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// utf8.h: utilities for converting to and from UTF-8
//
// Copyright (C) 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
//
// Based on the public domain work of Thatcher Ulrich <tu@tulrich.com> 2004
#ifndef UTF8_H
#define UTF8_H
#include <string>
#include <boost/cstdint.hpp> // for C99 int types
#include <vector>
#include "dsodefs.h" // For DSOEXPORT
namespace gnash {
/// Utilities to convert between std::string and std::wstring.
//
/// Strings in Gnash are generally stored as std::strings.
/// We have to deal, however, with characters larger than standard
/// ASCII (128), which can be encoded in two different ways.
///
/// SWF6 and later use UTF-8, encoded as multibyte characters and
/// allowing many thousands of unique codes. Multibyte characters are
/// difficult to handle, as their length - used for many string
/// operations - is not certain without parsing the string.
/// Converting the string to a wstring (generally a uint32_t - the
/// pp seems only to handle characters up to 65535 - two bytes is
/// the minimum size of a wchar) facilitates string operations, as
/// the length of the string is equal to the number of valid characters.
///
/// SWF5 and earlier, however, used the ISO-8859 specification,
/// allowing the standard 128 ASCII characters plus 128 extra
/// characters that depend on the particular subset of ISO-8859.
/// Characters are 8 bits, not the ASCII standard 7. SWF5 cannot
/// handle multi-byte characters without special functions.
///
/// It is important that SWF5 can distinguish between the two encodings,
/// so we cannot convert all strings to UTF-8.
//
/// Please note that, although this is called utf8, what the Adobe
/// player uses is only loosely related to real unicode, so the
/// encoding support here is correspondingly non-standard.
namespace utf8 {
/// Converts a std::string with multibyte characters into a std::wstring.
//
/// @return a version-dependent wstring.
/// @param str the canonical string to convert.
/// @param version the SWF version, used to decide how to decode the string.
//
/// For SWF5, UTF-8 (or any other) multibyte encoded characters are
/// converted char by char, mangling the string.
DSOEXPORT std::wstring decodeCanonicalString(const std::string& str, int version);
/// Converts a std::wstring into canonical std::string.
//
/// @return a version-dependent encoded std::string.
/// @param wstr the wide string to convert.
/// @param version the SWF version, used to decide how to encode the string.
///
/// For SWF 5, each character is stored as an 8-bit (at least) char, rather
/// than converting it to a canonical UTF-8 byte sequence. Gnash can then
/// distinguish between 8-bit characters, which it handles correctly, and
/// multi-byte characters, which are regarded as multiple characters for
/// string methods.
DSOEXPORT std::string encodeCanonicalString(const std::wstring& wstr, int version);
/// Return the next Unicode character in the UTF-8 encoded string.
//
/// Invalid UTF-8 sequences produce a U+FFFD character
/// as output. Advances string iterator past the character
/// returned, unless the returned character is '\0', in which
/// case the iterator does not advance.
DSOEXPORT boost::uint32_t decodeNextUnicodeCharacter(std::string::const_iterator& it,
const std::string::const_iterator& e);
/// \brief Encodes the given wide character into a canonical
/// string, theoretically up to 6 chars in length.
DSOEXPORT std::string encodeUnicodeCharacter(boost::uint32_t ucs_character);
/// Encodes the given wide character into an at least 8-bit character.
//
/// Allows storage of Latin1 (ISO-8859-1) characters. This
/// is the format of SWF5 and below.
DSOEXPORT std::string encodeLatin1Character(boost::uint32_t ucsCharacter);
enum TextEncoding {
encUNSPECIFIED,
encUTF8,
encUTF16BE,
encUTF16LE,
encUTF32BE,
encUTF32LE,
encSCSU,
encUTF7,
encUTFEBCDIC,
encBOCU1
};
/// Interpret (and skip) Byte Order Mark in input stream
//
/// This function takes a pointer to a buffer and returns
/// the start of actual data after an eventual BOM.
/// No conversion is performed, no bytes copy, just skipping of
/// the BOM snippet and interpretation of it returned to the
/// encoding input parameter.
///
/// See http://en.wikipedia.org/wiki/Byte-order_mark
///
/// @param in
/// The input buffer.
///
/// @param size
/// Size of the input buffer, will be decremented by the
/// size of the BOM, if any.
///
/// @param encoding
/// Output parameter, will always be set.
/// encUNSPECIFIED if no BOM is found.
///
/// @returns
/// A pointer either equal to 'in' or some bytes inside it.
///
DSOEXPORT char* stripBOM(char* in, size_t& size, TextEncoding& encoding);
/// Return name of a text encoding
DSOEXPORT const char* textEncodingName(TextEncoding enc);
enum EncodingGuess {
ENCGUESS_UNICODE = 0,
ENCGUESS_JIS = 1,
ENCGUESS_OTHER = 2
};
/// Common code for guessing at the encoding of random text, between
// Shift-Jis, UTF8, and other. Puts the DisplayObject count in length,
// and the offsets to the DisplayObjects in offsets, if offsets is not NULL.
// If not NULL, offsets should be at least s.length().
// offsets are not accurate if the return value is GUESSENC_OTHER
//
/// TODO: It's doubtful if this even works, and it may not be useful at
/// all.
EncodingGuess guessEncoding(const std::string& s, int& length,
std::vector<int>& offsets);
} // namespace utf8
} // namespace gnash
#endif // UTF8_H
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