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lavu: add av_bprintf and related.

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This commit is contained in:
Nicolas George 2012-02-01 20:37:50 +01:00
parent 594a3d6315
commit b75c67dc01
5 changed files with 350 additions and 3 deletions
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3
doc/APIchanges
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@ -13,6 +13,9 @@ libavutil: 2011-04-18
API changes, most recent first:
2012-03-21 - xxxxxxx - lavu 51.43.100
Add bprint.h for bprint API.
2012-02-21 - xxxxxxx - lavc 54.4.100
Add av_get_pcm_codec() function.

6
libavutil/Makefile
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@ -10,6 +10,7 @@ HEADERS = adler32.h \
avstring.h \
avutil.h \
base64.h \
bprint.h \
bswap.h \
common.h \
cpu.h \
@ -47,6 +48,7 @@ OBJS = adler32.o \
audioconvert.o \
avstring.o \
base64.o \
bprint.o \
cpu.o \
crc.o \
des.o \
@ -81,8 +83,8 @@ OBJS-$(ARCH_PPC) += ppc/cpu.o
OBJS-$(ARCH_X86) += x86/cpu.o
TESTPROGS = adler32 aes avstring base64 cpu crc des eval file fifo lfg lls \
md5 opt pca parseutils random_seed rational sha tree
TESTPROGS = adler32 aes avstring base64 bprint cpu crc des eval file fifo \
lfg lls md5 opt pca parseutils random_seed rational sha tree
TESTPROGS-$(HAVE_LZO1X_999_COMPRESS) += lzo
TOOLS = ffeval

2
libavutil/avutil.h
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@ -153,7 +153,7 @@
*/
#define LIBAVUTIL_VERSION_MAJOR 51
#define LIBAVUTIL_VERSION_MINOR 42
#define LIBAVUTIL_VERSION_MINOR 43
#define LIBAVUTIL_VERSION_MICRO 100
#define LIBAVUTIL_VERSION_INT AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \

206
libavutil/bprint.c Normal file
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@ -0,0 +1,206 @@
/*
* 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 "bprint.h"
#include "common.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_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_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);
}
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;
}
#ifdef TEST
#undef printf
static void bprint_pascal(AVBPrint *b, unsigned size)
{
unsigned p[size + 1], i, j;
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;
av_bprint_init(&b, 0, -1);
bprint_pascal(&b, 5);
printf("Short text in unlimited buffer: %zu/%u\n", 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: %zu/%u\n", 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: %zu/%u\n", 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: %zu/%u\n", strlen(b.str), b.len);
av_bprint_init(&b, 0, 1);
bprint_pascal(&b, 25);
printf("Long text in automatic buffer: %zu/%u\n", strlen(b.str), b.len);
/* Note that the size of the automatic buffer is arch-dependant. */
av_bprint_init(&b, 0, 0);
bprint_pascal(&b, 25);
printf("Long text count only buffer: %zu/%u\n", strlen(b.str), b.len);
return 0;
}
#endif

136
libavutil/bprint.h Normal file
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@ -0,0 +1,136 @@
/*
* 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
*/
#ifndef AVUTIL_BPRINT_H
#define AVUTIL_BPRINT_H
#include "attributes.h"
/**
* Define a structure with extra padding to a fixed size
* This helps ensuring binary compatibility with future versions.
*/
#define FF_PAD_STRUCTURE(size, ...) \
__VA_ARGS__ \
char reserved_padding[size - sizeof(struct { __VA_ARGS__ })];
/**
* Buffer to print data progressively
*
* The string buffer grows as necessary and is always 0-terminated.
* The content of the string is never accessed, and thus is
* encoding-agnostic and can even hold binary data.
*
* Small buffers are kept in the structure itself, and thus require no
* memory allocation at all (unless the contents of the buffer is needed
* after the structure goes out of scope). This is almost as lightweight as
* declaring a local "char buf[512]".
*
* The length of the string can go beyond the allocated size: the buffer is
* then truncated, but the functions still keep account of the actual total
* length.
*
* In other words, buf->len can be greater than buf->size and records the
* total length of what would have been to the buffer if there had been
* enough memory.
*
* Append operations do not need to be tested for failure: if a memory
* allocation fails, data stop being appended to the buffer, but the length
* is still updated. This situation can be tested with
* av_bprint_is_complete().
*
* The size_max field determines several possible behaviours:
*
* size_max = -1 (= UINT_MAX) or any large value will let the buffer be
* reallocated as necessary, with an amortized linear cost.
*
* size_max = 0 prevents writing anything to the buffer: only the total
* length is computed. The write operations can then possibly be repeated in
* a buffer with exactly the necessary size
* (using size_init = size_max = len + 1).
*
* size_max = 1 is automatically replaced by the exact size available in the
* structure itself, thus ensuring no dynamic memory allocation. The
* internal buffer is large enough to hold a reasonable paragraph of text,
* such as the current paragraph.
*/
typedef struct AVBPrint {
FF_PAD_STRUCTURE(1024,
char *str; /** string so far */
unsigned len; /** length so far */
unsigned size; /** allocated memory */
unsigned size_max; /** maximum allocated memory */
char reserved_internal_buffer[1];
)
} AVBPrint;
/**
* Init a print buffer.
*
* @param buf buffer to init
* @param size_init initial size (including the final 0)
* @param size_max maximum size;
* 0 means do not write anything, just count the length;
* 1 is replaced by the maximum value for automatic storage
*/
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max);
/**
* Convenience macros for special values for size_max.
*/
#define AV_BPRINT_SIZE_UNLIMITED ((unsigned)-1)
#define AV_BPRINT_SIZE_AUTOMATIC 1
#define AV_BPRINT_SIZE_COUNT_ONLY 0
/**
* Append a formated string to a print buffer.
*/
void av_bprintf(AVBPrint *buf, const char *fmt, ...) av_printf_format(2, 3);
/**
* Append char c n times to a print buffer.
*/
void av_bprint_chars(AVBPrint *buf, char c, unsigned n);
/**
* Test if the print buffer is complete (not truncated).
*
* It may have been truncated due to a memory allocation failure
* or the size_max limit (compare size and size_max if necessary).
*/
static inline int av_bprint_is_complete(AVBPrint *buf)
{
return buf->len < buf->size;
}
/**
* Finalize a print buffer.
*
* The print buffer can no longer be used afterwards,
* but the len and size fields are still valid.
*
* @arg[out] ret_str if not NULL, used to return a permanent copy of the
* buffer contents, or NULL if memory allocation fails;
* if NULL, the buffer is discarded and freed
* @return 0 for success or error code (probably AVERROR(ENOMEM))
*/
int av_bprint_finalize(AVBPrint *buf, char **ret_str);
#endif /* AVUTIL_BPRINT_H */