gecko/gfx/thebes/gfxScriptItemizer.cpp
2011-10-17 10:59:28 -04:00

346 lines
10 KiB
C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* ***** 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 Mozilla Corporation code.
*
* The Initial Developer of the Original Code is Mozilla Corporation.
* Portions created by the Initial Developer are Copyright (C) 2010
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Jonathan Kew <jfkthame@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.
*
*
* This file is based on usc_impl.c from ICU 4.2.0.1, slightly adapted
* for use within Mozilla Gecko, separate from a standard ICU build.
*
* The original ICU license of the code follows:
*
* ICU License - ICU 1.8.1 and later
*
* COPYRIGHT AND PERMISSION NOTICE
*
* Copyright (c) 1995-2009 International Business Machines Corporation and
* others
*
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, provided that the above copyright notice(s) and this
* permission notice appear in all copies of the Software and that both the
* above copyright notice(s) and this permission notice appear in supporting
* documentation.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
* IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS NOTICE
* BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES,
* OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
* WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
* ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*
* Except as contained in this notice, the name of a copyright holder shall
* not be used in advertising or otherwise to promote the sale, use or other
* dealings in this Software without prior written authorization of the
* copyright holder.
*
* All trademarks and registered trademarks mentioned herein are the property
* of their respective owners.
*/
#include "gfxScriptItemizer.h"
#include "gfxUnicodeProperties.h"
#include "gfxFontUtils.h" // for the FindHighestBit function
#include "harfbuzz/hb.h"
#include "nsCharTraits.h"
#define ARRAY_SIZE(array) (sizeof array / sizeof array[0])
#define MOD(sp) ((sp) % PAREN_STACK_DEPTH)
#define LIMIT_INC(sp) (((sp) < PAREN_STACK_DEPTH)? (sp) + 1 : PAREN_STACK_DEPTH)
#define INC(sp,count) (MOD((sp) + (count)))
#define INC1(sp) (INC(sp, 1))
#define DEC(sp,count) (MOD((sp) + PAREN_STACK_DEPTH - (count)))
#define DEC1(sp) (DEC(sp, 1))
#define STACK_IS_EMPTY() (pushCount <= 0)
#define STACK_IS_NOT_EMPTY() (! STACK_IS_EMPTY())
#define TOP() (parenStack[parenSP])
#define SYNC_FIXUP() (fixupCount = 0)
static const PRUint16 pairedChars[] = {
0x0028, 0x0029, /* ascii paired punctuation */
0x003c, 0x003e,
0x005b, 0x005d,
0x007b, 0x007d,
0x00ab, 0x00bb, /* guillemets */
0x2018, 0x2019, /* general punctuation */
0x201c, 0x201d,
0x2039, 0x203a,
0x207d, 0x207e, /* superscripts and subscripts */
0x208d, 0x208e,
0x275b, 0x275c, /* dingbat quotes and brackets */
0x275d, 0x275e,
0x2768, 0x2769,
0x276a, 0x276b,
0x276c, 0x276d,
0x276e, 0x276f,
0x2770, 0x2771,
0x2772, 0x2773,
0x2774, 0x2775,
/* omitted: lots of potentially-paired math symbols */
0x2e22, 0x2e23, /* supplemental punctuation */
0x2e24, 0x2e25,
0x2e26, 0x2e27,
0x2e28, 0x2e29,
0x3008, 0x3009, /* chinese paired punctuation */
0x300a, 0x300b,
0x300c, 0x300d,
0x300e, 0x300f,
0x3010, 0x3011,
0x3014, 0x3015,
0x3016, 0x3017,
0x3018, 0x3019,
0x301a, 0x301b,
0xfe59, 0xfe5a, /* small form variants */
0xfe5b, 0xfe5c,
0xfe5d, 0xfe5e,
0xfe64, 0xfe65,
0xff08, 0xff09, /* half-width and full-width forms */
0xff1c, 0xff1e,
0xff3b, 0xff3d,
0xff5b, 0xff5d,
0xff5f, 0xff60,
0xff62, 0xff63
};
void
gfxScriptItemizer::push(PRInt32 pairIndex, PRInt32 scriptCode)
{
pushCount = LIMIT_INC(pushCount);
fixupCount = LIMIT_INC(fixupCount);
parenSP = INC1(parenSP);
parenStack[parenSP].pairIndex = pairIndex;
parenStack[parenSP].scriptCode = scriptCode;
}
void
gfxScriptItemizer::pop()
{
if (STACK_IS_EMPTY()) {
return;
}
if (fixupCount > 0) {
fixupCount -= 1;
}
pushCount -= 1;
parenSP = DEC1(parenSP);
/* If the stack is now empty, reset the stack
pointers to their initial values.
*/
if (STACK_IS_EMPTY()) {
parenSP = -1;
}
}
void
gfxScriptItemizer::fixup(PRInt32 scriptCode)
{
PRInt32 fixupSP = DEC(parenSP, fixupCount);
while (fixupCount-- > 0) {
fixupSP = INC1(fixupSP);
parenStack[fixupSP].scriptCode = scriptCode;
}
}
static PRInt32
getPairIndex(PRUint32 ch)
{
PRInt32 pairedCharCount = ARRAY_SIZE(pairedChars);
PRInt32 pairedCharPower = mozilla::FindHighestBit(pairedCharCount);
PRInt32 pairedCharExtra = pairedCharCount - pairedCharPower;
PRInt32 probe = pairedCharPower;
PRInt32 pairIndex = 0;
if (ch >= pairedChars[pairedCharExtra]) {
pairIndex = pairedCharExtra;
}
while (probe > 1) {
probe >>= 1;
if (ch >= pairedChars[pairIndex + probe]) {
pairIndex += probe;
}
}
if (pairedChars[pairIndex] != ch) {
pairIndex = -1;
}
return pairIndex;
}
static bool
sameScript(PRInt32 scriptOne, PRInt32 scriptTwo)
{
return scriptOne <= HB_SCRIPT_INHERITED ||
scriptTwo <= HB_SCRIPT_INHERITED ||
scriptOne == scriptTwo;
}
gfxScriptItemizer::gfxScriptItemizer(const PRUnichar *src, PRUint32 length)
: textPtr(src), textLength(length)
{
reset();
}
void
gfxScriptItemizer::SetText(const PRUnichar *src, PRUint32 length)
{
textPtr = src;
textLength = length;
reset();
}
bool
gfxScriptItemizer::Next(PRUint32& aRunStart, PRUint32& aRunLimit,
PRInt32& aRunScript)
{
/* if we've fallen off the end of the text, we're done */
if (scriptLimit >= textLength) {
return false;
}
SYNC_FIXUP();
scriptCode = HB_SCRIPT_COMMON;
for (scriptStart = scriptLimit; scriptLimit < textLength; scriptLimit += 1) {
PRUint32 ch;
PRInt32 sc;
PRInt32 pairIndex;
PRUint32 startOfChar = scriptLimit;
ch = textPtr[scriptLimit];
/*
* MODIFICATION for Gecko - clear the paired-character stack
* when we see a space character, because we cannot trust
* context outside the current "word" when doing textrun
* construction
*/
if (ch == 0x20) {
while (STACK_IS_NOT_EMPTY()) {
pop();
}
sc = HB_SCRIPT_COMMON;
pairIndex = -1;
} else {
/* decode UTF-16 (may be surrogate pair) */
if (NS_IS_HIGH_SURROGATE(ch) && scriptLimit < textLength - 1) {
PRUint32 low = textPtr[scriptLimit + 1];
if (NS_IS_LOW_SURROGATE(low)) {
ch = SURROGATE_TO_UCS4(ch, low);
scriptLimit += 1;
}
}
sc = gfxUnicodeProperties::GetScriptCode(ch);
pairIndex = getPairIndex(ch);
/*
* Paired character handling:
*
* if it's an open character, push it onto the stack.
* if it's a close character, find the matching open on the
* stack, and use that script code. Any non-matching open
* characters above it on the stack will be poped.
*/
if (pairIndex >= 0) {
if ((pairIndex & 1) == 0) {
push(pairIndex, scriptCode);
} else {
PRInt32 pi = pairIndex & ~1;
while (STACK_IS_NOT_EMPTY() && TOP().pairIndex != pi) {
pop();
}
if (STACK_IS_NOT_EMPTY()) {
sc = TOP().scriptCode;
}
}
}
}
if (sameScript(scriptCode, sc)) {
if (scriptCode <= HB_SCRIPT_INHERITED && sc > HB_SCRIPT_INHERITED) {
scriptCode = sc;
fixup(scriptCode);
}
/*
* if this character is a close paired character,
* pop the matching open character from the stack
*/
if (pairIndex >= 0 && (pairIndex & 1) != 0) {
pop();
}
} else {
/*
* reset scriptLimit in case it was advanced during reading a
* multiple-code-unit character
*/
scriptLimit = startOfChar;
break;
}
}
aRunStart = scriptStart;
aRunLimit = scriptLimit;
aRunScript = scriptCode;
return true;
}