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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "nsUnicodeToBIG5.h"
NS_IMPL_ADDREF(nsUnicodeToBIG5)
NS_IMPL_RELEASE(nsUnicodeToBIG5)
NS_IMPL_QUERY_INTERFACE(nsUnicodeToBIG5,
nsIUnicodeEncoder)
nsUnicodeToBIG5::nsUnicodeToBIG5()
: mUtf16Lead(0)
, mPendingTrail(0)
, mSignal(true) // as in nsEncoderSupport
{
}
NS_IMETHODIMP
nsUnicodeToBIG5::Convert(const char16_t* aSrc,
int32_t* aSrcLength,
char* aDest,
int32_t * aDestLength)
{
const char16_t* in = aSrc;
const char16_t* inEnd = in + *aSrcLength;
uint8_t* out = reinterpret_cast<uint8_t*>(aDest);
uint8_t* outEnd = out + *aDestLength;
MOZ_ASSERT(!(mPendingTrail && mUtf16Lead),
"Can't have both pending output and pending input.");
if (mPendingTrail) {
if (out == outEnd) {
*aSrcLength = 0;
*aDestLength = 0;
return NS_OK_UENC_MOREOUTPUT;
}
*out++ = mPendingTrail;
mPendingTrail = 0;
}
for (;;) {
if (in == inEnd) {
*aSrcLength = in - aSrc;
*aDestLength = out - reinterpret_cast<uint8_t*>(aDest);
return mUtf16Lead ? NS_OK_UENC_MOREINPUT : NS_OK;
}
if (out == outEnd) {
*aSrcLength = in - aSrc;
*aDestLength = out - reinterpret_cast<uint8_t*>(aDest);
return NS_OK_UENC_MOREOUTPUT;
}
bool isAstral; // true means Plane 2, false means BMP
char16_t lowBits; // The low 16 bits of the code point
char16_t codeUnit = *in++;
size_t highBits = (codeUnit & 0xFC00);
if (highBits == 0xD800) {
// high surrogate
if (mUtf16Lead) {
// High surrogate follows another high surrogate. The
// *previous* code unit is in error.
if (mSignal) {
mUtf16Lead = 0;
// NOTE: Encode API differs from decode API!
--in;
*aSrcLength = in - aSrc;
*aDestLength = out - reinterpret_cast<uint8_t*>(aDest);
return NS_ERROR_UENC_NOMAPPING;
}
*out++ = '?';
}
mUtf16Lead = codeUnit;
continue;
}
if (highBits == 0xDC00) {
// low surrogate
if (!mUtf16Lead) {
// Got low surrogate without a previous high surrogate
if (mSignal) {
// NOTE: Encode API differs from decode API!
*aSrcLength = in - aSrc;
*aDestLength = out - reinterpret_cast<uint8_t*>(aDest);
return NS_ERROR_UENC_NOMAPPING;
}
*out++ = '?';
continue;
}
size_t codePoint = (mUtf16Lead << 10) + codeUnit -
(((0xD800 << 10) - 0x10000) + 0xDC00);
mUtf16Lead = 0;
// Plane 2 is the only astral plane that has potentially
// Big5-encodable characters.
if ((0xFF0000 & codePoint) != 0x20000) {
if (mSignal) {
// NOTE: Encode API differs from decode API!
// nsSaveAsCharset wants us to back up on step in the case of a
// surrogate pair.
--in;
*aSrcLength = in - aSrc;
*aDestLength = out - reinterpret_cast<uint8_t*>(aDest);
return NS_ERROR_UENC_NOMAPPING;
}
*out++ = '?';
continue;
}
isAstral = true;
lowBits = (char16_t)(codePoint & 0xFFFF);
} else {
// not a surrogate
if (mUtf16Lead) {
// Non-surrogate follows a high surrogate. The *previous*
// code unit is in error.
mUtf16Lead = 0;
if (mSignal) {
// NOTE: Encode API differs from decode API!
--in;
*aSrcLength = in - aSrc;
*aDestLength = out - reinterpret_cast<uint8_t*>(aDest);
return NS_ERROR_UENC_NOMAPPING;
}
*out++ = '?';
// Let's unconsume this code unit and reloop in order to
// re-check if the output buffer still has space.
--in;
continue;
}
isAstral = false;
lowBits = codeUnit;
}
// isAstral now tells us if we have a Plane 2 or a BMP character.
// lowBits tells us the low 16 bits.
// After all the above setup to deal with UTF-16, we are now
// finally ready to follow the spec.
if (!isAstral && lowBits <= 0x7F) {
*out++ = (uint8_t)lowBits;
continue;
}
size_t pointer = nsBIG5Data::FindPointer(lowBits, isAstral);
if (!pointer) {
if (mSignal) {
// NOTE: Encode API differs from decode API!
if (isAstral) {
// nsSaveAsCharset wants us to back up on step in the case of a
// surrogate pair.
--in;
}
*aSrcLength = in - aSrc;
*aDestLength = out - reinterpret_cast<uint8_t*>(aDest);
return NS_ERROR_UENC_NOMAPPING;
}
*out++ = '?';
continue;
}
uint8_t lead = (uint8_t)(pointer / 157 + 0x81);
uint8_t trail = (uint8_t)(pointer % 157);
if (trail < 0x3F) {
trail += 0x40;
} else {
trail += 0x62;
}
*out++ = lead;
if (out == outEnd) {
mPendingTrail = trail;
*aSrcLength = in - aSrc;
*aDestLength = out - reinterpret_cast<uint8_t*>(aDest);
return NS_OK_UENC_MOREOUTPUT;
}
*out++ = trail;
continue;
}
}
NS_IMETHODIMP
nsUnicodeToBIG5::Finish(char* aDest,
int32_t* aDestLength)
{
MOZ_ASSERT(!(mPendingTrail && mUtf16Lead),
"Can't have both pending output and pending input.");
uint8_t* out = reinterpret_cast<uint8_t*>(aDest);
if (mPendingTrail) {
if (*aDestLength < 1) {
*aDestLength = 0;
return NS_OK_UENC_MOREOUTPUT;
}
*out = mPendingTrail;
mPendingTrail = 0;
*aDestLength = 1;
return NS_OK;
}
if (mUtf16Lead) {
if (*aDestLength < 1) {
*aDestLength = 0;
return NS_OK_UENC_MOREOUTPUT;
}
mUtf16Lead = 0;
if (mSignal) {
*aDestLength = 0;
return NS_ERROR_UENC_NOMAPPING;
}
*out = '?';
*aDestLength = 1;
return NS_OK;
}
*aDestLength = 0;
return NS_OK;
}
NS_IMETHODIMP
nsUnicodeToBIG5::GetMaxLength(const char16_t* aSrc,
int32_t aSrcLength,
int32_t* aDestLength)
{
*aDestLength = (aSrcLength * 2) +
(mPendingTrail ? 1 : 0) +
// If the lead ends up being paired, the bytes produced
// are already included above.
// If not, it produces a single '?'.
(mUtf16Lead ? 1 : 0);
return NS_OK;
}
NS_IMETHODIMP
nsUnicodeToBIG5::Reset()
{
mUtf16Lead = 0;
mPendingTrail = 0;
return NS_OK;
}
NS_IMETHODIMP
nsUnicodeToBIG5::SetOutputErrorBehavior(int32_t aBehavior,
nsIUnicharEncoder* aEncoder,
char16_t aChar)
{
switch (aBehavior) {
case kOnError_Signal:
mSignal = true;
break;
case kOnError_Replace:
mSignal = false;
MOZ_ASSERT(aChar == '?', "Unsupported replacement.");
break;
case kOnError_CallBack:
MOZ_ASSERT_UNREACHABLE("kOnError_CallBack is supposed to be unused.");
break;
default:
MOZ_ASSERT_UNREACHABLE("Non-existent enum item.");
break;
}
return NS_OK;
}
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