1/*
2 * Copyright (c) 2012 Clément Bœsch
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
22 * @file
23 * JACOsub subtitle demuxer
24 * @see http://unicorn.us.com/jacosub/jscripts.html
25 * @todo Support P[ALETTE] directive.
26 */
27
28#include "avformat.h"
29#include "internal.h"
30#include "subtitles.h"
31#include "libavcodec/jacosub.h"
32#include "libavutil/avstring.h"
33#include "libavutil/bprint.h"
34#include "libavutil/intreadwrite.h"
35
36typedef struct {
37    FFDemuxSubtitlesQueue q;
38    int shift;
39    unsigned timeres;
40} JACOsubContext;
41
42static int timed_line(const char *ptr)
43{
44    char c;
45    int fs, fe;
46    return (sscanf(ptr, "%*u:%*u:%*u.%*u %*u:%*u:%*u.%*u %c", &c) == 1 ||
47            (sscanf(ptr, "@%u @%u %c", &fs, &fe, &c) == 3 && fs < fe));
48}
49
50static int jacosub_probe(const AVProbeData *p)
51{
52    const char *ptr     = p->buf;
53    const char *ptr_end = p->buf + p->buf_size;
54
55    if (AV_RB24(ptr) == 0xEFBBBF)
56        ptr += 3; /* skip UTF-8 BOM */
57
58    while (ptr < ptr_end) {
59        while (jss_whitespace(*ptr))
60            ptr++;
61        if (*ptr != '#' && *ptr != '\n') {
62            if (timed_line(ptr))
63                return AVPROBE_SCORE_EXTENSION + 1;
64            return 0;
65        }
66        ptr += ff_subtitles_next_line(ptr);
67    }
68    return 0;
69}
70
71static const char * const cmds[] = {
72    "CLOCKPAUSE",
73    "DIRECTIVE",
74    "FONT",
75    "HRES",
76    "INCLUDE",
77    "PALETTE",
78    "QUANTIZE",
79    "RAMP",
80    "SHIFT",
81    "TIMERES",
82};
83
84static int get_jss_cmd(char k)
85{
86    int i;
87
88    k = av_toupper(k);
89    for (i = 0; i < FF_ARRAY_ELEMS(cmds); i++)
90        if (k == cmds[i][0])
91            return i;
92    return -1;
93}
94
95static const char *read_ts(JACOsubContext *jacosub, const char *buf,
96                           int64_t *start, int64_t *duration)
97{
98    int len;
99    unsigned hs, ms, ss, fs; // hours, minutes, seconds, frame start
100    unsigned he, me, se, fe; // hours, minutes, seconds, frame end
101    int ts_start, ts_end;
102    int64_t ts_start64, ts_end64;
103
104    /* timed format */
105    if (sscanf(buf, "%u:%u:%u.%u %u:%u:%u.%u %n",
106               &hs, &ms, &ss, &fs,
107               &he, &me, &se, &fe, &len) == 8) {
108        ts_start = (hs*3600 + ms*60 + ss) * jacosub->timeres + fs;
109        ts_end   = (he*3600 + me*60 + se) * jacosub->timeres + fe;
110        goto shift_and_ret;
111    }
112
113    /* timestamps format */
114    if (sscanf(buf, "@%u @%u %n", &ts_start, &ts_end, &len) == 2)
115        goto shift_and_ret;
116
117    return NULL;
118
119shift_and_ret:
120    ts_start64  = (ts_start + (int64_t)jacosub->shift) * 100LL / jacosub->timeres;
121    ts_end64    = (ts_end   + (int64_t)jacosub->shift) * 100LL / jacosub->timeres;
122    *start    = ts_start64;
123    *duration = ts_end64 - ts_start64;
124    return buf + len;
125}
126
127static int get_shift(unsigned timeres, const char *buf)
128{
129    int sign = 1;
130    int a = 0, b = 0, c = 0, d = 0;
131    int64_t ret;
132#define SSEP "%*1[.:]"
133    int n = sscanf(buf, "%d"SSEP"%d"SSEP"%d"SSEP"%d", &a, &b, &c, &d);
134#undef SSEP
135
136    if (a == INT_MIN)
137        return 0;
138
139    if (*buf == '-' || a < 0) {
140        sign = -1;
141        a = FFABS(a);
142    }
143
144    ret = 0;
145    switch (n) {
146    case 1:                      a = 0;
147    case 2:        c = b; b = a; a = 0;
148    case 3: d = c; c = b; b = a; a = 0;
149    }
150
151    ret = (int64_t)a*3600 + (int64_t)b*60 + c;
152    if (FFABS(ret) > (INT64_MAX - FFABS(d)) / timeres)
153        return 0;
154    ret = sign * (ret * timeres + d);
155
156    if ((int)ret != ret)
157        ret = 0;
158
159    return ret;
160}
161
162static int jacosub_read_header(AVFormatContext *s)
163{
164    AVBPrint header;
165    AVIOContext *pb = s->pb;
166    char line[JSS_MAX_LINESIZE];
167    JACOsubContext *jacosub = s->priv_data;
168    int shift_set = 0; // only the first shift matters
169    int merge_line = 0;
170    int i, ret;
171
172    AVStream *st = avformat_new_stream(s, NULL);
173    if (!st)
174        return AVERROR(ENOMEM);
175    avpriv_set_pts_info(st, 64, 1, 100);
176    st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
177    st->codecpar->codec_id   = AV_CODEC_ID_JACOSUB;
178
179    jacosub->timeres = 30;
180
181    av_bprint_init(&header, 1024+AV_INPUT_BUFFER_PADDING_SIZE, 4096);
182
183    while (!avio_feof(pb)) {
184        int cmd_len;
185        const char *p = line;
186        int64_t pos = avio_tell(pb);
187        int len = ff_get_line(pb, line, sizeof(line));
188
189        p = jss_skip_whitespace(p);
190
191        /* queue timed line */
192        if (merge_line || timed_line(p)) {
193            AVPacket *sub;
194
195            sub = ff_subtitles_queue_insert(&jacosub->q, line, len, merge_line);
196            if (!sub) {
197                av_bprint_finalize(&header, NULL);
198                return AVERROR(ENOMEM);
199            }
200            sub->pos = pos;
201            merge_line = len > 1 && !strcmp(&line[len - 2], "\\\n");
202            continue;
203        }
204
205        /* skip all non-compiler commands and focus on the command */
206        if (*p != '#')
207            continue;
208        p++;
209        i = get_jss_cmd(p[0]);
210        if (i == -1)
211            continue;
212
213        /* trim command + spaces */
214        cmd_len = strlen(cmds[i]);
215        if (av_strncasecmp(p, cmds[i], cmd_len) == 0)
216            p += cmd_len;
217        else
218            p++;
219        p = jss_skip_whitespace(p);
220
221        /* handle commands which affect the whole script */
222        switch (cmds[i][0]) {
223        case 'S': // SHIFT command affect the whole script...
224            if (!shift_set) {
225                jacosub->shift = get_shift(jacosub->timeres, p);
226                shift_set = 1;
227            }
228            av_bprintf(&header, "#S %s", p);
229            break;
230        case 'T': { // ...but must be placed after TIMERES
231            int64_t timeres = strtol(p, NULL, 10);
232            if (timeres <= 0 || timeres > UINT32_MAX) {
233                jacosub->timeres = 30;
234            } else {
235                jacosub->timeres = timeres;
236                av_bprintf(&header, "#T %s", p);
237            }
238            break;
239        }
240        }
241    }
242
243    /* general/essential directives in the extradata */
244    ret = ff_bprint_to_codecpar_extradata(st->codecpar, &header);
245    if (ret < 0)
246        return ret;
247
248    /* SHIFT and TIMERES affect the whole script so packet timing can only be
249     * done in a second pass */
250    for (i = 0; i < jacosub->q.nb_subs; i++) {
251        AVPacket *sub = jacosub->q.subs[i];
252        read_ts(jacosub, sub->data, &sub->pts, &sub->duration);
253    }
254    ff_subtitles_queue_finalize(s, &jacosub->q);
255
256    return 0;
257}
258
259const AVInputFormat ff_jacosub_demuxer = {
260    .name           = "jacosub",
261    .long_name      = NULL_IF_CONFIG_SMALL("JACOsub subtitle format"),
262    .priv_data_size = sizeof(JACOsubContext),
263    .flags_internal = FF_FMT_INIT_CLEANUP,
264    .read_probe     = jacosub_probe,
265    .read_header    = jacosub_read_header,
266    .read_packet    = ff_subtitles_read_packet,
267    .read_seek2     = ff_subtitles_read_seek,
268    .read_close     = ff_subtitles_read_close,
269};
270