The Tor Browser: comparison intl/uconv/src/nsUTF8ToUnicode.cpp

--1:000000000000
+:8ebececf36b0
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* 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 "nsUCSupport.h"
+#include "nsUTF8ToUnicode.h"
+#include "mozilla/SSE.h"
+#include "nsCharTraits.h"
+#include <algorithm>
+#define UNICODE_BYTE_ORDER_MARK    0xFEFF
+static char16_t* EmitSurrogatePair(uint32_t ucs4, char16_t* aDest)
+{
+NS_ASSERTION(ucs4 > 0xFFFF, "Should be a supplementary character");
+ucs4 -= 0x00010000;
+*aDest++ = 0xD800 | (0x000003FF & (ucs4 >> 10));
+*aDest++ = 0xDC00 | (0x000003FF & ucs4);
+return aDest;
+}
+//----------------------------------------------------------------------
+// Class nsUTF8ToUnicode [implementation]
+nsUTF8ToUnicode::nsUTF8ToUnicode()
+: nsBasicDecoderSupport()
+{
+Reset();
+}
+//----------------------------------------------------------------------
+// Subclassing of nsTableDecoderSupport class [implementation]
+/**
+* Normally the maximum length of the output of the UTF8 decoder in UTF16
+*  code units is the same as the length of the input in UTF8 code units,
+*  since 1-byte, 2-byte and 3-byte UTF-8 sequences decode to a single
+*  UTF-16 character, and 4-byte UTF-8 sequences decode to a surrogate pair.
+*
+* However, there is an edge case where the output can be longer than the
+*  input: if the previous buffer ended with an incomplete multi-byte
+*  sequence and this buffer does not begin with a valid continuation
+*  byte, we will return NS_ERROR_ILLEGAL_INPUT and the caller may insert a
+*  replacement character in the output buffer which corresponds to no
+*  character in the input buffer. So in the worst case the destination
+*  will need to be one code unit longer than the source.
+*  See bug 301797.
+*/
+NS_IMETHODIMP nsUTF8ToUnicode::GetMaxLength(const char * aSrc,
+int32_t aSrcLength,
+int32_t * aDestLength)
+{
+*aDestLength = aSrcLength + 1;
+return NS_OK;
+}
+//----------------------------------------------------------------------
+// Subclassing of nsBasicDecoderSupport class [implementation]
+NS_IMETHODIMP nsUTF8ToUnicode::Reset()
+{
+mUcs4  = 0;     // cached Unicode character
+mState = 0;     // cached expected number of octets after the current octet
+// until the beginning of the next UTF8 character sequence
+mBytes = 1;     // cached expected number of octets in the current sequence
+mFirst = true;
+return NS_OK;
+}
+//----------------------------------------------------------------------
+// Subclassing of nsBasicDecoderSupport class [implementation]
+// Fast ASCII -> UTF16 inner loop implementations
+//
+// Convert_ascii_run will update src and dst to the new values, and
+// len must be the maximum number ascii chars that it would be valid
+// to take from src and place into dst.  (That is, the minimum of the
+// number of bytes left in src and the number of unichars available in
+// dst.)
+#if defined(__arm__) || defined(_M_ARM)
+// on ARM, do extra work to avoid byte/halfword reads/writes by
+// reading/writing a word at a time for as long as we can
+static inline void
+Convert_ascii_run (const char *&src,
+char16_t *&dst,
+int32_t len)
+{
+const uint32_t *src32;
+uint32_t *dst32;
+// with some alignments, we'd never actually break out of the slow loop, so
+// check and do the faster slow loop
+if ((((NS_PTR_TO_UINT32(dst) & 3) == 0) && ((NS_PTR_TO_UINT32(src) & 1) == 0)) ||
+(((NS_PTR_TO_UINT32(dst) & 3) == 2) && ((NS_PTR_TO_UINT32(src) & 1) == 1)))
+{
+while (((NS_PTR_TO_UINT32(src) & 3) ||
+(NS_PTR_TO_UINT32(dst) & 3)) &&
+len > 0)
+{
+if (*src & 0x80U)
+return;
+*dst++ = (char16_t) *src++;
+len--;
+}
+} else {
+goto finish;
+}
+// then go 4 bytes at a time
+src32 = (const uint32_t*) src;
+dst32 = (uint32_t*) dst;
+while (len > 4) {
+uint32_t in = *src32++;
+if (in & 0x80808080U) {
+src32--;
+break;
+}
+*dst32++ = ((in & 0x000000ff) >>  0) | ((in & 0x0000ff00) << 8);
+*dst32++ = ((in & 0x00ff0000) >> 16) | ((in & 0xff000000) >> 8);
+len -= 4;
+}
+src = (const char *) src32;
+dst = (char16_t *) dst32;
+finish:
+while (len-- > 0 && (*src & 0x80U) == 0) {
+*dst++ = (char16_t) *src++;
+}
+}
+#else
+#ifdef MOZILLA_MAY_SUPPORT_SSE2
+namespace mozilla {
+namespace SSE2 {
+void Convert_ascii_run(const char *&src, char16_t *&dst, int32_t len);
+}
+}
+#endif
+static inline void
+Convert_ascii_run (const char *&src,
+char16_t *&dst,
+int32_t len)
+{
+#ifdef MOZILLA_MAY_SUPPORT_SSE2
+if (mozilla::supports_sse2()) {
+mozilla::SSE2::Convert_ascii_run(src, dst, len);
+return;
+}
+#endif
+while (len-- > 0 && (*src & 0x80U) == 0) {
+*dst++ = (char16_t) *src++;
+}
+}
+#endif
+NS_IMETHODIMP nsUTF8ToUnicode::Convert(const char * aSrc,
+int32_t * aSrcLength,
+char16_t * aDest,
+int32_t * aDestLength)
+{
+uint32_t aSrcLen   = (uint32_t) (*aSrcLength);
+uint32_t aDestLen = (uint32_t) (*aDestLength);
+const char *in, *inend;
+inend = aSrc + aSrcLen;
+char16_t *out, *outend;
+outend = aDest + aDestLen;
+nsresult res = NS_OK; // conversion result
+out = aDest;
+if (mState == 0xFF) {
+// Emit supplementary character left over from previous iteration. It is
+// caller's responsibility to keep a sufficient buffer.
+if (aDestLen < 2) {
+*aSrcLength = *aDestLength = 0;
+return NS_OK_UDEC_MOREOUTPUT;
+}
+out = EmitSurrogatePair(mUcs4, out);
+mUcs4 = 0;
+mState = 0;
+mBytes = 1;
+mFirst = false;
+}
+// alias these locally for speed
+int32_t mUcs4 = this->mUcs4;
+uint8_t mState = this->mState;
+uint8_t mBytes = this->mBytes;
+bool mFirst = this->mFirst;
+// Set mFirst to false now so we don't have to every time through the ASCII
+// branch within the loop.
+if (mFirst && aSrcLen && (0 == (0x80 & (*aSrc))))
+mFirst = false;
+for (in = aSrc; ((in < inend) && (out < outend)); ++in) {
+uint8_t c = *in;
+if (0 == mState) {
+// When mState is zero we expect either a US-ASCII character or a
+// multi-octet sequence.
+if (c < 0x80) {  // 00..7F
+int32_t max_loops = std::min(inend - in, outend - out);
+Convert_ascii_run(in, out, max_loops);
+--in; // match the rest of the cases
+mBytes = 1;
+} else if (c < 0xC2) {  // C0/C1
+// Overlong 2 octet sequence
+if (mErrBehavior == kOnError_Signal) {
+res = NS_ERROR_ILLEGAL_INPUT;
+break;
+}
+*out++ = UCS2_REPLACEMENT_CHAR;
+mFirst = false;
+} else if (c < 0xE0) {  // C2..DF
+// First octet of 2 octet sequence
+mUcs4 = c;
+mUcs4 = (mUcs4 & 0x1F) << 6;
+mState = 1;
+mBytes = 2;
+} else if (c < 0xF0) {  // E0..EF
+// First octet of 3 octet sequence
+mUcs4 = c;
+mUcs4 = (mUcs4 & 0x0F) << 12;
+mState = 2;
+mBytes = 3;
+} else if (c < 0xF5) {  // F0..F4
+// First octet of 4 octet sequence
+mUcs4 = c;
+mUcs4 = (mUcs4 & 0x07) << 18;
+mState = 3;
+mBytes = 4;
+} else {  // F5..FF
+/* Current octet is neither in the US-ASCII range nor a legal first
+* octet of a multi-octet sequence.
+*/
+if (mErrBehavior == kOnError_Signal) {
+/* Return an error condition. Caller is responsible for flushing and
+* refilling the buffer and resetting state.
+*/
+res = NS_ERROR_ILLEGAL_INPUT;
+break;
+}
+*out++ = UCS2_REPLACEMENT_CHAR;
+mFirst = false;
+}
+} else {
+// When mState is non-zero, we expect a continuation of the multi-octet
+// sequence
+if (0x80 == (0xC0 & c)) {
+if (mState > 1) {
+// If we are here, all possibilities are:
+// mState == 2 && mBytes == 3 ||
+// mState == 2 && mBytes == 4 ||
+// mState == 3 && mBytes == 4
+if ((mBytes == 3 && ((!mUcs4 && c < 0xA0) ||             // E0 80..9F
+(mUcs4 == 0xD000 && c > 0x9F))) ||  // ED A0..BF
+(mState == 3 && ((!mUcs4 && c < 0x90) ||             // F0 80..8F
+(mUcs4 == 0x100000 && c > 0x8F)))) {// F4 90..BF
+// illegal sequences or sequences converted into illegal ranges.
+in--;
+if (mErrBehavior == kOnError_Signal) {
+res = NS_ERROR_ILLEGAL_INPUT;
+break;
+}
+*out++ = UCS2_REPLACEMENT_CHAR;
+mState = 0;
+mFirst = false;
+continue;
+}
+}
+// Legal continuation.
+uint32_t shift = (mState - 1) * 6;
+uint32_t tmp = c;
+tmp = (tmp & 0x0000003FL) << shift;
+mUcs4 |= tmp;
+if (0 == --mState) {
+/* End of the multi-octet sequence. mUcs4 now contains the final
+* Unicode codepoint to be output
+*/
+if (mUcs4 > 0xFFFF) {
+// mUcs4 is in the range 0x10000 - 0x10FFFF. Output a UTF-16 pair
+if (out + 2 > outend) {
+// insufficient space left in the buffer. Keep mUcs4 for the
+// next iteration.
+mState = 0xFF;
+++in;
+res = NS_OK_UDEC_MOREOUTPUT;
+break;
+}
+out = EmitSurrogatePair(mUcs4, out);
+} else if (UNICODE_BYTE_ORDER_MARK != mUcs4 || !mFirst) {
+// Don't output the BOM only if it is the first character
+*out++ = mUcs4;
+}
+//initialize UTF8 cache
+mUcs4  = 0;
+mState = 0;
+mBytes = 1;
+mFirst = false;
+}
+} else {
+/* ((0xC0 & c != 0x80) && (mState != 0))
+*
+* Incomplete multi-octet sequence. Unconsume this
+* octet and return an error condition. Caller is responsible
+* for flushing and refilling the buffer and resetting state.
+*/
+in--;
+if (mErrBehavior == kOnError_Signal) {
+res = NS_ERROR_ILLEGAL_INPUT;
+break;
+}
+*out++ = UCS2_REPLACEMENT_CHAR;
+mState = 0;
+mFirst = false;
+}
+}
+}
+// output not finished, output buffer too short
+if ((NS_OK == res) && (in < inend) && (out >= outend))
+res = NS_OK_UDEC_MOREOUTPUT;
+// last UCS4 is incomplete, make sure the caller
+// returns with properly aligned continuation of the buffer
+if ((NS_OK == res) && (mState != 0))
+res = NS_OK_UDEC_MOREINPUT;
+*aSrcLength = in - aSrc;
+*aDestLength = out - aDest;
+this->mUcs4 = mUcs4;
+this->mState = mState;
+this->mBytes = mBytes;
+this->mFirst = mFirst;
+return(res);
+}

The Tor Browser / file comparison

comparison: intl/uconv/src/nsUTF8ToUnicode.cpp

intl/uconv/src/nsUTF8ToUnicode.cpp