, stringlen++)
                ;
        return format_text(ptr, stringlen);
}

/*
 * Like "tvb_format_text_wsp()", but for null-padded strings; don't show
 * the null padding characters as "\000".
 */
gchar *
tvb_format_stringzpad_wsp(tvbuff_t *tvb, const gint offset, const gint size)
{
        const guint8 *ptr, *p;
        gint          len;
        gint          stringlen;

        len = (size > 0) ? size : 0;

        ptr = ensure_contiguous(tvb, offset, size);
        for (p = ptr, stringlen = 0; stringlen < len && *p != '\0'; p++, stringlen++)
                ;
        return format_text_wsp(ptr, stringlen);
}

/*
 * Given a tvbuff, an offset, and a length, allocate a buffer big enough
 * to hold a non-null-terminated string of that length at that offset,
 * plus a trailing '\0', copy the string into it, and return a pointer
 * to the string.
 * If scope is NULL, memory is allocated with g_malloc() and user must
 * explicitely free it with g_free().
 * If scope is not NULL, memory is allocated with the corresponding pool
 * lifetime.
 * Throws an exception if the tvbuff ends before the string does.
 */
guint8 *
tvb_get_string(wmem_allocator_t *scope, tvbuff_t *tvb, const gint offset, const gint length)
{
        guint8       *strbuf;

        tvb_ensure_bytes_exist(tvb, offset, length); /* make sure length = -1 fails */
        strbuf = (guint8 *)wmem_alloc(scope, length + 1);
        tvb_memcpy(tvb, strbuf, offset, length);
        strbuf[length] = '\0';
        return strbuf;
}

/*
 * Unicode (UTF-16) version of tvb_get_string()
 * XXX - this is UCS-2, not UTF-16, as it doesn't handle surrogate pairs
 *
 * Encoding paramter should be ENC_BIG_ENDIAN or ENC_LITTLE_ENDIAN
 *
 * Specify length in bytes
 *
 * If scope is NULL, memory is allocated with g_malloc() and user must
 * explicitely free it with g_free().
 * If scope is not NULL, memory is allocated with the corresponding pool
 * lifetime.
 *
 * Returns an UTF-8 string
 */
gchar *
tvb_get_unicode_string(wmem_allocator_t *scope, tvbuff_t *tvb, const gint offset, gint length, const guint encoding)
{
        gunichar2      uchar;
        gint           i;       /* Byte counter for tvbuff */
        wmem_strbuf_t *strbuf;

        tvb_ensure_bytes_exist(tvb, offset, length);

        strbuf = wmem_strbuf_new(scope, NULL);

        for(i = 0; i < length; i += 2) {
                if (encoding == ENC_BIG_ENDIAN)
                        uchar = tvb_get_ntohs(tvb, offset + i);
                else
                        uchar = tvb_get_letohs(tvb, offset + i);

                wmem_strbuf_append_unichar(strbuf, uchar);
        }

        return (gchar*)wmem_strbuf_get_str(strbuf);
}

/*
 * Given a tvbuff, an offset, a length, and an encoding, allocate a
 * buffer big enough to hold a non-null-terminated string of that length
 * at that offset, plus a trailing '\0', copy into the buffer the
 * string as converted from the appropriate encoding to UTF-8, and
 * return a pointer to the string.
 *
 * Throws an exception if the tvbuff ends before the string does.
 *
 * If scope is NULL, memory is allocated with g_malloc() and user must
 * explicitely free it with g_free().
 * If scope is not NULL, memory is allocated with the corresponding pool
 * lifetime.
 */
guint8 *
tvb_get_string_enc(wmem_allocator_t *scope, tvbuff_t *tvb, const gint offset,
                             const gint length, const guint encoding)
{
        const guint8 *ptr;
        guint8       *strbuf;

        switch (encoding & ENC_CHARENCODING_MASK) {

        case ENC_ASCII:
        default:
                /*
                 * For now, we treat bogus values as meaning
                 * "ASCII" rather than reporting an error,
                 * for the benefit of old dissectors written
                 * when the last argument to proto_tree_add_item()
                 * was a gboolean for the byte order, not an
                 * encoding value, and passed non-zero values
                 * other than TRUE to mean "little-endian".
                 *
                 * XXX - should map all octets with the 8th bit
                 * not set to a "substitute" UTF-8 character.
                 */
                strbuf = tvb_get_string(scope, tvb, offset, length);
                break;

        case ENC_UTF_8:
                /*
                 * XXX - should map all invalid UTF-8 sequences
                 * to a "substitute" UTF-8 character.
                 */
                strbuf = tvb_get_string(scope, tvb, offset, length);
                break;

        case ENC_UTF_16:
                /*
                 * XXX - needs to handle surrogate pairs and to map
                 * invalid characters and sequences to a "substitute"
                 * UTF-8 character.
                 */
                strbuf = tvb_get_unicode_string(scope, tvb, offset, length,
                    encoding & ENC_LITTLE_ENDIAN);
                break;

        case ENC_UCS_2:
                /*
                 * XXX - needs to map values that are not valid UCS-2
                 * characters (such as, I think, values used as the
                 * components of a UTF-16 surrogate pair) to a
                 * "substitute" UTF-8 character.
                 */
                strbuf = tvb_get_unicode_string(scope, tvb, offset, length,
                    encoding & ENC_LITTLE_ENDIAN);
                break;

        case ENC_EBCDIC:
                /*
                 * XXX - do the copy and conversion in one pass.
                 *
                 * XXX - multiple "dialects" of EBCDIC?
                 */
                tvb_ensure_bytes_exist(tvb, offset, length); /* make sure length = -1 fails */
                strbuf = (guint8 *)wmem_alloc(scope, length + 1);
                if (length != 0) {
                        ptr = ensure_contiguous(tvb, offset, length);
                        memcpy(strbuf, ptr, length);
                        EBCDIC_to_ASCII(strbuf, length);
                }
                strbuf[length] = '\0';
                break;
        }
        return strbuf;
}

/*
 * Given a tvbuff and an offset, with the offset assumed to refer to
 * a null-terminated string, find the length of that string (and throw
 * an exception if the tvbuff ends before we find the null), allocate
 * a buffer big enough to hold the string, copy the string into it,
 * and return a pointer to the string.  Also return the length of the
 * string (including the terminating null) through a pointer.
 *
 * If scope is NULL, memory is allocated with g_malloc() and user must
 * explicitely free it with g_free().
 * If scope is not NULL, memory is allocated with the corresponding pool
 * lifetime.
 */
guint8 *
tvb_get_stringz(wmem_allocator_t *scope, tvbuff_t *tvb, const gint offset, gint *lengthp)
{
        guint   size;
        guint8 *strptr;

        size   = tvb_strsize(tvb, offset);
        strptr = (guint8 *)wmem_alloc(scope, size);
        tvb_memcpy(tvb, strptr, offset, size);
        if (lengthp)
                *lengthp = size;
        return strptr;
}

guint8 *
tvb_get_stringz_enc(wmem_allocator_t *scope, tvbuff_t *tvb, const gint offset, gint *lengthp, const guint encoding)
{
        guint   size;
        guint8 *strptr;

        switch (encoding & ENC_CHARENCODING_MASK) {

        case ENC_ASCII:
        default:
                /*
                 * For now, we treat bogus values as meaning
                 * "ASCII" rather than reporting an error,
                 * for the benefit of old dissectors written
                 * when the last argument to proto_tree_add_item()
                 * was a gboolean for the byte order, not an
                 * encoding value, and passed non-zero values
                 * other than TRUE to mean "little-endian".
                 *
                 * XXX - should map all octets with the 8th bit
                 * not set to a "substitute" UTF-8 character.
                 */
                strptr = tvb_get_stringz(scope, tvb, offset, lengthp);
                break;

        case ENC_UTF_8:
                /*
                 * XXX - should map all invalid UTF-8 sequences
                 * to a "substitute" UTF-8 character.
                 */
                strptr = tvb_get_stringz(scope, tvb, offset, lengthp);
                break;

        case ENC_UTF_16:
                /*
                 * XXX - needs to handle surrogate pairs and to map
                 * invalid characters and sequences to a "substitute"
                 * UTF-8 character.
                 */
                strptr = tvb_get_unicode_stringz(scope, tvb, offset, lengthp,
                    encoding & ENC_LITTLE_ENDIAN);
                break;

        case ENC_UCS_2:
                /*
                 * XXX - needs to map values that are not valid UCS-2
                 * characters (such as, I think, values used as the
                 * components of a UTF-16 surrogate pair) to a
                 * "substitute" UTF-8 character.
                 */
                strptr = tvb_get_unicode_stringz(scope, tvb, offset, lengthp,
                    encoding & ENC_LITTLE_ENDIAN);
                break;

        case ENC_EBCDIC:
                /*
                 * XXX - do the copy and conversion in one pass.
                 *
                 * XXX - multiple "dialects" of EBCDIC?
                 */
                size = tvb_strsize(tvb, offset);
                strptr = (guint8 *)wmem_alloc(scope, size);
                tvb_memcpy(tvb, strptr, offset, size);
                EBCDIC_to_ASCII(strptr, size);
                if (lengthp)
                        *lengthp = size;
                break;
        }

        return strptr;
}

/*
 * Given a tvbuff and an offset, with the offset assumed to refer to
 * a null-terminated string, find the length of that string (and throw
 * an exception if the tvbuff ends before we find the null), ensure that
 * the TVB is flat, and return a pointer to the string (in the TVB).
 * Also return the length of the string (including the terminating null)
 * through a pointer.
 *
 * As long as we aren't using composite TVBs, this saves the cycles used
 * (often unnecessariliy) in allocating a buffer and copying the string into
 * it.  (If we do start using composite TVBs, we may want to replace this
 * function with the _ephemeral versoin.)
 */
const guint8 *
tvb_get_const_stringz(tvbuff_t *tvb, const gint offset, gint *lengthp)
{
        guint         size;
        const guint8 *strptr;

        size   = tvb_strsize(tvb, offset);
        strptr = ensure_contiguous(tvb, offset, size);
        if (lengthp)
                *lengthp = size;
        return strptr;
}

/*
 * Unicode (UTF-16) version of tvb_get_stringz()
 *
 * Encoding paramter should be ENC_BIG_ENDIAN or ENC_LITTLE_ENDIAN
 *
 * Returns an allocated UTF-8 string and updates lengthp pointer with length of string (in bytes)
 */
gchar *
tvb_get_unicode_stringz(wmem_allocator_t *scope, tvbuff_t *tvb, const gint offset, gint *lengthp, const guint encoding)
{
        gunichar2      uchar;
        gint           size;    /* Number of UTF-16 characters */
        gint           i;       /* Byte counter for tvbuff */
        wmem_strbuf_t *strbuf;

        size = tvb_unicode_strsize(tvb, offset);

        strbuf = wmem_strbuf_new(scope, NULL);

        for(i = 0; i < size; i += 2) {
                if (encoding == ENC_BIG_ENDIAN)
                        uchar = tvb_get_ntohs(tvb, offset + i);
                else
                        uchar = tvb_get_letohs(tvb, offset + i);

                wmem_strbuf_append_unichar(strbuf, uchar);
        }

        if (lengthp)
                *lengthp = i; /* Number of *bytes* processed */

        return (gchar*)wmem_strbuf_get_str(strbuf);
}

/* Looks for a stringz (NUL-terminated string) in tvbuff and copies
 * no more than bufsize number of bytes, including terminating NUL, to buffer.
 * Returns length of string (not including terminating NUL), or -1 if the string was
 * truncated in the buffer due to not having reached the terminating NUL.
 * In this way, it acts like g_snprintf().
 *
 * bufsize MUST be greater than 0.
 *
 * When processing a packet where the remaining number of bytes is less
 * than bufsize, an exception is not thrown if the end of the packet
 * is reached before the NUL is found. If no NUL is found before reaching
 * the end of the short packet, -1 is still returned, and the string
 * is truncated with a NUL, albeit not at buffer[bufsize - 1], but
 * at the correct spot, terminating the string.
 *
 * *bytes_copied will contain the number of bytes actually copied,
 * including the terminating-NUL.
 */
static gint
_tvb_get_nstringz(tvbuff_t *tvb, const gint offset, const guint bufsize, guint8* buffer, gint *bytes_copied)
{
        gint     stringlen;
        guint    abs_offset;
        gint     limit, len;
        gboolean decreased_max = FALSE;

        /* Only read to end of tvbuff, w/o throwing exception. */
        check_offset_length(tvb, offset, -1, &abs_offset, &len);

        /* There must at least be room for the terminating NUL. */
        DISSECTOR_ASSERT(bufsize != 0);

        /* If there's no room for anything else, just return the NUL. */
        if (bufsize == 1) {
                buffer[0] = 0;
                *bytes_copied = 1;
                return 0;
        }

        /* check_offset_length() won't throw an exception if we're
         * looking at the byte immediately after the end of the tvbuff. */
        if (len == 0) {
                THROW(ReportedBoundsError);
        }

        /* This should not happen because check_offset_length() would
         * have already thrown an exception if 'offset' were out-of-bounds.
         */
        DISSECTOR_ASSERT(len != -1);

        /*
         * If we've been passed a negative number, bufsize will
         * be huge.
         */
        DISSECTOR_ASSERT(bufsize <= G_MAXINT);

        if ((guint)len < bufsize) {
                limit = len;
                decreased_max = TRUE;
        }
        else {
                limit = bufsize;
        }

        stringlen = tvb_strnlen(tvb, abs_offset, limit - 1);
        /* If NUL wasn't found, copy the data and return -1 */
        if (stringlen == -1) {
                tvb_memcpy(tvb, buffer, abs_offset, limit);
                if (decreased_max) {
                        buffer[limit] = 0;
                        /* Add 1 for the extra NUL that we set at buffer[limit],
                         * pretending that it was copied as part of the string. */
                        *bytes_copied = limit + 1;
                }
                else {
                        *bytes_copied = limit;
                }
                return -1;
        }

        /* Copy the string to buffer */
        tvb_memcpy(tvb, buffer, abs_offset, stringlen + 1);
        *bytes_copied = stringlen + 1;
        return stringlen;
}

/* Looks for a stringz (NUL-terminated string) in tvbuff and copies
 * no more than bufsize number of bytes, including terminating NUL, to buffer.
 * Returns length of string (not including terminating NUL), or -1 if the string was
 * truncated in the buffer due to not having reached the terminating NUL.
 * In this way, it acts like g_snprintf().
 *
 * When processing a packet where the remaining number of bytes is less
 * than bufsize, an exception is not thrown if the end of the packet
 * is reached before the NUL is found. If no NUL is found before reaching
 * the end of the short packet, -1 is still returned, and the string
 * is truncated with a NUL, albeit not at buffer[bufsize - 1], but
 * at the correct spot, terminating the string.
 */
gint
tvb_get_nstringz(tvbuff_t *tvb, const gint offset, const guint bufsize, guint8* buffer)
{
        gint bytes_copied;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        return _tvb_get_nstringz(tvb, offset, bufsize, buffer, &bytes_copied);
}

/* Like tvb_get_nstringz(), but never returns -1. The string is guaranteed to
 * have a terminating NUL. If the string was truncated when copied into buffer,
 * a NUL is placed at the end of buffer to terminate it.
 */
gint
tvb_get_nstringz0(tvbuff_t *tvb, const gint offset, const guint bufsize, guint8* buffer)
{
        gint    len, bytes_copied;

        DISSECTOR_ASSERT(tvb && tvb->initialized);

        len = _tvb_get_nstringz(tvb, offset, bufsize, buffer, &bytes_copied);

        if (len == -1) {
                buffer[bufsize - 1] = 0;
                return bytes_copied - 1;
        }
        else {
                return len;
        }
}

/*
 * Given a tvbuff, an offset into the tvbuff, and a length that starts
 * at that offset (which may be -1 for "all the way to the end of the
 * tvbuff"), find the end of the (putative) line that starts at the
 * specified offset in the tvbuff, going no further than the specified
 * length.
 *
 * Return the length of the line (not counting the line terminator at
 * the end), or, if we don't find a line terminator:
 *
 *      if "deseg" is true, return -1;
 *
 *      if "deseg" is false, return the amount of data remaining in
 *      the buffer.
 *
 * Set "*next_offset" to the offset of the character past the line
 * terminator, or past the end of the buffer if we don't find a line
 * terminator.  (It's not set if we return -1.)
 */
gint
tvb_find_line_end(tvbuff_t *tvb, const gint offset, int len, gint *next_offset, const gboolean desegment)
{
        gint   eob_offset;
        gint   eol_offset;
        int    linelen;
        guchar found_needle = 0;

        if (len == -1)
                len = tvb_length_remaining(tvb, offset);
        /*
         * XXX - what if "len" is still -1, meaning "offset is past the
         * end of the tvbuff"?
         */
        eob_offset = offset + len;

        /*
         * Look either for a CR or an LF.
         */
        eol_offset = tvb_pbrk_guint8(tvb, offset, len, "\r\n", &found_needle);
        if (eol_offset == -1) {
                /*
                 * No CR or LF - line is presumably continued in next packet.
                 */
                if (desegment) {
                        /*
                         * Tell our caller we saw no EOL, so they can
                         * try to desegment and get the entire line
                         * into one tvbuff.
                         */
                        return -1;
                } else {
                        /*
                         * Pretend the line runs to the end of the tvbuff.
                         */
                        linelen = eob_offset - offset;
                        if (next_offset)
                                *next_offset = eob_offset;
                }
        } else {
                /*
                 * Find the number of bytes between the starting offset
                 * and the CR or LF.
                 */
                linelen = eol_offset - offset;

                /*
                 * Is it a CR?
                 */
                if (found_needle == '\r') {
                        /*
                         * Yes - is it followed by an LF?
                         */
                        if (eol_offset + 1 >= eob_offset) {
                                /*
                                 * Dunno - the next byte isn't in this
                                 * tvbuff.
                                 */
                                if (desegment) {
                                        /*
                                         * We'll return -1, although that
                                         * runs the risk that if the line
                                         * really *is* terminated with a CR,
                                         * we won't properly dissect this
                                         * tvbuff.
                                         *
                                         * It's probably more likely that
                                         * the line ends with CR-LF than
                                         * that it ends with CR by itself.
                                         */
                                        return -1;
                                }
                        } else {
                                /*
                                 * Well, we can at least look at the next
                                 * byte.
                                 */
                                if (tvb_get_guint8(tvb, eol_offset + 1) == '\n') {
                                        /*
                                         * It's an LF; skip over the CR.
                                         */
                                        eol_offset++;
                                }
                        }
                }

                /*
                 * Return the offset of the character after the last
                 * character in the line, skipping over the last character
                 * in the line terminator.
                 */
                if (next_offset)
                        *next_offset = eol_offset + 1;
        }
        return linelen;
}

/*
 * Given a tvbuff, an offset into the tvbuff, and a length that starts
 * at that offset (which may be -1 for "all the way to the end of the
 * tvbuff"), find the end of the (putative) line that starts at the
 * specified offset in the tvbuff, going no further than the specified
 * length.
 *
 * However, treat quoted strings inside the buffer specially - don't
 * treat newlines in quoted strings as line terminators.
 *
 * Return the length of the line (not counting the line terminator at
 * the end), or the amount of data remaining in the buffer if we don't
 * find a line terminator.
 *
 * Set "*next_offset" to the offset of the character past the line
 * terminator, or past the end of the buffer if we don't find a line
 * terminator.
 */
gint
tvb_find_line_end_unquoted(tvbuff_t *tvb, const gint offset, int len, gint *next_offset)
{
        gint     cur_offset, char_offset;
        gboolean is_quoted;
        guchar   c = 0;
        gint     eob_offset;
        int      linelen;

        if (len == -1)
                len = tvb_length_remaining(tvb, offset);
        /*
         * XXX - what if "len" is still -1, meaning "offset is past the
         * end of the tvbuff"?
         */
        eob_offset = offset + len;

        cur_offset = offset;
        is_quoted  = FALSE;
        for (;;) {
                        /*
                 * Is this part of the string quoted?
                 */
                if (is_quoted) {
                        /*
                         * Yes - look only for the terminating quote.
                         */
                        char_offset = tvb_find_guint8(tvb, cur_offset, len,
                                '"');
                } else {
                        /*
                         * Look either for a CR, an LF, or a '"'.
                         */
                        char_offset = tvb_pbrk_guint8(tvb, cur_offset, len, "\r\n\"", &c);
                }
                if (char_offset == -1) {
                        /*
                         * Not found - line is presumably continued in
                         * next packet.
                         * We pretend the line runs to the end of the tvbuff.
                         */
                        linelen = eob_offset - offset;
                        if (next_offset)
                                *next_offset = eob_offset;
                        break;
                }

                if (is_quoted) {
                        /*
                         * We're processing a quoted string.
                         * We only looked for ", so we know it's a ";
                         * as we're processing a quoted string, it's a
                         * closing quote.
                         */
                        is_quoted = FALSE;
                } else {
                        /*
                         * OK, what is it?
                         */
                        if (c == '"') {
                                /*
                                 * Un-quoted "; it begins a quoted
                                 * string.
                                 */
                                is_quoted = TRUE;
                        } else {
                                /*
                                 * It's a CR or LF; we've found a line
                                 * terminator.
                                 *
                                 * Find the number of bytes between the
                                 * starting offset and the CR or LF.
                                 */
                                linelen = char_offset - offset;

                                /*
                                 * Is it a CR?
                                 */
                                if (c == '\r') {
                                        /*
                                         * Yes; is it followed by an LF?
                                         */
                                        if (char_offset + 1 < eob_offset &&
                                                tvb_get_guint8(tvb, char_offset + 1)
                                                  == '\n') {
                                                /*
                                                 * Yes; skip over the CR.
                                                 */
                                                char_offset++;
                                        }
                                }

                                /*
                                 * Return the offset of the character after
                                 * the last character in the line, skipping
                                 * over the last character in the line
                                 * terminator, and quit.
                                 */
                                if (next_offset)
                                        *next_offset = char_offset + 1;
                                break;
                        }
                }

                /*
                 * Step past the character we found.
                 */
                cur_offset = char_offset + 1;
                if (cur_offset >= eob_offset) {
                        /*
                         * The character we found was the last character
                         * in the tvbuff - line is presumably continued in
                         * next packet.
                         * We pretend the line runs to the end of the tvbuff.
                         */
                        linelen = eob_offset - offset;
                        if (next_offset)
                                *next_offset = eob_offset;
                        break;
                }
        }
        return linelen;
}

/*
 * Copied from the mgcp dissector. (This function should be moved to /epan )
 * tvb_skip_wsp - Returns the position in tvb of the first non-whitespace
 *                                character following offset or offset + maxlength -1 whichever
 *                                is smaller.
 *
 * Parameters:
 * tvb - The tvbuff in which we are skipping whitespace.
 * offset - The offset in tvb from which we begin trying to skip whitespace.
 * maxlength - The maximum distance from offset that we may try to skip
 * whitespace.
 *
 * Returns: The position in tvb of the first non-whitespace
 *                      character following offset or offset + maxlength -1 whichever
 *                      is smaller.
 */
gint
tvb_skip_wsp(tvbuff_t *tvb, const gint offset, const gint maxlength)
{
        gint   counter = offset;
        gint   end, tvb_len;
        guint8 tempchar;

        /* Get the length remaining */
        tvb_len = tvb_length(tvb);
        end     = offset + maxlength;
        if (end >= tvb_len)
        {
                end = tvb_len;
        }

        /* Skip past spaces, tabs, CRs and LFs until run out or meet something else */
        for (counter = offset;
                 counter < end &&
                  ((tempchar = tvb_get_guint8(tvb,counter)) == ' ' ||
                  tempchar == '\t' || tempchar == '\r' || tempchar == '\n');
                 counter++);

        return (counter);
}

gint
tvb_skip_wsp_return(tvbuff_t *tvb, const gint offset) {
        gint   counter = offset;
        guint8 tempchar;

        for(counter = offset; counter > 0 &&
                ((tempchar = tvb_get_guint8(tvb,counter)) == ' ' ||
                tempchar == '\t' || tempchar == '\n' || tempchar == '\r'); counter--);
        counter++;
        return (counter);
}


/*
 * Format a bunch of data from a tvbuff as bytes, returning a pointer
 * to the string with the formatted data, with "punct" as a byte
 * separator.
 */
gchar *
tvb_bytes_to_str_punct(tvbuff_t *tvb, const gint offset, const gint len, const gchar punct)
{
        return bytes_to_str_punct(ensure_contiguous(tvb, offset, len), len, punct);
}


/*
 * Given a tvbuff, an offset into the tvbuff, and a length that starts
 * at that offset (which may be -1 for "all the way to the end of the
 * tvbuff"), fetch BCD encoded digits from a tvbuff starting from either
 * the low or high half byte, formating the digits according to an input digit set,
 * if NUll a default digit set of 0-9 returning "?" for overdecadic digits will be used.
 * A pointer to the packet scope allocated string will be returned.
 * Note a tvbuff content of 0xf is considered a 'filler' and will end the conversion.
 */
static dgt_set_t Dgt1_9_bcd = {
        {
                /*  0   1   2   3   4   5   6   7   8   9   a   b   c   d   e */
                '0','1','2','3','4','5','6','7','8','9','?','?','?','?','?'
        }
};
const gchar *
tvb_bcd_dig_to_wmem_packet_str(tvbuff_t *tvb, const gint offset, const gint len, dgt_set_t *dgt, gboolean skip_first)
{
        int     length;
        guint8  octet;
        int     i        = 0;
        char   *digit_str;
        gint    t_offset = offset;

        if (!dgt)
                dgt = &Dgt1_9_bcd;

        if (len == -1) {
                length = tvb_length(tvb);
                if (length < offset) {
                        return "";
                }
        } else {
                length = offset + len;
        }
        digit_str = (char *)wmem_alloc(wmem_packet_scope(), (length - offset)*2+1);

        while (t_offset < length) {

                octet = tvb_get_guint8(tvb,t_offset);
                if (!skip_first) {
                        digit_str[i] = dgt->out[octet & 0x0f];
                        i++;
                }
                skip_first = FALSE;

                /*
                 * unpack second value in byte
                 */
                octet = octet >> 4;

                if (octet == 0x0f)      /* odd number bytes - hit filler */
                        break;

                digit_str[i] = dgt->out[octet & 0x0f];
                i++;
                t_offset++;

        }
        digit_str[i]= '\0';
        return digit_str;

}

/*
 * Format a bunch of data from a tvbuff as bytes, returning a pointer
 * to the string with the formatted data.
 */
gchar *
tvb_bytes_to_str(tvbuff_t *tvb, const gint offset, const gint len)
{
        return bytes_to_str(ensure_contiguous(tvb, offset, len), len);
}

/* Find a needle tvbuff within a haystack tvbuff. */
gint
tvb_find_tvb(tvbuff_t *haystack_tvb, tvbuff_t *needle_tvb, const gint haystack_offset)
{
        guint         haystack_abs_offset, haystack_abs_length;
        const guint8 *haystack_data;
        const guint8 *needle_data;
        const guint   needle_len = needle_tvb->length;
        const guint8 *location;

        DISSECTOR_ASSERT(haystack_tvb && haystack_tvb->initialized);

        if (haystack_tvb->length < 1 || needle_tvb->length < 1) {
                return -1;
        }

        /* Get pointers to the tvbuffs' data. */
        haystack_data = ensure_contiguous(haystack_tvb, 0, -1);
        needle_data   = ensure_contiguous(needle_tvb, 0, -1);

        check_offset_length(haystack_tvb, haystack_offset, -1,
                        &haystack_abs_offset, &haystack_abs_length);

        location = epan_memmem(haystack_data + haystack_abs_offset, haystack_abs_length,
                        needle_data, needle_len);

        if (location) {
                return (gint) (location - haystack_data);
        }

        return -1;
}

#ifdef HAVE_LIBZ
/*
 * Uncompresses a zlib compressed packet inside a message of tvb at offset with
 * length comprlen.  Returns an uncompressed tvbuffer if uncompression
 * succeeded or NULL if uncompression failed.
 */
#define TVB_Z_MIN_BUFSIZ 32768
#define TVB_Z_MAX_BUFSIZ 1048576 * 10
/* #define TVB_Z_DEBUG 1 */
#undef TVB_Z_DEBUG

tvbuff_t *
tvb_uncompress(tvbuff_t *tvb, const int offset, int comprlen)
{
        gint       err            = Z_OK;
        guint      bytes_out      = 0;
        guint8    *compr          = NULL;
        guint8    *uncompr        = NULL;
        tvbuff_t  *uncompr_tvb    = NULL;
        z_streamp  strm           = NULL;
        Bytef     *strmbuf        = NULL;
        guint      inits_done     = 0;
        gint       wbits          = MAX_WBITS;
        guint8    *next           = NULL;
        guint      bufsiz         = TVB_Z_MIN_BUFSIZ;
#ifdef TVB_Z_DEBUG
        guint      inflate_passes = 0;
        guint      bytes_in       = tvb_length_remaining(tvb, offset);
#endif

        if (tvb == NULL) {
                return NULL;
        }

        compr = (guint8 *)tvb_memdup(NULL, tvb, offset, comprlen);

        if (!compr)
                return NULL;

        /*
         * Assume that the uncompressed data is at least twice as big as
         * the compressed size.
         */
        bufsiz = tvb_length_remaining(tvb, offset) * 2;
        bufsiz = CLAMP(bufsiz, TVB_Z_MIN_BUFSIZ, TVB_Z_MAX_BUFSIZ);

#ifdef TVB_Z_DEBUG
        printf("bufsiz: %u bytes\n", bufsiz);
#endif

        next = compr;

        strm            = g_new0(z_stream, 1);
        strm->next_in   = next;
        strm->avail_in  = comprlen;

        strmbuf         = (Bytef *)g_malloc0(bufsiz);
        strm->next_out  = strmbuf;
        strm->avail_out = bufsiz;

        err = inflateInit2(strm, wbits);
        inits_done = 1;
        if (err != Z_OK) {
                inflateEnd(strm);
                g_free(strm);
                g_free(compr);
                g_free(strmbuf);
                return NULL;
        }

        while (1) {
                memset(strmbuf, '\0', bufsiz);
                strm->next_out  = strmbuf;
                strm->avail_out = bufsiz;

                err = inflate(strm, Z_SYNC_FLUSH);

                if (err == Z_OK || err == Z_STREAM_END) {
                        guint bytes_pass = bufsiz - strm->avail_out;

#ifdef TVB_Z_DEBUG
                        ++inflate_passes;
#endif

                        if (uncompr == NULL) {
                                /*
                                 * This is ugly workaround for bug #6480
                                 * (https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=6480)
                                 *
                                 * g_memdup(..., 0) returns NULL (g_malloc(0) also)
                                 * when uncompr is NULL logic below doesn't create tvb
                                 * which is later interpreted as decompression failed.
                                 */
                                uncompr = (guint8 *)((bytes_pass || err != Z_STREAM_END) ?
                                                g_memdup(strmbuf, bytes_pass) :
                                                g_strdup(""));
                        } else {
                                guint8 *new_data = (guint8 *)g_malloc0(bytes_out + bytes_pass);

                                memcpy(new_data, uncompr, bytes_out);
                                memcpy(new_data + bytes_out, strmbuf, bytes_pass);

                                g_free(uncompr);
                                uncompr = new_data;
                        }

                        bytes_out += bytes_pass;

                        if (err == Z_STREAM_END) {
                                inflateEnd(strm);
                                g_free(strm);
                                g_free(strmbuf);
                                break;
                        }
                } else if (err == Z_BUF_ERROR) {
                        /*
                         * It's possible that not enough frames were captured
                         * to decompress this fully, so return what we've done
                         * so far, if any.
                         */
                        inflateEnd(strm);
                        g_free(strm);
                        g_free(strmbuf);

                        if (uncompr != NULL) {
                                break;
                        } else {
                                g_free(compr);
                                return NULL;
                        }

                } else if (err == Z_DATA_ERROR && inits_done == 1
                        && uncompr == NULL && (*compr  == 0x1f) &&
                        (*(compr + 1) == 0x8b)) {
                        /*
                         * inflate() is supposed to handle both gzip and deflate
                         * streams automatically, but in reality it doesn't
                         * seem to handle either (at least not within the
                         * context of an HTTP response.)  We have to try
                         * several tweaks, depending on the type of data and
                         * version of the library installed.
                         */

                        /*
                         * Gzip file format.  Skip past the header, since the
                         * fix to make it work (setting windowBits to 31)
                         * doesn't work with all versions of the library.
                         */
                        Bytef *c     = compr + 2;
                        Bytef  flags = 0;

                        if (*c == Z_DEFLATED) {
                                c++;
                        } else {
                                inflateEnd(strm);
                                g_free(strm);
                                g_free(compr);
                                g_free(strmbuf);
                                return NULL;
                        }

                        flags = *c;

                        /* Skip past the MTIME, XFL, and OS fields. */
                        c += 7;

                        if (flags & (1 << 2)) {
                                /* An Extra field is present. */
                                gint xsize = (gint)(*c |
                                        (*(c + 1) << 8));

                                c += xsize;
                        }

                        if (flags & (1 << 3)) {
                                /* A null terminated filename */

                                while ((c - compr) < comprlen && *c != '\0') {
                                        c++;
                                }

                                c++;
                        }

                        if (flags & (1 << 4)) {
                                /* A null terminated comment */

                                while ((c - compr) < comprlen && *c != '\0') {
                                        c++;
                                }

                                c++;
                        }


                        inflateReset(strm);
                        next = c;
                        strm->next_in = next;
                        if (c - compr > comprlen) {
                                inflateEnd(strm);
                                g_free(strm);
                                g_free(compr);
                                g_free(strmbuf);
                                return NULL;
                        }
                        comprlen -= (int) (c - compr);

                        inflateEnd(strm);
                        inflateInit2(strm, wbits);
                        inits_done++;
                } else if (err == Z_DATA_ERROR && uncompr == NULL &&
                        inits_done <= 3) {

                        /*
                         * Re-init the stream with a negative
                         * MAX_WBITS. This is necessary due to
                         * some servers (Apache) not sending
                         * the deflate header with the
                         * content-encoded response.
                         */
                        wbits = -MAX_WBITS;

                        inflateReset(strm);

                        strm->next_in   = next;
                        strm->avail_in  = comprlen;

                        inflateEnd(strm);
                        memset(strmbuf, '\0', bufsiz);
                        strm->next_out  = strmbuf;
                        strm->avail_out = bufsiz;

                        err = inflateInit2(strm, wbits);

                        inits_done++;

                        if (err != Z_OK) {
                                g_free(strm);
                                g_free(strmbuf);
                                g_free(compr);
                                g_free(uncompr);

                                return NULL;
                        }
                } else {
                        inflateEnd(strm);
                        g_free(strm);
                        g_free(strmbuf);

                        if (uncompr == NULL) {
                                g_free(compr);
                                return NULL;
                        }

                        break;
                }
        }

#ifdef TVB_Z_DEBUG
        printf("inflate() total passes: %u\n", inflate_passes);
        printf("bytes  in: %u\nbytes out: %u\n\n", bytes_in, bytes_out);
#endif

        if (uncompr != NULL) {
                uncompr_tvb =  tvb_new_real_data((guint8*) uncompr, bytes_out, bytes_out);
                tvb_set_free_cb(uncompr_tvb, g_free);
        }
        g_free(compr);
        return uncompr_tvb;
}
#else
tvbuff_t *
tvb_uncompress(tvbuff_t *tvb _U_, const int offset _U_, int comprlen _U_)
{
        return NULL;
}
#endif

tvbuff_t *
tvb_child_uncompress(tvbuff_t *parent, tvbuff_t *tvb, const int offset, int comprlen)
{
        tvbuff_t *new_tvb = tvb_uncompress(tvb, offset, comprlen);
        if (new_tvb)
                tvb_set_child_real_data_tvbuff (parent, new_tvb);
        return new_tvb;
}

gint
tvb_raw_offset(tvbuff_t *tvb)
{
        return ((tvb->raw_offset==-1)?(tvb->raw_offset = tvb_offset_from_real_beginning(tvb)):tvb->raw_offset);
}

void
tvb_set_fragment(tvbuff_t *tvb)
{
        tvb->flags |= TVBUFF_FRAGMENT;
}

struct tvbuff *
tvb_get_ds_tvb(tvbuff_t *tvb)
{
        return(tvb->ds_tvb);
}

/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */