libc/stdio/fread.c

   1 /* Copyright (C) 2004       Manuel Novoa III    <mjn3@codepoet.org>
   2  *
   3  * GNU Library General Public License (LGPL) version 2 or later.
   4  *
   5  * Dedicated to Toni.  See uClibc/DEDICATION.mjn3 for details.
   6  */
   7
   8 #include "_stdio.h"
   9
  10
  11 #ifdef __DO_UNLOCKED
  12
  13
  14 size_t fread_unlocked(void * __restrict ptr, size_t size, size_t nmemb,
  15                                                 FILE * __restrict stream)
  16 {
  17         __STDIO_STREAM_VALIDATE(stream);
  18         assert(stream->__filedes >= -1);
  19
  20         /* Note: If nmbem * size > SIZE_MAX then there is an application
  21          * bug since no array can be larger than SIZE_MAX in size. */
  22
  23         if ((__STDIO_STREAM_IS_NARROW_READING(stream)
  24                  || !__STDIO_STREAM_TRANS_TO_READ(stream, __FLAG_NARROW))
  25                 && size && nmemb
  26                 ) {
  27
  28                 if (nmemb <= (SIZE_MAX / size)) {
  29                         unsigned char *buffer = (unsigned char *) ptr;
  30                         size_t todo, bytes, avail;
  31
  32                         todo = bytes = size * nmemb;
  33
  34                         /* Check for ungots... */
  35                         while (stream->__modeflags & __FLAG_UNGOT) {
  36                                 *buffer++ = stream->__ungot[(stream->__modeflags--) & 1];
  37                                 stream->__ungot[1] = 0;
  38                                 if (!--todo) {
  39                                         goto DONE;
  40                                 }
  41                         }
  42
  43 #ifdef __STDIO_BUFFERS
  44                         /* Next check for available buffered... */
  45                         if ((avail = stream->__bufread - stream->__bufpos) > 0) {
  46                                 if (avail > todo) {
  47                                         avail = todo;
  48                                 }
  49                                 memcpy(buffer, stream->__bufpos, avail);
  50                                 buffer += avail;
  51                                 stream->__bufpos += avail;
  52                                 if (!(todo -= avail)) {
  53                                         goto DONE;
  54                                 }
  55                         }
  56
  57                         /* We need to read from the host environment, so we must
  58                          * flush all line buffered streams if the stream is not
  59                          * fully buffered. */
  60                         if (!__STDIO_STREAM_IS_FBF(stream)) {
  61                                 __STDIO_FLUSH_LBF_STREAMS;
  62                         }
  63 #endif
  64                         while ((avail = __stdio_READ(stream, buffer, todo)) > 0) {
  65                                 buffer += avail;
  66                                 if (!(todo -= avail)) {
  67                                         break;
  68                                 }
  69                         }
  70
  71                 DONE:
  72                         __STDIO_STREAM_VALIDATE(stream);
  73                         return (bytes - todo) / size;
  74                 }
  75
  76                 __STDIO_STREAM_SET_ERROR(stream);
  77                 __set_errno(EINVAL);
  78         }
  79
  80         __STDIO_STREAM_VALIDATE(stream);
  81         return 0;
  82 }
  83 libc_hidden_def(fread_unlocked)
  84
  85 #ifndef __UCLIBC_HAS_THREADS__
  86 strong_alias(fread_unlocked,fread)
  87 libc_hidden_def(fread)
  88 #endif
  89
  90 #elif defined __UCLIBC_HAS_THREADS__
  91
  92 size_t fread(void * __restrict ptr, size_t size, size_t nmemb,
  93                          register FILE * __restrict stream)
  94 {
  95         size_t retval;
  96         __STDIO_AUTO_THREADLOCK_VAR;
  97
  98         __STDIO_AUTO_THREADLOCK(stream);
  99
 100         retval = fread_unlocked(ptr, size, nmemb, stream);
 101
 102         __STDIO_AUTO_THREADUNLOCK(stream);
 103
 104         return retval;
 105 }
 106 libc_hidden_def(fread)
 107
 108 #endif