libopenmpt_stream_callbacks_file_posix.h

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/*
 * libopenmpt_stream_callbacks_file_posix.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_FILE_POSIX_H
#define LIBOPENMPT_STREAM_CALLBACKS_FILE_POSIX_H
 
#include "libopenmpt.h"
 
#include <stdint.h>
#include <stdio.h>
#include <string.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
static size_t openmpt_stream_file_posix_read_func( void * stream, void * dst, size_t bytes ) {
  FILE * f = 0;
  size_t retval = 0;
  f = (FILE*)stream;
  if ( !f ) {
    return 0;
  }
  retval = fread( dst, 1, bytes, f );
  if ( retval <= 0 ) {
    return 0;
  }
  return retval;
}
 
static int openmpt_stream_file_posix_seek_func( void * stream, int64_t offset, int whence ) {
  FILE * f = 0;
  int fwhence = 0;
  f = (FILE*)stream;
  if ( !f ) {
    return -1;
  }
  switch ( whence ) {
    case OPENMPT_STREAM_SEEK_SET:
      fwhence = SEEK_SET;
      break;
    case OPENMPT_STREAM_SEEK_CUR:
      fwhence = SEEK_CUR;
      break;
    case OPENMPT_STREAM_SEEK_END:
      fwhence = SEEK_END;
      break;
    default:
      return -1;
      break;
  }
  if ( (off_t)offset != offset ) {
    return -1;
  }
  return fseeko( f, (off_t)offset, fwhence ) ? -1 : 0;
}
 
static int64_t openmpt_stream_file_posix_tell_func( void * stream ) {
  FILE * f = 0;
  off_t result = 0;
  int64_t retval = 0;
  f = (FILE*)stream;
  if ( !f ) {
    return -1;
  }
  result = ftello( f );
  if ( (int64_t)result != result ) {
    return -1;
  }
  retval = (int64_t)result;
  if ( retval < 0 ) {
    return -1;
  }
  return retval;
}
 
static openmpt_stream_callbacks openmpt_stream_get_file_posix_callbacks(void) {
  openmpt_stream_callbacks retval;
  memset( &retval, 0, sizeof( openmpt_stream_callbacks ) );
  retval.read = openmpt_stream_file_posix_read_func;
  retval.seek = openmpt_stream_file_posix_seek_func;
  retval.tell = openmpt_stream_file_posix_tell_func;
  return retval;
}
 
#ifdef __cplusplus
}
#endif
 
#endif /* LIBOPENMPT_STREAM_CALLBACKS_FILE_POSIX_H */