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/*
* Copyright (C) 2005, 2006, 2007, 2014 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "StringTruncator.h"
#include "FontCascade.h"
#include <wtf/text/TextBreakIterator.h>
#include "TextRun.h"
#include <unicode/ubrk.h>
#include <wtf/Assertions.h>
#include <wtf/Vector.h>
#include <wtf/text/StringView.h>
#include <wtf/unicode/CharacterNames.h>
namespace WebCore {
#define STRING_BUFFER_SIZE 2048
typedef unsigned TruncationFunction(const String&, unsigned length, unsigned keepCount, UChar* buffer, bool shouldInsertEllipsis);
static inline int textBreakAtOrPreceding(UBreakIterator* it, int offset)
{
if (ubrk_isBoundary(it, offset))
return offset;
int result = ubrk_preceding(it, offset);
return result == UBRK_DONE ? 0 : result;
}
static inline int boundedTextBreakFollowing(UBreakIterator* it, int offset, int length)
{
int result = ubrk_following(it, offset);
return result == UBRK_DONE ? length : result;
}
static unsigned centerTruncateToBuffer(const String& string, unsigned length, unsigned keepCount, UChar* buffer, bool shouldInsertEllipsis)
{
ASSERT_WITH_SECURITY_IMPLICATION(keepCount < length);
ASSERT_WITH_SECURITY_IMPLICATION(keepCount < STRING_BUFFER_SIZE);
unsigned omitStart = (keepCount + 1) / 2;
NonSharedCharacterBreakIterator it(StringView(string).substring(0, length));
unsigned omitEnd = boundedTextBreakFollowing(it, omitStart + (length - keepCount) - 1, length);
omitStart = textBreakAtOrPreceding(it, omitStart);
#if PLATFORM(IOS)
// FIXME: We should guard this code behind an editing behavior. Then we can remove the PLATFORM(IOS)-guard.
// Or just turn it on for all platforms. It seems like good behavior everywhere. Might be better to generalize
// it to handle all whitespace, not just "space".
// Strip single character before ellipsis character, when that character is preceded by a space
if (omitStart > 1 && string[omitStart - 1] != space && omitStart > 2 && string[omitStart - 2] == space)
--omitStart;
// Strip whitespace before and after the ellipsis character
while (omitStart > 1 && string[omitStart - 1] == space)
--omitStart;
// Strip single character after ellipsis character, when that character is followed by a space
if ((length - omitEnd) > 1 && string[omitEnd] != space && (length - omitEnd) > 2 && string[omitEnd + 1] == space)
++omitEnd;
while ((length - omitEnd) > 1 && string[omitEnd] == space)
++omitEnd;
#endif
unsigned truncatedLength = omitStart + shouldInsertEllipsis + (length - omitEnd);
ASSERT(truncatedLength <= length);
StringView(string).substring(0, omitStart).getCharactersWithUpconvert(buffer);
if (shouldInsertEllipsis)
buffer[omitStart++] = horizontalEllipsis;
StringView(string).substring(omitEnd, length - omitEnd).getCharactersWithUpconvert(&buffer[omitStart]);
return truncatedLength;
}
static unsigned rightTruncateToBuffer(const String& string, unsigned length, unsigned keepCount, UChar* buffer, bool shouldInsertEllipsis)
{
ASSERT_WITH_SECURITY_IMPLICATION(keepCount < length);
ASSERT_WITH_SECURITY_IMPLICATION(keepCount < STRING_BUFFER_SIZE);
#if PLATFORM(IOS)
// FIXME: We should guard this code behind an editing behavior. Then we can remove the PLATFORM(IOS)-guard.
// Or just turn it on for all platforms. It seems like good behavior everywhere. Might be better to generalize
// it to handle all whitespace, not just "space".
// Strip single character before ellipsis character, when that character is preceded by a space
if (keepCount > 1 && string[keepCount - 1] != space && keepCount > 2 && string[keepCount - 2] == space)
--keepCount;
// Strip whitespace before the ellipsis character
while (keepCount > 1 && string[keepCount - 1] == space)
--keepCount;
#endif
NonSharedCharacterBreakIterator it(StringView(string).substring(0, length));
unsigned keepLength = textBreakAtOrPreceding(it, keepCount);
unsigned truncatedLength = shouldInsertEllipsis ? keepLength + 1 : keepLength;
StringView(string).substring(0, keepLength).getCharactersWithUpconvert(buffer);
if (shouldInsertEllipsis)
buffer[keepLength] = horizontalEllipsis;
return truncatedLength;
}
static unsigned rightClipToCharacterBuffer(const String& string, unsigned length, unsigned keepCount, UChar* buffer, bool)
{
ASSERT(keepCount < length);
ASSERT(keepCount < STRING_BUFFER_SIZE);
NonSharedCharacterBreakIterator it(StringView(string).substring(0, length));
unsigned keepLength = textBreakAtOrPreceding(it, keepCount);
StringView(string).substring(0, keepLength).getCharactersWithUpconvert(buffer);
return keepLength;
}
static unsigned rightClipToWordBuffer(const String& string, unsigned length, unsigned keepCount, UChar* buffer, bool)
{
ASSERT(keepCount < length);
ASSERT(keepCount < STRING_BUFFER_SIZE);
UBreakIterator* it = wordBreakIterator(StringView(string).substring(0, length));
unsigned keepLength = textBreakAtOrPreceding(it, keepCount);
StringView(string).substring(0, keepLength).getCharactersWithUpconvert(buffer);
#if PLATFORM(IOS)
// FIXME: We should guard this code behind an editing behavior. Then we can remove the PLATFORM(IOS)-guard.
// Or just turn it on for all platforms. It seems like good behavior everywhere. Might be better to generalize
// it to handle all whitespace, not just "space".
// Motivated by <rdar://problem/7439327> truncation should not include a trailing space
while (keepLength && string[keepLength - 1] == space)
--keepLength;
#endif
return keepLength;
}
static unsigned leftTruncateToBuffer(const String& string, unsigned length, unsigned keepCount, UChar* buffer, bool shouldInsertEllipsis)
{
ASSERT(keepCount < length);
ASSERT(keepCount < STRING_BUFFER_SIZE);
unsigned startIndex = length - keepCount;
NonSharedCharacterBreakIterator it(string);
unsigned adjustedStartIndex = startIndex;
boundedTextBreakFollowing(it, startIndex, length - startIndex);
// Strip single character after ellipsis character, when that character is preceded by a space
if (adjustedStartIndex < length && string[adjustedStartIndex] != space
&& adjustedStartIndex < length - 1 && string[adjustedStartIndex + 1] == space)
++adjustedStartIndex;
// Strip whitespace after the ellipsis character
while (adjustedStartIndex < length && string[adjustedStartIndex] == space)
++adjustedStartIndex;
if (shouldInsertEllipsis) {
buffer[0] = horizontalEllipsis;
StringView(string).substring(adjustedStartIndex, length - adjustedStartIndex + 1).getCharactersWithUpconvert(&buffer[1]);
return length - adjustedStartIndex + 1;
}
StringView(string).substring(adjustedStartIndex, length - adjustedStartIndex + 1).getCharactersWithUpconvert(&buffer[0]);
return length - adjustedStartIndex;
}
static float stringWidth(const FontCascade& renderer, const UChar* characters, unsigned length)
{
TextRun run(StringView(characters, length));
return renderer.width(run);
}
static String truncateString(const String& string, float maxWidth, const FontCascade& font, TruncationFunction truncateToBuffer, float* resultWidth = nullptr, bool shouldInsertEllipsis = true, float customTruncationElementWidth = 0, bool alwaysTruncate = false)
{
if (string.isEmpty())
return string;
if (resultWidth)
*resultWidth = 0;
ASSERT(maxWidth >= 0);
float currentEllipsisWidth = shouldInsertEllipsis ? stringWidth(font, &horizontalEllipsis, 1) : customTruncationElementWidth;
UChar stringBuffer[STRING_BUFFER_SIZE];
unsigned truncatedLength;
unsigned keepCount;
unsigned length = string.length();
if (length > STRING_BUFFER_SIZE) {
if (shouldInsertEllipsis)
keepCount = STRING_BUFFER_SIZE - 1; // need 1 character for the ellipsis
else
keepCount = 0;
truncatedLength = centerTruncateToBuffer(string, length, keepCount, stringBuffer, shouldInsertEllipsis);
} else {
keepCount = length;
StringView(string).getCharactersWithUpconvert(stringBuffer);
truncatedLength = length;
}
float width = stringWidth(font, stringBuffer, truncatedLength);
if (!shouldInsertEllipsis && alwaysTruncate)
width += customTruncationElementWidth;
if ((width - maxWidth) < 0.0001) { // Ignore rounding errors.
if (resultWidth)
*resultWidth = width;
return string;
}
unsigned keepCountForLargestKnownToFit = 0;
float widthForLargestKnownToFit = currentEllipsisWidth;
unsigned keepCountForSmallestKnownToNotFit = keepCount;
float widthForSmallestKnownToNotFit = width;
if (currentEllipsisWidth >= maxWidth) {
keepCountForLargestKnownToFit = 1;
keepCountForSmallestKnownToNotFit = 2;
}
while (keepCountForLargestKnownToFit + 1 < keepCountForSmallestKnownToNotFit) {
ASSERT_WITH_SECURITY_IMPLICATION(widthForLargestKnownToFit <= maxWidth);
ASSERT_WITH_SECURITY_IMPLICATION(widthForSmallestKnownToNotFit > maxWidth);
float ratio = (keepCountForSmallestKnownToNotFit - keepCountForLargestKnownToFit)
/ (widthForSmallestKnownToNotFit - widthForLargestKnownToFit);
keepCount = static_cast<unsigned>(maxWidth * ratio);
if (keepCount <= keepCountForLargestKnownToFit)
keepCount = keepCountForLargestKnownToFit + 1;
else if (keepCount >= keepCountForSmallestKnownToNotFit)
keepCount = keepCountForSmallestKnownToNotFit - 1;
ASSERT_WITH_SECURITY_IMPLICATION(keepCount < length);
ASSERT(keepCount > 0);
ASSERT_WITH_SECURITY_IMPLICATION(keepCount < keepCountForSmallestKnownToNotFit);
ASSERT_WITH_SECURITY_IMPLICATION(keepCount > keepCountForLargestKnownToFit);
truncatedLength = truncateToBuffer(string, length, keepCount, stringBuffer, shouldInsertEllipsis);
width = stringWidth(font, stringBuffer, truncatedLength);
if (!shouldInsertEllipsis)
width += customTruncationElementWidth;
if (width <= maxWidth) {
keepCountForLargestKnownToFit = keepCount;
widthForLargestKnownToFit = width;
if (resultWidth)
*resultWidth = width;
} else {
keepCountForSmallestKnownToNotFit = keepCount;
widthForSmallestKnownToNotFit = width;
}
}
if (keepCountForLargestKnownToFit == 0) {
keepCountForLargestKnownToFit = 1;
}
if (keepCount != keepCountForLargestKnownToFit) {
keepCount = keepCountForLargestKnownToFit;
truncatedLength = truncateToBuffer(string, length, keepCount, stringBuffer, shouldInsertEllipsis);
}
return String(stringBuffer, truncatedLength);
}
String StringTruncator::centerTruncate(const String& string, float maxWidth, const FontCascade& font)
{
return truncateString(string, maxWidth, font, centerTruncateToBuffer);
}
String StringTruncator::rightTruncate(const String& string, float maxWidth, const FontCascade& font)
{
return truncateString(string, maxWidth, font, rightTruncateToBuffer);
}
float StringTruncator::width(const String& string, const FontCascade& font)
{
return stringWidth(font, StringView(string).upconvertedCharacters(), string.length());
}
String StringTruncator::centerTruncate(const String& string, float maxWidth, const FontCascade& font, float& resultWidth, bool shouldInsertEllipsis, float customTruncationElementWidth)
{
return truncateString(string, maxWidth, font, centerTruncateToBuffer, &resultWidth, shouldInsertEllipsis, customTruncationElementWidth);
}
String StringTruncator::rightTruncate(const String& string, float maxWidth, const FontCascade& font, float& resultWidth, bool shouldInsertEllipsis, float customTruncationElementWidth)
{
return truncateString(string, maxWidth, font, rightTruncateToBuffer, &resultWidth, shouldInsertEllipsis, customTruncationElementWidth);
}
String StringTruncator::leftTruncate(const String& string, float maxWidth, const FontCascade& font, float& resultWidth, bool shouldInsertEllipsis, float customTruncationElementWidth)
{
return truncateString(string, maxWidth, font, leftTruncateToBuffer, &resultWidth, shouldInsertEllipsis, customTruncationElementWidth);
}
String StringTruncator::rightClipToCharacter(const String& string, float maxWidth, const FontCascade& font, float& resultWidth, bool shouldInsertEllipsis, float customTruncationElementWidth)
{
return truncateString(string, maxWidth, font, rightClipToCharacterBuffer, &resultWidth, shouldInsertEllipsis, customTruncationElementWidth);
}
String StringTruncator::rightClipToWord(const String& string, float maxWidth, const FontCascade& font, float& resultWidth, bool shouldInsertEllipsis, float customTruncationElementWidth, bool alwaysTruncate)
{
return truncateString(string, maxWidth, font, rightClipToWordBuffer, &resultWidth, shouldInsertEllipsis, customTruncationElementWidth, alwaysTruncate);
}
} // namespace WebCore