libavutil_avstring.pas

(*
 * 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
 *)

(*
 * FFVCL - Delphi FFmpeg VCL Components
 * http://www.DelphiFFmpeg.com
 *
 * Original file: libavutil/avstring.h
 * Ported by CodeCoolie@CNSW 2008/03/26 -> $Date:: 2016-08-29 #$
 *)

(*
FFmpeg Delphi/Pascal Headers and Examples License Agreement

A modified part of FFVCL - Delphi FFmpeg VCL Components.
Copyright (c) 2008-2016 DelphiFFmpeg.com
All rights reserved.
http://www.DelphiFFmpeg.com

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.

This source code is provided "as is" by DelphiFFmpeg.com without
warranty of any kind, either expressed or implied, including but not
limited to the implied warranties of merchantability and/or fitness
for a particular purpose.

Please also notice the License agreement of FFmpeg libraries.
*)

unit libavutil_avstring;

interface

{$I CompilerDefines.inc}

uses
  FFTypes;

{$I libversion.inc}

(**
 * @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
 *)
function av_strstart(const str, pfx: PAnsiChar; const ptr: PPAnsiChar): Integer; cdecl; external AVUTIL_LIBNAME name _PU + 'av_strstart';

(**
 * 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
 *)
function av_stristart(const str, pfx: PAnsiChar; const ptr: PPAnsiChar): Integer; cdecl; external AVUTIL_LIBNAME name _PU + 'av_stristart';

(**
 * 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
 *)
function av_stristr(const haystack, needle: PAnsiChar): PAnsiChar; cdecl; external AVUTIL_LIBNAME name _PU + 'av_stristr';

(**
 * 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
 *)
function av_strnstr(const haystack, needle: PAnsiChar; hay_length: Cardinal): PAnsiChar; cdecl; external AVUTIL_LIBNAME name _PU + 'av_strnstr';

(**
 * 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.
 *)
function av_strlcpy(dst: PAnsiChar; const src: PAnsiChar; size: Cardinal{size_t}): Cardinal{size_t}; cdecl; external AVUTIL_LIBNAME name _PU + 'av_strlcpy';

(**
 * 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.
 *)
function av_strlcat(dst: PAnsiChar; const src: PAnsiChar; size: Cardinal{size_t}): Cardinal{size_t}; cdecl; external AVUTIL_LIBNAME name _PU + 'av_strlcat';

(**
 * 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
 *)
function av_strlcatf(dst: PAnsiChar; size: Cardinal{size_t}; const fmt: PAnsiChar): Cardinal{size_t}; cdecl varargs; external AVUTIL_LIBNAME name _PU + 'av_strlcatf';

(**
 * Get the count of continuous non zero chars starting from the beginning.
 *
 * @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().
 *)
function av_asprintf(const fmt: PAnsiChar): PAnsiChar; cdecl varargs; external AVUTIL_LIBNAME name _PU + 'av_asprintf';

(**
 * Convert a number to an av_malloced string.
 *)
function av_d2str(d: Double): PAnsiChar; cdecl; external AVUTIL_LIBNAME name _PU + 'av_d2str';

(**
 * 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
 *)
function av_get_token(const buf: PPAnsiChar; const term: PAnsiChar): PAnsiChar; cdecl; external AVUTIL_LIBNAME name _PU + 'av_get_token';

(**
 * 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
 *)
function av_strtok(s: PAnsiChar; const delim: PAnsiChar; saveptr: PPAnsiChar): PAnsiChar; cdecl; external AVUTIL_LIBNAME name _PU + 'av_strtok';

(**
 * 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 int av_toupper(int c)
{
    if (c >= 'a' && c <= 'z')
        c ^= 0x20;
    return c;
}

(**
 * Locale-independent conversion of ASCII characters to lowercase.
 *)
//static inline 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
 *)
function av_strcasecmp(const a, b: PAnsiChar): Integer; cdecl; external AVUTIL_LIBNAME name _PU + 'av_strcasecmp';

(**
 * Locale-independent case-insensitive compare.
 * @note This means only ASCII-range characters are case-insensitive
 *)
function av_strncasecmp(const a, b: PAnsiChar; n: Cardinal{size_t}): Integer; cdecl; external AVUTIL_LIBNAME name _PU + 'av_strncasecmp';


(**
 * Thread safe basename.
 * @param path the path, on DOS both \ and / are considered separators.
 * @return pointer to the basename substring.
 *)
function av_basename(const path: PAnsiChar): PAnsiChar; cdecl; external AVUTIL_LIBNAME name _PU + 'av_basename';

(**
 * Thread safe dirname.
 * @param path the path, on DOS both \ and / are considered separators.
 * @return the path with the separator replaced by the string terminator or ".".
 * @note the function may change the input string.
 *)
function av_dirname(path: PAnsiChar): PAnsiChar; cdecl; external AVUTIL_LIBNAME name _PU + 'av_dirname';

(**
 * 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.
 *)
function av_match_name(const name, names: PAnsiChar): Integer; cdecl; external AVUTIL_LIBNAME name _PU + 'av_match_name';

{**
 * 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.
 *}
function av_append_path_component(const path: PAnsiChar; const component: PAnsiChar): PAnsiChar; cdecl; external AVUTIL_LIBNAME name _PU + 'av_append_path_component';

type
  TAVEscapeMode = (
    AV_ESCAPE_MODE_AUTO,      ///< Use auto-selected escaping mode.
    AV_ESCAPE_MODE_BACKSLASH, ///< Use backslash escaping.
    AV_ESCAPE_MODE_QUOTE      ///< Use single-quote 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.
 *)
const
  AV_ESCAPE_FLAG_WHITESPACE = $01;

(**
 * 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.
 *)
  AV_ESCAPE_FLAG_STRICT = $02;

(**
 * 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()
 *)
function av_escape(dst: PAnsiChar; const src, special_chars: PAnsiChar;
                  mode: TAVEscapeMode; flags: Integer): Integer; cdecl; external AVUTIL_LIBNAME name _PU + 'av_escape';

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

  AV_UTF8_FLAG_ACCEPT_ALL =
    AV_UTF8_FLAG_ACCEPT_INVALID_BIG_CODES or AV_UTF8_FLAG_ACCEPT_NON_CHARACTERS or 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
 *)
function av_utf8_decode(codep: PLongInt; const bufp: PPByte; const buf_end: PByte;
                   flags: Cardinal): Integer; cdecl; external AVUTIL_LIBNAME name _PU + 'av_utf8_decode';

(**
 * 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.
 *)
function av_match_list(const name, list: PAnsiChar; separator: AnsiChar): Integer; cdecl; external AVUTIL_LIBNAME name _PU + 'av_match_list';

(**
 * @}
 *)

function av_strnlen(const s: PAnsiChar; len: Cardinal): Cardinal; {$IFDEF USE_INLINE}inline;{$ENDIF}

implementation

function av_strnlen(const s: PAnsiChar; len: Cardinal): Cardinal;
var
  i: Cardinal;
begin
  for i := 0 to len - 1 do
    if s[i] = #0 then
    begin
      Result := i;
      Exit;
    end;
  Result := len;
end;

end.