michael@0: /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "gfxDWriteTextAnalysis.h"
michael@0: 
michael@0: TextAnalysis::TextAnalysis(const wchar_t* text,
michael@0:                            UINT32 textLength,
michael@0:                            const wchar_t* localeName,
michael@0:                            DWRITE_READING_DIRECTION readingDirection)
michael@0:   : mText(text)
michael@0:   , mTextLength(textLength)
michael@0:   , mLocaleName(localeName)
michael@0:   , mReadingDirection(readingDirection)
michael@0:   , mCurrentRun(nullptr)
michael@0: {
michael@0: }
michael@0: 
michael@0: TextAnalysis::~TextAnalysis()
michael@0: {
michael@0:     // delete runs, except mRunHead which is part of the TextAnalysis object
michael@0:     for (Run *run = mRunHead.nextRun; run;) {
michael@0:         Run *origRun = run;
michael@0:         run = run->nextRun;
michael@0:         delete origRun;
michael@0:     }
michael@0: }
michael@0: 
michael@0: STDMETHODIMP 
michael@0: TextAnalysis::GenerateResults(IDWriteTextAnalyzer* textAnalyzer,
michael@0:                               OUT Run **runHead)
michael@0: {
michael@0:     // Analyzes the text using the script analyzer and returns
michael@0:     // the result as a series of runs.
michael@0: 
michael@0:     HRESULT hr = S_OK;
michael@0: 
michael@0:     // Initially start out with one result that covers the entire range.
michael@0:     // This result will be subdivided by the analysis processes.
michael@0:     mRunHead.mTextStart = 0;
michael@0:     mRunHead.mTextLength = mTextLength;
michael@0:     mRunHead.mBidiLevel = 
michael@0:         (mReadingDirection == DWRITE_READING_DIRECTION_RIGHT_TO_LEFT);
michael@0:     mRunHead.nextRun = nullptr;
michael@0:     mCurrentRun = &mRunHead;
michael@0: 
michael@0:     // Call each of the analyzers in sequence, recording their results.
michael@0:     if (SUCCEEDED(hr = textAnalyzer->AnalyzeScript(this,
michael@0:                                                    0,
michael@0:                                                    mTextLength,
michael@0:                                                    this))) {
michael@0:         *runHead = &mRunHead;
michael@0:     }
michael@0: 
michael@0:     return hr;
michael@0: }
michael@0: 
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: // IDWriteTextAnalysisSource source implementation
michael@0: 
michael@0: IFACEMETHODIMP 
michael@0: TextAnalysis::GetTextAtPosition(UINT32 textPosition,
michael@0:                                 OUT WCHAR const** textString,
michael@0:                                 OUT UINT32* textLength)
michael@0: {
michael@0:     if (textPosition >= mTextLength) {
michael@0:         // No text at this position, valid query though.
michael@0:         *textString = nullptr;
michael@0:         *textLength = 0;
michael@0:     } else {
michael@0:         *textString = mText + textPosition;
michael@0:         *textLength = mTextLength - textPosition;
michael@0:     }
michael@0:     return S_OK;
michael@0: }
michael@0: 
michael@0: 
michael@0: IFACEMETHODIMP 
michael@0: TextAnalysis::GetTextBeforePosition(UINT32 textPosition,
michael@0:                                     OUT WCHAR const** textString,
michael@0:                                     OUT UINT32* textLength)
michael@0: {
michael@0:     if (textPosition == 0 || textPosition > mTextLength) {
michael@0:         // Either there is no text before here (== 0), or this
michael@0:         // is an invalid position. The query is considered valid thouh.
michael@0:         *textString = nullptr;
michael@0:         *textLength = 0;
michael@0:     } else {
michael@0:         *textString = mText;
michael@0:         *textLength = textPosition;
michael@0:     }
michael@0:     return S_OK;
michael@0: }
michael@0: 
michael@0: 
michael@0: DWRITE_READING_DIRECTION STDMETHODCALLTYPE 
michael@0: TextAnalysis::GetParagraphReadingDirection()
michael@0: {
michael@0:     // We support only a single reading direction.
michael@0:     return mReadingDirection;
michael@0: }
michael@0: 
michael@0: 
michael@0: IFACEMETHODIMP 
michael@0: TextAnalysis::GetLocaleName(UINT32 textPosition,
michael@0:                             OUT UINT32* textLength,
michael@0:                             OUT WCHAR const** localeName)
michael@0: {
michael@0:     // Single locale name is used, valid until the end of the string.
michael@0:     *localeName = mLocaleName;
michael@0:     *textLength = mTextLength - textPosition;
michael@0: 
michael@0:     return S_OK;
michael@0: }
michael@0: 
michael@0: 
michael@0: IFACEMETHODIMP 
michael@0: TextAnalysis::GetNumberSubstitution(UINT32 textPosition,
michael@0:                                     OUT UINT32* textLength,
michael@0:                                     OUT IDWriteNumberSubstitution** numberSubstitution)
michael@0: {
michael@0:     // We do not support number substitution.
michael@0:     *numberSubstitution = nullptr;
michael@0:     *textLength = mTextLength - textPosition;
michael@0: 
michael@0:     return S_OK;
michael@0: }
michael@0: 
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: // IDWriteTextAnalysisSink implementation
michael@0: 
michael@0: IFACEMETHODIMP 
michael@0: TextAnalysis::SetLineBreakpoints(UINT32 textPosition,
michael@0:                                  UINT32 textLength,
michael@0:                                  DWRITE_LINE_BREAKPOINT const* lineBreakpoints)
michael@0: {
michael@0:     // We don't use this for now.
michael@0:     return S_OK;
michael@0: }
michael@0: 
michael@0: 
michael@0: IFACEMETHODIMP 
michael@0: TextAnalysis::SetScriptAnalysis(UINT32 textPosition,
michael@0:                                 UINT32 textLength,
michael@0:                                 DWRITE_SCRIPT_ANALYSIS const* scriptAnalysis)
michael@0: {
michael@0:     SetCurrentRun(textPosition);
michael@0:     SplitCurrentRun(textPosition);
michael@0:     while (textLength > 0) {
michael@0:         Run *run = FetchNextRun(&textLength);
michael@0:         run->mScript = *scriptAnalysis;
michael@0:     }
michael@0: 
michael@0:     return S_OK;
michael@0: }
michael@0: 
michael@0: 
michael@0: IFACEMETHODIMP 
michael@0: TextAnalysis::SetBidiLevel(UINT32 textPosition,
michael@0:                            UINT32 textLength,
michael@0:                            UINT8 explicitLevel,
michael@0:                            UINT8 resolvedLevel)
michael@0: {
michael@0:     // We don't use this for now.
michael@0:     return S_OK;
michael@0: }
michael@0: 
michael@0: 
michael@0: IFACEMETHODIMP 
michael@0: TextAnalysis::SetNumberSubstitution(UINT32 textPosition,
michael@0:                                     UINT32 textLength,
michael@0:                                     IDWriteNumberSubstitution* numberSubstitution)
michael@0: {
michael@0:     // We don't use this for now.
michael@0:     return S_OK;
michael@0: }
michael@0: 
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: // Run modification.
michael@0: 
michael@0: TextAnalysis::Run *
michael@0: TextAnalysis::FetchNextRun(IN OUT UINT32* textLength)
michael@0: {
michael@0:     // Used by the sink setters, this returns a reference to the next run.
michael@0:     // Position and length are adjusted to now point after the current run
michael@0:     // being returned.
michael@0: 
michael@0:     Run *origRun = mCurrentRun;
michael@0:     // Split the tail if needed (the length remaining is less than the
michael@0:     // current run's size).
michael@0:     if (*textLength < mCurrentRun->mTextLength) {
michael@0:         SplitCurrentRun(mCurrentRun->mTextStart + *textLength);
michael@0:     } else {
michael@0:         // Just advance the current run.
michael@0:         mCurrentRun = mCurrentRun->nextRun;
michael@0:     }
michael@0:     *textLength -= origRun->mTextLength;
michael@0: 
michael@0:     // Return a reference to the run that was just current.
michael@0:     return origRun;
michael@0: }
michael@0: 
michael@0: 
michael@0: void TextAnalysis::SetCurrentRun(UINT32 textPosition)
michael@0: {
michael@0:     // Move the current run to the given position.
michael@0:     // Since the analyzers generally return results in a forward manner,
michael@0:     // this will usually just return early. If not, find the
michael@0:     // corresponding run for the text position.
michael@0: 
michael@0:     if (mCurrentRun && mCurrentRun->ContainsTextPosition(textPosition)) {
michael@0:         return;
michael@0:     }
michael@0: 
michael@0:     for (Run *run = &mRunHead; run; run = run->nextRun) {
michael@0:         if (run->ContainsTextPosition(textPosition)) {
michael@0:             mCurrentRun = run;
michael@0:             return;
michael@0:         }
michael@0:     }
michael@0:     NS_NOTREACHED("We should always be able to find the text position in one \
michael@0:         of our runs");
michael@0: }
michael@0: 
michael@0: 
michael@0: void TextAnalysis::SplitCurrentRun(UINT32 splitPosition)
michael@0: {
michael@0:     if (!mCurrentRun) {
michael@0:         NS_ASSERTION(false, "SplitCurrentRun called without current run.");
michael@0:         // Shouldn't be calling this when no current run is set!
michael@0:         return;
michael@0:     }
michael@0:     // Split the current run.
michael@0:     if (splitPosition <= mCurrentRun->mTextStart) {
michael@0:         // No need to split, already the start of a run
michael@0:         // or before it. Usually the first.
michael@0:         return;
michael@0:     }
michael@0:     Run *newRun = new Run;
michael@0: 
michael@0:     *newRun = *mCurrentRun;
michael@0: 
michael@0:     // Insert the new run in our linked list.
michael@0:     newRun->nextRun = mCurrentRun->nextRun;
michael@0:     mCurrentRun->nextRun = newRun;
michael@0: 
michael@0:     // Adjust runs' text positions and lengths.
michael@0:     UINT32 splitPoint = splitPosition - mCurrentRun->mTextStart;
michael@0:     newRun->mTextStart += splitPoint;
michael@0:     newRun->mTextLength -= splitPoint;
michael@0:     mCurrentRun->mTextLength = splitPoint;
michael@0:     mCurrentRun = newRun;
michael@0: }