libopenmpt_stream_callbacks_fd.h

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/*
 * libopenmpt_stream_callbacks_fd.h
 * --------------------------------
 * Purpose: libopenmpt public c interface
 * Notes  : (currently none)
 * Authors: OpenMPT Devs
 * The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
 */
 
#ifndef LIBOPENMPT_STREAM_CALLBACKS_FD_H
#define LIBOPENMPT_STREAM_CALLBACKS_FD_H
 
#include "libopenmpt.h"
 
#ifndef _MSC_VER
#include <errno.h>
#endif
#ifdef _MSC_VER
#include <io.h>
#endif
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#ifndef _MSC_VER
#include <unistd.h>
#endif
 
#ifdef __cplusplus
extern "C" {
#endif
 
/* This stuff has to be in a header file because of possibly different MSVC CRTs which cause problems for fd crossing CRT boundaries. */
 
static size_t openmpt_stream_fd_read_func( void * stream, void * dst, size_t bytes ) {
  int fd = 0;
  #if defined(_MSC_VER)
    size_t retval = 0;
    int to_read = 0;
    int ret_read = 0;
  #else
    ssize_t retval = 0;
  #endif
  fd = (int)(uintptr_t)stream;
  if ( fd < 0 ) {
    return 0;
  }
  #if defined(_MSC_VER)
    retval = 0;
    while ( bytes > 0 ) {
      to_read = 0;
      if ( bytes < (size_t)INT_MAX ) {
        to_read = (int)bytes;
      } else {
        to_read = INT_MAX;
      }
      ret_read = _read( fd, dst, to_read );
      if ( ret_read <= 0 ) {
        return retval;
      }
      bytes -= ret_read;
      retval += ret_read;
    }
  #else
    do {
      retval = read( fd, dst, bytes );
    } while ( ( retval == -1 ) && ( errno == EINTR ) );
  #endif
  if ( retval <= 0 ) {
    return 0;
  }
  return retval;
}
 
static openmpt_stream_callbacks openmpt_stream_get_fd_callbacks(void) {
  openmpt_stream_callbacks retval;
  memset( &retval, 0, sizeof( openmpt_stream_callbacks ) );
  retval.read = openmpt_stream_fd_read_func;
  return retval;
}
 
#ifdef __cplusplus
}
#endif
 
#endif /* LIBOPENMPT_STREAM_CALLBACKS_FD_H */