mpv/subreader.c

/*
 * Subtitle reader with format autodetection
 *
 * Written by laaz
 * Some code cleanup & realloc() by A'rpi/ESP-team
 */


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "subreader.h"

#define ERR (void *)-1


int sub_uses_time=0;
int sub_errs=0;
int sub_num=0;          // number of subtitle structs
int sub_format=-1;     // 0 for microdvd
		      // 1 for SubRip
		     // 2 for the third format (what's this?)
		    // 3 for SAMI (smi)

int eol(char p) {
    return (p=='\r' || p=='\n' || p=='\0');
}

static inline void trail_space(char *s) {
	int i;
	while (isspace(*s)) strcpy(s, s + 1);
	i = strlen(s) - 1;
	while (i > 0 && isspace(s[i])) s[i--] = '\0';
}

subtitle *sub_read_line_sami(FILE *fd, subtitle *current) {
    static char line[1001];
    static char *s = NULL;
    char text[1000], *p, *q;
    int state;

    current->lines = current->start = current->end = 0;
    state = 0;

    /* read the first line */
    if (!s)
	    if (!(s = fgets(line, 1000, fd))) return 0;

    do {
	switch (state) {

	case 0: /* find "START=" */
	    s = strstr (s, "Start=");
	    if (s) {
		current->start = strtol (s + 6, &s, 0) / 10;
		state = 1; continue;
	    }
	    break;
 
	case 1: /* find "<P" */
	    if ((s = strstr (s, "<P"))) { s += 2; state = 2; continue; }
	    break;
 
	case 2: /* find ">" */
	    if ((s = strchr (s, '>'))) { s++; state = 3; p = text; continue; }
	    break;
 
	case 3: /* get all text until '<' appears */
	    if (*s == '\0') { break; }
	    else if (*s == '<') { state = 4; }
	    else if (!strncasecmp (s, "&nbsp;", 6)) { *p++ = ' '; s += 6; }
	    else if (*s == '\r') { s++; }
	    else if (!strncasecmp (s, "<br>", 4) || *s == '\n') {
		*p = '\0'; p = text; trail_space (text);
		if (text[0] != '\0')
		    current->text[current->lines++] = strdup (text);
		if (*s == '\n') s++; else s += 4;
	    }
	    else *p++ = *s++;
	    continue;

	case 4: /* get current->end or skip <TAG> */
	    q = strstr (s, "Start=");
	    if (q) {
		current->end = strtol (q + 6, &q, 0) / 10 - 1;
		*p = '\0'; trail_space (text);
		if (text[0] != '\0')
		    current->text[current->lines++] = strdup (text);
		if (current->lines > 0) { state = 99; break; }
		state = 0; continue;
	    }
	    s = strchr (s, '>');
	    if (s) { s++; state = 3; continue; }
	    break;
	}

	/* read next line */
	if (state != 99 && !(s = fgets (line, 1000, fd))) return 0;

    } while (state != 99);

    return current;
}


char *sub_readtext(char *source, char **dest) {
    int len=0;
    char *p;
    
    for (p=source;*p!='\r' && *p!='\n' && *p!='|'; p++,len++);
    
    *dest= (char *)malloc (len+1);
    if (!dest) {return ERR;}
    
    strncpy(*dest, source, len);
    (*dest)[len]=0;
    
    while (*p=='\r' || *p=='\n' || *p=='|') p++;
    
    if (*p) return p;  // not-last text field
    else return NULL;  // last text field
}

subtitle *sub_read_line_microdvd(FILE *fd,subtitle *current) {
    char line[1001];
    char line2[1001];
    char *p, *next;
    int i;

    bzero (current, sizeof(current));

    do {
	if (!fgets (line, 1000, fd)) return NULL;
    } while (*line=='\n' || *line == '\r' || !*line);
    
    if (sscanf (line, "{%ld}{%ld}%s", &(current->start), &(current->end),line2) <2) {return ERR;}

    p=line;
    while (*p++!='}');
    while (*p++!='}');

    next=p, i=0;
    while ((next =sub_readtext (next, &(current->text[i])))) {
        if (current->text[i]==ERR) {return ERR;}
	i++;
	if (i>=SUB_MAX_TEXT) { printf ("Too many lines in a subtitle\n");current->lines=i;return;}
    }
    current->lines=i+1;

    return current;
}

subtitle *sub_read_line_subrip(FILE *fd, subtitle *current) {
    char line[1001];
    int a1,a2,a3,a4,b1,b2,b3,b4;
    char *p=NULL, *q=NULL;
    int len;
    
    bzero (current, sizeof(current));
    
    while (!current->text[0]) {
	if (!fgets (line, 1000, fd)) return NULL;
	if (sscanf (line, "%d:%d:%d.%d,%d:%d:%d.%d",&a1,&a2,&a3,&a4,&b1,&b2,&b3,&b4) < 8) continue;
	current->start = a1*360000+a2*6000+a3*100+a4;
	current->end   = b1*360000+b2*6000+b3*100+b4;

	if (!fgets (line, 1000, fd)) return NULL;

	p=q=line;
	for (current->lines=1; current->lines < SUB_MAX_TEXT; current->lines++) {
	    for (q=p,len=0; *p && *p!='\r' && *p!='\n' && strncmp(p,"[br]",4); p++,len++);
	    current->text[current->lines-1]=(char *)malloc (len+1);
	    if (!current->text[current->lines-1]) return ERR;
	    strncpy (current->text[current->lines-1], q, len);
	    current->text[current->lines-1][len]='\0';
	    if (!*p || *p=='\r' || *p=='\n') break;
	    while (*p++!=']');
	}
    }
    return current;
}

subtitle *sub_read_line_third(FILE *fd,subtitle *current) {
    char line[1001];
    int a1,a2,a3,a4,b1,b2,b3,b4;
    char *p=NULL;
    int i,len;
    
    bzero (current, sizeof(current));
    
    while (!current->text[0]) {
	if (!fgets (line, 1000, fd)) return NULL;
	if ((len=sscanf (line, "%d:%d:%d,%d --> %d:%d:%d,%d",&a1,&a2,&a3,&a4,&b1,&b2,&b3,&b4)) < 8)
	    continue;
	current->start = a1*360000+a2*6000+a3*100+a4/10;
	current->end   = b1*360000+b2*6000+b3*100+b4/10;
	for (i=0; i<SUB_MAX_TEXT;) {
	    if (!fgets (line, 1000, fd)) break;
	    len=0;
	    for (p=line; *p!='\n' && *p!='\r' && *p; p++,len++);
	    if (len) {
		current->text[i]=(char *)malloc (len+1);
		if (!current->text[i]) return ERR;
		strncpy (current->text[i], line, len); current->text[i][len]='\0';
		i++;
	    } else {
		break;
	    }
	}
	current->lines=i;
    }
    return current;
}


int sub_autodetect (FILE *fd) {
    char line[1001];
    int i,j=0;
//    char *p;
    
    while (j < 100) {
	j++;
	if (!fgets (line, 1000, fd))
	    return -1;

	if (sscanf (line, "{%d}{%d}", &i, &i)==2)
		{sub_uses_time=0;return 0;}
	if (sscanf (line, "%d:%d:%d.%d,%d:%d:%d.%d",     &i, &i, &i, &i, &i, &i, &i, &i)==8)
		{sub_uses_time=1;return 1;}
	if (sscanf (line, "%d:%d:%d,%d --> %d:%d:%d,%d", &i, &i, &i, &i, &i, &i, &i, &i)==8)
		{sub_uses_time=1;return 2;}
	if (strstr (line, "<SAMI>"))
		{sub_uses_time=1; return 3;}
    }

    return -1;  // too many bad lines
}


subtitle* sub_read_file (char *filename) {
    FILE *fd;
    int n_max;
    subtitle *first;
    subtitle * (*func[4])(FILE *fd,subtitle *dest)=
    {
	    sub_read_line_microdvd,
	    sub_read_line_subrip,
	    sub_read_line_third,
	    sub_read_line_sami
    };

    fd=fopen (filename, "r"); if (!fd) return NULL;

    sub_format=sub_autodetect (fd);
    if (sub_format==-1) {printf ("SUB: Could not determine file format\n");return NULL;}
    printf ("SUB: Detected subtitle file format: %d\n",sub_format);
    
    rewind (fd);

    sub_num=0;n_max=32;
    first=(subtitle *)malloc(n_max*sizeof(subtitle));
    if(!first) return NULL;
    
    while(1){
        subtitle *sub;
        if(sub_num>=n_max){
            n_max+=16;
            first=realloc(first,n_max*sizeof(subtitle));
        }
        sub=func[sub_format](fd,&first[sub_num]);
        if(!sub) break;   // EOF
        if(sub==ERR) ++sub_errs; else ++sub_num; // Error vs. Valid
    }
    
    fclose(fd);

//    printf ("SUB: Subtitle format %s time.\n", sub_uses_time?"uses":"doesn't use");
    printf ("SUB: Read %i subtitles", sub_num);
    if (sub_errs) printf (", %i bad line(s).\n", sub_errs);
    else 	  printf (".\n");

    return first;
}

char * strreplace( char * in,char * what,char * whereof )
{
 int i;
 char * tmp;
 
 if ( ( in == NULL )||( what == NULL )||( whereof == NULL )||( ( tmp=strstr( in,what ) ) == NULL ) ) return NULL;
 for( i=0;i<strlen( whereof );i++ ) tmp[i]=whereof[i];
 if ( strlen( what ) > strlen( whereof ) ) tmp[i]=0;
 return in;
}

char * sub_filename( char * fname )
{
 char * sub_name = NULL;
 char * sub_tmp  = NULL;
 int    i;
#define SUB_EXTS 6
 char * sub_exts[SUB_EXTS] = 
  { ".sub",
    ".SUB",
    ".srt",
    ".SRT",
    ".smi",
    ".SMI"};
 
 if ( fname == NULL ) return NULL;
 for( i=strlen( fname );i>0;i-- ) 
   if( fname[i] == '.' ) 
     {
      sub_tmp=(char *)&fname[i];
      break;
     } 
 if ( i == 0 ) return NULL;
 sub_name=strdup( fname );
 for ( i=0;i<SUB_EXTS;i++ )
  {
   FILE * f;
   
   strcpy( sub_name,fname );
   f=fopen( strreplace( sub_name,sub_tmp,sub_exts[i] ),"rt" );
   if ( f != NULL ) 
    {
     fclose( f );
     printf( "SUB: Detected sub file: %s\n",sub_name );
     return sub_name;
    }
  }
 return NULL;
}

#if 0
int main(int argc, char **argv) {  // for testing

    int i,j;
    subtitle *subs;
    subtitle *egysub;
    
    if(argc<2){
        printf("\nUsage: subreader filename.sub\n\n");
        exit(1);
    }
    
    subs=sub_read_file(argv[1]);
    if(!subs){
        printf("Couldn't load file... let's write a bugreport :)\n");
        exit(1);
    }

    for(j=0;j<sub_num;j++){
	egysub=&subs[j];
        printf ("%i line%c (%i-%i) ",
		    egysub->lines,
		    (1==egysub->lines)?' ':'s',
		    egysub->start,
		    egysub->end);
	for (i=0; i<egysub->lines; i++) {
	    printf ("%s%s",egysub->text[i], i==egysub->lines-1?"":" <BREAK> ");
	}
	printf ("\n");
    }

    printf ("Subtitle format %s time.\n", sub_uses_time?"uses":"doesn't use");
    printf ("Read %i subtitles, %i errors.\n", sub_num, sub_errs);
    return 0;
}
#endif