mirror of
https://github.com/mozilla/gecko-dev.git
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433 lines
11 KiB
C++
433 lines
11 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/*
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* A class which represents a fragment of text (eg inside a text
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* node); if only codepoints below 256 are used, the text is stored as
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* a char*; otherwise the text is stored as a PRUnichar*
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*/
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#include "nsTextFragment.h"
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#include "nsCRT.h"
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#include "nsReadableUtils.h"
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#include "nsMemory.h"
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#include "nsBidiUtils.h"
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#include "nsUnicharUtils.h"
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#include "nsUTF8Utils.h"
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#include "mozilla/MemoryReporting.h"
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#include "mozilla/SSE.h"
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#include "nsTextFragmentImpl.h"
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#include <algorithm>
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#define TEXTFRAG_WHITE_AFTER_NEWLINE 50
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#define TEXTFRAG_MAX_NEWLINES 7
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// Static buffer used for common fragments
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static char* sSpaceSharedString[TEXTFRAG_MAX_NEWLINES + 1];
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static char* sTabSharedString[TEXTFRAG_MAX_NEWLINES + 1];
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static char sSingleCharSharedString[256];
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// static
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nsresult
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nsTextFragment::Init()
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{
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// Create whitespace strings
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uint32_t i;
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for (i = 0; i <= TEXTFRAG_MAX_NEWLINES; ++i) {
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sSpaceSharedString[i] = new char[1 + i + TEXTFRAG_WHITE_AFTER_NEWLINE];
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sTabSharedString[i] = new char[1 + i + TEXTFRAG_WHITE_AFTER_NEWLINE];
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NS_ENSURE_TRUE(sSpaceSharedString[i] && sTabSharedString[i],
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NS_ERROR_OUT_OF_MEMORY);
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sSpaceSharedString[i][0] = ' ';
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sTabSharedString[i][0] = ' ';
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uint32_t j;
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for (j = 1; j < 1 + i; ++j) {
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sSpaceSharedString[i][j] = '\n';
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sTabSharedString[i][j] = '\n';
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}
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for (; j < (1 + i + TEXTFRAG_WHITE_AFTER_NEWLINE); ++j) {
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sSpaceSharedString[i][j] = ' ';
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sTabSharedString[i][j] = '\t';
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}
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}
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// Create single-char strings
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for (i = 0; i < 256; ++i) {
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sSingleCharSharedString[i] = i;
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}
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return NS_OK;
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}
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// static
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void
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nsTextFragment::Shutdown()
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{
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uint32_t i;
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for (i = 0; i <= TEXTFRAG_MAX_NEWLINES; ++i) {
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delete [] sSpaceSharedString[i];
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delete [] sTabSharedString[i];
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sSpaceSharedString[i] = nullptr;
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sTabSharedString[i] = nullptr;
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}
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}
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nsTextFragment::~nsTextFragment()
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{
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ReleaseText();
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MOZ_COUNT_DTOR(nsTextFragment);
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}
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void
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nsTextFragment::ReleaseText()
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{
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if (mState.mLength && m1b && mState.mInHeap) {
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nsMemory::Free(m2b); // m1b == m2b as far as nsMemory is concerned
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}
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m1b = nullptr;
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mState.mIsBidi = false;
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// Set mState.mIs2b, mState.mInHeap, and mState.mLength = 0 with mAllBits;
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mAllBits = 0;
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}
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nsTextFragment&
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nsTextFragment::operator=(const nsTextFragment& aOther)
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{
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ReleaseText();
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if (aOther.mState.mLength) {
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if (!aOther.mState.mInHeap) {
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m1b = aOther.m1b; // This will work even if aOther is using m2b
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}
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else {
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m2b = static_cast<PRUnichar*>
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(nsMemory::Clone(aOther.m2b, aOther.mState.mLength *
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(aOther.mState.mIs2b ? sizeof(PRUnichar) : sizeof(char))));
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}
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if (m1b) {
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mAllBits = aOther.mAllBits;
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}
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}
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return *this;
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}
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static inline int32_t
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FirstNon8BitUnvectorized(const PRUnichar *str, const PRUnichar *end)
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{
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typedef Non8BitParameters<sizeof(size_t)> p;
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const size_t mask = p::mask();
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const uint32_t alignMask = p::alignMask();
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const uint32_t numUnicharsPerWord = p::numUnicharsPerWord();
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const int32_t len = end - str;
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int32_t i = 0;
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// Align ourselves to a word boundary.
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int32_t alignLen =
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std::min(len, int32_t(((-NS_PTR_TO_INT32(str)) & alignMask) / sizeof(PRUnichar)));
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for (; i < alignLen; i++) {
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if (str[i] > 255)
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return i;
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}
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// Check one word at a time.
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const int32_t wordWalkEnd = ((len - i) / numUnicharsPerWord) * numUnicharsPerWord;
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for (; i < wordWalkEnd; i += numUnicharsPerWord) {
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const size_t word = *reinterpret_cast<const size_t*>(str + i);
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if (word & mask)
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return i;
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}
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// Take care of the remainder one character at a time.
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for (; i < len; i++) {
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if (str[i] > 255)
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return i;
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}
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return -1;
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}
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#ifdef MOZILLA_MAY_SUPPORT_SSE2
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namespace mozilla {
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namespace SSE2 {
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int32_t FirstNon8Bit(const PRUnichar *str, const PRUnichar *end);
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}
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}
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#endif
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/*
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* This function returns -1 if all characters in str are 8 bit characters.
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* Otherwise, it returns a value less than or equal to the index of the first
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* non-8bit character in str. For example, if first non-8bit character is at
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* position 25, it may return 25, or for example 24, or 16. But it guarantees
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* there is no non-8bit character before returned value.
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*/
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static inline int32_t
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FirstNon8Bit(const PRUnichar *str, const PRUnichar *end)
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{
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#ifdef MOZILLA_MAY_SUPPORT_SSE2
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if (mozilla::supports_sse2()) {
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return mozilla::SSE2::FirstNon8Bit(str, end);
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}
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#endif
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return FirstNon8BitUnvectorized(str, end);
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}
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void
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nsTextFragment::SetTo(const PRUnichar* aBuffer, int32_t aLength, bool aUpdateBidi)
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{
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ReleaseText();
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if (aLength == 0) {
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return;
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}
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PRUnichar firstChar = *aBuffer;
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if (aLength == 1 && firstChar < 256) {
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m1b = sSingleCharSharedString + firstChar;
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mState.mInHeap = false;
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mState.mIs2b = false;
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mState.mLength = 1;
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return;
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}
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const PRUnichar *ucp = aBuffer;
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const PRUnichar *uend = aBuffer + aLength;
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// Check if we can use a shared string
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if (aLength <= 1 + TEXTFRAG_WHITE_AFTER_NEWLINE + TEXTFRAG_MAX_NEWLINES &&
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(firstChar == ' ' || firstChar == '\n' || firstChar == '\t')) {
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if (firstChar == ' ') {
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++ucp;
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}
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const PRUnichar* start = ucp;
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while (ucp < uend && *ucp == '\n') {
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++ucp;
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}
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const PRUnichar* endNewLine = ucp;
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PRUnichar space = ucp < uend && *ucp == '\t' ? '\t' : ' ';
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while (ucp < uend && *ucp == space) {
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++ucp;
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}
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if (ucp == uend &&
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endNewLine - start <= TEXTFRAG_MAX_NEWLINES &&
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ucp - endNewLine <= TEXTFRAG_WHITE_AFTER_NEWLINE) {
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char** strings = space == ' ' ? sSpaceSharedString : sTabSharedString;
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m1b = strings[endNewLine - start];
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// If we didn't find a space in the beginning, skip it now.
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if (firstChar != ' ') {
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++m1b;
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}
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mState.mInHeap = false;
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mState.mIs2b = false;
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mState.mLength = aLength;
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return;
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}
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}
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// See if we need to store the data in ucs2 or not
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int32_t first16bit = FirstNon8Bit(ucp, uend);
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if (first16bit != -1) { // aBuffer contains no non-8bit character
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// Use ucs2 storage because we have to
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m2b = (PRUnichar *)nsMemory::Clone(aBuffer,
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aLength * sizeof(PRUnichar));
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if (!m2b) {
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return;
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}
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mState.mIs2b = true;
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if (aUpdateBidi) {
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UpdateBidiFlag(aBuffer + first16bit, aLength - first16bit);
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}
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} else {
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// Use 1 byte storage because we can
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char* buff = (char *)nsMemory::Alloc(aLength * sizeof(char));
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if (!buff) {
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return;
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}
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// Copy data
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LossyConvertEncoding16to8 converter(buff);
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copy_string(aBuffer, aBuffer+aLength, converter);
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m1b = buff;
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mState.mIs2b = false;
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}
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// Setup our fields
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mState.mInHeap = true;
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mState.mLength = aLength;
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}
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void
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nsTextFragment::CopyTo(PRUnichar *aDest, int32_t aOffset, int32_t aCount)
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{
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NS_ASSERTION(aOffset >= 0, "Bad offset passed to nsTextFragment::CopyTo()!");
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NS_ASSERTION(aCount >= 0, "Bad count passed to nsTextFragment::CopyTo()!");
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if (aOffset < 0) {
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aOffset = 0;
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}
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if (uint32_t(aOffset + aCount) > GetLength()) {
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aCount = mState.mLength - aOffset;
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}
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if (aCount != 0) {
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if (mState.mIs2b) {
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memcpy(aDest, m2b + aOffset, sizeof(PRUnichar) * aCount);
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} else {
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const char *cp = m1b + aOffset;
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const char *end = cp + aCount;
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LossyConvertEncoding8to16 converter(aDest);
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copy_string(cp, end, converter);
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}
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}
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}
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void
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nsTextFragment::Append(const PRUnichar* aBuffer, uint32_t aLength, bool aUpdateBidi)
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{
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// This is a common case because some callsites create a textnode
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// with a value by creating the node and then calling AppendData.
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if (mState.mLength == 0) {
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SetTo(aBuffer, aLength, aUpdateBidi);
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return;
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}
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// Should we optimize for aData.Length() == 0?
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if (mState.mIs2b) {
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// Already a 2-byte string so the result will be too
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PRUnichar* buff = (PRUnichar*)nsMemory::Realloc(m2b, (mState.mLength + aLength) * sizeof(PRUnichar));
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if (!buff) {
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return;
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}
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memcpy(buff + mState.mLength, aBuffer, aLength * sizeof(PRUnichar));
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mState.mLength += aLength;
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m2b = buff;
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if (aUpdateBidi) {
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UpdateBidiFlag(aBuffer, aLength);
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}
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return;
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}
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// Current string is a 1-byte string, check if the new data fits in one byte too.
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int32_t first16bit = FirstNon8Bit(aBuffer, aBuffer + aLength);
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if (first16bit != -1) { // aBuffer contains no non-8bit character
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// The old data was 1-byte, but the new is not so we have to expand it
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// all to 2-byte
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PRUnichar* buff = (PRUnichar*)nsMemory::Alloc((mState.mLength + aLength) *
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sizeof(PRUnichar));
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if (!buff) {
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return;
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}
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// Copy data into buff
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LossyConvertEncoding8to16 converter(buff);
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copy_string(m1b, m1b+mState.mLength, converter);
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memcpy(buff + mState.mLength, aBuffer, aLength * sizeof(PRUnichar));
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mState.mLength += aLength;
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mState.mIs2b = true;
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if (mState.mInHeap) {
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nsMemory::Free(m2b);
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}
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m2b = buff;
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mState.mInHeap = true;
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if (aUpdateBidi) {
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UpdateBidiFlag(aBuffer + first16bit, aLength - first16bit);
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}
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return;
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}
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// The new and the old data is all 1-byte
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char* buff;
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if (mState.mInHeap) {
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buff = (char*)nsMemory::Realloc(const_cast<char*>(m1b),
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(mState.mLength + aLength) * sizeof(char));
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if (!buff) {
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return;
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}
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}
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else {
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buff = (char*)nsMemory::Alloc((mState.mLength + aLength) * sizeof(char));
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if (!buff) {
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return;
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}
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memcpy(buff, m1b, mState.mLength);
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mState.mInHeap = true;
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}
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// Copy aBuffer into buff.
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LossyConvertEncoding16to8 converter(buff + mState.mLength);
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copy_string(aBuffer, aBuffer + aLength, converter);
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m1b = buff;
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mState.mLength += aLength;
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}
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/* virtual */ size_t
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nsTextFragment::SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
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{
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if (Is2b()) {
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return aMallocSizeOf(m2b);
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}
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if (mState.mInHeap) {
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return aMallocSizeOf(m1b);
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}
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return 0;
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}
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// To save time we only do this when we really want to know, not during
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// every allocation
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void
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nsTextFragment::UpdateBidiFlag(const PRUnichar* aBuffer, uint32_t aLength)
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{
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if (mState.mIs2b && !mState.mIsBidi) {
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const PRUnichar* cp = aBuffer;
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const PRUnichar* end = cp + aLength;
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while (cp < end) {
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PRUnichar ch1 = *cp++;
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uint32_t utf32Char = ch1;
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if (NS_IS_HIGH_SURROGATE(ch1) &&
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cp < end &&
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NS_IS_LOW_SURROGATE(*cp)) {
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PRUnichar ch2 = *cp++;
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utf32Char = SURROGATE_TO_UCS4(ch1, ch2);
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}
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if (UTF32_CHAR_IS_BIDI(utf32Char) || IS_BIDI_CONTROL_CHAR(utf32Char)) {
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mState.mIsBidi = true;
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break;
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}
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}
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}
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}
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