Clean up handling of fallbacks and improve behavior somewhat with glibc iconv
Originally committed to SVN as r4776.
This commit is contained in:
Thomas Goyne
parent
9780243586
commit
3512c4e1fe
2 changed files with 138 additions and 112 deletions
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@ -75,16 +75,100 @@ static const char* GetRealEncodingName(const char* name) {
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namespace agi {
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namespace charset {
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static size_t get_bom_size(iconv_t cd) {
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// Most (but not all) iconv implementations automatically insert a BOM
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// at the beginning of text converted to UTF-8, UTF-16 and UTF-32, but
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// we usually don't want this, as some of the wxString using code
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// assumes there is no BOM (as the exact encoding is known externally)
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// As such, when doing conversions we will strip the BOM if it exists,
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// then manually add it when writing files
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char buff[8];
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const char* src = "";
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char *dst = buff;
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size_t srcLen = 1;
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size_t dstLen = 8;
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size_t res = iconv(cd, ICONV_CONST_CAST(&src), &srcLen, &dst, &dstLen);
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assert(res != iconv_failed);
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assert(srcLen == 0);
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size_t size = 0;
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for (src = buff; src < dst; ++src) {
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if (*src) ++size;
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}
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if (size) {
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// If there is a BOM, it will always be at least as big as the NUL
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size = std::max(size, (8 - dstLen) / 2);
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}
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return size;
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}
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static void eat_bom(iconv_t cd, size_t bomSize, const char** inbuf, size_t* inbytesleft, char** outbuf, size_t* outbytesleft) {
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// If this encoding has a forced BOM (i.e. it's UTF-16 or UTF-32 without
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// a specified byte order), skip over it
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if (bomSize > 0 && inbytesleft && *inbytesleft) {
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// libiconv marks the bom as written after writing the first
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// character after the bom rather than when it writes the bom, so
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// convert at least one extra character
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char bom[8];
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char *dst = bom;
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size_t dstSize = std::min((size_t)8, bomSize + *outbytesleft);
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const char *src = *inbuf;
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size_t srcSize = *inbytesleft;
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iconv(cd, ICONV_CONST_CAST(&src), &srcSize, &dst, &dstSize);
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}
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}
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#ifdef ICONV_POSIX
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struct iconv_fallbacks {
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class Converter {
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size_t bomSize;
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iconv_t cd;
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public:
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// subst is not used here because POSIX doesn't let you disable substitution
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Converter(bool, const char* sourceEncoding, const char* destEncoding)
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: cd(cd)
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{
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const char *dstEnc = GetRealEncodingName(destEncoding);
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cd = iconv_open(dstEnc, "UTF-8");
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if (cd == iconv_invalid) {
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throw UnsupportedConversion(std::string(dstEnc) + " is not a supported character set");
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}
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bomSize = get_bom_size(cd);
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iconv_close(cd);
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cd = iconv_open(dstEnc, 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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}
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~Converter() {
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if (cd != iconv_invalid) iconv_close(cd);
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}
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size_t Convert(const char** inbuf, size_t* inbytesleft, char** outbuf, size_t* outbytesleft) {
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eat_bom(cd, bomSize, inbuf, inbytesleft, outbuf, outbytesleft);
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size_t res = iconv(cd, ICONV_CONST_CAST(inbuf), inbytesleft, outbuf, outbytesleft);
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// This loop never does anything useful with a POSIX-compliant iconv
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// implementation, but those don't seem to actually exist
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while (res == iconv_failed && errno != E2BIG) {
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++*inbuf;
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--*inbytesleft;
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res = iconv(cd, ICONV_CONST_CAST(inbuf), inbytesleft, outbuf, outbytesleft);
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}
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return res;
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}
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};
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#endif
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#else
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class Converter : public iconv_fallbacks {
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bool subst;
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size_t bomSize;
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char invalidRep[8];
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size_t invalidRepSize;
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iconv_t cd;
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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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@ -101,137 +185,88 @@ class Converter : public iconv_fallbacks {
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callback(self->invalidRep, self->invalidRepSize, callback_arg);
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}
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}
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Converter(Converter const&);
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Converter& operator=(Converter const&);
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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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Converter(bool subst, const char* sourceEncoding, const char* destEncoding)
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{
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#ifndef ICONV_POSIX
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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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#endif
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char buff[8];
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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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// Most (but not all) iconv implementations automatically insert a BOM
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// at the beginning of text converted to UTF-8, UTF-16 and UTF-32, but
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// we usually don't want this, as some of the wxString using code
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// assumes there is no BOM (as the exact encoding is known externally)
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// As such, when doing conversions we will strip the BOM if it exists,
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// then manually add it when writing files
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const char* src = "";
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char *dst = buff;
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size_t srcLen = 1;
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size_t dstLen = 8;
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size_t res = iconv(cd, ICONV_CONST_CAST(&src), &srcLen, &dst, &dstLen);
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assert(res != iconv_failed);
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assert(srcLen == 0);
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bomSize = 0;
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for (src = buff; src < dst; ++src) {
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if (*src) ++bomSize;
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}
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if (bomSize) {
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// If there is a BOM, it will always be at least as big as the NUL
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bomSize = std::min(bomSize, (8 - dstLen) / 2);
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const char *dstEnc = GetRealEncodingName(destEncoding);
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cd = iconv_open(dstEnc, "UTF-8");
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if (cd == iconv_invalid) {
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throw UnsupportedConversion(std::string(dstEnc) + " is not a supported character set");
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}
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bomSize = get_bom_size(cd);
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// Get fallback character
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char sbuff[] = "?";
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src = sbuff;
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dst = invalidRep;
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dstLen = 4;
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srcLen = 1;
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const char sbuff[] = "?";
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const 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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res = operator()(cd, &src, &srcLen, &dst, &dstLen);
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size_t res = Convert(&src, &srcLen, &dst, &dstLen);
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assert(res != iconv_failed);
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assert(srcLen == 0);
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invalidRepSize = 4 - dstLen;
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iconv_close(cd);
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}
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size_t operator()(iconv_t cd, const char** inbuf, size_t* inbytesleft, char** outbuf, size_t* outbytesleft) {
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// If this encoding has a forced BOM (i.e. it's UTF-16 or UTF-32 without
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// a specified byte order), skip over it
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if (bomSize > 0 && inbytesleft && *inbytesleft) {
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// libiconv marks the bom as written after writing the first
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// character after the bom rather than when it writes the bom, so
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// convert at least one extra character
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char bom[8];
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char *dst = bom;
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size_t dstSize = std::min((size_t)8, bomSize + *outbytesleft);
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const char *src = *inbuf;
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size_t srcSize = *inbytesleft;
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iconv(cd, ICONV_CONST_CAST(&src), &srcSize, &dst, &dstSize);
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cd = iconv_open(dstEnc, 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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size_t res = iconv(cd, ICONV_CONST_CAST(inbuf), inbytesleft, outbuf, outbytesleft);
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#ifndef ICONV_POSIX
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if (!subst) return res;
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if (subst) {
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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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// 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, ICONV_CONST_CAST(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, ICONV_CONST_CAST(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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}
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~Converter() {
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if (cd != iconv_invalid) iconv_close(cd);
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}
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size_t Convert(const char** inbuf, size_t* inbytesleft, char** outbuf, size_t* outbytesleft) {
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eat_bom(cd, bomSize, inbuf, inbytesleft, outbuf, outbytesleft);
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size_t res = iconv(cd, ICONV_CONST_CAST(inbuf), inbytesleft, outbuf, outbytesleft);
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if (res == iconv_failed && errno == E2BIG && *outbytesleft == 0) {
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// libiconv checks if there are any bytes left in the output buffer
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// before checking if the conversion would actually write any
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// characters to the output buffer, resulting in occasional invalid
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// E2BIG false positives
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char buff[8];
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size_t buffsize = 8;
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char* out = buff;
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const 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, ICONV_CONST_CAST(&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 == 8) {
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err = errno;
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}
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else {
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if (buffsize != 8) {
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errno = E2BIG;
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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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#endif
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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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Converter conv(false, GetRealEncodingName(encoding));
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Converter cd(false, "UTF-8", encoding);
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char dbuff[4];
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char sbuff[] = "";
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@ -240,10 +275,9 @@ static size_t NulSize(const char* encoding) {
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size_t dstLen = sizeof(dbuff);
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size_t srcLen = 1;
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size_t ret = conv(cd, &src, &srcLen, &dst, &dstLen);
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size_t ret = cd.Convert(&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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@ -251,21 +285,14 @@ static size_t NulSize(const char* encoding) {
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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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, conv(new Converter(enableSubst, sourceEncoding, destEncoding))
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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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// These need to be set only after we verify that the source and dest
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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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@ -282,8 +309,8 @@ void IconvWrapper::Convert(std::string const& source, std::string &dest) {
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do {
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char *dst = buff;
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size_t dstLen = sizeof(buff);
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res = (*conv)(cd, &src, &srcLen, &dst, &dstLen);
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if (res == 0) (*conv)(cd, NULL, NULL, &dst, &dstLen);
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res = conv->Convert(&src, &srcLen, &dst, &dstLen);
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if (res == 0) conv->Convert(NULL, NULL, &dst, &dstLen);
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dest.append(buff, sizeof(buff) - dstLen);
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} while (res == iconv_failed && errno == E2BIG);
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@ -313,8 +340,8 @@ size_t IconvWrapper::Convert(const char* source, size_t sourceSize, char *dest,
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}
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size_t res = (*conv)(cd, &source, &sourceSize, &dest, &destSize);
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if (res == 0) res = (*conv)(cd, NULL, NULL, &dest, &destSize);
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size_t res = conv->Convert(&source, &sourceSize, &dest, &destSize);
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if (res == 0) res = conv->Convert(NULL, NULL, &dest, &destSize);
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if (res == iconv_failed) {
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switch (errno) {
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@ -341,7 +368,7 @@ size_t IconvWrapper::Convert(const char* source, size_t sourceSize, char *dest,
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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, source, sourceSize, dest, destSize);
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return conv->Convert(source, sourceSize, dest, destSize);
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}
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size_t IconvWrapper::RequiredBufferSize(std::string const& str) {
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@ -356,8 +383,8 @@ size_t IconvWrapper::RequiredBufferSize(const char* src, size_t srcLen) {
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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, &src, &srcLen, &dst, &dstSize);
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(*conv)(cd, NULL, NULL, &dst, &dstSize);
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res = conv->Convert(&src, &srcLen, &dst, &dstSize);
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conv->Convert(NULL, NULL, &dst, &dstSize);
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charsWritten += dst - buff;
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} while (res == iconv_failed && errno == E2BIG);
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@ -59,7 +59,6 @@ class Converter;
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/// @brief A C++ wrapper for iconv
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class IconvWrapper {
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iconv_t cd;
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size_t toNulLen;
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size_t fromNulLen;
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std::auto_ptr<Converter> conv;
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