gecko-dev/layout/generic/nsTextFrameUtils.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Novell code.
*
* The Initial Developer of the Original Code is Novell Corporation.
* Portions created by the Initial Developer are Copyright (C) 2006
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* robert@ocallahan.org
* Ehsan Akhgari <ehsan.akhgari@gmail.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "nsTextFrameUtils.h"
#include "nsContentUtils.h"
#include "nsIWordBreaker.h"
#include "gfxFont.h"
#include "nsUnicharUtils.h"
#include "nsBidiUtils.h"
// XXX TODO implement transform of backslash to yen that nsTextTransform does
// when requested by PresContext->LanguageSpecificTransformType(). Do it with
// a new factory type that just munges the input stream. But first, check
// that we really still need this, it's only enabled via a hidden pref
// which defaults false...
#define UNICODE_ZWSP 0x200B
static PRBool IsDiscardable(PRUnichar ch, PRUint32* aFlags)
{
// Unlike IS_DISCARDABLE, we don't discard \r. \r will be ignored by gfxTextRun
// and discarding it would force us to copy text in many cases of preformatted
// text containing \r\n.
if (ch == CH_SHY) {
*aFlags |= nsTextFrameUtils::TEXT_HAS_SHY;
return PR_TRUE;
}
if ((ch & 0xFF00) != 0x2000) {
// Not a Bidi control character
return PR_FALSE;
}
return IS_BIDI_CONTROL_CHAR(ch);
}
static PRBool IsDiscardable(PRUint8 ch, PRUint32* aFlags)
{
if (ch == CH_SHY) {
*aFlags |= nsTextFrameUtils::TEXT_HAS_SHY;
return PR_TRUE;
}
return PR_FALSE;
}
PRUnichar*
nsTextFrameUtils::TransformText(const PRUnichar* aText, PRUint32 aLength,
PRUnichar* aOutput,
CompressionMode aCompression,
PRUint8* aIncomingFlags,
gfxSkipCharsBuilder* aSkipChars,
PRUint32* aAnalysisFlags)
{
PRUint32 flags = 0;
PRUnichar* outputStart = aOutput;
PRBool lastCharArabic = PR_FALSE;
if (aCompression == COMPRESS_NONE) {
// Skip discardables.
PRUint32 i;
for (i = 0; i < aLength; ++i) {
PRUnichar ch = *aText++;
if (IsDiscardable(ch, &flags)) {
aSkipChars->SkipChar();
} else {
aSkipChars->KeepChar();
if (ch == '\t') {
flags |= TEXT_HAS_TAB;
} else if (ch != ' ' && ch != '\n') {
// we already know it's not a tab from the previous check
lastCharArabic = IS_ARABIC_CHAR(ch);
}
*aOutput++ = ch;
}
}
if (lastCharArabic) {
*aIncomingFlags |= INCOMING_ARABICCHAR;
} else {
*aIncomingFlags &= ~INCOMING_ARABICCHAR;
}
*aIncomingFlags &= ~INCOMING_WHITESPACE;
} else {
PRBool inWhitespace = (*aIncomingFlags & INCOMING_WHITESPACE) != 0;
PRUint32 i;
for (i = 0; i < aLength; ++i) {
PRUnichar ch = *aText++;
PRBool nowInWhitespace;
if (ch == ' ' &&
(i + 1 >= aLength ||
!IsSpaceCombiningSequenceTail(aText, aLength - (i + 1)))) {
nowInWhitespace = PR_TRUE;
} else if (ch == '\n' && aCompression == COMPRESS_WHITESPACE_NEWLINE) {
if (i > 0 && IS_CJ_CHAR(aText[-1]) &&
i + 1 < aLength && IS_CJ_CHAR(aText[1])) {
// Discard newlines between CJK chars.
// XXX this really requires more context to get right!
aSkipChars->SkipChar();
continue;
}
nowInWhitespace = PR_TRUE;
} else {
nowInWhitespace = ch == '\t';
}
if (!nowInWhitespace) {
if (IsDiscardable(ch, &flags)) {
aSkipChars->SkipChar();
nowInWhitespace = inWhitespace;
} else {
*aOutput++ = ch;
aSkipChars->KeepChar();
lastCharArabic = IS_ARABIC_CHAR(ch);
}
} else {
if (inWhitespace) {
aSkipChars->SkipChar();
} else {
if (ch != ' ') {
flags |= TEXT_WAS_TRANSFORMED;
}
*aOutput++ = ' ';
aSkipChars->KeepChar();
}
}
inWhitespace = nowInWhitespace;
}
if (lastCharArabic) {
*aIncomingFlags |= INCOMING_ARABICCHAR;
} else {
*aIncomingFlags &= ~INCOMING_ARABICCHAR;
}
if (inWhitespace) {
*aIncomingFlags |= INCOMING_WHITESPACE;
} else {
*aIncomingFlags &= ~INCOMING_WHITESPACE;
}
}
if (outputStart + aLength != aOutput) {
flags |= TEXT_WAS_TRANSFORMED;
}
*aAnalysisFlags = flags;
return aOutput;
}
PRUint8*
nsTextFrameUtils::TransformText(const PRUint8* aText, PRUint32 aLength,
PRUint8* aOutput,
CompressionMode aCompression,
PRUint8* aIncomingFlags,
gfxSkipCharsBuilder* aSkipChars,
PRUint32* aAnalysisFlags)
{
PRUint32 flags = 0;
PRUint8* outputStart = aOutput;
if (aCompression == COMPRESS_NONE) {
// Skip discardables.
PRUint32 i;
for (i = 0; i < aLength; ++i) {
PRUint8 ch = *aText++;
if (IsDiscardable(ch, &flags)) {
aSkipChars->SkipChar();
} else {
aSkipChars->KeepChar();
if (ch == '\t') {
flags |= TEXT_HAS_TAB;
}
*aOutput++ = ch;
}
}
*aIncomingFlags &= ~(INCOMING_ARABICCHAR | INCOMING_WHITESPACE);
} else {
PRBool inWhitespace = (*aIncomingFlags & INCOMING_WHITESPACE) != 0;
PRUint32 i;
for (i = 0; i < aLength; ++i) {
PRUint8 ch = *aText++;
PRBool nowInWhitespace = ch == ' ' || ch == '\t' ||
(ch == '\n' && aCompression == COMPRESS_WHITESPACE_NEWLINE);
if (!nowInWhitespace) {
if (IsDiscardable(ch, &flags)) {
aSkipChars->SkipChar();
nowInWhitespace = inWhitespace;
} else {
*aOutput++ = ch;
aSkipChars->KeepChar();
}
} else {
if (inWhitespace) {
aSkipChars->SkipChar();
} else {
if (ch != ' ') {
flags |= TEXT_WAS_TRANSFORMED;
}
*aOutput++ = ' ';
aSkipChars->KeepChar();
}
}
inWhitespace = nowInWhitespace;
}
*aIncomingFlags &= ~INCOMING_ARABICCHAR;
if (inWhitespace) {
*aIncomingFlags |= INCOMING_WHITESPACE;
} else {
*aIncomingFlags &= ~INCOMING_WHITESPACE;
}
}
if (outputStart + aLength != aOutput) {
flags |= TEXT_WAS_TRANSFORMED;
}
*aAnalysisFlags = flags;
return aOutput;
}
PRBool nsSkipCharsRunIterator::NextRun() {
do {
if (mRunLength) {
mIterator.AdvanceOriginal(mRunLength);
NS_ASSERTION(mRunLength > 0, "No characters in run (initial length too large?)");
if (!mSkipped || mLengthIncludesSkipped) {
mRemainingLength -= mRunLength;
}
}
if (!mRemainingLength)
return PR_FALSE;
PRInt32 length;
mSkipped = mIterator.IsOriginalCharSkipped(&length);
mRunLength = NS_MIN(length, mRemainingLength);
} while (!mVisitSkipped && mSkipped);
return PR_TRUE;
}