1/*
2 * Copyright (c) 2012-2013 Cl��ment B��sch <u pkh me>
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#include "avformat.h"
22#include "subtitles.h"
23#include "libavutil/avassert.h"
24#include "libavutil/avstring.h"
25
26AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
27                                    const uint8_t *event, int len, int merge)
28{
29    AVPacket *subs, *sub;
30
31    if (merge && q->nb_subs > 0) {
32        /* merge with previous event */
33
34        int old_len;
35        sub = &q->subs[q->nb_subs - 1];
36        old_len = sub->size;
37        if (av_grow_packet(sub, len) < 0)
38            return NULL;
39        memcpy(sub->data + old_len, event, len);
40    } else {
41        /* new event */
42
43        if (q->nb_subs >= INT_MAX/sizeof(*q->subs) - 1)
44            return NULL;
45        subs = av_fast_realloc(q->subs, &q->allocated_size,
46                               (q->nb_subs + 1) * sizeof(*q->subs));
47        if (!subs)
48            return NULL;
49        q->subs = subs;
50        sub = &subs[q->nb_subs++];
51        if (av_new_packet(sub, len) < 0)
52            return NULL;
53        sub->flags |= AV_PKT_FLAG_KEY;
54        sub->pts = sub->dts = 0;
55        memcpy(sub->data, event, len);
56    }
57    return sub;
58}
59
60static int cmp_pkt_sub_ts_pos(const void *a, const void *b)
61{
62    const AVPacket *s1 = a;
63    const AVPacket *s2 = b;
64    if (s1->pts == s2->pts) {
65        if (s1->pos == s2->pos)
66            return 0;
67        return s1->pos > s2->pos ? 1 : -1;
68    }
69    return s1->pts > s2->pts ? 1 : -1;
70}
71
72static int cmp_pkt_sub_pos_ts(const void *a, const void *b)
73{
74    const AVPacket *s1 = a;
75    const AVPacket *s2 = b;
76    if (s1->pos == s2->pos) {
77        if (s1->pts == s2->pts)
78            return 0;
79        return s1->pts > s2->pts ? 1 : -1;
80    }
81    return s1->pos > s2->pos ? 1 : -1;
82}
83
84void ff_subtitles_queue_finalize(FFDemuxSubtitlesQueue *q)
85{
86    int i;
87
88    qsort(q->subs, q->nb_subs, sizeof(*q->subs),
89          q->sort == SUB_SORT_TS_POS ? cmp_pkt_sub_ts_pos
90                                     : cmp_pkt_sub_pos_ts);
91    for (i = 0; i < q->nb_subs; i++)
92        if (q->subs[i].duration == -1 && i < q->nb_subs - 1)
93            q->subs[i].duration = q->subs[i + 1].pts - q->subs[i].pts;
94}
95
96int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
97{
98    AVPacket *sub = q->subs + q->current_sub_idx;
99
100    if (q->current_sub_idx == q->nb_subs)
101        return AVERROR_EOF;
102    if (av_copy_packet(pkt, sub) < 0) {
103        return AVERROR(ENOMEM);
104    }
105
106    pkt->dts = pkt->pts;
107    q->current_sub_idx++;
108    return 0;
109}
110
111static int search_sub_ts(const FFDemuxSubtitlesQueue *q, int64_t ts)
112{
113    int s1 = 0, s2 = q->nb_subs - 1;
114
115    if (s2 < s1)
116        return AVERROR(ERANGE);
117
118    for (;;) {
119        int mid;
120
121        if (s1 == s2)
122            return s1;
123        if (s1 == s2 - 1)
124            return q->subs[s1].pts <= q->subs[s2].pts ? s1 : s2;
125        mid = (s1 + s2) / 2;
126        if (q->subs[mid].pts <= ts)
127            s1 = mid;
128        else
129            s2 = mid;
130    }
131}
132
133int ff_subtitles_queue_seek(FFDemuxSubtitlesQueue *q, AVFormatContext *s, int stream_index,
134                            int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
135{
136    if (flags & AVSEEK_FLAG_BYTE) {
137        return AVERROR(ENOSYS);
138    } else if (flags & AVSEEK_FLAG_FRAME) {
139        if (ts < 0 || ts >= q->nb_subs)
140            return AVERROR(ERANGE);
141        q->current_sub_idx = ts;
142    } else {
143        int i, idx = search_sub_ts(q, ts);
144        int64_t ts_selected;
145
146        if (idx < 0)
147            return idx;
148        for (i = idx; i < q->nb_subs && q->subs[i].pts < min_ts; i++)
149            if (stream_index == -1 || q->subs[i].stream_index == stream_index)
150                idx = i;
151        for (i = idx; i > 0 && q->subs[i].pts > max_ts; i--)
152            if (stream_index == -1 || q->subs[i].stream_index == stream_index)
153                idx = i;
154
155        ts_selected = q->subs[idx].pts;
156        if (ts_selected < min_ts || ts_selected > max_ts)
157            return AVERROR(ERANGE);
158
159        /* look back in the latest subtitles for overlapping subtitles */
160        for (i = idx - 1; i >= 0; i--) {
161            int64_t pts = q->subs[i].pts;
162            if (q->subs[i].duration <= 0 ||
163                (stream_index != -1 && q->subs[i].stream_index != stream_index))
164                continue;
165            if (pts >= min_ts && pts > ts_selected - q->subs[i].duration)
166                idx = i;
167            else
168                break;
169        }
170
171        /* If the queue is used to store multiple subtitles streams (like with
172         * VobSub) and the stream index is not specified, we need to make sure
173         * to focus on the smallest file position offset for a same timestamp;
174         * queue is ordered by pts and then filepos, so we can take the first
175         * entry for a given timestamp. */
176        if (stream_index == -1)
177            while (idx > 0 && q->subs[idx - 1].pts == q->subs[idx].pts)
178                idx--;
179
180        q->current_sub_idx = idx;
181    }
182    return 0;
183}
184
185void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
186{
187    int i;
188
189    for (i = 0; i < q->nb_subs; i++)
190        av_free_packet(&q->subs[i]);
191    av_freep(&q->subs);
192    q->nb_subs = q->allocated_size = q->current_sub_idx = 0;
193}
194
195int ff_smil_extract_next_chunk(AVIOContext *pb, AVBPrint *buf, char *c)
196{
197    int i = 0;
198    char end_chr;
199
200    if (!*c) // cached char?
201        *c = avio_r8(pb);
202    if (!*c)
203        return 0;
204
205    end_chr = *c == '<' ? '>' : '<';
206    do {
207        av_bprint_chars(buf, *c, 1);
208        *c = avio_r8(pb);
209        i++;
210    } while (*c != end_chr && *c);
211    if (end_chr == '>') {
212        av_bprint_chars(buf, '>', 1);
213        *c = 0;
214    }
215    return i;
216}
217
218const char *ff_smil_get_attr_ptr(const char *s, const char *attr)
219{
220    int in_quotes = 0;
221    const int len = strlen(attr);
222
223    while (*s) {
224        while (*s) {
225            if (!in_quotes && av_isspace(*s))
226                break;
227            in_quotes ^= *s == '"'; // XXX: support escaping?
228            s++;
229        }
230        while (av_isspace(*s))
231            s++;
232        if (!av_strncasecmp(s, attr, len) && s[len] == '=')
233            return s + len + 1 + (s[len + 1] == '"');
234    }
235    return NULL;
236}
237
238static inline int is_eol(char c)
239{
240    return c == '\r' || c == '\n';
241}
242
243void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
244{
245    char eol_buf[5], last_was_cr = 0;
246    int n = 0, i = 0, nb_eol = 0;
247
248    av_bprint_clear(buf);
249
250    for (;;) {
251        char c = avio_r8(pb);
252
253        if (!c)
254            break;
255
256        /* ignore all initial line breaks */
257        if (n == 0 && is_eol(c))
258            continue;
259
260        /* line break buffering: we don't want to add the trailing \r\n */
261        if (is_eol(c)) {
262            nb_eol += c == '\n' || last_was_cr;
263            if (nb_eol == 2)
264                break;
265            eol_buf[i++] = c;
266            if (i == sizeof(eol_buf) - 1)
267                break;
268            last_was_cr = c == '\r';
269            continue;
270        }
271
272        /* only one line break followed by data: we flush the line breaks
273         * buffer */
274        if (i) {
275            eol_buf[i] = 0;
276            av_bprintf(buf, "%s", eol_buf);
277            i = nb_eol = 0;
278        }
279
280        av_bprint_chars(buf, c, 1);
281        n++;
282    }
283}
284