/*
  * 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 <stdarg.h>
 

 #include "attributes.h"

 #include "avstring.h"

 
 /**
  * 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, 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.
  */

 
 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];

 )

 
 /**

  * Convenience macros for special values for av_bprint_init() size_max
  * parameter.
  */
 #define AV_BPRINT_SIZE_UNLIMITED  ((unsigned)-1)
 #define AV_BPRINT_SIZE_AUTOMATIC  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 */