1 /*
2 * Copyright (c) 2012 Nicolas George
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 <stdarg.h>
22 #include <stdio.h>
23 #include <string.h>
24 #include <time.h>
25 #include "avassert.h"
26 #include "avstring.h"
27 #include "bprint.h"
28 #include "common.h"
29 #include "compat/va_copy.h"
30 #include "error.h"
31 #include "mem.h"
32
33 #define av_bprint_room(buf) ((buf)->size - FFMIN((buf)->len, (buf)->size))
34 #define av_bprint_is_allocated(buf) ((buf)->str != (buf)->reserved_internal_buffer)
35
av_bprint_alloc(AVBPrint * buf,unsigned room)36 static int av_bprint_alloc(AVBPrint *buf, unsigned room)
37 {
38 char *old_str, *new_str;
39 unsigned min_size, new_size;
40
41 if (buf->size == buf->size_max)
42 return AVERROR(EIO);
43 if (!av_bprint_is_complete(buf))
44 return AVERROR_INVALIDDATA; /* it is already truncated anyway */
45 min_size = buf->len + 1 + FFMIN(UINT_MAX - buf->len - 1, room);
46 new_size = buf->size > buf->size_max / 2 ? buf->size_max : buf->size * 2;
47 if (new_size < min_size)
48 new_size = FFMIN(buf->size_max, min_size);
49 old_str = av_bprint_is_allocated(buf) ? buf->str : NULL;
50 new_str = av_realloc(old_str, new_size);
51 if (!new_str)
52 return AVERROR(ENOMEM);
53 if (!old_str)
54 memcpy(new_str, buf->str, buf->len + 1);
55 buf->str = new_str;
56 buf->size = new_size;
57 return 0;
58 }
59
av_bprint_grow(AVBPrint * buf,unsigned extra_len)60 static void av_bprint_grow(AVBPrint *buf, unsigned extra_len)
61 {
62 /* arbitrary margin to avoid small overflows */
63 extra_len = FFMIN(extra_len, UINT_MAX - 5 - buf->len);
64 buf->len += extra_len;
65 if (buf->size)
66 buf->str[FFMIN(buf->len, buf->size - 1)] = 0;
67 }
68
av_bprint_init(AVBPrint * buf,unsigned size_init,unsigned size_max)69 void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
70 {
71 unsigned size_auto = (char *)buf + sizeof(*buf) -
72 buf->reserved_internal_buffer;
73
74 if (size_max == 1)
75 size_max = size_auto;
76 buf->str = buf->reserved_internal_buffer;
77 buf->len = 0;
78 buf->size = FFMIN(size_auto, size_max);
79 buf->size_max = size_max;
80 *buf->str = 0;
81 if (size_init > buf->size)
82 av_bprint_alloc(buf, size_init - 1);
83 }
84
av_bprint_init_for_buffer(AVBPrint * buf,char * buffer,unsigned size)85 void av_bprint_init_for_buffer(AVBPrint *buf, char *buffer, unsigned size)
86 {
87 buf->str = buffer;
88 buf->len = 0;
89 buf->size = size;
90 buf->size_max = size;
91 *buf->str = 0;
92 }
93
av_bprintf(AVBPrint * buf,const char * fmt,...)94 void av_bprintf(AVBPrint *buf, const char *fmt, ...)
95 {
96 unsigned room;
97 char *dst;
98 va_list vl;
99 int extra_len;
100
101 while (1) {
102 room = av_bprint_room(buf);
103 dst = room ? buf->str + buf->len : NULL;
104 va_start(vl, fmt);
105 extra_len = vsnprintf(dst, room, fmt, vl);
106 va_end(vl);
107 if (extra_len <= 0)
108 return;
109 if (extra_len < room)
110 break;
111 if (av_bprint_alloc(buf, extra_len))
112 break;
113 }
114 av_bprint_grow(buf, extra_len);
115 }
116
av_vbprintf(AVBPrint * buf,const char * fmt,va_list vl_arg)117 void av_vbprintf(AVBPrint *buf, const char *fmt, va_list vl_arg)
118 {
119 unsigned room;
120 char *dst;
121 int extra_len;
122 va_list vl;
123
124 while (1) {
125 room = av_bprint_room(buf);
126 dst = room ? buf->str + buf->len : NULL;
127 va_copy(vl, vl_arg);
128 extra_len = vsnprintf(dst, room, fmt, vl);
129 va_end(vl);
130 if (extra_len <= 0)
131 return;
132 if (extra_len < room)
133 break;
134 if (av_bprint_alloc(buf, extra_len))
135 break;
136 }
137 av_bprint_grow(buf, extra_len);
138 }
139
av_bprint_chars(AVBPrint * buf,char c,unsigned n)140 void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
141 {
142 unsigned room, real_n;
143
144 while (1) {
145 room = av_bprint_room(buf);
146 if (n < room)
147 break;
148 if (av_bprint_alloc(buf, n))
149 break;
150 }
151 if (room) {
152 real_n = FFMIN(n, room - 1);
153 memset(buf->str + buf->len, c, real_n);
154 }
155 av_bprint_grow(buf, n);
156 }
157
av_bprint_append_data(AVBPrint * buf,const char * data,unsigned size)158 void av_bprint_append_data(AVBPrint *buf, const char *data, unsigned size)
159 {
160 unsigned room, real_n;
161
162 while (1) {
163 room = av_bprint_room(buf);
164 if (size < room)
165 break;
166 if (av_bprint_alloc(buf, size))
167 break;
168 }
169 if (room) {
170 real_n = FFMIN(size, room - 1);
171 memcpy(buf->str + buf->len, data, real_n);
172 }
173 av_bprint_grow(buf, size);
174 }
175
av_bprint_strftime(AVBPrint * buf,const char * fmt,const struct tm * tm)176 void av_bprint_strftime(AVBPrint *buf, const char *fmt, const struct tm *tm)
177 {
178 unsigned room;
179 size_t l;
180
181 if (!*fmt)
182 return;
183 while (1) {
184 room = av_bprint_room(buf);
185 if (room && (l = strftime(buf->str + buf->len, room, fmt, tm)))
186 break;
187 /* strftime does not tell us how much room it would need: let us
188 retry with twice as much until the buffer is large enough */
189 room = !room ? strlen(fmt) + 1 :
190 room <= INT_MAX / 2 ? room * 2 : INT_MAX;
191 if (av_bprint_alloc(buf, room)) {
192 /* impossible to grow, try to manage something useful anyway */
193 room = av_bprint_room(buf);
194 if (room < 1024) {
195 /* if strftime fails because the buffer has (almost) reached
196 its maximum size, let us try in a local buffer; 1k should
197 be enough to format any real date+time string */
198 char buf2[1024];
199 if ((l = strftime(buf2, sizeof(buf2), fmt, tm))) {
200 av_bprintf(buf, "%s", buf2);
201 return;
202 }
203 }
204 if (room) {
205 /* if anything else failed and the buffer is not already
206 truncated, let us add a stock string and force truncation */
207 static const char txt[] = "[truncated strftime output]";
208 memset(buf->str + buf->len, '!', room);
209 memcpy(buf->str + buf->len, txt, FFMIN(sizeof(txt) - 1, room));
210 av_bprint_grow(buf, room); /* force truncation */
211 }
212 return;
213 }
214 }
215 av_bprint_grow(buf, l);
216 }
217
av_bprint_get_buffer(AVBPrint * buf,unsigned size,unsigned char ** mem,unsigned * actual_size)218 void av_bprint_get_buffer(AVBPrint *buf, unsigned size,
219 unsigned char **mem, unsigned *actual_size)
220 {
221 if (size > av_bprint_room(buf))
222 av_bprint_alloc(buf, size);
223 *actual_size = av_bprint_room(buf);
224 *mem = *actual_size ? buf->str + buf->len : NULL;
225 }
226
av_bprint_clear(AVBPrint * buf)227 void av_bprint_clear(AVBPrint *buf)
228 {
229 if (buf->len) {
230 *buf->str = 0;
231 buf->len = 0;
232 }
233 }
234
av_bprint_finalize(AVBPrint * buf,char ** ret_str)235 int av_bprint_finalize(AVBPrint *buf, char **ret_str)
236 {
237 unsigned real_size = FFMIN(buf->len + 1, buf->size);
238 char *str;
239 int ret = 0;
240
241 if (ret_str) {
242 if (av_bprint_is_allocated(buf)) {
243 str = av_realloc(buf->str, real_size);
244 if (!str)
245 str = buf->str;
246 buf->str = NULL;
247 } else {
248 str = av_malloc(real_size);
249 if (str)
250 memcpy(str, buf->str, real_size);
251 else
252 ret = AVERROR(ENOMEM);
253 }
254 *ret_str = str;
255 } else {
256 if (av_bprint_is_allocated(buf))
257 av_freep(&buf->str);
258 }
259 buf->size = real_size;
260 return ret;
261 }
262
263 #define WHITESPACES " \n\t\r"
264
av_bprint_escape(AVBPrint * dstbuf,const char * src,const char * special_chars,enum AVEscapeMode mode,int flags)265 void av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_chars,
266 enum AVEscapeMode mode, int flags)
267 {
268 const char *src0 = src;
269
270 if (mode == AV_ESCAPE_MODE_AUTO)
271 mode = AV_ESCAPE_MODE_BACKSLASH; /* TODO: implement a heuristic */
272
273 switch (mode) {
274 case AV_ESCAPE_MODE_QUOTE:
275 /* enclose the string between '' */
276 av_bprint_chars(dstbuf, '\'', 1);
277 for (; *src; src++) {
278 if (*src == '\'')
279 av_bprintf(dstbuf, "'\\''");
280 else
281 av_bprint_chars(dstbuf, *src, 1);
282 }
283 av_bprint_chars(dstbuf, '\'', 1);
284 break;
285
286 case AV_ESCAPE_MODE_XML:
287 /* escape XML non-markup character data as per 2.4 by default: */
288 /* [^<&]* - ([^<&]* ']]>' [^<&]*) */
289
290 /* additionally, given one of the AV_ESCAPE_FLAG_XML_* flags, */
291 /* escape those specific characters as required. */
292 for (; *src; src++) {
293 switch (*src) {
294 case '&' : av_bprintf(dstbuf, "%s", "&"); break;
295 case '<' : av_bprintf(dstbuf, "%s", "<"); break;
296 case '>' : av_bprintf(dstbuf, "%s", ">"); break;
297 case '\'':
298 if (!(flags & AV_ESCAPE_FLAG_XML_SINGLE_QUOTES))
299 goto XML_DEFAULT_HANDLING;
300
301 av_bprintf(dstbuf, "%s", "'");
302 break;
303 case '"' :
304 if (!(flags & AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES))
305 goto XML_DEFAULT_HANDLING;
306
307 av_bprintf(dstbuf, "%s", """);
308 break;
309 XML_DEFAULT_HANDLING:
310 default: av_bprint_chars(dstbuf, *src, 1);
311 }
312 }
313 break;
314
315 /* case AV_ESCAPE_MODE_BACKSLASH or unknown mode */
316 default:
317 /* \-escape characters */
318 for (; *src; src++) {
319 int is_first_last = src == src0 || !*(src+1);
320 int is_ws = !!strchr(WHITESPACES, *src);
321 int is_strictly_special = special_chars && strchr(special_chars, *src);
322 int is_special =
323 is_strictly_special || strchr("'\\", *src) ||
324 (is_ws && (flags & AV_ESCAPE_FLAG_WHITESPACE));
325
326 if (is_strictly_special ||
327 (!(flags & AV_ESCAPE_FLAG_STRICT) &&
328 (is_special || (is_ws && is_first_last))))
329 av_bprint_chars(dstbuf, '\\', 1);
330 av_bprint_chars(dstbuf, *src, 1);
331 }
332 break;
333 }
334 }
335