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ffmpeg/libavutil/bprint.c

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/*
* Copyright (c) 2012 Nicolas George
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include "avassert.h"
#include "avstring.h"
#include "bprint.h"
#include "common.h"
#include "compat/va_copy.h"
#include "error.h"
#include "mem.h"
#define av_bprint_room(buf) ((buf)->size - FFMIN((buf)->len, (buf)->size))
#define av_bprint_is_allocated(buf) ((buf)->str != (buf)->reserved_internal_buffer)
static int av_bprint_alloc(AVBPrint *buf, unsigned room)
{
char *old_str, *new_str;
unsigned min_size, new_size;
if (buf->size == buf->size_max)
return AVERROR(EIO);
if (!av_bprint_is_complete(buf))
return AVERROR_INVALIDDATA; /* it is already truncated anyway */
min_size = buf->len + 1 + FFMIN(UINT_MAX - buf->len - 1, room);
new_size = buf->size > buf->size_max / 2 ? buf->size_max : buf->size * 2;
if (new_size < min_size)
new_size = FFMIN(buf->size_max, min_size);
old_str = av_bprint_is_allocated(buf) ? buf->str : NULL;
new_str = av_realloc(old_str, new_size);
if (!new_str)
return AVERROR(ENOMEM);
if (!old_str)
memcpy(new_str, buf->str, buf->len + 1);
buf->str = new_str;
buf->size = new_size;
return 0;
}
static void av_bprint_grow(AVBPrint *buf, unsigned extra_len)
{
/* arbitrary margin to avoid small overflows */
extra_len = FFMIN(extra_len, UINT_MAX - 5 - buf->len);
buf->len += extra_len;
if (buf->size)
buf->str[FFMIN(buf->len, buf->size - 1)] = 0;
}
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
{
unsigned size_auto = (char *)buf + sizeof(*buf) -
buf->reserved_internal_buffer;
if (size_max == 1)
size_max = size_auto;
buf->str = buf->reserved_internal_buffer;
buf->len = 0;
buf->size = FFMIN(size_auto, size_max);
buf->size_max = size_max;
*buf->str = 0;
if (size_init > buf->size)
av_bprint_alloc(buf, size_init - 1);
}
void av_bprint_init_for_buffer(AVBPrint *buf, char *buffer, unsigned size)
{
buf->str = buffer;
buf->len = 0;
buf->size = size;
buf->size_max = size;
*buf->str = 0;
}
void av_bprintf(AVBPrint *buf, const char *fmt, ...)
{
unsigned room;
char *dst;
va_list vl;
int extra_len;
while (1) {
room = av_bprint_room(buf);
dst = room ? buf->str + buf->len : NULL;
va_start(vl, fmt);
extra_len = vsnprintf(dst, room, fmt, vl);
va_end(vl);
if (extra_len <= 0)
return;
if (extra_len < room)
break;
if (av_bprint_alloc(buf, extra_len))
break;
}
av_bprint_grow(buf, extra_len);
}
void av_vbprintf(AVBPrint *buf, const char *fmt, va_list vl_arg)
{
unsigned room;
char *dst;
int extra_len;
va_list vl;
while (1) {
room = av_bprint_room(buf);
dst = room ? buf->str + buf->len : NULL;
va_copy(vl, vl_arg);
extra_len = vsnprintf(dst, room, fmt, vl);
va_end(vl);
if (extra_len <= 0)
return;
if (extra_len < room)
break;
if (av_bprint_alloc(buf, extra_len))
break;
}
av_bprint_grow(buf, extra_len);
}
void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
{
unsigned room, real_n;
while (1) {
room = av_bprint_room(buf);
if (n < room)
break;
if (av_bprint_alloc(buf, n))
break;
}
if (room) {
real_n = FFMIN(n, room - 1);
memset(buf->str + buf->len, c, real_n);
}
av_bprint_grow(buf, n);
}
void av_bprint_append_data(AVBPrint *buf, const char *data, unsigned size)
{
unsigned room, real_n;
while (1) {
room = av_bprint_room(buf);
if (size < room)
break;
if (av_bprint_alloc(buf, size))
break;
}
if (room) {
real_n = FFMIN(size, room - 1);
memcpy(buf->str + buf->len, data, real_n);
}
av_bprint_grow(buf, size);
}
void av_bprint_strftime(AVBPrint *buf, const char *fmt, const struct tm *tm)
{
unsigned room;
size_t l;
if (!*fmt)
return;
while (1) {
room = av_bprint_room(buf);
if (room && (l = strftime(buf->str + buf->len, room, fmt, tm)))
break;
/* strftime does not tell us how much room it would need: let us
retry with twice as much until the buffer is large enough */
room = !room ? strlen(fmt) + 1 :
room <= INT_MAX / 2 ? room * 2 : INT_MAX;
if (av_bprint_alloc(buf, room)) {
/* impossible to grow, try to manage something useful anyway */
room = av_bprint_room(buf);
if (room < 1024) {
/* if strftime fails because the buffer has (almost) reached
its maximum size, let us try in a local buffer; 1k should
be enough to format any real date+time string */
char buf2[1024];
if ((l = strftime(buf2, sizeof(buf2), fmt, tm))) {
av_bprintf(buf, "%s", buf2);
return;
}
}
if (room) {
/* if anything else failed and the buffer is not already
truncated, let us add a stock string and force truncation */
static const char txt[] = "[truncated strftime output]";
memset(buf->str + buf->len, '!', room);
memcpy(buf->str + buf->len, txt, FFMIN(sizeof(txt) - 1, room));
av_bprint_grow(buf, room); /* force truncation */
}
return;
}
}
av_bprint_grow(buf, l);
}
void av_bprint_get_buffer(AVBPrint *buf, unsigned size,
unsigned char **mem, unsigned *actual_size)
{
if (size > av_bprint_room(buf))
av_bprint_alloc(buf, size);
*actual_size = av_bprint_room(buf);
*mem = *actual_size ? buf->str + buf->len : NULL;
}
void av_bprint_clear(AVBPrint *buf)
{
if (buf->len) {
*buf->str = 0;
buf->len = 0;
}
}
int av_bprint_finalize(AVBPrint *buf, char **ret_str)
{
unsigned real_size = FFMIN(buf->len + 1, buf->size);
char *str;
int ret = 0;
if (ret_str) {
if (av_bprint_is_allocated(buf)) {
str = av_realloc(buf->str, real_size);
if (!str)
str = buf->str;
buf->str = NULL;
} else {
str = av_malloc(real_size);
if (str)
memcpy(str, buf->str, real_size);
else
ret = AVERROR(ENOMEM);
}
*ret_str = str;
} else {
if (av_bprint_is_allocated(buf))
av_freep(&buf->str);
}
buf->size = real_size;
return ret;
}
#define WHITESPACES " \n\t"
void av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_chars,
enum AVEscapeMode mode, int flags)
{
const char *src0 = src;
if (mode == AV_ESCAPE_MODE_AUTO)
mode = AV_ESCAPE_MODE_BACKSLASH; /* TODO: implement a heuristic */
switch (mode) {
case AV_ESCAPE_MODE_QUOTE:
/* enclose the string between '' */
av_bprint_chars(dstbuf, '\'', 1);
for (; *src; src++) {
if (*src == '\'')
av_bprintf(dstbuf, "'\\''");
else
av_bprint_chars(dstbuf, *src, 1);
}
av_bprint_chars(dstbuf, '\'', 1);
break;
/* case AV_ESCAPE_MODE_BACKSLASH or unknown mode */
default:
/* \-escape characters */
for (; *src; src++) {
int is_first_last = src == src0 || !*(src+1);
int is_ws = !!strchr(WHITESPACES, *src);
int is_strictly_special = special_chars && strchr(special_chars, *src);
int is_special =
is_strictly_special || strchr("'\\", *src) ||
(is_ws && (flags & AV_ESCAPE_FLAG_WHITESPACE));
if (is_strictly_special ||
(!(flags & AV_ESCAPE_FLAG_STRICT) &&
(is_special || (is_ws && is_first_last))))
av_bprint_chars(dstbuf, '\\', 1);
av_bprint_chars(dstbuf, *src, 1);
}
break;
}
}
#ifdef TEST
#undef printf
static void bprint_pascal(AVBPrint *b, unsigned size)
{
unsigned i, j;
unsigned p[42];
av_assert0(size < FF_ARRAY_ELEMS(p));
p[0] = 1;
av_bprintf(b, "%8d\n", 1);
for (i = 1; i <= size; i++) {
p[i] = 1;
for (j = i - 1; j > 0; j--)
p[j] = p[j] + p[j - 1];
for (j = 0; j <= i; j++)
av_bprintf(b, "%8d", p[j]);
av_bprintf(b, "\n");
}
}
int main(void)
{
AVBPrint b;
char buf[256];
struct tm testtime = { .tm_year = 100, .tm_mon = 11, .tm_mday = 20 };
av_bprint_init(&b, 0, -1);
bprint_pascal(&b, 5);
printf("Short text in unlimited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
printf("%s\n", b.str);
av_bprint_finalize(&b, NULL);
av_bprint_init(&b, 0, -1);
bprint_pascal(&b, 25);
printf("Long text in unlimited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
av_bprint_finalize(&b, NULL);
av_bprint_init(&b, 0, 2048);
bprint_pascal(&b, 25);
printf("Long text in limited buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
av_bprint_finalize(&b, NULL);
av_bprint_init(&b, 0, 1);
bprint_pascal(&b, 5);
printf("Short text in automatic buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
av_bprint_init(&b, 0, 1);
bprint_pascal(&b, 25);
printf("Long text in automatic buffer: %u/%u\n", (unsigned)strlen(b.str)/8*8, b.len);
/* Note that the size of the automatic buffer is arch-dependent. */
av_bprint_init(&b, 0, 0);
bprint_pascal(&b, 25);
printf("Long text count only buffer: %u/%u\n", (unsigned)strlen(b.str), b.len);
av_bprint_init_for_buffer(&b, buf, sizeof(buf));
bprint_pascal(&b, 25);
printf("Long text count only buffer: %u/%u\n", (unsigned)strlen(buf), b.len);
av_bprint_init(&b, 0, -1);
av_bprint_strftime(&b, "%Y-%m-%d", &testtime);
printf("strftime full: %u/%u \"%s\"\n", (unsigned)strlen(buf), b.len, b.str);
av_bprint_finalize(&b, NULL);
av_bprint_init(&b, 0, 8);
av_bprint_strftime(&b, "%Y-%m-%d", &testtime);
printf("strftime truncated: %u/%u \"%s\"\n", (unsigned)strlen(buf), b.len, b.str);
return 0;
}
#endif
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