srt: Adjust signedness of sscanf format strings
[libav.git] / libavcodec / srtdec.c
1 /*
2 * SubRip subtitle decoder
3 * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
4 *
5 * This file is part of Libav.
6 *
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "libavutil/avstring.h"
23 #include "libavutil/common.h"
24 #include "libavutil/parseutils.h"
25 #include "avcodec.h"
26 #include "ass.h"
27
28 static int html_color_parse(AVCodecContext *avctx, const char *str)
29 {
30 uint8_t rgba[4];
31 if (av_parse_color(rgba, str, strcspn(str, "\" >"), avctx) < 0)
32 return -1;
33 return rgba[0] | rgba[1] << 8 | rgba[2] << 16;
34 }
35
36 enum {
37 PARAM_UNKNOWN = -1,
38 PARAM_SIZE,
39 PARAM_COLOR,
40 PARAM_FACE,
41 PARAM_NUMBER
42 };
43
44 typedef struct SrtStack {
45 char tag[128];
46 char param[PARAM_NUMBER][128];
47 } SrtStack;
48
49 static const char *srt_to_ass(AVCodecContext *avctx, char *out, char *out_end,
50 const char *in, int x1, int y1, int x2, int y2)
51 {
52 char c, *param, buffer[128], tmp[128];
53 int len, tag_close, sptr = 1, line_start = 1, an = 0, end = 0;
54 SrtStack stack[16];
55
56 stack[0].tag[0] = 0;
57 strcpy(stack[0].param[PARAM_SIZE], "{\\fs}");
58 strcpy(stack[0].param[PARAM_COLOR], "{\\c}");
59 strcpy(stack[0].param[PARAM_FACE], "{\\fn}");
60
61 if (x1 >= 0 && y1 >= 0) {
62 if (x2 >= 0 && y2 >= 0 && (x2 != x1 || y2 != y1))
63 out += snprintf(out, out_end-out,
64 "{\\an1}{\\move(%d,%d,%d,%d)}", x1, y1, x2, y2);
65 else
66 out += snprintf(out, out_end-out, "{\\an1}{\\pos(%d,%d)}", x1, y1);
67 }
68
69 for (; out < out_end && !end && *in; in++) {
70 switch (*in) {
71 case '\r':
72 break;
73 case '\n':
74 if (line_start) {
75 end = 1;
76 break;
77 }
78 while (out[-1] == ' ')
79 out--;
80 out += snprintf(out, out_end-out, "\\N");
81 line_start = 1;
82 break;
83 case ' ':
84 if (!line_start)
85 *out++ = *in;
86 break;
87 case '{': /* skip all {\xxx} substrings except for {\an%d}
88 and all microdvd like styles such as {Y:xxx} */
89 an += sscanf(in, "{\\an%*1u}%c", &c) == 1;
90 if ((an != 1 && sscanf(in, "{\\%*[^}]}%n%c", &len, &c) > 0) ||
91 sscanf(in, "{%*1[CcFfoPSsYy]:%*[^}]}%n%c", &len, &c) > 0) {
92 in += len - 1;
93 } else
94 *out++ = *in;
95 break;
96 case '<':
97 tag_close = in[1] == '/';
98 if (sscanf(in+tag_close+1, "%127[^>]>%n%c", buffer, &len,&c) >= 2) {
99 if ((param = strchr(buffer, ' ')))
100 *param++ = 0;
101 if ((!tag_close && sptr < FF_ARRAY_ELEMS(stack)) ||
102 ( tag_close && sptr > 0 && !strcmp(stack[sptr-1].tag, buffer))) {
103 int i, j, unknown = 0;
104 in += len + tag_close;
105 if (!tag_close)
106 memset(stack+sptr, 0, sizeof(*stack));
107 if (!strcmp(buffer, "font")) {
108 if (tag_close) {
109 for (i=PARAM_NUMBER-1; i>=0; i--)
110 if (stack[sptr-1].param[i][0])
111 for (j=sptr-2; j>=0; j--)
112 if (stack[j].param[i][0]) {
113 out += snprintf(out, out_end-out,
114 "%s", stack[j].param[i]);
115 break;
116 }
117 } else {
118 while (param) {
119 if (!strncmp(param, "size=", 5)) {
120 unsigned font_size;
121 param += 5 + (param[5] == '"');
122 if (sscanf(param, "%u", &font_size) == 1) {
123 snprintf(stack[sptr].param[PARAM_SIZE],
124 sizeof(stack[0].param[PARAM_SIZE]),
125 "{\\fs%u}", font_size);
126 }
127 } else if (!strncmp(param, "color=", 6)) {
128 param += 6 + (param[6] == '"');
129 snprintf(stack[sptr].param[PARAM_COLOR],
130 sizeof(stack[0].param[PARAM_COLOR]),
131 "{\\c&H%X&}",
132 html_color_parse(avctx, param));
133 } else if (!strncmp(param, "face=", 5)) {
134 param += 5 + (param[5] == '"');
135 len = strcspn(param,
136 param[-1] == '"' ? "\"" :" ");
137 av_strlcpy(tmp, param,
138 FFMIN(sizeof(tmp), len+1));
139 param += len;
140 snprintf(stack[sptr].param[PARAM_FACE],
141 sizeof(stack[0].param[PARAM_FACE]),
142 "{\\fn%s}", tmp);
143 }
144 if ((param = strchr(param, ' ')))
145 param++;
146 }
147 for (i=0; i<PARAM_NUMBER; i++)
148 if (stack[sptr].param[i][0])
149 out += snprintf(out, out_end-out,
150 "%s", stack[sptr].param[i]);
151 }
152 } else if (!buffer[1] && strspn(buffer, "bisu") == 1) {
153 out += snprintf(out, out_end-out,
154 "{\\%c%d}", buffer[0], !tag_close);
155 } else {
156 unknown = 1;
157 snprintf(tmp, sizeof(tmp), "</%s>", buffer);
158 }
159 if (tag_close) {
160 sptr--;
161 } else if (unknown && !strstr(in, tmp)) {
162 in -= len + tag_close;
163 *out++ = *in;
164 } else
165 av_strlcpy(stack[sptr++].tag, buffer,
166 sizeof(stack[0].tag));
167 break;
168 }
169 }
170 default:
171 *out++ = *in;
172 break;
173 }
174 if (*in != ' ' && *in != '\r' && *in != '\n')
175 line_start = 0;
176 }
177
178 out = FFMIN(out, out_end-3);
179 while (!strncmp(out-2, "\\N", 2))
180 out -= 2;
181 while (out[-1] == ' ')
182 out--;
183 out += snprintf(out, out_end-out, "\r\n");
184 return in;
185 }
186
187 static const char *read_ts(const char *buf, int *ts_start, int *ts_end,
188 int *x1, int *y1, int *x2, int *y2)
189 {
190 int i, hs, ms, ss, he, me, se;
191
192 for (i=0; i<2; i++) {
193 /* try to read timestamps in either the first or second line */
194 int c = sscanf(buf, "%d:%2d:%2d%*1[,.]%3d --> %d:%2d:%2d%*1[,.]%3d"
195 "%*[ ]X1:%d X2:%d Y1:%d Y2:%d",
196 &hs, &ms, &ss, ts_start, &he, &me, &se, ts_end,
197 x1, x2, y1, y2);
198 buf += strcspn(buf, "\n") + 1;
199 if (c >= 8) {
200 *ts_start = 100*(ss + 60*(ms + 60*hs)) + *ts_start/10;
201 *ts_end = 100*(se + 60*(me + 60*he)) + *ts_end /10;
202 return buf;
203 }
204 }
205 return NULL;
206 }
207
208 static int srt_decode_frame(AVCodecContext *avctx,
209 void *data, int *got_sub_ptr, AVPacket *avpkt)
210 {
211 AVSubtitle *sub = data;
212 int ts_start, ts_end, x1 = -1, y1 = -1, x2 = -1, y2 = -1;
213 char buffer[2048];
214 const char *ptr = avpkt->data;
215 const char *end = avpkt->data + avpkt->size;
216
217 if (avpkt->size <= 0)
218 return avpkt->size;
219
220 ff_ass_init(sub);
221
222 while (ptr < end && *ptr) {
223 ptr = read_ts(ptr, &ts_start, &ts_end, &x1, &y1, &x2, &y2);
224 if (!ptr)
225 break;
226 ptr = srt_to_ass(avctx, buffer, buffer+sizeof(buffer), ptr,
227 x1, y1, x2, y2);
228 ff_ass_add_rect(sub, buffer, ts_start, ts_end, 0);
229 }
230
231 *got_sub_ptr = sub->num_rects > 0;
232 return avpkt->size;
233 }
234
235 AVCodec ff_srt_decoder = {
236 .name = "srt",
237 .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
238 .type = AVMEDIA_TYPE_SUBTITLE,
239 .id = AV_CODEC_ID_SRT,
240 .init = ff_ass_subtitle_header_default,
241 .decode = srt_decode_frame,
242 };