/*
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include "file.h"
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <unistd.h>
 #if HAVE_MMAP
 #include <sys/mman.h>

 #elif HAVE_MAPVIEWOFFILE
 #include <io.h>
 #include <windows.h>

 #endif
 
 typedef struct {
     const AVClass *class;
     int   log_offset;
     void *log_ctx;
 } FileLogContext;
 
 static const AVClass file_log_ctx_class = {
     "FILE", av_default_item_name, NULL, LIBAVUTIL_VERSION_INT,
     offsetof(FileLogContext, log_offset), offsetof(FileLogContext, log_ctx)
 };
 
 int av_file_map(const char *filename, uint8_t **bufptr, size_t *size,
                 int log_offset, void *log_ctx)
 {
     FileLogContext file_log_ctx = { &file_log_ctx_class, log_offset, log_ctx };
     int err, fd = open(filename, O_RDONLY);
     struct stat st;
     av_unused void *ptr;
     off_t off_size;
     char errbuf[128];
     *bufptr = NULL;
 
     if (fd < 0) {
         err = AVERROR(errno);
         av_strerror(err, errbuf, sizeof(errbuf));
         av_log(&file_log_ctx, AV_LOG_ERROR, "Cannot read file '%s': %s\n", filename, errbuf);
         return err;
     }
 

     if (fstat(fd, &st) < 0) {

         err = AVERROR(errno);
         av_strerror(err, errbuf, sizeof(errbuf));

         av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in fstat(): %s\n", errbuf);

         close(fd);
         return err;
     }
 
     off_size = st.st_size;

     if (off_size > SIZE_MAX) {

         av_log(&file_log_ctx, AV_LOG_ERROR,
                "File size for file '%s' is too big\n", filename);
         close(fd);
         return AVERROR(EINVAL);
     }
     *size = off_size;
 
 #if HAVE_MMAP
     ptr = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);

     if (ptr == MAP_FAILED) {

         err = AVERROR(errno);
         av_strerror(err, errbuf, sizeof(errbuf));
         av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in mmap(): %s\n", errbuf);
         close(fd);
         return err;
     }
     *bufptr = ptr;

 #elif HAVE_MAPVIEWOFFILE
     {
         HANDLE mh, fh = (HANDLE)_get_osfhandle(fd);
 
         mh = CreateFileMapping(fh, NULL, PAGE_READONLY, 0, 0, NULL);
         if (!mh) {
             av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in CreateFileMapping()\n");
             close(fd);
             return -1;
         }
 
         ptr = MapViewOfFile(mh, FILE_MAP_READ, 0, 0, *size);
         CloseHandle(mh);
         if (!ptr) {
             av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in MapViewOfFile()\n");
             close(fd);
             return -1;
         }
 
         *bufptr = ptr;
     }

 #else
     *bufptr = av_malloc(*size);
     if (!*bufptr) {
         av_log(&file_log_ctx, AV_LOG_ERROR, "Memory allocation error occurred\n");
         close(fd);
         return AVERROR(ENOMEM);
     }
     read(fd, *bufptr, *size);
 #endif
 
     close(fd);
     return 0;
 }
 
 void av_file_unmap(uint8_t *bufptr, size_t size)
 {
 #if HAVE_MMAP
     munmap(bufptr, size);

 #elif HAVE_MAPVIEWOFFILE
     UnmapViewOfFile(bufptr);

 #else
     av_free(bufptr);
 #endif
 }
 
 #ifdef TEST
 
 #undef printf
 
 int main(void)
 {
     uint8_t *buf;
     size_t size;
     if (av_file_map("file.c", &buf, &size, 0, NULL) < 0)
         return 1;
 
     buf[0] = 's';
     printf("%s", buf);
     av_file_unmap(buf, size);
     return 0;
 }
 #endif