path: root/vobsub.c

/*
 * Some code freely inspired from VobSub <URL:http://vobsub.edensrising.com>,
 * with kind permission from Gabest <gabest@freemail.hu>
 */
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>

#include "config.h"
#include "version.h"

#include "vobsub.h"
#include "spudec.h"
#include "mp_msg.h"
#ifdef USE_UNRARLIB
#include "unrarlib.h"
#endif
#include "libavutil/common.h"

extern int vobsub_id;

/**********************************************************************
 * RAR stream handling
 * The RAR file must have the same basename as the file to open
 * See <URL:http://www.unrarlib.org/>
 **********************************************************************/
#ifdef USE_UNRARLIB
typedef struct {
    FILE *file;
    unsigned char *data;
    unsigned long size;
    unsigned long pos;
} rar_stream_t;
static rar_stream_t *
rar_open(const char *const filename, const char *const mode)
{
    rar_stream_t *stream;
    /* unrarlib can only read */
    if (strcmp("r", mode) && strcmp("rb", mode)) {
	errno = EINVAL;
	return NULL;
    }
    stream = malloc(sizeof(rar_stream_t));
    if (stream == NULL)
	return NULL;
    /* first try normal access */
    stream->file = fopen(filename, mode);
    if (stream->file == NULL) {
	char *rar_filename;
	const char *p;
	int rc;
	/* Guess the RAR archive filename */
	rar_filename = NULL;
	p = strrchr(filename, '.');
	if (p) {
	    ptrdiff_t l = p - filename;
	    rar_filename = malloc(l + 5);
	    if (rar_filename == NULL) {
		free(stream);
		return NULL;
	    }
	    strncpy(rar_filename, filename, l);
	    strcpy(rar_filename + l, ".rar");
	}
	else {
	    rar_filename = malloc(strlen(filename) + 5);
	    if (rar_filename == NULL) {
		free(stream);
		return NULL;
	    }
	    strcpy(rar_filename, filename);
	    strcat(rar_filename, ".rar");
	}
	/* get rid of the path if there is any */
	if ((p = strrchr(filename, '/')) == NULL) {
		p = filename;
	} else {
		p++;
	}
	rc = urarlib_get(&stream->data, &stream->size, (char*) p, rar_filename, "");
	if (!rc) {
	    /* There is no matching filename in the archive. However, sometimes
	     * the files we are looking for have been given arbitrary names in the archive.
	     * Let's look for a file with an exact match in the extension only. */
	    int i, num_files, name_len;
	    ArchiveList_struct *list, *lp;
	    /* the cast in the next line is a hack to overcome a design flaw (IMHO) in unrarlib */
	    num_files = urarlib_list (rar_filename, (ArchiveList_struct *)&list);
	    if (num_files > 0) {
		char *demanded_ext;
		demanded_ext = strrchr (p, '.');
		if (demanded_ext) {
		    int demanded_ext_len = strlen (demanded_ext);
	    	    for (i=0, lp=list; i<num_files; i++, lp=lp->next) {
			name_len = strlen (lp->item.Name);
			if (name_len >= demanded_ext_len && !strcasecmp (lp->item.Name + name_len - demanded_ext_len, demanded_ext)) {
		            if ((rc = urarlib_get(&stream->data, &stream->size, lp->item.Name, rar_filename, ""))) {
				break;
		   	    }
			}
		    }
		}
	    	urarlib_freelist (list);
	    }
	    if (!rc) {
		free(rar_filename);
		free(stream);
		return NULL;
	    }
	}

	free(rar_filename);
	stream->pos = 0;
    }
    return stream;
}

static int
rar_close(rar_stream_t *stream)
{
    if (stream->file)
	return fclose(stream->file);
    free(stream->data);
    return 0;
}

static int
rar_eof(rar_stream_t *stream)
{
    if (stream->file)
	return feof(stream->file);
    return stream->pos >= stream->size;
}

static long
rar_tell(rar_stream_t *stream)
{
    if (stream->file)
	return ftell(stream->file);
    return stream->pos;
}

static int
rar_seek(rar_stream_t *stream, long offset, int whence)
{
    if (stream->file)
	return fseek(stream->file, offset, whence);
    switch (whence) {
    case SEEK_SET:
	if (offset < 0) {
	    errno = EINVAL;
	    return -1;
	}
	stream->pos = offset;
	break;
    case SEEK_CUR:
	if (offset < 0 && stream->pos < (unsigned long) -offset) {
	    errno = EINVAL;
	    return -1;
	}
	stream->pos += offset;
	break;
    case SEEK_END:
	if (offset < 0 && stream->size < (unsigned long) -offset) {
	    errno = EINVAL;
	    return -1;
	}
	stream->pos = stream->size + offset;
	break;
    default:
	errno = EINVAL;
	return -1;
    }
    return 0;
}

static int
rar_getc(rar_stream_t *stream)
{
    if (stream->file)
	return getc(stream->file);
    if (rar_eof(stream))
	return EOF;
    return stream->data[stream->pos++];
}

static size_t
rar_read(void *ptr, size_t size, size_t nmemb, rar_stream_t *stream)
{
    size_t res;
    unsigned long remain;
    if (stream->file)
	return fread(ptr, size, nmemb, stream->file);
    if (rar_eof(stream))
	return 0;
    res = size * nmemb;
    remain = stream->size - stream->pos;
    if (res > remain)
	res = remain / size * size;
    memcpy(ptr, stream->data + stream->pos, res);
    stream->pos += res;
    res /= size;
    return res;
}

#else
typedef FILE rar_stream_t;
#define rar_open	fopen
#define rar_close	fclose
#define rar_eof		feof
#define rar_tell	ftell
#define rar_seek	fseek
#define rar_getc	getc
#define rar_read	fread
#endif

/**********************************************************************/

static ssize_t
vobsub_getline(char **lineptr, size_t *n, rar_stream_t *stream)
{
    size_t res = 0;
    int c;
    if (*lineptr == NULL) {
	*lineptr = malloc(4096);
	if (*lineptr)
	    *n = 4096;
    }
    else if (*n == 0) {
	char *tmp = realloc(*lineptr, 4096);
	if (tmp) {
	    *lineptr = tmp;
	    *n = 4096;
	}
    }
    if (*lineptr == NULL || *n == 0)
	return -1;

    for (c = rar_getc(stream); c != EOF; c = rar_getc(stream)) {
	if (res + 1 >= *n) {
	    char *tmp = realloc(*lineptr, *n * 2);
	    if (tmp == NULL)
		return -1;
	    *lineptr = tmp;
	    *n *= 2;
	}
	(*lineptr)[res++] = c;
	if (c == '\n') {
	    (*lineptr)[res] = 0;
	    return res;
	}
    }
    if (res == 0)
	return -1;
    (*lineptr)[res] = 0;
    return res;
}

/**********************************************************************
 * MPEG parsing
 **********************************************************************/

typedef struct {
    rar_stream_t *stream;
    unsigned int pts;
    int aid;
    unsigned char *packet;
    unsigned int packet_reserve;
    unsigned int packet_size;
} mpeg_t;

static mpeg_t *
mpeg_open(const char *filename)
{
    mpeg_t *res = malloc(sizeof(mpeg_t));
    int err = res == NULL;
    if (!err) {
	res->pts = 0;
	res->aid = -1;
	res->packet = NULL;
	res->packet_size = 0;
	res->packet_reserve = 0;
	res->stream = rar_open(filename, "rb");
	err = res->stream == NULL;
	if (err)
	    perror("fopen Vobsub file failed");
	if (err)
	    free(res);
    }
    return err ? NULL : res;
}

static void
mpeg_free(mpeg_t *mpeg)
{
    if (mpeg->packet)
	free(mpeg->packet);
    if (mpeg->stream)
	rar_close(mpeg->stream);
    free(mpeg);
}

static int
mpeg_eof(mpeg_t *mpeg)
{
    return rar_eof(mpeg->stream);
}

static off_t
mpeg_tell(mpeg_t *mpeg)
{
    return rar_tell(mpeg->stream);
}

static int
mpeg_run(mpeg_t *mpeg)
{
    unsigned int len, idx, version;
    int c;
    /* Goto start of a packet, it starts with 0x000001?? */
    const unsigned char wanted[] = { 0, 0, 1 };