gecko-dev/layout/base/nsBidi.cpp

47 строки
1.7 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=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 "nsBidi.h"
nsresult
nsBidi::CountRuns(int32_t* aRunCount)
{
UErrorCode errorCode = U_ZERO_ERROR;
*aRunCount = ubidi_countRuns(mBiDi, &errorCode);
if (U_SUCCESS(errorCode)) {
mLength = ubidi_getProcessedLength(mBiDi);
mLevels = mLength > 0 ? ubidi_getLevels(mBiDi, &errorCode) : nullptr;
}
return ICUUtils::UErrorToNsResult(errorCode);
}
void
nsBidi::GetLogicalRun(int32_t aLogicalStart,
int32_t* aLogicalLimit, nsBidiLevel* aLevel)
{
MOZ_ASSERT(mLevels, "CountRuns hasn't been run?");
MOZ_RELEASE_ASSERT(aLogicalStart < mLength, "Out of bound");
// This function implements an alternative approach to get logical
// run that is based on levels of characters, which would avoid O(n^2)
// performance issue when used in a loop over runs.
// Per comment in ubidi_getLogicalRun, that function doesn't use this
// approach because levels have special interpretation when reordering
// mode is UBIDI_REORDER_RUNS_ONLY. Since we don't use this mode in
// Gecko, it should be safe to just use levels for this function.
MOZ_ASSERT(ubidi_getReorderingMode(mBiDi) != UBIDI_REORDER_RUNS_ONLY,
"Don't support UBIDI_REORDER_RUNS_ONLY mode");
nsBidiLevel level = mLevels[aLogicalStart];
int32_t limit;
for (limit = aLogicalStart + 1; limit < mLength; limit++) {
if (mLevels[limit] != level) {
break;
}
}
*aLogicalLimit = limit;
*aLevel = level;
}