tor-browser

avstring.h (14940B)

---

/*
* 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 <stdint.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);

/**
* Locate the first occurrence of the string needle in the string haystack
* where not more than hay_length characters are searched. A zero-length
* string needle is considered to match at the start of haystack.
*
* This function is a length-limited version of the standard strstr().
*
* @param haystack   string to search in
* @param needle     string to search for
* @param hay_length length of string to search in
* @return           pointer to the located match within haystack
*                   or a null pointer if no match
*/
char *av_strnstr(const char *haystack, const char *needle, size_t hay_length);

/**
* 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);

/**
* Get the count of continuous non zero chars starting from the beginning.
*
* @param s   the string whose length to count
* @param len maximum number of characters to check in the string, that
*            is the maximum value which is returned by the function
*/
static inline size_t av_strnlen(const char *s, size_t len)
{
   size_t i;
   for (i = 0; i < len && s[i]; i++)
       ;
   return i;
}

/**
* 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);

/**
* 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 isdigit.
*/
static inline av_const int av_isdigit(int c)
{
   return c >= '0' && c <= '9';
}

/**
* Locale-independent conversion of ASCII isgraph.
*/
static inline av_const int av_isgraph(int c)
{
   return c > 32 && c < 127;
}

/**
* Locale-independent conversion of ASCII isspace.
*/
static inline av_const int av_isspace(int c)
{
   return c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' ||
          c == '\v';
}

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

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

/**
* Locale-independent conversion of ASCII isxdigit.
*/
static inline av_const int av_isxdigit(int c)
{
   c = av_tolower(c);
   return av_isdigit(c) || (c >= 'a' && c <= 'f');
}

/**
* 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);

/**
* Locale-independent strings replace.
* @note This means only ASCII-range characters are replaced.
*/
char *av_strireplace(const char *str, const char *from, const char *to);

/**
* Thread safe basename.
* @param path the string to parse, on DOS both \ and / are considered separators.
* @return pointer to the basename substring.
* If path does not contain a slash, the function returns a copy of path.
* If path is a NULL pointer or points to an empty string, a pointer
* to a string "." is returned.
*/
const char *av_basename(const char *path);

/**
* Thread safe dirname.
* @param path the string to parse, on DOS both \ and / are considered separators.
* @return A pointer to a string that's the parent directory of path.
* If path is a NULL pointer or points to an empty string, a pointer
* to a string "." is returned.
* @note the function may modify the contents of the path, so copies should be passed.
*/
const char *av_dirname(char *path);

/**
* Match instances of a name in a comma-separated list of names.
* List entries are checked from the start to the end of the names list,
* the first match ends further processing. If an entry prefixed with '-'
* matches, then 0 is returned. The "ALL" list entry is considered to
* match all names.
*
* @param name  Name to look for.
* @param names List of names.
* @return 1 on match, 0 otherwise.
*/
int av_match_name(const char *name, const char *names);

/**
* Append path component to the existing path.
* Path separator '/' is placed between when needed.
* Resulting string have to be freed with av_free().
* @param path      base path
* @param component component to be appended
* @return new path or NULL on error.
*/
char *av_append_path_component(const char *path, const char *component);

enum AVEscapeMode {
   AV_ESCAPE_MODE_AUTO,      ///< Use auto-selected escaping mode.
   AV_ESCAPE_MODE_BACKSLASH, ///< Use backslash escaping.
   AV_ESCAPE_MODE_QUOTE,     ///< Use single-quote escaping.
   AV_ESCAPE_MODE_XML,       ///< Use XML non-markup character data escaping.
};

/**
* Consider spaces special and escape them even in the middle of the
* string.
*
* This is equivalent to adding the whitespace characters to the special
* characters lists, except it is guaranteed to use the exact same list
* of whitespace characters as the rest of libavutil.
*/
#define AV_ESCAPE_FLAG_WHITESPACE (1 << 0)

/**
* Escape only specified special characters.
* Without this flag, escape also any characters that may be considered
* special by av_get_token(), such as the single quote.
*/
#define AV_ESCAPE_FLAG_STRICT (1 << 1)

/**
* Within AV_ESCAPE_MODE_XML, additionally escape single quotes for single
* quoted attributes.
*/
#define AV_ESCAPE_FLAG_XML_SINGLE_QUOTES (1 << 2)

/**
* Within AV_ESCAPE_MODE_XML, additionally escape double quotes for double
* quoted attributes.
*/
#define AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES (1 << 3)


/**
* Escape string in src, and put the escaped string in an allocated
* string in *dst, which must be freed with av_free().
*
* @param dst           pointer where an allocated string is put
* @param src           string to escape, must be non-NULL
* @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
* @return the length of the allocated string, or a negative error code in case of error
* @see av_bprint_escape()
*/
av_warn_unused_result
int av_escape(char **dst, const char *src, const char *special_chars,
             enum AVEscapeMode mode, int flags);

#define AV_UTF8_FLAG_ACCEPT_INVALID_BIG_CODES          1 ///< accept codepoints over 0x10FFFF
#define AV_UTF8_FLAG_ACCEPT_NON_CHARACTERS             2 ///< accept non-characters - 0xFFFE and 0xFFFF
#define AV_UTF8_FLAG_ACCEPT_SURROGATES                 4 ///< accept UTF-16 surrogates codes
#define AV_UTF8_FLAG_EXCLUDE_XML_INVALID_CONTROL_CODES 8 ///< exclude control codes not accepted by XML

#define AV_UTF8_FLAG_ACCEPT_ALL \
   AV_UTF8_FLAG_ACCEPT_INVALID_BIG_CODES|AV_UTF8_FLAG_ACCEPT_NON_CHARACTERS|AV_UTF8_FLAG_ACCEPT_SURROGATES

/**
* Read and decode a single UTF-8 code point (character) from the
* buffer in *buf, and update *buf to point to the next byte to
* decode.
*
* In case of an invalid byte sequence, the pointer will be updated to
* the next byte after the invalid sequence and the function will
* return an error code.
*
* Depending on the specified flags, the function will also fail in
* case the decoded code point does not belong to a valid range.
*
* @note For speed-relevant code a carefully implemented use of
* GET_UTF8() may be preferred.
*
* @param codep   pointer used to return the parsed code in case of success.
*                The value in *codep is set even in case the range check fails.
* @param bufp    pointer to the address the first byte of the sequence
*                to decode, updated by the function to point to the
*                byte next after the decoded sequence
* @param buf_end pointer to the end of the buffer, points to the next
*                byte past the last in the buffer. This is used to
*                avoid buffer overreads (in case of an unfinished
*                UTF-8 sequence towards the end of the buffer).
* @param flags   a collection of AV_UTF8_FLAG_* flags
* @return >= 0 in case a sequence was successfully read, a negative
* value in case of invalid sequence
*/
av_warn_unused_result
int av_utf8_decode(int32_t *codep, const uint8_t **bufp, const uint8_t *buf_end,
                  unsigned int flags);

/**
* Check if a name is in a list.
* @returns 0 if not found, or the 1 based index where it has been found in the
*            list.
*/
int av_match_list(const char *name, const char *list, char separator);

/**
* See libc sscanf manual for more information.
* Locale-independent sscanf implementation.
*/
int av_sscanf(const char *string, const char *format, ...);

/**
* @}
*/

#endif /* AVUTIL_AVSTRING_H */