/*

  * buffered file I/O

  * Copyright (c) 2001 Fabrice Bellard

  *

  * 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 "libavutil/avstring.h"

 #include "libavutil/internal.h"

 #include "libavutil/opt.h"

 #include "avformat.h"

 #include <fcntl.h>

 #if HAVE_IO_H

 #include <io.h>
 #endif

 #if HAVE_UNISTD_H

 #include <unistd.h>

 #endif

 #include <sys/stat.h>

 #include <stdlib.h>

 #include "os_support.h"

 #include "url.h"

 /* Some systems may not have S_ISFIFO */
 #ifndef S_ISFIFO
 #  ifdef S_IFIFO
 #    define S_ISFIFO(m) (((m) & S_IFMT) == S_IFIFO)
 #  else
 #    define S_ISFIFO(m) 0
 #  endif
 #endif

 
 /* standard file protocol */
 

 typedef struct FileContext {

     const AVClass *class;

     int fd;

     int trunc;

     int blocksize;

 } FileContext;
 

 static const AVOption file_options[] = {

     { "truncate", "truncate existing files on write", offsetof(FileContext, trunc), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, AV_OPT_FLAG_ENCODING_PARAM },

     { "blocksize", "set I/O operation maximum block size", offsetof(FileContext, blocksize), AV_OPT_TYPE_INT, { .i64 = INT_MAX }, 1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
     { NULL }
 };
 
 static const AVOption pipe_options[] = {
     { "blocksize", "set I/O operation maximum block size", offsetof(FileContext, blocksize), AV_OPT_TYPE_INT, { .i64 = INT_MAX }, 1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },

     { NULL }
 };
 
 static const AVClass file_class = {
     .class_name = "file",
     .item_name  = av_default_item_name,
     .option     = file_options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 static const AVClass pipe_class = {
     .class_name = "pipe",
     .item_name  = av_default_item_name,
     .option     = pipe_options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 static int file_read(URLContext *h, unsigned char *buf, int size)
 {

     FileContext *c = h->priv_data;

     int r;
     size = FFMIN(size, c->blocksize);
     r = read(c->fd, buf, size);

     return (-1 == r)?AVERROR(errno):r;

 }
 
 static int file_write(URLContext *h, const unsigned char *buf, int size)
 {

     FileContext *c = h->priv_data;

     int r;
     size = FFMIN(size, c->blocksize);
     r = write(c->fd, buf, size);

     return (-1 == r)?AVERROR(errno):r;

 }
 
 static int file_get_handle(URLContext *h)
 {

     FileContext *c = h->priv_data;
     return c->fd;

 }
 

 static int file_check(URLContext *h, int mask)
 {

     int ret = 0;

     const char *filename = h->filename;
     av_strstart(filename, "file:", &filename);
 
     {
 #if HAVE_ACCESS && defined(R_OK)
     if (access(filename, F_OK) < 0)

         return AVERROR(errno);

     if (mask&AVIO_FLAG_READ)

         if (access(filename, R_OK) >= 0)

             ret |= AVIO_FLAG_READ;
     if (mask&AVIO_FLAG_WRITE)

         if (access(filename, W_OK) >= 0)

             ret |= AVIO_FLAG_WRITE;

 #else
     struct stat st;

     ret = stat(filename, &st);

     if (ret < 0)
         return AVERROR(errno);
 
     ret |= st.st_mode&S_IRUSR ? mask&AVIO_FLAG_READ  : 0;
     ret |= st.st_mode&S_IWUSR ? mask&AVIO_FLAG_WRITE : 0;
 #endif

     }

     return ret;
 }
 

 #if CONFIG_FILE_PROTOCOL
 

 static int file_open(URLContext *h, const char *filename, int flags)
 {

     FileContext *c = h->priv_data;

     int access;
     int fd;

     struct stat st;

     av_strstart(filename, "file:", &filename);

     if (flags & AVIO_FLAG_WRITE && flags & AVIO_FLAG_READ) {

         access = O_CREAT | O_RDWR;
         if (c->trunc)
             access |= O_TRUNC;

     } else if (flags & AVIO_FLAG_WRITE) {

         access = O_CREAT | O_WRONLY;
         if (c->trunc)
             access |= O_TRUNC;

     } else {
         access = O_RDONLY;
     }

 #ifdef O_BINARY

     access |= O_BINARY;
 #endif

     fd = avpriv_open(filename, access, 0666);

     if (fd == -1)

         return AVERROR(errno);

     c->fd = fd;

     h->is_streamed = !fstat(fd, &st) && S_ISFIFO(st.st_mode);

     return 0;
 }
 
 /* XXX: use llseek */

 static int64_t file_seek(URLContext *h, int64_t pos, int whence)

 {

     FileContext *c = h->priv_data;

     int64_t ret;

     if (whence == AVSEEK_SIZE) {
         struct stat st;

         ret = fstat(c->fd, &st);

         return ret < 0 ? AVERROR(errno) : (S_ISFIFO(st.st_mode) ? 0 : st.st_size);

     }

 
     ret = lseek(c->fd, pos, whence);
 
     return ret < 0 ? AVERROR(errno) : ret;

 }
 
 static int file_close(URLContext *h)
 {

     FileContext *c = h->priv_data;
     return close(c->fd);

 }
 

 URLProtocol ff_file_protocol = {

     .name                = "file",
     .url_open            = file_open,
     .url_read            = file_read,
     .url_write           = file_write,
     .url_seek            = file_seek,
     .url_close           = file_close,

     .url_get_file_handle = file_get_handle,

     .url_check           = file_check,

     .priv_data_size      = sizeof(FileContext),

     .priv_data_class     = &file_class,

 };
 

 #endif /* CONFIG_FILE_PROTOCOL */
 
 #if CONFIG_PIPE_PROTOCOL

 
 static int pipe_open(URLContext *h, const char *filename, int flags)
 {

     FileContext *c = h->priv_data;

     int fd;

     char *final;

     av_strstart(filename, "pipe:", &filename);

     fd = strtol(filename, &final, 10);
     if((filename == final) || *final ) {/* No digits found, or something like 10ab */

         if (flags & AVIO_FLAG_WRITE) {

             fd = 1;
         } else {
             fd = 0;
         }

     }

 #if HAVE_SETMODE

     setmode(fd, O_BINARY);
 #endif

     c->fd = fd;

     h->is_streamed = 1;

     return 0;
 }
 

 URLProtocol ff_pipe_protocol = {

     .name                = "pipe",
     .url_open            = pipe_open,
     .url_read            = file_read,
     .url_write           = file_write,

     .url_get_file_handle = file_get_handle,

     .url_check           = file_check,

     .priv_data_size      = sizeof(FileContext),

     .priv_data_class     = &pipe_class,

 };

 
 #endif /* CONFIG_PIPE_PROTOCOL */