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bprint.c
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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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
227 void av_bprint_clear(AVBPrint *buf)
228 {
229  if (buf->len) {
230  *buf->str = 0;
231  buf->len = 0;
232  }
233 }
234 
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"
264 
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) {
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_BACKSLASH or unknown mode */
287  default:
288  /* \-escape characters */
289  for (; *src; src++) {
290  int is_first_last = src == src0 || !*(src+1);
291  int is_ws = !!strchr(WHITESPACES, *src);
292  int is_strictly_special = special_chars && strchr(special_chars, *src);
293  int is_special =
294  is_strictly_special || strchr("'\\", *src) ||
295  (is_ws && (flags & AV_ESCAPE_FLAG_WHITESPACE));
296 
297  if (is_strictly_special ||
298  (!(flags & AV_ESCAPE_FLAG_STRICT) &&
299  (is_special || (is_ws && is_first_last))))
300  av_bprint_chars(dstbuf, '\\', 1);
301  av_bprint_chars(dstbuf, *src, 1);
302  }
303  break;
304  }
305 }
306 
307 #ifdef TEST
308 
309 #undef printf
310 
311 static void bprint_pascal(AVBPrint *b, unsigned size)
312 {
313  unsigned i, j;
314  unsigned p[42];
315 
316  av_assert0(size < FF_ARRAY_ELEMS(p));
317 
318  p[0] = 1;
319  av_bprintf(b, "%8d\n", 1);
320  for (i = 1; i <= size; i++) {
321  p[i] = 1;
322  for (j = i - 1; j > 0; j--)
323  p[j] = p[j] + p[j - 1];
324  for (j = 0; j <= i; j++)
325  av_bprintf(b, "%8d", p[j]);
326  av_bprintf(b, "\n");
327  }
328 }
329 
330 int main(void)
331 {
332  AVBPrint b;
333  char buf[256];
334  struct tm testtime = { .tm_year = 100, .tm_mon = 11, .tm_mday = 20 };
335 
336  av_bprint_init(&b, 0, -1);
337  bprint_pascal(&b, 5);
338  printf("Short text in unlimited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
339  printf("%s\n", b.str);
341 
342  av_bprint_init(&b, 0, -1);
343  bprint_pascal(&b, 25);
344  printf("Long text in unlimited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
346 
347  av_bprint_init(&b, 0, 2048);
348  bprint_pascal(&b, 25);
349  printf("Long text in limited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
351 
352  av_bprint_init(&b, 0, 1);
353  bprint_pascal(&b, 5);
354  printf("Short text in automatic buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
355 
356  av_bprint_init(&b, 0, 1);
357  bprint_pascal(&b, 25);
358  printf("Long text in automatic buffer: %u/%u\n", (unsigned)strlen(b.str)/8*8, b.len);
359  /* Note that the size of the automatic buffer is arch-dependent. */
360 
361  av_bprint_init(&b, 0, 0);
362  bprint_pascal(&b, 25);
363  printf("Long text count only buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
364 
365  av_bprint_init_for_buffer(&b, buf, sizeof(buf));
366  bprint_pascal(&b, 25);
367  printf("Long text count only buffer: %u/%u\n", (unsigned)strlen(buf), b.len);
368 
369  av_bprint_init(&b, 0, -1);
370  av_bprint_strftime(&b, "%Y-%m-%d", &testtime);
371  printf("strftime full: %u/%u \"%s\"\n", (unsigned)strlen(buf), b.len, b.str);
373 
374  av_bprint_init(&b, 0, 8);
375  av_bprint_strftime(&b, "%Y-%m-%d", &testtime);
376  printf("strftime truncated: %u/%u \"%s\"\n", (unsigned)strlen(buf), b.len, b.str);
377 
378  return 0;
379 }
380 
381 #endif
uint32_t p[AV_BF_ROUNDS+2]
Definition: blowfish.h:38
#define NULL
Definition: coverity.c:32
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:94
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
const char * fmt
Definition: avisynth_c.h:632
memory handling functions
#define vsnprintf
Definition: snprintf.h:36
const char * b
Definition: vf_curves.c:109
Use backslash escaping.
Definition: avstring.h:291
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
Finalize a print buffer.
Definition: bprint.c:235
#define WHITESPACES
Definition: bprint.c:263
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
int mem
Definition: avisynth_c.h:684
#define av_malloc(s)
mode
Definition: f_perms.c:27
#define va_copy(dst, src)
Definition: va_copy.h:28
void av_bprint_append_data(AVBPrint *buf, const char *data, unsigned size)
Append data to a print buffer.
Definition: bprint.c:158
Use single-quote escaping.
Definition: avstring.h:292
void av_bprint_init_for_buffer(AVBPrint *buf, char *buffer, unsigned size)
Init a print buffer using a pre-existing buffer.
Definition: bprint.c:85
ptrdiff_t size
Definition: opengl_enc.c:101
error code definitions
#define AVERROR(e)
Definition: error.h:43
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
Definition: bprint.c:69
#define AV_ESCAPE_FLAG_STRICT
Escape only specified special characters.
Definition: avstring.h:310
simple assert() macros that are a bit more flexible than ISO C assert().
Use auto-selected escaping mode.
Definition: avstring.h:290
#define FFMIN(a, b)
Definition: common.h:66
#define av_bprint_is_allocated(buf)
Definition: bprint.c:34
int n
Definition: avisynth_c.h:547
static int av_bprint_is_complete(const AVBPrint *buf)
Test if the print buffer is complete (not truncated).
Definition: bprint.h:185
static const char * ret_str(int v)
Definition: seek-test.c:33
void av_bprint_get_buffer(AVBPrint *buf, unsigned size, unsigned char **mem, unsigned *actual_size)
Allocate bytes in the buffer for external use.
Definition: bprint.c:218
#define FF_ARRAY_ELEMS(a)
#define av_bprint_room(buf)
Definition: bprint.c:33
AVS_Value src
Definition: avisynth_c.h:482
void * buf
Definition: avisynth_c.h:553
void av_vbprintf(AVBPrint *buf, const char *fmt, va_list vl_arg)
Append a formatted string to a print buffer.
Definition: bprint.c:117
#define src0
Definition: h264pred.c:138
static int flags
Definition: cpu.c:47
void av_bprint_strftime(AVBPrint *buf, const char *fmt, const struct tm *tm)
Append a formatted date and time to a print buffer.
Definition: bprint.c:176
void av_bprint_clear(AVBPrint *buf)
Reset the string to "" but keep internal allocated data.
Definition: bprint.c:227
unsigned unsigned size_max
Definition: bprint.h:111
static void av_bprint_grow(AVBPrint *buf, unsigned extra_len)
Definition: bprint.c:60
void av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_chars, enum AVEscapeMode mode, int flags)
Escape the content in src and append it to dstbuf.
Definition: bprint.c:265
static int av_bprint_alloc(AVBPrint *buf, unsigned room)
Definition: bprint.c:36
common internal and external API header
void * av_realloc(void *ptr, size_t size)
Allocate or reallocate a block of memory.
Definition: mem.c:145
static double c[64]
#define AV_ESCAPE_FLAG_WHITESPACE
Consider spaces special and escape them even in the middle of the string.
Definition: avstring.h:303
unsigned size_init
Definition: bprint.h:111
AVEscapeMode
Definition: avstring.h:289
#define av_freep(p)
int main(int argc, char **argv)
Definition: main.c:22
GLuint buffer
Definition: opengl_enc.c:102
void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
Append char c n times to a print buffer.
Definition: bprint.c:140