libio/strops.c

   1 /* Copyright (C) 1993, 1997-2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.
  18
  19    As a special exception, if you link the code in this file with
  20    files compiled with a GNU compiler to produce an executable,
  21    that does not cause the resulting executable to be covered by
  22    the GNU Lesser General Public License.  This exception does not
  23    however invalidate any other reasons why the executable file
  24    might be covered by the GNU Lesser General Public License.
  25    This exception applies to code released by its copyright holders
  26    in files containing the exception.  */
  27
  28 #include "strfile.h"
  29 #include "libioP.h"
  30 #include <string.h>
  31 #include <stdio_ext.h>
  32
  33 #if 0
  34 /* The following definitions are for exposition only.
  35    They map the terminology used in the ANSI/ISO C++ draft standard
  36    to the implementation. */
  37
  38 /* allocated:  set  when a dynamic array object has been allocated, and
  39    hence should be freed by the destructor for the strstreambuf object. */
  40 #define ALLOCATED(FP) ((FP)->_f._IO_buf_base && DYNAMIC(FP))
  41
  42 /* constant:  set when the array object has const elements,
  43    so the output sequence cannot be written. */
  44 #define CONSTANT(FP) ((FP)->_f._IO_file_flags & _IO_NO_WRITES)
  45
  46 /* alsize:  the suggested minimum size for a dynamic array object. */
  47 #define ALSIZE(FP) ??? /* not stored */
  48
  49 /* palloc: points to the function to call to allocate a dynamic array object.*/
  50 #define PALLOC(FP) \
  51   ((FP)->_s._allocate_buffer == default_alloc ? 0 : (FP)->_s._allocate_buffer)
  52
  53 /* pfree: points  to  the  function  to call to free a dynamic array object. */
  54 #define PFREE(FP) \
  55   ((FP)->_s._free_buffer == default_free ? 0 : (FP)->_s._free_buffer)
  56
  57 #endif
  58
  59 #ifdef TODO
  60 /* An "unbounded buffer" is when a buffer is supplied, but with no
  61    specified length.  An example is the buffer argument to sprintf.
  62    */
  63 #endif
  64
  65 void
  66 _IO_str_init_static_internal (sf, ptr, size, pstart)
  67      _IO_strfile *sf;
  68      char *ptr;
  69      _IO_size_t size;
  70      char *pstart;
  71 {
  72   _IO_FILE *fp = &sf->_sbf._f;
  73   char *end;
  74
  75   if (size == 0)
  76     end = __rawmemchr (ptr, '\0');
  77   else if ((_IO_size_t) ptr + size > (_IO_size_t) ptr)
  78     end = ptr + size;
  79   else
  80     end = (char *) -1;
  81   INTUSE(_IO_setb) (fp, ptr, end, 0);
  82
  83   fp->_IO_write_base = ptr;
  84   fp->_IO_read_base = ptr;
  85   fp->_IO_read_ptr = ptr;
  86   if (pstart)
  87     {
  88       fp->_IO_write_ptr = pstart;
  89       fp->_IO_write_end = end;
  90       fp->_IO_read_end = pstart;
  91     }
  92   else
  93     {
  94       fp->_IO_write_ptr = ptr;
  95       fp->_IO_write_end = ptr;
  96       fp->_IO_read_end = end;
  97     }
  98   /* A null _allocate_buffer function flags the strfile as being static. */
  99   sf->_s._allocate_buffer = (_IO_alloc_type) 0;
 100 }
 101
 102 void
 103 _IO_str_init_static (sf, ptr, size, pstart)
 104      _IO_strfile *sf;
 105      char *ptr;
 106      int size;
 107      char *pstart;
 108 {
 109   return _IO_str_init_static_internal (sf, ptr, size < 0 ? -1 : size, pstart);
 110 }
 111
 112 void
 113 _IO_str_init_readonly (sf, ptr, size)
 114      _IO_strfile *sf;
 115      const char *ptr;
 116      int size;
 117 {
 118   _IO_str_init_static_internal (sf, (char *) ptr, size < 0 ? -1 : size, NULL);
 119   sf->_sbf._f._IO_file_flags |= _IO_NO_WRITES;
 120 }
 121
 122 int
 123 _IO_str_overflow (fp, c)
 124      _IO_FILE *fp;
 125      int c;
 126 {
 127   int flush_only = c == EOF;
 128   _IO_size_t pos;
 129   if (fp->_flags & _IO_NO_WRITES)
 130       return flush_only ? 0 : EOF;
 131   if ((fp->_flags & _IO_TIED_PUT_GET) && !(fp->_flags & _IO_CURRENTLY_PUTTING))
 132     {
 133       fp->_flags |= _IO_CURRENTLY_PUTTING;
 134       fp->_IO_write_ptr = fp->_IO_read_ptr;
 135       fp->_IO_read_ptr = fp->_IO_read_end;
 136     }
 137   pos =  fp->_IO_write_ptr - fp->_IO_write_base;
 138   if (pos >= (_IO_size_t) (_IO_blen (fp) + flush_only))
 139     {
 140       if (fp->_flags & _IO_USER_BUF) /* not allowed to enlarge */
 141         return EOF;
 142       else
 143         {
 144           char *new_buf;
 145           char *old_buf = fp->_IO_buf_base;
 146           _IO_size_t new_size = 2 * _IO_blen (fp) + 100;
 147           new_buf
 148             = (char *) (*((_IO_strfile *) fp)->_s._allocate_buffer) (new_size);
 149           if (new_buf == NULL)
 150             {
 151               /*          __ferror(fp) = 1; */
 152               return EOF;
 153             }
 154           if (old_buf)
 155             {
 156               memcpy (new_buf, old_buf, _IO_blen (fp));
 157               (*((_IO_strfile *) fp)->_s._free_buffer) (old_buf);
 158               /* Make sure _IO_setb won't try to delete _IO_buf_base. */
 159               fp->_IO_buf_base = NULL;
 160             }
 161 #if 0
 162           if (lenp == &LEN(fp)) /* use '\0'-filling */
 163               memset (new_buf + pos, 0, blen() - pos);
 164 #endif
 165           INTUSE(_IO_setb) (fp, new_buf, new_buf + new_size, 1);
 166           fp->_IO_read_base = new_buf + (fp->_IO_read_base - old_buf);
 167           fp->_IO_read_ptr = new_buf + (fp->_IO_read_ptr - old_buf);
 168           fp->_IO_read_end = new_buf + (fp->_IO_read_end - old_buf);
 169           fp->_IO_write_ptr = new_buf + (fp->_IO_write_ptr - old_buf);
 170
 171           fp->_IO_write_base = new_buf;
 172           fp->_IO_write_end = fp->_IO_buf_end;
 173         }
 174     }
 175
 176   if (!flush_only)
 177     *fp->_IO_write_ptr++ = (unsigned char) c;
 178   if (fp->_IO_write_ptr > fp->_IO_read_end)
 179     fp->_IO_read_end = fp->_IO_write_ptr;
 180   return c;
 181 }
 182 INTDEF(_IO_str_overflow)
 183
 184 int
 185 _IO_str_underflow (fp)
 186      _IO_FILE *fp;
 187 {
 188   if (fp->_IO_write_ptr > fp->_IO_read_end)
 189     fp->_IO_read_end = fp->_IO_write_ptr;
 190   if ((fp->_flags & _IO_TIED_PUT_GET) && (fp->_flags & _IO_CURRENTLY_PUTTING))
 191     {
 192       fp->_flags &= ~_IO_CURRENTLY_PUTTING;
 193       fp->_IO_read_ptr = fp->_IO_write_ptr;
 194       fp->_IO_write_ptr = fp->_IO_write_end;
 195     }
 196   if (fp->_IO_read_ptr < fp->_IO_read_end)
 197     return *((unsigned char *) fp->_IO_read_ptr);
 198   else
 199     return EOF;
 200 }
 201 INTDEF(_IO_str_underflow)
 202
 203 /* The size of the valid part of the buffer.  */
 204
 205 _IO_ssize_t
 206 _IO_str_count (fp)
 207      _IO_FILE *fp;
 208 {
 209   return ((fp->_IO_write_ptr > fp->_IO_read_end
 210            ? fp->_IO_write_ptr : fp->_IO_read_end)
 211           - fp->_IO_read_base);
 212 }
 213
 214 _IO_off64_t
 215 _IO_str_seekoff (fp, offset, dir, mode)
 216      _IO_FILE *fp;
 217      _IO_off64_t offset;
 218      int dir;
 219      int mode;
 220 {
 221   _IO_off64_t new_pos;
 222
 223   if (mode == 0 && (fp->_flags & _IO_TIED_PUT_GET))
 224     mode = (fp->_flags & _IO_CURRENTLY_PUTTING ? _IOS_OUTPUT : _IOS_INPUT);
 225
 226   if (mode == 0)
 227     {
 228       /* Don't move any pointers. But there is no clear indication what
 229          mode FP is in. Let's guess. */
 230       if (fp->_IO_file_flags & _IO_NO_WRITES)
 231         new_pos = fp->_IO_read_ptr - fp->_IO_read_base;
 232       else
 233         new_pos = fp->_IO_write_ptr - fp->_IO_write_base;
 234     }
 235   else
 236     {
 237       _IO_ssize_t cur_size = _IO_str_count(fp);
 238       new_pos = EOF;
 239
 240       /* Move the get pointer, if requested. */
 241       if (mode & _IOS_INPUT)
 242         {
 243           switch (dir)
 244             {
 245             case _IO_seek_end:
 246               offset += cur_size;
 247               break;
 248             case _IO_seek_cur:
 249               offset += fp->_IO_read_ptr - fp->_IO_read_base;
 250               break;
 251             default: /* case _IO_seek_set: */
 252               break;
 253             }
 254           if (offset < 0 || (_IO_ssize_t) offset > cur_size)
 255             return EOF;
 256           fp->_IO_read_ptr = fp->_IO_read_base + offset;
 257           fp->_IO_read_end = fp->_IO_read_base + cur_size;
 258           new_pos = offset;
 259         }
 260
 261       /* Move the put pointer, if requested. */
 262       if (mode & _IOS_OUTPUT)
 263         {
 264           switch (dir)
 265             {
 266             case _IO_seek_end:
 267               offset += cur_size;
 268               break;
 269             case _IO_seek_cur:
 270               offset += fp->_IO_write_ptr - fp->_IO_write_base;
 271               break;
 272             default: /* case _IO_seek_set: */
 273               break;
 274             }
 275           if (offset < 0 || (_IO_ssize_t) offset > cur_size)
 276             return EOF;
 277           fp->_IO_write_ptr = fp->_IO_write_base + offset;
 278           new_pos = offset;
 279         }
 280     }
 281   return new_pos;
 282 }
 283 INTDEF(_IO_str_seekoff)
 284
 285 int
 286 _IO_str_pbackfail (fp, c)
 287      _IO_FILE *fp;
 288      int c;
 289 {
 290   if ((fp->_flags & _IO_NO_WRITES) && c != EOF)
 291     return EOF;
 292   return INTUSE(_IO_default_pbackfail) (fp, c);
 293 }
 294 INTDEF(_IO_str_pbackfail)
 295
 296 void
 297 _IO_str_finish (fp, dummy)
 298      _IO_FILE *fp;
 299      int dummy;
 300 {
 301   if (fp->_IO_buf_base && !(fp->_flags & _IO_USER_BUF))
 302     (((_IO_strfile *) fp)->_s._free_buffer) (fp->_IO_buf_base);
 303   fp->_IO_buf_base = NULL;
 304
 305   INTUSE(_IO_default_finish) (fp, 0);
 306 }
 307
 308 struct _IO_jump_t _IO_str_jumps =
 309 {
 310   JUMP_INIT_DUMMY,
 311   JUMP_INIT(finish, _IO_str_finish),
 312   JUMP_INIT(overflow, INTUSE(_IO_str_overflow)),
 313   JUMP_INIT(underflow, INTUSE(_IO_str_underflow)),
 314   JUMP_INIT(uflow, INTUSE(_IO_default_uflow)),
 315   JUMP_INIT(pbackfail, INTUSE(_IO_str_pbackfail)),
 316   JUMP_INIT(xsputn, INTUSE(_IO_default_xsputn)),
 317   JUMP_INIT(xsgetn, INTUSE(_IO_default_xsgetn)),
 318   JUMP_INIT(seekoff, INTUSE(_IO_str_seekoff)),
 319   JUMP_INIT(seekpos, _IO_default_seekpos),
 320   JUMP_INIT(setbuf, _IO_default_setbuf),
 321   JUMP_INIT(sync, _IO_default_sync),
 322   JUMP_INIT(doallocate, INTUSE(_IO_default_doallocate)),
 323   JUMP_INIT(read, _IO_default_read),
 324   JUMP_INIT(write, _IO_default_write),
 325   JUMP_INIT(seek, _IO_default_seek),
 326   JUMP_INIT(close, _IO_default_close),
 327   JUMP_INIT(stat, _IO_default_stat),
 328   JUMP_INIT(showmanyc, _IO_default_showmanyc),
 329   JUMP_INIT(imbue, _IO_default_imbue)
 330 };