libio/strops.c

   1 /* Copyright (C) 1993, 1997, 1998, 1999, 2000 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
  32 #if 0
  33 /* The following definitions are for exposition only.
  34    They map the terminology used in the ANSI/ISO C++ draft standard
  35    to the implementation. */
  36
  37 /* allocated:  set  when a dynamic array object has been allocated, and
  38    hence should be freed by the destructor for the strstreambuf object. */
  39 #define ALLOCATED(FP) ((FP)->_f._IO_buf_base && DYNAMIC(FP))
  40
  41 /* constant:  set when the array object has const elements,
  42    so the output sequence cannot be written. */
  43 #define CONSTANT(FP) ((FP)->_f._IO_file_flags & _IO_NO_WRITES)
  44
  45 /* alsize:  the suggested minimum size for a dynamic array object. */
  46 #define ALSIZE(FP) ??? /* not stored */
  47
  48 /* palloc: points to the function to call to allocate a dynamic array object.*/
  49 #define PALLOC(FP) \
  50   ((FP)->_s._allocate_buffer == default_alloc ? 0 : (FP)->_s._allocate_buffer)
  51
  52 /* pfree: points  to  the  function  to call to free a dynamic array object. */
  53 #define PFREE(FP) \
  54   ((FP)->_s._free_buffer == default_free ? 0 : (FP)->_s._free_buffer)
  55
  56 #endif
  57
  58 #ifdef TODO
  59 /* An "unbounded buffer" is when a buffer is supplied, but with no
  60    specified length.  An example is the buffer argument to sprintf.
  61    */
  62 #endif
  63
  64 void
  65 _IO_str_init_static (sf, ptr, size, pstart)
  66      _IO_strfile *sf;
  67      char *ptr;
  68      int size;
  69      char *pstart;
  70 {
  71   _IO_FILE *fp = &sf->_sbf._f;
  72
  73   if (size == 0)
  74     size = strlen (ptr);
  75   else if (size < 0)
  76     {
  77       /* If size is negative 'the characters are assumed to
  78          continue indefinitely.'  This is kind of messy ... */
  79       int s;
  80       size = 512;
  81       /* Try increasing powers of 2, as long as we don't wrap around. */
  82       for (; s = 2*size, s > 0 && ptr + s > ptr && s < 0x4000000L; )
  83         size = s;
  84       /* Try increasing size as much as we can without wrapping around. */
  85       for (s = size >> 1; s > 0; s >>= 1)
  86         {
  87           if (ptr + size + s > ptr)
  88             size += s;
  89         }
  90     }
  91   _IO_setb (fp, ptr, ptr + size, 0);
  92
  93   fp->_IO_write_base = ptr;
  94   fp->_IO_read_base = ptr;
  95   fp->_IO_read_ptr = ptr;
  96   if (pstart)
  97     {
  98       fp->_IO_write_ptr = pstart;
  99       fp->_IO_write_end = ptr + size;
 100       fp->_IO_read_end = pstart;
 101     }
 102   else
 103     {
 104       fp->_IO_write_ptr = ptr;
 105       fp->_IO_write_end = ptr;
 106       fp->_IO_read_end = ptr+size;
 107     }
 108   /* A null _allocate_buffer function flags the strfile as being static. */
 109   sf->_s._allocate_buffer = (_IO_alloc_type) 0;
 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 (sf, (char *) ptr, 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           _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
 183 int
 184 _IO_str_underflow (fp)
 185      _IO_FILE *fp;
 186 {
 187   if (fp->_IO_write_ptr > fp->_IO_read_end)
 188     fp->_IO_read_end = fp->_IO_write_ptr;
 189   if ((fp->_flags & _IO_TIED_PUT_GET) && (fp->_flags & _IO_CURRENTLY_PUTTING))
 190     {
 191       fp->_flags &= ~_IO_CURRENTLY_PUTTING;
 192       fp->_IO_read_ptr = fp->_IO_write_ptr;
 193       fp->_IO_write_ptr = fp->_IO_write_end;
 194     }
 195   if (fp->_IO_read_ptr < fp->_IO_read_end)
 196     return *((unsigned char *) fp->_IO_read_ptr);
 197   else
 198     return EOF;
 199 }
 200
 201 /* The size of the valid part of the buffer.  */
 202
 203 _IO_ssize_t
 204 _IO_str_count (fp)
 205      _IO_FILE *fp;
 206 {
 207   return ((fp->_IO_write_ptr > fp->_IO_read_end
 208            ? fp->_IO_write_ptr : fp->_IO_read_end)
 209           - fp->_IO_read_base);
 210 }
 211
 212 _IO_off64_t
 213 _IO_str_seekoff (fp, offset, dir, mode)
 214      _IO_FILE *fp;
 215      _IO_off64_t offset;
 216      int dir;
 217      int mode;
 218 {
 219   _IO_off64_t new_pos;
 220
 221   if (mode == 0 && (fp->_flags & _IO_TIED_PUT_GET))
 222     mode = (fp->_flags & _IO_CURRENTLY_PUTTING ? _IOS_OUTPUT : _IOS_INPUT);
 223
 224   if (mode == 0)
 225     {
 226       /* Don't move any pointers. But there is no clear indication what
 227          mode FP is in. Let's guess. */
 228       if (fp->_IO_file_flags & _IO_NO_WRITES)
 229         new_pos = fp->_IO_read_ptr - fp->_IO_read_base;
 230       else
 231         new_pos = fp->_IO_write_ptr - fp->_IO_write_base;
 232     }
 233   else
 234     {
 235       _IO_ssize_t cur_size = _IO_str_count(fp);
 236       new_pos = EOF;
 237
 238       /* Move the get pointer, if requested. */
 239       if (mode & _IOS_INPUT)
 240         {
 241           switch (dir)
 242             {
 243             case _IO_seek_end:
 244               offset += cur_size;
 245               break;
 246             case _IO_seek_cur:
 247               offset += fp->_IO_read_ptr - fp->_IO_read_base;
 248               break;
 249             default: /* case _IO_seek_set: */
 250               break;
 251             }
 252           if (offset < 0 || (_IO_ssize_t) offset > cur_size)
 253             return EOF;
 254           fp->_IO_read_ptr = fp->_IO_read_base + offset;
 255           fp->_IO_read_end = fp->_IO_read_base + cur_size;
 256           new_pos = offset;
 257         }
 258
 259       /* Move the put pointer, if requested. */
 260       if (mode & _IOS_OUTPUT)
 261         {
 262           switch (dir)
 263             {
 264             case _IO_seek_end:
 265               offset += cur_size;
 266               break;
 267             case _IO_seek_cur:
 268               offset += fp->_IO_write_ptr - fp->_IO_write_base;
 269               break;
 270             default: /* case _IO_seek_set: */
 271               break;
 272             }
 273           if (offset < 0 || (_IO_ssize_t) offset > cur_size)
 274             return EOF;
 275           fp->_IO_write_ptr = fp->_IO_write_base + offset;
 276           new_pos = offset;
 277         }
 278     }
 279   return new_pos;
 280 }
 281
 282 int
 283 _IO_str_pbackfail (fp, c)
 284      _IO_FILE *fp;
 285      int c;
 286 {
 287   if ((fp->_flags & _IO_NO_WRITES) && c != EOF)
 288     return EOF;
 289   return _IO_default_pbackfail (fp, c);
 290 }
 291
 292 void
 293 _IO_str_finish (fp, dummy)
 294      _IO_FILE *fp;
 295      int dummy;
 296 {
 297   if (fp->_IO_buf_base && !(fp->_flags & _IO_USER_BUF))
 298     (((_IO_strfile *) fp)->_s._free_buffer) (fp->_IO_buf_base);
 299   fp->_IO_buf_base = NULL;
 300
 301   _IO_default_finish (fp, 0);
 302 }
 303
 304 struct _IO_jump_t _IO_str_jumps =
 305 {
 306   JUMP_INIT_DUMMY,
 307   JUMP_INIT(finish, _IO_str_finish),
 308   JUMP_INIT(overflow, _IO_str_overflow),
 309   JUMP_INIT(underflow, _IO_str_underflow),
 310   JUMP_INIT(uflow, _IO_default_uflow),
 311   JUMP_INIT(pbackfail, _IO_str_pbackfail),
 312   JUMP_INIT(xsputn, _IO_default_xsputn),
 313   JUMP_INIT(xsgetn, _IO_default_xsgetn),
 314   JUMP_INIT(seekoff, _IO_str_seekoff),
 315   JUMP_INIT(seekpos, _IO_default_seekpos),
 316   JUMP_INIT(setbuf, _IO_default_setbuf),
 317   JUMP_INIT(sync, _IO_default_sync),
 318   JUMP_INIT(doallocate, _IO_default_doallocate),
 319   JUMP_INIT(read, _IO_default_read),
 320   JUMP_INIT(write, _IO_default_write),
 321   JUMP_INIT(seek, _IO_default_seek),
 322   JUMP_INIT(close, _IO_default_close),
 323   JUMP_INIT(stat, _IO_default_stat),
 324   JUMP_INIT(showmanyc, _IO_default_showmanyc),
 325   JUMP_INIT(imbue, _IO_default_imbue)
 326 };