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 libc_hidden_proto(fread_unlocked)
  11
  12 #ifdef __DO_UNLOCKED
  13
  14 libc_hidden_proto(memcpy)
  15 libc_hidden_proto(fflush_unlocked)
  16
  17 size_t fread_unlocked(void * __restrict ptr, size_t size, size_t nmemb,
  18                                                 FILE * __restrict stream)
  19 {
  20         __STDIO_STREAM_VALIDATE(stream);
  21         assert(stream->__filedes >= -1);
  22
  23         /* Note: If nmbem * size > SIZE_MAX then there is an application
  24          * bug since no array can be larger than SIZE_MAX in size. */
  25
  26         if ((__STDIO_STREAM_IS_NARROW_READING(stream)
  27                  || !__STDIO_STREAM_TRANS_TO_READ(stream, __FLAG_NARROW))
  28                 && size && nmemb
  29                 ) {
  30
  31                 if (nmemb <= (SIZE_MAX / size)) {
  32                         unsigned char *buffer = (unsigned char *) ptr;
  33                         size_t todo, bytes, avail;
  34
  35                         todo = bytes = size * nmemb;
  36
  37                         /* Check for ungots... */
  38                         while (stream->__modeflags & __FLAG_UNGOT) {
  39                                 *buffer++ = stream->__ungot[(stream->__modeflags--) & 1];
  40                                 stream->__ungot[1] = 0;
  41                                 if (!--todo) {
  42                                         goto DONE;
  43                                 }
  44                         }
  45
  46 #ifdef __STDIO_BUFFERS
  47                         /* Next check for available buffered... */
  48                         if ((avail = stream->__bufread - stream->__bufpos) > 0) {
  49                                 if (avail > todo) {
  50                                         avail = todo;
  51                                 }
  52                                 memcpy(buffer, stream->__bufpos, avail);
  53                                 buffer += avail;
  54                                 stream->__bufpos += avail;
  55                                 if (!(todo -= avail)) {
  56                                         goto DONE;
  57                                 }
  58                         }
  59
  60                         /* We need to read from the host environment, so we must
  61                          * flush all line buffered streams if the stream is not
  62                          * fully buffered. */
  63                         if (!__STDIO_STREAM_IS_FBF(stream)) {
  64                                 __STDIO_FLUSH_LBF_STREAMS;
  65                         }
  66 #endif
  67
  68 #ifdef __UCLIBC_MJN3_ONLY__
  69 #warning CONSIDER: should we refill and read from the buffer sometimes?
  70 #endif
  71                         while ((avail = __stdio_READ(stream, buffer, todo)) > 0) {
  72                                 buffer += avail;
  73                                 if (!(todo -= avail)) {
  74                                         break;
  75                                 }
  76                         }
  77
  78                 DONE:
  79                         __STDIO_STREAM_VALIDATE(stream);
  80                         return (bytes - todo) / size;
  81                 }
  82
  83                 __STDIO_STREAM_SET_ERROR(stream);
  84                 __set_errno(EINVAL);
  85         }
  86
  87         __STDIO_STREAM_VALIDATE(stream);
  88         return 0;
  89 }
  90 libc_hidden_def(fread_unlocked)
  91
  92 #ifndef __UCLIBC_HAS_THREADS__
  93 strong_alias(fread_unlocked,fread)
  94 libc_hidden_proto(fread)
  95 libc_hidden_def(fread)
  96 #endif
  97
  98 #elif defined __UCLIBC_HAS_THREADS__
  99
 100 size_t fread(void * __restrict ptr, size_t size, size_t nmemb,
 101                          register FILE * __restrict stream)
 102 {
 103         size_t retval;
 104         __STDIO_AUTO_THREADLOCK_VAR;
 105
 106         __STDIO_AUTO_THREADLOCK(stream);
 107
 108         retval = fread_unlocked(ptr, size, nmemb, stream);
 109
 110         __STDIO_AUTO_THREADUNLOCK(stream);
 111
 112         return retval;
 113 }
 114 libc_hidden_proto(fread)
 115 libc_hidden_def(fread)
 116
 117 #endif