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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
/*
* 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 "nsUnicodeProperties.h"
#include "nsCharTraits.h"
#include "harfbuzz/hb.h"
#include "unicode/uscript.h"
using namespace mozilla::unicode;
#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)
void gfxScriptItemizer::push(uint32_t endPairChar, Script newScriptCode) {
pushCount = LIMIT_INC(pushCount);
fixupCount = LIMIT_INC(fixupCount);
parenSP = INC1(parenSP);
parenStack[parenSP].endPairChar = endPairChar;
parenStack[parenSP].scriptCode = newScriptCode;
}
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(Script newScriptCode) {
int32_t fixupSP = DEC(parenSP, fixupCount);
while (fixupCount-- > 0) {
fixupSP = INC1(fixupSP);
parenStack[fixupSP].scriptCode = newScriptCode;
}
}
static inline bool CanMergeWithContext(Script aScript) {
return aScript <= Script::INHERITED || aScript == Script::UNKNOWN;
}
// We regard the current char as having the same script as the in-progress run
// if either script is Common/Inherited/Unknown, or if the run script appears
// in the character's ScriptExtensions, or if the char is a cluster extender.
static inline bool SameScript(Script runScript, Script currCharScript,
uint32_t aCurrCh) {
return CanMergeWithContext(runScript) ||
CanMergeWithContext(currCharScript) || currCharScript == runScript ||
IsClusterExtender(aCurrCh) || HasScript(aCurrCh, runScript);
}
gfxScriptItemizer::gfxScriptItemizer(const char16_t* src, uint32_t length)
: textPtr(src), textLength(length) {
reset();
}
void gfxScriptItemizer::SetText(const char16_t* src, uint32_t length) {
textPtr = src;
textLength = length;
reset();
}
bool gfxScriptItemizer::Next(uint32_t& aRunStart, uint32_t& aRunLimit,
Script& aRunScript) {
/* if we've fallen off the end of the text, we're done */
if (scriptLimit >= textLength) {
return false;
}
SYNC_FIXUP();
scriptCode = Script::COMMON;
Script fallbackScript = Script::UNKNOWN;
for (scriptStart = scriptLimit; scriptLimit < textLength; scriptLimit += 1) {
uint32_t ch;
Script sc;
uint32_t startOfChar = scriptLimit;
ch = textPtr[scriptLimit];
/* decode UTF-16 (may be surrogate pair) */
if (NS_IS_HIGH_SURROGATE(ch) && scriptLimit < textLength - 1) {
uint32_t low = textPtr[scriptLimit + 1];
if (NS_IS_LOW_SURROGATE(low)) {
ch = SURROGATE_TO_UCS4(ch, low);
scriptLimit += 1;
}
}
// Initialize gc to UNASSIGNED; we'll only set it to the true GC
// if the character has script=COMMON, otherwise we don't care.
uint8_t gc = HB_UNICODE_GENERAL_CATEGORY_UNASSIGNED;
sc = GetScriptCode(ch);
if (sc == Script::COMMON) {
/*
* 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 popped.
*
* We only do this if the script is COMMON; for chars with
* specific script assignments, we just use them as-is.
*/
gc = GetGeneralCategory(ch);
if (gc == HB_UNICODE_GENERAL_CATEGORY_OPEN_PUNCTUATION) {
uint32_t endPairChar = mozilla::unicode::GetMirroredChar(ch);
if (endPairChar != ch) {
push(endPairChar, scriptCode);
}
} else if (gc == HB_UNICODE_GENERAL_CATEGORY_CLOSE_PUNCTUATION &&
HasMirroredChar(ch)) {
while (STACK_IS_NOT_EMPTY() && TOP().endPairChar != ch) {
pop();
}
if (STACK_IS_NOT_EMPTY()) {
sc = TOP().scriptCode;
}
}
}
if (SameScript(scriptCode, sc, ch)) {
if (scriptCode == Script::COMMON) {
// If we have not yet resolved a specific scriptCode for the run,
// check whether this character provides it.
if (!CanMergeWithContext(sc)) {
// Use this character's script.
scriptCode = sc;
fixup(scriptCode);
} else if (fallbackScript == Script::UNKNOWN) {
// See if the character has a ScriptExtensions property we can
// store for use in the event the run remains unresolved.
UErrorCode error = U_ZERO_ERROR;
UScriptCode extension;
int32_t n = uscript_getScriptExtensions(ch, &extension, 1, &error);
if (error == U_BUFFER_OVERFLOW_ERROR && n > 0) {
fallbackScript = Script(extension);
}
}
}
/*
* if this character is a close paired character,
* pop the matching open character from the stack
*/
if (gc == HB_UNICODE_GENERAL_CATEGORY_CLOSE_PUNCTUATION &&
HasMirroredChar(ch)) {
pop();
}
} else {
/*
* reset scriptLimit in case it was advanced during reading a
* multiple-code-unit character
*/
scriptLimit = startOfChar;
break;
}
}
aRunStart = scriptStart;
aRunLimit = scriptLimit;
if (scriptCode == Script::COMMON && fallbackScript != Script::UNKNOWN) {
aRunScript = fallbackScript;
} else {
aRunScript = scriptCode;
}
return true;
}