/*
 * 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 "config.h"
#include "error.h"
#include "file.h"
#include "file_open.h"
#include "internal.h"
#include "log.h"
#include "mem.h"
#include <fcntl.h>
#include <sys/stat.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_IO_H
#include <io.h>
#endif
#if HAVE_MMAP
#include <sys/mman.h>
#elif HAVE_MAPVIEWOFFILE
#include <windows.h>
#endif

typedef struct FileLogContext {
 const AVClass *class;
 int log_offset;
 void *log_ctx;
} FileLogContext;

static const AVClass file_log_ctx_class = {
 .class_name = "FILE",
 .item_name = av_default_item_name,
 .option = NULL,
 .version = LIBAVUTIL_VERSION_INT,
 .log_level_offset_offset = offsetof(FileLogContext, log_offset),
 .parent_log_context_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 = avpriv_open(filename, O_RDONLY);
 struct stat st;
 av_unused void *ptr;
 off_t off_size;
 char errbuf[128];
 *bufptr = NULL;
 *size = 0;

 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 (!*size) {
 *bufptr = NULL;
 goto out;
 }

#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);
 *size = 0;
 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);
 *size = 0;
 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);
 *size = 0;
 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);
 *size = 0;
 return AVERROR(ENOMEM);
 }
 read(fd, *bufptr, *size);
#endif

out:
 close(fd);
 return 0;
}

void av_file_unmap(uint8_t *bufptr, size_t size)
{
 if (!size || !bufptr)
 return;
#if HAVE_MMAP
 munmap(bufptr, size);
#elif HAVE_MAPVIEWOFFILE
 UnmapViewOfFile(bufptr);
#else
 av_free(bufptr);
#endif
}