libio/strops.c

   1 /* Copyright (C) 1993-2016 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, see
  16    <http://www.gnu.org/licenses/>.
  17
  18    As a special exception, if you link the code in this file with
  19    files compiled with a GNU compiler to produce an executable,
  20    that does not cause the resulting executable to be covered by
  21    the GNU Lesser General Public License.  This exception does not
  22    however invalidate any other reasons why the executable file
  23    might be covered by the GNU Lesser General Public License.
  24    This exception applies to code released by its copyright holders
  25    in files containing the exception.  */
  26
  27 #include <assert.h>
  28 #include "strfile.h"
  29 #include "libioP.h"
  30 #include <string.h>
  31 #include <stdio_ext.h>
  32
  33 void
  34 _IO_str_init_static_internal (_IO_strfile *sf, char *ptr, _IO_size_t size,
  35                               char *pstart)
  36 {
  37   _IO_FILE *fp = &sf->_sbf._f;
  38   char *end;
  39
  40   if (size == 0)
  41     end = __rawmemchr (ptr, '\0');
  42   else if ((_IO_size_t) ptr + size > (_IO_size_t) ptr)
  43     end = ptr + size;
  44   else
  45     end = (char *) -1;
  46   _IO_setb (fp, ptr, end, 0);
  47
  48   fp->_IO_write_base = ptr;
  49   fp->_IO_read_base = ptr;
  50   fp->_IO_read_ptr = ptr;
  51   if (pstart)
  52     {
  53       fp->_IO_write_ptr = pstart;
  54       fp->_IO_write_end = end;
  55       fp->_IO_read_end = pstart;
  56     }
  57   else
  58     {
  59       fp->_IO_write_ptr = ptr;
  60       fp->_IO_write_end = ptr;
  61       fp->_IO_read_end = end;
  62     }
  63   /* A null _allocate_buffer function flags the strfile as being static. */
  64   sf->_s._allocate_buffer = (_IO_alloc_type) 0;
  65 }
  66
  67 void
  68 _IO_str_init_static (_IO_strfile *sf, char *ptr, int size, char *pstart)
  69 {
  70   return _IO_str_init_static_internal (sf, ptr, size < 0 ? -1 : size, pstart);
  71 }
  72
  73 void
  74 _IO_str_init_readonly (_IO_strfile *sf, const char *ptr, int size)
  75 {
  76   _IO_str_init_static_internal (sf, (char *) ptr, size < 0 ? -1 : size, NULL);
  77   sf->_sbf._f._IO_file_flags |= _IO_NO_WRITES;
  78 }
  79
  80 int
  81 _IO_str_overflow (_IO_FILE *fp, int c)
  82 {
  83   int flush_only = c == EOF;
  84   _IO_size_t pos;
  85   if (fp->_flags & _IO_NO_WRITES)
  86       return flush_only ? 0 : EOF;
  87   if ((fp->_flags & _IO_TIED_PUT_GET) && !(fp->_flags & _IO_CURRENTLY_PUTTING))
  88     {
  89       fp->_flags |= _IO_CURRENTLY_PUTTING;
  90       fp->_IO_write_ptr = fp->_IO_read_ptr;
  91       fp->_IO_read_ptr = fp->_IO_read_end;
  92     }
  93   pos = fp->_IO_write_ptr - fp->_IO_write_base;
  94   if (pos >= (_IO_size_t) (_IO_blen (fp) + flush_only))
  95     {
  96       if (fp->_flags & _IO_USER_BUF) /* not allowed to enlarge */
  97         return EOF;
  98       else
  99         {
 100           char *new_buf;
 101           char *old_buf = fp->_IO_buf_base;
 102           size_t old_blen = _IO_blen (fp);
 103           _IO_size_t new_size = 2 * old_blen + 100;
 104           if (new_size < old_blen)
 105             return EOF;
 106           new_buf
 107             = (char *) (*((_IO_strfile *) fp)->_s._allocate_buffer) (new_size);
 108           if (new_buf == NULL)
 109             {
 110               /*          __ferror(fp) = 1; */
 111               return EOF;
 112             }
 113           if (old_buf)
 114             {
 115               memcpy (new_buf, old_buf, old_blen);
 116               (*((_IO_strfile *) fp)->_s._free_buffer) (old_buf);
 117               /* Make sure _IO_setb won't try to delete _IO_buf_base. */
 118               fp->_IO_buf_base = NULL;
 119             }
 120           memset (new_buf + old_blen, '\0', new_size - old_blen);
 121
 122           _IO_setb (fp, new_buf, new_buf + new_size, 1);
 123           fp->_IO_read_base = new_buf + (fp->_IO_read_base - old_buf);
 124           fp->_IO_read_ptr = new_buf + (fp->_IO_read_ptr - old_buf);
 125           fp->_IO_read_end = new_buf + (fp->_IO_read_end - old_buf);
 126           fp->_IO_write_ptr = new_buf + (fp->_IO_write_ptr - old_buf);
 127
 128           fp->_IO_write_base = new_buf;
 129           fp->_IO_write_end = fp->_IO_buf_end;
 130         }
 131     }
 132
 133   if (!flush_only)
 134     *fp->_IO_write_ptr++ = (unsigned char) c;
 135   if (fp->_IO_write_ptr > fp->_IO_read_end)
 136     fp->_IO_read_end = fp->_IO_write_ptr;
 137   return c;
 138 }
 139 libc_hidden_def (_IO_str_overflow)
 140
 141 int
 142 _IO_str_underflow (_IO_FILE *fp)
 143 {
 144   if (fp->_IO_write_ptr > fp->_IO_read_end)
 145     fp->_IO_read_end = fp->_IO_write_ptr;
 146   if ((fp->_flags & _IO_TIED_PUT_GET) && (fp->_flags & _IO_CURRENTLY_PUTTING))
 147     {
 148       fp->_flags &= ~_IO_CURRENTLY_PUTTING;
 149       fp->_IO_read_ptr = fp->_IO_write_ptr;
 150       fp->_IO_write_ptr = fp->_IO_write_end;
 151     }
 152   if (fp->_IO_read_ptr < fp->_IO_read_end)
 153     return *((unsigned char *) fp->_IO_read_ptr);
 154   else
 155     return EOF;
 156 }
 157 libc_hidden_def (_IO_str_underflow)
 158
 159 /* The size of the valid part of the buffer.  */
 160
 161 _IO_ssize_t
 162 _IO_str_count (_IO_FILE *fp)
 163 {
 164   return ((fp->_IO_write_ptr > fp->_IO_read_end
 165            ? fp->_IO_write_ptr : fp->_IO_read_end)
 166           - fp->_IO_read_base);
 167 }
 168
 169
 170 static int
 171 enlarge_userbuf (_IO_FILE *fp, _IO_off64_t offset, int reading)
 172 {
 173   if ((_IO_ssize_t) offset <= _IO_blen (fp))
 174     return 0;
 175
 176   _IO_ssize_t oldend = fp->_IO_write_end - fp->_IO_write_base;
 177
 178   /* Try to enlarge the buffer.  */
 179   if (fp->_flags & _IO_USER_BUF)
 180     /* User-provided buffer.  */
 181     return 1;
 182
 183   _IO_size_t newsize = offset + 100;
 184   char *oldbuf = fp->_IO_buf_base;
 185   char *newbuf
 186     = (char *) (*((_IO_strfile *) fp)->_s._allocate_buffer) (newsize);
 187   if (newbuf == NULL)
 188     return 1;
 189
 190   if (oldbuf != NULL)
 191     {
 192       memcpy (newbuf, oldbuf, _IO_blen (fp));
 193       (*((_IO_strfile *) fp)->_s._free_buffer) (oldbuf);
 194       /* Make sure _IO_setb won't try to delete
 195          _IO_buf_base. */
 196       fp->_IO_buf_base = NULL;
 197     }
 198
 199   _IO_setb (fp, newbuf, newbuf + newsize, 1);
 200
 201   if (reading)
 202     {
 203       fp->_IO_write_base = newbuf + (fp->_IO_write_base - oldbuf);
 204       fp->_IO_write_ptr = newbuf + (fp->_IO_write_ptr - oldbuf);
 205       fp->_IO_write_end = newbuf + (fp->_IO_write_end - oldbuf);
 206       fp->_IO_read_ptr = newbuf + (fp->_IO_read_ptr - oldbuf);
 207
 208       fp->_IO_read_base = newbuf;
 209       fp->_IO_read_end = fp->_IO_buf_end;
 210     }
 211   else
 212     {
 213       fp->_IO_read_base = newbuf + (fp->_IO_read_base - oldbuf);
 214       fp->_IO_read_ptr = newbuf + (fp->_IO_read_ptr - oldbuf);
 215       fp->_IO_read_end = newbuf + (fp->_IO_read_end - oldbuf);
 216       fp->_IO_write_ptr = newbuf + (fp->_IO_write_ptr - oldbuf);
 217
 218       fp->_IO_write_base = newbuf;
 219       fp->_IO_write_end = fp->_IO_buf_end;
 220     }
 221
 222   /* Clear the area between the last write position and th
 223      new position.  */
 224   assert (offset >= oldend);
 225   if (reading)
 226     memset (fp->_IO_read_base + oldend, '\0', offset - oldend);
 227   else
 228     memset (fp->_IO_write_base + oldend, '\0', offset - oldend);
 229
 230   return 0;
 231 }
 232
 233
 234 _IO_off64_t
 235 _IO_str_seekoff (_IO_FILE *fp, _IO_off64_t offset, int dir, int mode)
 236 {
 237   _IO_off64_t new_pos;
 238
 239   if (mode == 0 && (fp->_flags & _IO_TIED_PUT_GET))
 240     mode = (fp->_flags & _IO_CURRENTLY_PUTTING ? _IOS_OUTPUT : _IOS_INPUT);
 241
 242   if (mode == 0)
 243     {
 244       /* Don't move any pointers. But there is no clear indication what
 245          mode FP is in. Let's guess. */
 246       if (fp->_IO_file_flags & _IO_NO_WRITES)
 247         new_pos = fp->_IO_read_ptr - fp->_IO_read_base;
 248       else
 249         new_pos = fp->_IO_write_ptr - fp->_IO_write_base;
 250     }
 251   else
 252     {
 253       _IO_ssize_t cur_size = _IO_str_count(fp);
 254       new_pos = EOF;
 255
 256       /* Move the get pointer, if requested. */
 257       if (mode & _IOS_INPUT)
 258         {
 259           switch (dir)
 260             {
 261             case _IO_seek_end:
 262               offset += cur_size;
 263               break;
 264             case _IO_seek_cur:
 265               offset += fp->_IO_read_ptr - fp->_IO_read_base;
 266               break;
 267             default: /* case _IO_seek_set: */
 268               break;
 269             }
 270           if (offset < 0)
 271             return EOF;
 272           if ((_IO_ssize_t) offset > cur_size
 273               && enlarge_userbuf (fp, offset, 1) != 0)
 274             return EOF;
 275           fp->_IO_read_ptr = fp->_IO_read_base + offset;
 276           fp->_IO_read_end = fp->_IO_read_base + cur_size;
 277           new_pos = offset;
 278         }
 279
 280       /* Move the put pointer, if requested. */
 281       if (mode & _IOS_OUTPUT)
 282         {
 283           switch (dir)
 284             {
 285             case _IO_seek_end:
 286               offset += cur_size;
 287               break;
 288             case _IO_seek_cur:
 289               offset += fp->_IO_write_ptr - fp->_IO_write_base;
 290               break;
 291             default: /* case _IO_seek_set: */
 292               break;
 293             }
 294           if (offset < 0)
 295             return EOF;
 296           if ((_IO_ssize_t) offset > cur_size
 297               && enlarge_userbuf (fp, offset, 0) != 0)
 298             return EOF;
 299           fp->_IO_write_ptr = fp->_IO_write_base + offset;
 300           new_pos = offset;
 301         }
 302     }
 303   return new_pos;
 304 }
 305 libc_hidden_def (_IO_str_seekoff)
 306
 307 int
 308 _IO_str_pbackfail (_IO_FILE *fp, int c)
 309 {
 310   if ((fp->_flags & _IO_NO_WRITES) && c != EOF)
 311     return EOF;
 312   return _IO_default_pbackfail (fp, c);
 313 }
 314 libc_hidden_def (_IO_str_pbackfail)
 315
 316 void
 317 _IO_str_finish (_IO_FILE *fp, int dummy)
 318 {
 319   if (fp->_IO_buf_base && !(fp->_flags & _IO_USER_BUF))
 320     (((_IO_strfile *) fp)->_s._free_buffer) (fp->_IO_buf_base);
 321   fp->_IO_buf_base = NULL;
 322
 323   _IO_default_finish (fp, 0);
 324 }
 325
 326 const struct _IO_jump_t _IO_str_jumps =
 327 {
 328   JUMP_INIT_DUMMY,
 329   JUMP_INIT(finish, _IO_str_finish),
 330   JUMP_INIT(overflow, _IO_str_overflow),
 331   JUMP_INIT(underflow, _IO_str_underflow),
 332   JUMP_INIT(uflow, _IO_default_uflow),
 333   JUMP_INIT(pbackfail, _IO_str_pbackfail),
 334   JUMP_INIT(xsputn, _IO_default_xsputn),
 335   JUMP_INIT(xsgetn, _IO_default_xsgetn),
 336   JUMP_INIT(seekoff, _IO_str_seekoff),
 337   JUMP_INIT(seekpos, _IO_default_seekpos),
 338   JUMP_INIT(setbuf, _IO_default_setbuf),
 339   JUMP_INIT(sync, _IO_default_sync),
 340   JUMP_INIT(doallocate, _IO_default_doallocate),
 341   JUMP_INIT(read, _IO_default_read),
 342   JUMP_INIT(write, _IO_default_write),
 343   JUMP_INIT(seek, _IO_default_seek),
 344   JUMP_INIT(close, _IO_default_close),
 345   JUMP_INIT(stat, _IO_default_stat),
 346   JUMP_INIT(showmanyc, _IO_default_showmanyc),
 347   JUMP_INIT(imbue, _IO_default_imbue)
 348 };