ffmpeg/libavutil/avstring.h

/*
 * Copyright (c) 2007 Mans Rullgard
 *
 * 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_AVSTRING_H
#define AVUTIL_AVSTRING_H

#include <stddef.h>
#include "attributes.h"

/**
 * @addtogroup lavu_string
 * @{
 */

/**
 * Return non-zero if pfx is a prefix of str. If it is, *ptr is set to
 * the address of the first character in str after the prefix.
 *
 * @param str input string
 * @param pfx prefix to test
 * @param ptr updated if the prefix is matched inside str
 * @return non-zero if the prefix matches, zero otherwise
 */
int av_strstart(const char *str, const char *pfx, const char **ptr);

/**
 * Return non-zero if pfx is a prefix of str independent of case. If
 * it is, *ptr is set to the address of the first character in str
 * after the prefix.
 *
 * @param str input string
 * @param pfx prefix to test
 * @param ptr updated if the prefix is matched inside str
 * @return non-zero if the prefix matches, zero otherwise
 */
int av_stristart(const char *str, const char *pfx, const char **ptr);

/**
 * Locate the first case-independent occurrence in the string haystack
 * of the string needle.  A zero-length string needle is considered to
 * match at the start of haystack.
 *
 * This function is a case-insensitive version of the standard strstr().
 *
 * @param haystack string to search in
 * @param needle   string to search for
 * @return         pointer to the located match within haystack
 *                 or a null pointer if no match
 */
char *av_stristr(const char *haystack, const char *needle);

/**
 * Copy the string src to dst, but no more than size - 1 bytes, and
 * null-terminate dst.
 *
 * This function is the same as BSD strlcpy().
 *
 * @param dst destination buffer
 * @param src source string
 * @param size size of destination buffer
 * @return the length of src
 *
 * @warning since the return value is the length of src, src absolutely
 * _must_ be a properly 0-terminated string, otherwise this will read beyond
 * the end of the buffer and possibly crash.
 */
size_t av_strlcpy(char *dst, const char *src, size_t size);

/**
 * Append the string src to the string dst, but to a total length of
 * no more than size - 1 bytes, and null-terminate dst.
 *
 * This function is similar to BSD strlcat(), but differs when
 * size <= strlen(dst).
 *
 * @param dst destination buffer
 * @param src source string
 * @param size size of destination buffer
 * @return the total length of src and dst
 *
 * @warning since the return value use the length of src and dst, these
 * absolutely _must_ be a properly 0-terminated strings, otherwise this
 * will read beyond the end of the buffer and possibly crash.
 */
size_t av_strlcat(char *dst, const char *src, size_t size);

/**
 * Append output to a string, according to a format. Never write out of
 * the destination buffer, and always put a terminating 0 within
 * the buffer.
 * @param dst destination buffer (string to which the output is
 *  appended)
 * @param size total size of the destination buffer
 * @param fmt printf-compatible format string, specifying how the
 *  following parameters are used
 * @return the length of the string that would have been generated
 *  if enough space had been available
 */
size_t av_strlcatf(char *dst, size_t size, const char *fmt, ...) av_printf_format(3, 4);

/**
 * Print arguments following specified format into a large enough auto
 * allocated buffer. It is similar to GNU asprintf().
 * @param fmt printf-compatible format string, specifying how the
 *            following parameters are used.
 * @return the allocated string
 * @note You have to free the string yourself with av_free().
 */
char *av_asprintf(const char *fmt, ...) av_printf_format(1, 2);

/**
 * Convert a number to a av_malloced string.
 */
char *av_d2str(double d);

/**
 * Unescape the given string until a non escaped terminating char,
 * and return the token corresponding to the unescaped string.
 *
 * The normal \ and ' escaping is supported. Leading and trailing
 * whitespaces are removed, unless they are escaped with '\' or are
 * enclosed between ''.
 *
 * @param buf the buffer to parse, buf will be updated to point to the
 * terminating char
 * @param term a 0-terminated list of terminating chars
 * @return the malloced unescaped string, which must be av_freed by
 * the user, NULL in case of allocation failure
 */
char *av_get_token(const char **buf, const char *term);

/**
 * Split the string into several tokens which can be accessed by
 * successive calls to av_strtok().
 *
 * A token is defined as a sequence of characters not belonging to the
 * set specified in delim.
 *
 * On the first call to av_strtok(), s should point to the string to
 * parse, and the value of saveptr is ignored. In subsequent calls, s
 * should be NULL, and saveptr should be unchanged since the previous
 * call.
 *
 * This function is similar to strtok_r() defined in POSIX.1.
 *
 * @param s the string to parse, may be NULL
 * @param delim 0-terminated list of token delimiters, must be non-NULL
 * @param saveptr user-provided pointer which points to stored
 * information necessary for av_strtok() to continue scanning the same
 * string. saveptr is updated to point to the next character after the
 * first delimiter found, or to NULL if the string was terminated
 * @return the found token, or NULL when no token is found
 */
char *av_strtok(char *s, const char *delim, char **saveptr);

/**
 * Locale independent conversion of ASCII characters to upper case.
 */
static inline int av_toupper(int c)
{
    if (c >= 'a' && c <= 'z')
        c ^= 0x20;
    return c;
}

/**
 * Locale independent conversion of ASCII characters to lower case.
 */
static inline int av_tolower(int c)
{
    if (c >= 'A' && c <= 'Z')
        c ^= 0x20;
    return c;
}

/**
 * Locale independent case-insensitive compare.
 * @note This means only ASCII-range characters are case-insensitive
 */
int av_strcasecmp(const char *a, const char *b);

/**
 * Locale independent case-insensitive compare.
 * @note This means only ASCII-range characters are case-insensitive
 */
int av_strncasecmp(const char *a, const char *b, size_t n);

/**
 * @}
 */

#endif /* AVUTIL_AVSTRING_H */