mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2024-12-26 17:32:06 +00:00
58b86d8b68
Declare proper group, add the file to that group, group the defines and document them. Use lists to represents lists of cases.
252 lines
8.5 KiB
C
252 lines
8.5 KiB
C
/*
|
|
* 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
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* @ingroup lavu_avbprint
|
|
* AVBPrint public header
|
|
*/
|
|
|
|
#ifndef AVUTIL_BPRINT_H
|
|
#define AVUTIL_BPRINT_H
|
|
|
|
#include <stdarg.h>
|
|
|
|
#include "attributes.h"
|
|
#include "avstring.h"
|
|
|
|
/**
|
|
* @defgroup lavu_avbprint AVBPrint
|
|
* @ingroup lavu_data
|
|
*
|
|
* A buffer to print data progressively
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* Define a structure with extra padding to a fixed size
|
|
* This helps ensuring binary compatibility with future versions.
|
|
*/
|
|
|
|
#define FF_PAD_STRUCTURE(name, size, ...) \
|
|
struct ff_pad_helper_##name { __VA_ARGS__ }; \
|
|
typedef struct name { \
|
|
__VA_ARGS__ \
|
|
char reserved_padding[size - sizeof(struct ff_pad_helper_##name)]; \
|
|
} name;
|
|
|
|
/**
|
|
* 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, AVBPrint.len can be greater than AVBPrint.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 AVBPrint.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.
|
|
*/
|
|
|
|
FF_PAD_STRUCTURE(AVBPrint, 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];
|
|
)
|
|
|
|
/**
|
|
* @name Max size special values
|
|
* Convenience macros for special values for av_bprint_init() size_max
|
|
* parameter.
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* Buffer will be reallocated as necessary, with an amortized linear cost.
|
|
*/
|
|
#define AV_BPRINT_SIZE_UNLIMITED ((unsigned)-1)
|
|
/**
|
|
* Use the exact size available in the AVBPrint 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.
|
|
*/
|
|
#define AV_BPRINT_SIZE_AUTOMATIC 1
|
|
/**
|
|
* Do not write anything to the buffer, only calculate the total length.
|
|
*
|
|
* The write operations can then possibly be repeated in a buffer with
|
|
* exactly the necessary size (using `size_init = size_max = AVBPrint.len + 1`).
|
|
*/
|
|
#define AV_BPRINT_SIZE_COUNT_ONLY 0
|
|
/** @} */
|
|
|
|
/**
|
|
* 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
|
|
* any large value means that the internal buffer will be
|
|
* reallocated as needed up to that limit
|
|
* - `-1` is converted to `UINT_MAX`, the largest limit possible.
|
|
* Check also `AV_BPRINT_SIZE_*` macros.
|
|
*/
|
|
void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max);
|
|
|
|
/**
|
|
* Init a print buffer using a pre-existing buffer.
|
|
*
|
|
* The buffer will not be reallocated.
|
|
*
|
|
* @param buf buffer structure to init
|
|
* @param buffer byte buffer to use for the string data
|
|
* @param size size of buffer
|
|
*/
|
|
void av_bprint_init_for_buffer(AVBPrint *buf, char *buffer, unsigned size);
|
|
|
|
/**
|
|
* Append a formatted string to a print buffer.
|
|
*/
|
|
void av_bprintf(AVBPrint *buf, const char *fmt, ...) av_printf_format(2, 3);
|
|
|
|
/**
|
|
* Append a formatted string to a print buffer.
|
|
*/
|
|
void av_vbprintf(AVBPrint *buf, const char *fmt, va_list vl_arg);
|
|
|
|
/**
|
|
* Append char c n times to a print buffer.
|
|
*/
|
|
void av_bprint_chars(AVBPrint *buf, char c, unsigned n);
|
|
|
|
/**
|
|
* Append data to a print buffer.
|
|
*
|
|
* param buf bprint buffer to use
|
|
* param data pointer to data
|
|
* param size size of data
|
|
*/
|
|
void av_bprint_append_data(AVBPrint *buf, const char *data, unsigned size);
|
|
|
|
struct tm;
|
|
/**
|
|
* Append a formatted date and time to a print buffer.
|
|
*
|
|
* param buf bprint buffer to use
|
|
* param fmt date and time format string, see strftime()
|
|
* param tm broken-down time structure to translate
|
|
*
|
|
* @note due to poor design of the standard strftime function, it may
|
|
* produce poor results if the format string expands to a very long text and
|
|
* the bprint buffer is near the limit stated by the size_max option.
|
|
*/
|
|
void av_bprint_strftime(AVBPrint *buf, const char *fmt, const struct tm *tm);
|
|
|
|
/**
|
|
* Allocate bytes in the buffer for external use.
|
|
*
|
|
* @param[in] buf buffer structure
|
|
* @param[in] size required size
|
|
* @param[out] mem pointer to the memory area
|
|
* @param[out] actual_size size of the memory area after allocation;
|
|
* can be larger or smaller than size
|
|
*/
|
|
void av_bprint_get_buffer(AVBPrint *buf, unsigned size,
|
|
unsigned char **mem, unsigned *actual_size);
|
|
|
|
/**
|
|
* Reset the string to "" but keep internal allocated data.
|
|
*/
|
|
void av_bprint_clear(AVBPrint *buf);
|
|
|
|
/**
|
|
* 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(const 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);
|
|
|
|
/**
|
|
* Escape the content in src and append it to dstbuf.
|
|
*
|
|
* @param dstbuf already inited destination bprint buffer
|
|
* @param src string containing the text to escape
|
|
* @param special_chars string containing the special characters which
|
|
* need to be escaped, can be NULL
|
|
* @param mode escape mode to employ, see AV_ESCAPE_MODE_* macros.
|
|
* Any unknown value for mode will be considered equivalent to
|
|
* AV_ESCAPE_MODE_BACKSLASH, but this behaviour can change without
|
|
* notice.
|
|
* @param flags flags which control how to escape, see AV_ESCAPE_FLAG_* macros
|
|
*/
|
|
void av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_chars,
|
|
enum AVEscapeMode mode, int flags);
|
|
|
|
/** @} */
|
|
|
|
#endif /* AVUTIL_BPRINT_H */
|