Fix typo

[prads.git] / src / bstraux.c

/*
 * This source file is part of the bstring string library.  This code was
 * written by Paul Hsieh in 2002-2008, and is covered by the BSD open source
 * license and the GPL. Refer to the accompanying documentation for details
 * on usage and license.
 */

/*
 * bstraux.c
 *
 * This file is not necessarily part of the core bstring library itself, but
 * is just an auxilliary module which includes miscellaneous or trivial
 * functions.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <ctype.h>
#include "bstrlib.h"
#include "bstraux.h"

/*  bstring bTail (bstring b, int n)
 *
 *  Return with a string of the last n characters of b.
 */
bstring bTail (bstring b, int n) {
        if (b == NULL || n < 0 || (b->mlen < b->slen && b->mlen > 0)) return NULL;
        if (n >= b->slen) return bstrcpy (b);
        return bmidstr (b, b->slen - n, n);
}

/*  bstring bHead (bstring b, int n)
 *
 *  Return with a string of the first n characters of b.
 */
bstring bHead (bstring b, int n) {
        if (b == NULL || n < 0 || (b->mlen < b->slen && b->mlen > 0)) return NULL;
        if (n >= b->slen) return bstrcpy (b);
        return bmidstr (b, 0, n);
}

/*  int bFill (bstring a, char c, int len)
 *
 *  Fill a given bstring with the character in parameter c, for a length n.
 */
int bFill (bstring b, char c, int len) {
        if (b == NULL || len < 0 || (b->mlen < b->slen && b->mlen > 0)) return -__LINE__;
        b->slen = 0;
        return bsetstr (b, len, NULL, c);
}

/*  int bReplicate (bstring b, int n)
 *
 *  Replicate the contents of b end to end n times and replace it in b.
 */
int bReplicate (bstring b, int n) {
        return bpattern (b, n * b->slen);
}

/*  int bReverse (bstring b)
 *
 *  Reverse the contents of b in place.
 */
int bReverse (bstring b) {
int i, n, m;
unsigned char t;

        if (b == NULL || b->slen < 0 || b->mlen < b->slen) return -__LINE__;
        n = b->slen;
        if (2 <= n) {
                m = ((unsigned)n) >> 1;
                n--;
                for (i=0; i < m; i++) {
                        t = b->data[n - i];
                        b->data[n - i] = b->data[i];
                        b->data[i] = t;
                }
        }
        return 0;
}

/*  int bInsertChrs (bstring b, int pos, int len, unsigned char c, unsigned char fill)
 *
 *  Insert a repeated sequence of a given character into the string at
 *  position pos for a length len.
 */
int bInsertChrs (bstring b, int pos, int len, unsigned char c, unsigned char fill) {
        if (b == NULL || b->slen < 0 || b->mlen < b->slen || pos < 0 || len <= 0) return -__LINE__;

        if (pos > b->slen
         && 0 > bsetstr (b, pos, NULL, fill)) return -__LINE__;

        if (0 > balloc (b, b->slen + len)) return -__LINE__;
        if (pos < b->slen) memmove (b->data + pos + len, b->data + pos, b->slen - pos);
        memset (b->data + pos, c, len);
        b->slen += len;
        b->data[b->slen] = (unsigned char) '\0';
        return BSTR_OK;
}

/*  int bJustifyLeft (bstring b, int space)
 *
 *  Left justify a string.
 */
int bJustifyLeft (bstring b, int space) {
int j, i, s, t;
unsigned char c = (unsigned char) space;

        if (b == NULL || b->slen < 0 || b->mlen < b->slen) return -__LINE__;
        if (space != (int) c) return BSTR_OK;

        for (s=j=i=0; i < b->slen; i++) {
                t = s;
                s = c != (b->data[j] = b->data[i]);
                j += (t|s);
        }
        if (j > 0 && b->data[j-1] == c) j--;

        b->data[j] = (unsigned char) '\0';
        b->slen = j;
        return BSTR_OK;
}

/*  int bJustifyRight (bstring b, int width, int space)
 *
 *  Right justify a string to within a given width.
 */
int bJustifyRight (bstring b, int width, int space) {
int ret;
        if (width <= 0) return -__LINE__;
        if (0 > (ret = bJustifyLeft (b, space))) return ret;
        if (b->slen <= width)
                return bInsertChrs (b, 0, width - b->slen, (unsigned char) space, (unsigned char) space);
        return BSTR_OK;
}

/*  int bJustifyCenter (bstring b, int width, int space)
 *
 *  Center a string's non-white space characters to within a given width by
 *  inserting whitespaces at the beginning.
 */
int bJustifyCenter (bstring b, int width, int space) {
int ret;
        if (width <= 0) return -__LINE__;
        if (0 > (ret = bJustifyLeft (b, space))) return ret;
        if (b->slen <= width)
                return bInsertChrs (b, 0, (width - b->slen + 1) >> 1, (unsigned char) space, (unsigned char) space);
        return BSTR_OK;
}

/*  int bJustifyMargin (bstring b, int width, int space)
 *
 *  Stretch a string to flush against left and right margins by evenly
 *  distributing additional white space between words.  If the line is too
 *  long to be margin justified, it is left justified.
 */
int bJustifyMargin (bstring b, int width, int space) {
struct bstrList * sl;
int i, l, c;

        if (b == NULL || b->slen < 0 || b->mlen == 0 || b->mlen < b->slen) return -__LINE__;
        if (NULL == (sl = bsplit (b, (unsigned char) space))) return -__LINE__;
        for (l=c=i=0; i < sl->qty; i++) {
                if (sl->entry[i]->slen > 0) {
                        c ++;
                        l += sl->entry[i]->slen;
                }
        }

        if (l + c >= width || c < 2) {
                bstrListDestroy (sl);
                return bJustifyLeft (b, space);
        }

        b->slen = 0;
        for (i=0; i < sl->qty; i++) {
                if (sl->entry[i]->slen > 0) {
                        if (b->slen > 0) {
                                int s = (width - l + (c / 2)) / c;
                                bInsertChrs (b, b->slen, s, (unsigned char) space, (unsigned char) space);
                                l += s;
                        }
                        bconcat (b, sl->entry[i]);
                        c--;
                        if (c <= 0) break;
                }
        }

        bstrListDestroy (sl);
        return BSTR_OK;
}

static size_t readNothing (void *buff, size_t elsize, size_t nelem, void *parm) {
        buff = buff;
        elsize = elsize;
        nelem = nelem;
        parm = parm;
        return 0; /* Immediately indicate EOF. */
}

/*  struct bStream * bsFromBstr (const_bstring b);
 *
 *  Create a bStream whose contents are a copy of the bstring passed in.
 *  This allows the use of all the bStream APIs with bstrings.
 */
struct bStream * bsFromBstr (const_bstring b) {
struct bStream * s = bsopen ((bNread) readNothing, NULL);
        bsunread (s, b); /* Push the bstring data into the empty bStream. */
        return s;
}

static size_t readRef (void *buff, size_t elsize, size_t nelem, void *parm) {
struct tagbstring * t = (struct tagbstring *) parm;
size_t tsz = elsize * nelem;

        if (tsz > (size_t) t->slen) tsz = (size_t) t->slen;
        if (tsz > 0) {
                memcpy (buff, t->data, tsz);
                t->slen -= (int) tsz;
                t->data += tsz;
                return tsz / elsize;
        }
        return 0;
}

/*  The "by reference" version of the above function.  This function puts
 *  a number of restrictions on the call site (the passed in struct
 *  tagbstring *will* be modified by this function, and the source data
 *  must remain alive and constant for the lifetime of the bStream).
 *  Hence it is not presented as an extern.
 */
static struct bStream * bsFromBstrRef (struct tagbstring * t) {
        if (!t) return NULL;
        return bsopen ((bNread) readRef, t);
}

/*  char * bStr2NetStr (const_bstring b)
 *
 *  Convert a bstring to a netstring.  See
 *  http://cr.yp.to/proto/netstrings.txt for a description of netstrings.
 *  Note: 1) The value returned should be freed with a call to bcstrfree() at
 *           the point when it will no longer be referenced to avoid a memory
 *           leak.
 *        2) If the returned value is non-NULL, then it also '\0' terminated
 *           in the character position one past the "," terminator.
 */
char * bStr2NetStr (const_bstring b) {
char strnum[sizeof (b->slen) * 3 + 1];
bstring s;
unsigned char * buff;

        if (b == NULL || b->data == NULL || b->slen < 0) return NULL;
        sprintf (strnum, "%d:", b->slen);
        if (NULL == (s = bfromcstr (strnum))
         || bconcat (s, b) == BSTR_ERR || bconchar (s, (char) ',') == BSTR_ERR) {
                bdestroy (s);
                return NULL;
        }
        buff = s->data;
        bcstrfree ((char *) s);
        return (char *) buff;
}

/*  bstring bNetStr2Bstr (const char * buf)
 *
 *  Convert a netstring to a bstring.  See
 *  http://cr.yp.to/proto/netstrings.txt for a description of netstrings.
 *  Note that the terminating "," *must* be present, however a following '\0'
 *  is *not* required.
 */
bstring bNetStr2Bstr (const char * buff) {
int i, x;
bstring b;
        if (buff == NULL) return NULL;
        x = 0;
        for (i=0; buff[i] != ':'; i++) {
                unsigned int v = buff[i] - '0';
                if (v > 9 || x > ((INT_MAX - (signed int)v) / 10)) return NULL;
                x = (x * 10) + v;
        }

        /* This thing has to be properly terminated */
        if (buff[i + 1 + x] != ',') return NULL;

        if (NULL == (b = bfromcstr (""))) return NULL;
        if (balloc (b, x + 1) != BSTR_OK)  {
                bdestroy (b);
                return NULL;
        }
        memcpy (b->data, buff + i + 1, x);
        b->data[x] = (unsigned char) '\0';
        b->slen = x;
        return b;
}

static char b64ETable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

/*  bstring bBase64Encode (const_bstring b)
 *
 *  Generate a base64 encoding.  See: RFC1341
 */
bstring bBase64Encode (const_bstring b) {
int i, c0, c1, c2, c3;
bstring out;

        if (b == NULL || b->slen < 0 || b->data == NULL) return NULL;

        out = bfromcstr ("");
        for (i=0; i + 2 < b->slen; i += 3) {
                if (i && ((i % 57) == 0)) {
                        if (bconchar (out, (char) '\015') < 0 || bconchar (out, (char) '\012') < 0) {
                                bdestroy (out);
                                return NULL;
                        }
                }
                c0 = b->data[i] >> 2;
                c1 = ((b->data[i] << 4) |
                      (b->data[i+1] >> 4)) & 0x3F;
                c2 = ((b->data[i+1] << 2) |
                      (b->data[i+2] >> 6)) & 0x3F;
                c3 = b->data[i+2] & 0x3F;
                if (bconchar (out, b64ETable[c0]) < 0 ||
                        bconchar (out, b64ETable[c1]) < 0 ||
                        bconchar (out, b64ETable[c2]) < 0 ||
                        bconchar (out, b64ETable[c3]) < 0) {
                        bdestroy (out);
                        return NULL;
                }
        }

        if (i && ((i % 57) == 0)) {
                if (bconchar (out, (char) '\015') < 0 || bconchar (out, (char) '\012') < 0) {
                        bdestroy (out);
                        return NULL;
                }
        }

        switch (i + 2 - b->slen) {
                case 0: c0 = b->data[i] >> 2;
                                c1 = ((b->data[i] << 4) |
                                          (b->data[i+1] >> 4)) & 0x3F;
                                c2 = (b->data[i+1] << 2) & 0x3F;
                        if (bconchar (out, b64ETable[c0]) < 0 ||
                                bconchar (out, b64ETable[c1]) < 0 ||
                                bconchar (out, b64ETable[c2]) < 0 ||
                                bconchar (out, (char) '=') < 0) {
                                bdestroy (out);
                                return NULL;
                        }
                        break;
                case 1: c0 =  b->data[i] >> 2;
                                c1 = (b->data[i] << 4) & 0x3F;
                        if (bconchar (out, b64ETable[c0]) < 0 ||
                                bconchar (out, b64ETable[c1]) < 0 ||
                                bconchar (out, (char) '=') < 0 ||
                                bconchar (out, (char) '=') < 0) {
                                bdestroy (out);
                                return NULL;
                        }
                        break;
                case 2: break;
        }

        return out;
}

#define B64_PAD (-2)
#define B64_ERR (-1)

static int base64DecodeSymbol (unsigned char alpha) {
   if      ((alpha >= 'A') && (alpha <= 'Z')) return (int)(alpha - 'A');
   else if ((alpha >= 'a') && (alpha <= 'z'))
        return 26 + (int)(alpha - 'a');
   else if ((alpha >= '0') && (alpha <= '9'))
        return 52 + (int)(alpha - '0');
   else if (alpha == '+') return 62;
   else if (alpha == '/') return 63;
   else if (alpha == '=') return B64_PAD;
   else                   return B64_ERR;
}

/*  bstring bBase64DecodeEx (const_bstring b, int * boolTruncError)
 *
 *  Decode a base64 block of data.  All MIME headers are assumed to have been
 *  removed.  See: RFC1341
 */
bstring bBase64DecodeEx (const_bstring b, int * boolTruncError) {
int i, v;
unsigned char c0, c1, c2;
bstring out;

        if (b == NULL || b->slen < 0 || b->data == NULL) return NULL;
        if (boolTruncError) *boolTruncError = 0;
        out = bfromcstr ("");
        i = 0;
        for (;;) {
                do {
                        if (i >= b->slen) return out;
                        if (b->data[i] == '=') {        /* Bad "too early" truncation */
                                if (boolTruncError) {
                                        *boolTruncError = 1;
                                        return out;
                                }
                                bdestroy (out);
                                return NULL;
                        }
                        v = base64DecodeSymbol (b->data[i]);
                        i++;
                } while (v < 0);
                c0 = (unsigned char) (v << 2);
                do {
                        if (i >= b->slen || b->data[i] == '=') {        /* Bad "too early" truncation */
                                if (boolTruncError) {
                                        *boolTruncError = 1;
                                        return out;
                                }
                                bdestroy (out);
                                return NULL;
                        }
                        v = base64DecodeSymbol (b->data[i]);
                        i++;
                } while (v < 0);
                c0 |= (unsigned char) (v >> 4);
                c1  = (unsigned char) (v << 4);
                do {
                        if (i >= b->slen) {
                                if (boolTruncError) {
                                        *boolTruncError = 1;
                                        return out;
                                }
                                bdestroy (out);
                                return NULL;
                        }
                        if (b->data[i] == '=') {
                                i++;
                                if (i >= b->slen || b->data[i] != '=' || bconchar (out, c0) < 0) {
                                        if (boolTruncError) {
                                                *boolTruncError = 1;
                                                return out;
                                        }
                                        bdestroy (out); /* Missing "=" at the end. */
                                        return NULL;
                                }
                                return out;
                        }
                        v = base64DecodeSymbol (b->data[i]);
                        i++;
                } while (v < 0);
                c1 |= (unsigned char) (v >> 2);
                c2  = (unsigned char) (v << 6);
                do {
                        if (i >= b->slen) {
                                if (boolTruncError) {
                                        *boolTruncError = 1;
                                        return out;
                                }
                                bdestroy (out);
                                return NULL;
                        }
                        if (b->data[i] == '=') {
                                if (bconchar (out, c0) < 0 || bconchar (out, c1) < 0) {
                                        if (boolTruncError) {
                                                *boolTruncError = 1;
                                                return out;
                                        }
                                        bdestroy (out);
                                        return NULL;
                                }
                                if (boolTruncError) *boolTruncError = 0;
                                return out;
                        }
                        v = base64DecodeSymbol (b->data[i]);
                        i++;
                } while (v < 0);
                c2 |= (unsigned char) (v);
                if (bconchar (out, c0) < 0 ||
                        bconchar (out, c1) < 0 ||
                        bconchar (out, c2) < 0) {
                        if (boolTruncError) {
                                *boolTruncError = -1;
                                return out;
                        }
                        bdestroy (out);
                        return NULL;
                }
        }
}

#define UU_DECODE_BYTE(b) (((b) == (signed int)'`') ? 0 : (b) - (signed int)' ')

struct bUuInOut {
        bstring src, dst;
        int * badlines;
};

#define UU_MAX_LINELEN 45

static int bUuDecLine (void * parm, int ofs, int len) {
struct bUuInOut * io = (struct bUuInOut *) parm;
bstring s = io->src;
bstring t = io->dst;
int i, llen, otlen, ret, c0, c1, c2, c3, d0, d1, d2, d3;

        if (len == 0) return 0;
        llen = UU_DECODE_BYTE (s->data[ofs]);
        ret = 0;

        otlen = t->slen;

        if (((unsigned) llen) > UU_MAX_LINELEN) { ret = -__LINE__;
                goto bl;
        }

        llen += t->slen;

        for (i=1; i < s->slen && t->slen < llen;i += 4) {
                unsigned char outoctet[3];
                c0 = UU_DECODE_BYTE (d0 = (int) bchare (s, i+ofs+0, ' ' - 1));
                c1 = UU_DECODE_BYTE (d1 = (int) bchare (s, i+ofs+1, ' ' - 1));
                c2 = UU_DECODE_BYTE (d2 = (int) bchare (s, i+ofs+2, ' ' - 1));
                c3 = UU_DECODE_BYTE (d3 = (int) bchare (s, i+ofs+3, ' ' - 1));

                if (((unsigned) (c0|c1) >= 0x40)) { if (!ret) ret = -__LINE__;
                        if (d0 > 0x60 || (d0 < (' ' - 1) && !isspace (d0)) ||
                            d1 > 0x60 || (d1 < (' ' - 1) && !isspace (d1))) {
                                t->slen = otlen;
                                goto bl;
                        }
                        c0 = c1 = 0;
                }
                outoctet[0] = (unsigned char) ((c0 << 2) | ((unsigned) c1 >> 4));
                if (t->slen+1 >= llen) {
                        if (0 > bconchar (t, (char) outoctet[0])) return -__LINE__;
                        break;
                }
                if ((unsigned) c2 >= 0x40) { if (!ret) ret = -__LINE__;
                        if (d2 > 0x60 || (d2 < (' ' - 1) && !isspace (d2))) {
                                t->slen = otlen;
                                goto bl;
                        }
                        c2 = 0;
                }
                outoctet[1] = (unsigned char) ((c1 << 4) | ((unsigned) c2 >> 2));
                if (t->slen+2 >= llen) {
                        if (0 > bcatblk (t, outoctet, 2)) return -__LINE__;
                        break;
                }
                if ((unsigned) c3 >= 0x40) { if (!ret) ret = -__LINE__;
                        if (d3 > 0x60 || (d3 < (' ' - 1) && !isspace (d3))) {
                                t->slen = otlen;
                                goto bl;
                        }
                        c3 = 0;
                }
                outoctet[2] = (unsigned char) ((c2 << 6) | ((unsigned) c3));
                if (0 > bcatblk (t, outoctet, 3)) return -__LINE__;
        }
        if (t->slen < llen) { if (0 == ret) ret = -__LINE__;
                t->slen = otlen;
        }
        bl:;
        if (ret && io->badlines) {
                (*io->badlines)++;
                return 0;
        }
        return ret;
}

/*  bstring bUuDecodeEx (const_bstring src, int * badlines)
 *
 *  Performs a UUDecode of a block of data.  If there are errors in the
 *  decoding, they are counted up and returned in "badlines", if badlines is
 *  not NULL. It is assumed that the "begin" and "end" lines have already
 *  been stripped off.  The potential security problem of writing the
 *  filename in the begin line is something that is beyond the scope of a
 *  portable library.
 */

#ifdef _MSC_VER
#pragma warning(disable:4204)
#endif

bstring bUuDecodeEx (const_bstring src, int * badlines) {
struct tagbstring t;
struct bStream * s;
struct bStream * d;
bstring b;

        if (!src) return NULL;
        t = *src; /* Short lifetime alias to header of src */
        s = bsFromBstrRef (&t); /* t is undefined after this */
        if (!s) return NULL;
        d = bsUuDecode (s, badlines);
        b = bfromcstralloc (256, "");
        if (NULL == b || 0 > bsread (b, d, INT_MAX)) {
                bdestroy (b);
                bsclose (d);
                bsclose (s);
                return NULL;
        }
        return b;
}

struct bsUuCtx {
        struct bUuInOut io;
        struct bStream * sInp;
};

static size_t bsUuDecodePart (void *buff, size_t elsize, size_t nelem, void *parm) {
static struct tagbstring eol = bsStatic ("\r\n");
struct bsUuCtx * luuCtx = (struct bsUuCtx *) parm;
size_t tsz;
int l, lret;

        if (NULL == buff || NULL == parm) return 0;
        tsz = elsize * nelem;

        CheckInternalBuffer:;
        /* If internal buffer has sufficient data, just output it */
        if (((size_t) luuCtx->io.dst->slen) > tsz) {
                memcpy (buff, luuCtx->io.dst->data, tsz);
                bdelete (luuCtx->io.dst, 0, (int) tsz);
                return nelem;
        }

        DecodeMore:;
        if (0 <= (l = binchr (luuCtx->io.src, 0, &eol))) {
                int ol = 0;
                struct tagbstring t;
                bstring s = luuCtx->io.src;
                luuCtx->io.src = &t;

                do {
                        if (l > ol) {
                                bmid2tbstr (t, s, ol, l - ol);
                                lret = bUuDecLine (&luuCtx->io, 0, t.slen);
                                if (0 > lret) {
                                        luuCtx->io.src = s;
                                        goto Done;
                                }
                        }
                        ol = l + 1;
                        if (((size_t) luuCtx->io.dst->slen) > tsz) break;
                        l = binchr (s, ol, &eol);
                } while (BSTR_ERR != l);
                bdelete (s, 0, ol);
                luuCtx->io.src = s;
                goto CheckInternalBuffer;
        }

        if (BSTR_ERR != bsreada (luuCtx->io.src, luuCtx->sInp, bsbufflength (luuCtx->sInp, BSTR_BS_BUFF_LENGTH_GET))) {
                goto DecodeMore;
        }

        bUuDecLine (&luuCtx->io, 0, luuCtx->io.src->slen);

        Done:;
        /* Output any lingering data that has been translated */
        if (((size_t) luuCtx->io.dst->slen) > 0) {
                if (((size_t) luuCtx->io.dst->slen) > tsz) goto CheckInternalBuffer;
                memcpy (buff, luuCtx->io.dst->data, luuCtx->io.dst->slen);
                tsz = luuCtx->io.dst->slen / elsize;
                luuCtx->io.dst->slen = 0;
                if (tsz > 0) return tsz;
        }

        /* Deallocate once EOF becomes triggered */
        bdestroy (luuCtx->io.dst);
        bdestroy (luuCtx->io.src);
        free (luuCtx);
        return 0;
}

/*  bStream * bsUuDecode (struct bStream * sInp, int * badlines)
 *
 *  Creates a bStream which performs the UUDecode of an an input stream.  If
 *  there are errors in the decoding, they are counted up and returned in
 *  "badlines", if badlines is not NULL. It is assumed that the "begin" and
 *  "end" lines have already been stripped off.  The potential security
 *  problem of writing the filename in the begin line is something that is
 *  beyond the scope of a portable library.
 */

struct bStream * bsUuDecode (struct bStream * sInp, int * badlines) {
struct bsUuCtx * luuCtx = (struct bsUuCtx *) malloc (sizeof (struct bsUuCtx));
struct bStream * sOut;

        if (NULL == luuCtx) return NULL;

        luuCtx->io.src = bfromcstr ("");
        luuCtx->io.dst = bfromcstr ("");
        if (NULL == luuCtx->io.dst || NULL == luuCtx->io.src) {
                CleanUpFailureToAllocate:;
                bdestroy (luuCtx->io.dst);
                bdestroy (luuCtx->io.src);
                free (luuCtx);
                return NULL;
        }
        luuCtx->io.badlines = badlines;
        if (badlines) *badlines = 0;

        luuCtx->sInp = sInp;

        sOut = bsopen ((bNread) bsUuDecodePart, luuCtx);
        if (NULL == sOut) goto CleanUpFailureToAllocate;
        return sOut;
}

#define UU_ENCODE_BYTE(b) (char) (((b) == 0) ? '`' : ((b) + ' '))

/*  bstring bUuEncode (const_bstring src)
 *
 *  Performs a UUEncode of a block of data.  The "begin" and "end" lines are
 *  not appended.
 */
bstring bUuEncode (const_bstring src) {
bstring out;
int i, j, jm;
unsigned int c0, c1, c2;
        if (src == NULL || src->slen < 0 || src->data == NULL) return NULL;
        if ((out = bfromcstr ("")) == NULL) return NULL;
        for (i=0; i < src->slen; i += UU_MAX_LINELEN) {
                if ((jm = i + UU_MAX_LINELEN) > src->slen) jm = src->slen;
                if (bconchar (out, UU_ENCODE_BYTE (jm - i)) < 0) {
                        bstrFree (out);
                        break;
                }
                for (j = i; j < jm; j += 3) {
                        c0 = (unsigned int) bchar (src, j    );
                        c1 = (unsigned int) bchar (src, j + 1);
                        c2 = (unsigned int) bchar (src, j + 2);
                        if (bconchar (out, UU_ENCODE_BYTE ( (c0 & 0xFC) >> 2)) < 0 ||
                            bconchar (out, UU_ENCODE_BYTE (((c0 & 0x03) << 4) | ((c1 & 0xF0) >> 4))) < 0 ||
                            bconchar (out, UU_ENCODE_BYTE (((c1 & 0x0F) << 2) | ((c2 & 0xC0) >> 6))) < 0 ||
                            bconchar (out, UU_ENCODE_BYTE ( (c2 & 0x3F))) < 0) {
                                bstrFree (out);
                                goto End;
                        }
                }
                if (bconchar (out, (char) '\r') < 0 || bconchar (out, (char) '\n') < 0) {
                        bstrFree (out);
                        break;
                }
        }
        End:;
        return out;
}

/*  bstring bYEncode (const_bstring src)
 *
 *  Performs a YEncode of a block of data.  No header or tail info is
 *  appended.  See: http://www.yenc.org/whatis.htm and
 *  http://www.yenc.org/yenc-draft.1.3.txt
 */
bstring bYEncode (const_bstring src) {
int i;
bstring out;
unsigned char c;

        if (src == NULL || src->slen < 0 || src->data == NULL) return NULL;
        if ((out = bfromcstr ("")) == NULL) return NULL;
        for (i=0; i < src->slen; i++) {
                c = (unsigned char)(src->data[i] + 42);
                if (c == '=' || c == '\0' || c == '\r' || c == '\n') {
                        if (0 > bconchar (out, (char) '=')) {
                                bdestroy (out);
                                return NULL;
                        }
                        c += (unsigned char) 64;
                }
                if (0 > bconchar (out, c)) {
                        bdestroy (out);
                        return NULL;
                }
        }
        return out;
}

/*  bstring bYDecode (const_bstring src)
 *
 *  Performs a YDecode of a block of data.  See:
 *  http://www.yenc.org/whatis.htm and http://www.yenc.org/yenc-draft.1.3.txt
 */
#define MAX_OB_LEN (64)

bstring bYDecode (const_bstring src) {
int i;
bstring out;
unsigned char c;
unsigned char octetbuff[MAX_OB_LEN];
int obl;

        if (src == NULL || src->slen < 0 || src->data == NULL) return NULL;
        if ((out = bfromcstr ("")) == NULL) return NULL;

        obl = 0;

        for (i=0; i < src->slen; i++) {
                if ('=' == (c = src->data[i])) { /* The = escape mode */
                        i++;
                        if (i >= src->slen) {
                                bdestroy (out);
                                return NULL;
                        }
                        c = (unsigned char) (src->data[i] - 64);
                } else {
                        if ('\0' == c) {
                                bdestroy (out);
                                return NULL;
                        }

                        /* Extraneous CR/LFs are to be ignored. */
                        if (c == '\r' || c == '\n') continue;
                }

                octetbuff[obl] = (unsigned char) ((int) c - 42);
                obl++;

                if (obl >= MAX_OB_LEN) {
                        if (0 > bcatblk (out, octetbuff, obl)) {
                                bdestroy (out);
                                return NULL;
                        }
                        obl = 0;
                }
        }

        if (0 > bcatblk (out, octetbuff, obl)) {
                bdestroy (out);
                out = NULL;
        }
        return out;
}

/*  bstring bStrfTime (const char * fmt, const struct tm * timeptr)
 *
 *  Takes a format string that is compatible with strftime and a struct tm
 *  pointer, formats the time according to the format string and outputs
 *  the bstring as a result. Note that if there is an early generation of a
 *  '\0' character, the bstring will be truncated to this end point.
 */
bstring bStrfTime (const char * fmt, const struct tm * timeptr) {
#if defined (__TURBOC__) && !defined (__BORLANDC__)
static struct tagbstring ns = bsStatic ("bStrfTime Not supported");
        fmt = fmt;
        timeptr = timeptr;
        return &ns;
#else
bstring buff;
int n;
size_t r;

        if (fmt == NULL) return NULL;

        /* Since the length is not determinable beforehand, a search is
           performed using the truncating "strftime" call on increasing
           potential sizes for the output result. */

        if ((n = (int) (2*strlen (fmt))) < 16) n = 16;
        buff = bfromcstralloc (n+2, "");

        for (;;) {
                if (BSTR_OK != balloc (buff, n + 2)) {
                        bdestroy (buff);
                        return NULL;
                }

                r = strftime ((char *) buff->data, n + 1, fmt, timeptr);

                if (r > 0) {
                        buff->slen = (int) r;
                        break;
                }

                n += n;
        }

        return buff;
#endif
}

/*  int bSetCstrChar (bstring a, int pos, char c)
 *
 *  Sets the character at position pos to the character c in the bstring a.
 *  If the character c is NUL ('\0') then the string is truncated at this
 *  point.  Note: this does not enable any other '\0' character in the bstring
 *  as terminator indicator for the string.  pos must be in the position
 *  between 0 and b->slen inclusive, otherwise BSTR_ERR will be returned.
 */
int bSetCstrChar (bstring b, int pos, char c) {
        if (NULL == b || b->mlen <= 0 || b->slen < 0 || b->mlen < b->slen)
                return BSTR_ERR;
        if (pos < 0 || pos > b->slen) return BSTR_ERR;

        if (pos == b->slen) {
                if ('\0' != c) return bconchar (b, c);
                return 0;
        }

        b->data[pos] = (unsigned char) c;
        if ('\0' == c) b->slen = pos;

        return 0;
}

/*  int bSetChar (bstring b, int pos, char c)
 *
 *  Sets the character at position pos to the character c in the bstring a.
 *  The string is not truncated if the character c is NUL ('\0').  pos must
 *  be in the position between 0 and b->slen inclusive, otherwise BSTR_ERR
 *  will be returned.
 */
int bSetChar (bstring b, int pos, char c) {
        if (NULL == b || b->mlen <= 0 || b->slen < 0 || b->mlen < b->slen)
                return BSTR_ERR;
        if (pos < 0 || pos > b->slen) return BSTR_ERR;

        if (pos == b->slen) {
                return bconchar (b, c);
        }

        b->data[pos] = (unsigned char) c;
        return 0;
}

#define INIT_SECURE_INPUT_LENGTH (256)

/*  bstring bSecureInput (int maxlen, int termchar,
 *                        bNgetc vgetchar, void * vgcCtx)
 *
 *  Read input from an abstracted input interface, for a length of at most
 *  maxlen characters.  If maxlen <= 0, then there is no length limit put
 *  on the input.  The result is terminated early if vgetchar() return EOF
 *  or the user specified value termchar.
 *
 */
bstring bSecureInput (int maxlen, int termchar, bNgetc vgetchar, void * vgcCtx) {
int i, m, c;
bstring b, t;

        if (!vgetchar) return NULL;

        b = bfromcstralloc (INIT_SECURE_INPUT_LENGTH, "");
        if ((c = UCHAR_MAX + 1) == termchar) c++;

        for (i=0; ; i++) {
                if (termchar == c || (maxlen > 0 && i >= maxlen)) c = EOF;
                else c = vgetchar (vgcCtx);

                if (EOF == c) break;

                if (i+1 >= b->mlen) {

                        /* Double size, but deal with unusual case of numeric
                           overflows */

                        if ((m = b->mlen << 1)   <= b->mlen &&
                            (m = b->mlen + 1024) <= b->mlen &&
                            (m = b->mlen + 16)   <= b->mlen &&
                            (m = b->mlen + 1)    <= b->mlen) t = NULL;
                        else t = bfromcstralloc (m, "");

                        if (t) memcpy (t->data, b->data, i);
                        bSecureDestroy (b); /* Cleanse previous buffer */
                        b = t;
                        if (!b) return b;
                }

                b->data[i] = (unsigned char) c;
        }

        b->slen = i;
        b->data[i] = (unsigned char) '\0';
        return b;
}

#define BWS_BUFF_SZ (1024)

struct bwriteStream {
    bstring buff;    /* Buffer for underwrites                   */
    void * parm;     /* The stream handle for core stream        */
    bNwrite writeFn; /* fwrite work-a-like fnptr for core stream */
    int isEOF;       /* track stream's EOF state                 */
    int minBuffSz;
};

/*  struct bwriteStream * bwsOpen (bNwrite writeFn, void * parm)
 *
 *  Wrap a given open stream (described by a fwrite work-a-like function
 *  pointer and stream handle) into an open bwriteStream suitable for write
 *  streaming functions.
 */
struct bwriteStream * bwsOpen (bNwrite writeFn, void * parm) {
struct bwriteStream * ws;

        if (NULL == writeFn) return NULL;
        ws = (struct bwriteStream *) malloc (sizeof (struct bwriteStream));
        if (ws) {
                if (NULL == (ws->buff = bfromcstr (""))) {
                        free (ws);
                        ws = NULL;
                } else {
                        ws->parm = parm;
                        ws->writeFn = writeFn;
                        ws->isEOF = 0;
                        ws->minBuffSz = BWS_BUFF_SZ;
                }
        }
        return ws;
}

#define internal_bwswriteout(ws,b) { \
        if ((b)->slen > 0) { \
                if (1 != (ws->writeFn ((b)->data, (b)->slen, 1, ws->parm))) { \
                        ws->isEOF = 1; \
                        return BSTR_ERR; \
                } \
        } \
}

/*  int bwsWriteFlush (struct bwriteStream * ws)
 *
 *  Force any pending data to be written to the core stream.
 */
int bwsWriteFlush (struct bwriteStream * ws) {
        if (NULL == ws || ws->isEOF || 0 >= ws->minBuffSz ||
            NULL == ws->writeFn || NULL == ws->buff) return BSTR_ERR;
        internal_bwswriteout (ws, ws->buff);
        ws->buff->slen = 0;
        return 0;
}

/*  int bwsWriteBstr (struct bwriteStream * ws, const_bstring b)
 *
 *  Send a bstring to a bwriteStream.  If the stream is at EOF BSTR_ERR is
 *  returned.  Note that there is no deterministic way to determine the exact
 *  cut off point where the core stream stopped accepting data.
 */
int bwsWriteBstr (struct bwriteStream * ws, const_bstring b) {
struct tagbstring t;
int l;

        if (NULL == ws || NULL == b || NULL == ws->buff ||
            ws->isEOF || 0 >= ws->minBuffSz || NULL == ws->writeFn)
                return BSTR_ERR;

        /* Buffer prepacking optimization */
        if (b->slen > 0 && ws->buff->mlen - ws->buff->slen > b->slen) {
                static struct tagbstring empty = bsStatic ("");
                if (0 > bconcat (ws->buff, b)) return BSTR_ERR;
                return bwsWriteBstr (ws, &empty);
        }

        if (0 > (l = ws->minBuffSz - ws->buff->slen)) {
                internal_bwswriteout (ws, ws->buff);
                ws->buff->slen = 0;
                l = ws->minBuffSz;
        }

        if (b->slen < l) return bconcat (ws->buff, b);

        if (0 > bcatblk (ws->buff, b->data, l)) return BSTR_ERR;
        internal_bwswriteout (ws, ws->buff);
        ws->buff->slen = 0;

        bmid2tbstr (t, (bstring) b, l, b->slen);

        if (t.slen >= ws->minBuffSz) {
                internal_bwswriteout (ws, &t);
                return 0;
        }

        return bassign (ws->buff, &t);
}

/*  int bwsWriteBlk (struct bwriteStream * ws, void * blk, int len)
 *
 *  Send a block of data a bwriteStream.  If the stream is at EOF BSTR_ERR is
 *  returned.
 */
int bwsWriteBlk (struct bwriteStream * ws, void * blk, int len) {
struct tagbstring t;
        if (NULL == blk || len < 0) return BSTR_ERR;
        blk2tbstr (t, blk, len);
        return bwsWriteBstr (ws, &t);
}

/*  int bwsIsEOF (const struct bwriteStream * ws)
 *
 *  Returns 0 if the stream is currently writable, 1 if the core stream has
 *  responded by not accepting the previous attempted write.
 */
int bwsIsEOF (const struct bwriteStream * ws) {
        if (NULL == ws || NULL == ws->buff || 0 > ws->minBuffSz ||
            NULL == ws->writeFn) return BSTR_ERR;
        return ws->isEOF;
}

/*  int bwsBuffLength (struct bwriteStream * ws, int sz)
 *
 *  Set the length of the buffer used by the bwsStream.  If sz is zero, the
 *  length is not set.  This function returns with the previous length.
 */
int bwsBuffLength (struct bwriteStream * ws, int sz) {
int oldSz;
        if (ws == NULL || sz < 0) return BSTR_ERR;
        oldSz = ws->minBuffSz;
        if (sz > 0) ws->minBuffSz = sz;
        return oldSz;
}

/*  void * bwsClose (struct bwriteStream * s)
 *
 *  Close the bwriteStream, and return the handle to the stream that was
 *  originally used to open the given stream.  Note that even if the stream
 *  is at EOF it still needs to be closed with a call to bwsClose.
 */
void * bwsClose (struct bwriteStream * ws) {
void * parm;
        if (NULL == ws || NULL == ws->buff || 0 >= ws->minBuffSz ||
            NULL == ws->writeFn) return NULL;
        bwsWriteFlush (ws);
        parm = ws->parm;
        ws->parm = NULL;
        ws->minBuffSz = -1;
        ws->writeFn = NULL;
        bstrFree (ws->buff);
        free (ws);
        return parm;
}