327 lines
9.8 KiB
C++
327 lines
9.8 KiB
C++
// Copyright (c) 2010, Thomas Goyne <plorkyeran@aegisub.org>
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//
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// Permission to use, copy, modify, and distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice appear in all copies.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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//
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// $Id$
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/// @file charset_conv.cpp
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/// @brief Wrapper for libiconv to present a more C++-friendly API
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/// @ingroup libaegisub
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#ifndef LAGI_PRE
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#endif
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#include <libaegisub/charset_conv.h>
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#include <iconv.h>
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// Check if we can use advanced fallback capabilities added in GNU's iconv
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// implementation
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#if !defined(_LIBICONV_VERSION) || _LIBICONV_VERSION < 0x010A || defined(LIBICONV_PLUG)
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#define ICONV_POSIX
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#endif
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static const iconv_t iconv_invalid = (iconv_t)-1;
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static const size_t iconv_failed = (size_t)-1;
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namespace {
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struct ltstr {
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bool operator()(const char* s1, const char* s2) const {
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return strcmp(s1, s2) < 0;
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}
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};
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}
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/// @brief Map a user-friendly encoding name to the real encoding name
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static const char* GetRealEncodingName(const char* name) {
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static std::map<const char*, const char*, ltstr> prettyNames;
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if (prettyNames.empty()) {
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# define ADD(pretty, real) prettyNames[pretty] = real
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# include <libaegisub/charsets.def>
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# undef ADD
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}
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std::map<const char*, const char*, ltstr>::iterator real = prettyNames.find(name);
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if (real != prettyNames.end()) {
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return real->second;
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}
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return name;
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}
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namespace agi {
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namespace charset {
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#ifdef ICONV_POSIX
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class IconvWrapper::Converter {
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public:
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Converter(bool, const char*) { }
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size_t operator()(iconv_t cd, char** inbuf, size_t* inbytesleft, char** outbuf, size_t* outbytesleft) {
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return iconv(cd, inbuf, inbytesleft, outbuf, outbytesleft);
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}
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};
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#else
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class IconvWrapper::Converter : public iconv_fallbacks {
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private:
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bool subst;
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char invalidRep[4];
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size_t invalidRepSize;
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static void fallback(
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unsigned int code,
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void (*callback) (const char *buf, size_t buflen, void* callback_arg),
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void *callback_arg,
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void *convPtr)
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{
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// At some point in the future, this should probably switch to a real mapping
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// For now, there's just three cases: BOM to nothing, '\' to itself
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// (for Shift-JIS, which does not have \) and everything else to '?'
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if (code == 0xFEFF) return;
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if (code == 0x5C) callback("\\", 1, callback_arg);
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else {
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Converter *self = static_cast<Converter *>(convPtr);
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callback(self->invalidRep, self->invalidRepSize, callback_arg);
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}
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}
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public:
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Converter(bool subst, const char* targetEnc)
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: subst(subst)
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{
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data = this;
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mb_to_uc_fallback = NULL;
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mb_to_wc_fallback = NULL;
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uc_to_mb_fallback = fallback;
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wc_to_mb_fallback = NULL;
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char sbuff[] = "?";
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char* src = sbuff;
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char* dst = invalidRep;
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size_t dstLen = 4;
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size_t srcLen = 1;
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iconv_t cd = iconv_open(GetRealEncodingName(targetEnc), "UTF-8");
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assert(cd != iconv_invalid);
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size_t res = iconv(cd, &src, &srcLen, &dst, &dstLen);
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assert(res != iconv_failed);
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assert(srcLen == 0);
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iconv_close(cd);
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invalidRepSize = 4 - dstLen;
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}
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size_t operator()(iconv_t cd, char** inbuf, size_t* inbytesleft, char** outbuf, size_t* outbytesleft) {
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size_t res = iconv(cd, inbuf, inbytesleft, outbuf, outbytesleft);
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if (!subst) return res;
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// Save original errno so we can return it rather than the result from iconvctl
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int err = errno;
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// Some characters in the input string do not exist in the output encoding
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if (res == iconv_failed && err == EILSEQ) {
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// first try transliteration only
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int transliterate = 1;
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iconvctl(cd, ICONV_SET_TRANSLITERATE, &transliterate);
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res = iconv(cd, inbuf, inbytesleft, outbuf, outbytesleft);
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err = errno;
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transliterate = 0;
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iconvctl(cd, ICONV_SET_TRANSLITERATE, &transliterate);
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}
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if (res == iconv_failed && err == EILSEQ) {
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// Conversion still failed with transliteration enabled, so try our substitution
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iconvctl(cd, ICONV_SET_FALLBACKS, this);
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res = iconv(cd, inbuf, inbytesleft, outbuf, outbytesleft);
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err = errno;
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iconvctl(cd, ICONV_SET_FALLBACKS, NULL);
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}
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if (res == iconv_failed && err == E2BIG && *outbytesleft == 0) {
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// Check for E2BIG false positives
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char buff[4];
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size_t buffsize = 4;
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char* out = buff;
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char* in = *inbuf;
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size_t insize = *inbytesleft;
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iconvctl(cd, ICONV_SET_FALLBACKS, this);
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res = iconv(cd, &in, &insize, &out, &buffsize);
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// If no bytes of the output buffer were used, the original
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// conversion may have been successful
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if (buffsize == 4) {
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err = errno;
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}
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else {
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res = iconv_failed;
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}
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iconvctl(cd, ICONV_SET_FALLBACKS, NULL);
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}
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errno = err;
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return res;
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}
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};
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#endif
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// Calculate the size of NUL in the given character set
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static size_t NulSize(const char* encoding) {
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// We need a character set to convert from with a known encoding of NUL
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// UTF-8 seems like the obvious choice
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iconv_t cd = iconv_open(GetRealEncodingName(encoding), "UTF-8");
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assert(cd != iconv_invalid);
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char dbuff[4];
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char sbuff[] = "";
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char* dst = dbuff;
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char* src = sbuff;
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size_t dstLen = sizeof(dbuff);
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size_t srcLen = 1;
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size_t ret = iconv(cd, &src, &srcLen, &dst, &dstLen);
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assert(ret != iconv_failed);
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assert(dst - dbuff > 0);
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iconv_close(cd);
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return dst - dbuff;
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}
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IconvWrapper::IconvWrapper(const char* sourceEncoding, const char* destEncoding, bool enableSubst)
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: toNulLen(0)
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, fromNulLen(0)
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, conv(NULL)
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{
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cd = iconv_open(GetRealEncodingName(destEncoding), GetRealEncodingName(sourceEncoding));
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if (cd == iconv_invalid) {
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throw UnsupportedConversion(std::string("Cannot convert from ") + sourceEncoding + " to " + destEncoding);
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}
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// These need to be set only after we verify that the source and des
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// charsets are valid
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toNulLen = NulSize(destEncoding);
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fromNulLen = NulSize(sourceEncoding);
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conv.reset(new Converter(enableSubst, destEncoding));
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}
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IconvWrapper::~IconvWrapper() {
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if (cd != iconv_invalid) iconv_close(cd);
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}
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std::string IconvWrapper::Convert(std::string const& source) {
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std::string dest;
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Convert(source, dest);
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return dest;
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}
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void IconvWrapper::Convert(std::string const& source, std::string &dest) {
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/// @todo Investigate if it's worth using ropes to avoid having to convert
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/// everything twice. It probably isn't.
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size_t len = RequiredBufferSize(source);
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dest.resize(len);
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// This is technically invalid as C++03 does not require that strings use
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// a single contiguous block of memory. However, no implementation has ever
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// not done so and C++0x does require that it be contiguous
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Convert(source.data(), source.size(), &dest[0], len);
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}
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size_t IconvWrapper::Convert(const char* source, size_t sourceSize, char *dest, size_t destSize) {
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if (sourceSize == (size_t)-1) {
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sourceSize = SrcStrLen(source);
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}
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// POSIX requires that inbuf be const char **, but libiconv uses char**
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size_t res = (*conv)(cd, const_cast<char **>(&source), &sourceSize, &dest, &destSize);
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if (res == iconv_failed) {
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switch (errno) {
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case E2BIG:
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throw BufferTooSmall(
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"Destination buffer was not large enough to fit converted "
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"string.");
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case EINVAL:
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throw BadInput(
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"One or more characters in the input string were not valid "
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"characters in the given input encoding");
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case EILSEQ:
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throw BadOutput(
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"One or more characters could not be converted to the "
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"selected target encoding and the version of iconv "
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"Aegisub was built with does not have useful fallbacks. "
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"For best results, please build Aegisub using a recent "
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"version of GNU iconv.");
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default:
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throw ConversionFailure("An unknown conversion failure occured");
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}
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}
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return res;
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}
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size_t IconvWrapper::Convert(const char** source, size_t* sourceSize, char** dest, size_t* destSize) {
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return (*conv)(cd, const_cast<char **>(source), sourceSize, dest, destSize);
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}
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size_t IconvWrapper::RequiredBufferSize(std::string const& str) {
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return RequiredBufferSize(str.data(), str.size());
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}
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size_t IconvWrapper::RequiredBufferSize(const char* src, size_t srcLen) {
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char buff[512];
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size_t charsWritten = 0;
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size_t res;
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do {
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char* dst = buff;
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size_t dstSize = sizeof(buff);
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res = (*conv)(cd, const_cast<char **>(&src), &srcLen, &dst, &dstSize);
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charsWritten += dst - buff;
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} while (res == iconv_failed && errno == E2BIG);
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if (res == iconv_failed) {
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switch (errno) {
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case EINVAL:
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throw BadInput(
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"One or more characters in the input string were not valid "
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"characters in the given input encoding");
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case EILSEQ:
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throw BadOutput(
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"One or more characters could not be converted to the "
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"selected target encoding and the version of iconv "
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"Aegisub was built with does not have useful fallbacks. "
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"For best results, please build Aegisub using a recent "
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"version of GNU iconv.");
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default:
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throw ConversionFailure("An unknown conversion failure occured");
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}
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}
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return charsWritten;
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}
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static size_t mbstrlen(const char* str, size_t nulLen) {
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const char *ptr;
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switch (nulLen) {
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case 1:
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return strlen(str);
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case 2:
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for (ptr = str; *reinterpret_cast<const uint16_t *>(ptr) != 0; ptr += 2) ;
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return ptr - str;
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case 4:
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for (ptr = str; *reinterpret_cast<const uint32_t *>(ptr) != 0; ptr += 4) ;
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return ptr - str;
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default:
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return (size_t)-1;
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}
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}
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size_t IconvWrapper::SrcStrLen(const char* str) {
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return mbstrlen(str, fromNulLen);
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}
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size_t IconvWrapper::DstStrLen(const char* str) {
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return mbstrlen(str, toNulLen);
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}
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}
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}
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