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/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "minikin/Hyphenator.h"
#include <algorithm>
#include <memory>
#include <string>
#include <vector>
#include <unicode/uchar.h>
#include <unicode/uscript.h>
#include "minikin/Characters.h"
namespace minikin {
// The following are structs that correspond to tables inside the hyb file format
struct AlphabetTable0 {
uint32_t version;
uint32_t min_codepoint;
uint32_t max_codepoint;
uint8_t data[1]; // actually flexible array, size is known at runtime
};
struct AlphabetTable1 {
uint32_t version;
uint32_t n_entries;
uint32_t data[1]; // actually flexible array, size is known at runtime
static uint32_t codepoint(uint32_t entry) { return entry >> 11; }
static uint32_t value(uint32_t entry) { return entry & 0x7ff; }
};
struct Trie {
uint32_t version;
uint32_t char_mask;
uint32_t link_shift;
uint32_t link_mask;
uint32_t pattern_shift;
uint32_t n_entries;
uint32_t data[1]; // actually flexible array, size is known at runtime
};
struct Pattern {
uint32_t version;
uint32_t n_entries;
uint32_t pattern_offset;
uint32_t pattern_size;
uint32_t data[1]; // actually flexible array, size is known at runtime
// accessors
static uint32_t len(uint32_t entry) { return entry >> 26; }
static uint32_t shift(uint32_t entry) { return (entry >> 20) & 0x3f; }
const uint8_t* buf(uint32_t entry) const {
return reinterpret_cast<const uint8_t*>(this) + pattern_offset + (entry & 0xfffff);
}
};
struct Header {
uint32_t magic;
uint32_t version;
uint32_t alphabet_offset;
uint32_t trie_offset;
uint32_t pattern_offset;
uint32_t file_size;
// accessors
const uint8_t* bytes() const { return reinterpret_cast<const uint8_t*>(this); }
uint32_t alphabetVersion() const {
return *reinterpret_cast<const uint32_t*>(bytes() + alphabet_offset);
}
const AlphabetTable0* alphabetTable0() const {
return reinterpret_cast<const AlphabetTable0*>(bytes() + alphabet_offset);
}
const AlphabetTable1* alphabetTable1() const {
return reinterpret_cast<const AlphabetTable1*>(bytes() + alphabet_offset);
}
const Trie* trieTable() const { return reinterpret_cast<const Trie*>(bytes() + trie_offset); }
const Pattern* patternTable() const {
return reinterpret_cast<const Pattern*>(bytes() + pattern_offset);
}
};
// static
Hyphenator* Hyphenator::loadBinary(const uint8_t* patternData, size_t minPrefix, size_t minSuffix,
const std::string& locale) {
HyphenationLocale hyphenLocale = HyphenationLocale::OTHER;
if (locale == "pl") {
hyphenLocale = HyphenationLocale::POLISH;
} else if (locale == "ca") {
hyphenLocale = HyphenationLocale::CATALAN;
} else if (locale == "sl") {
hyphenLocale = HyphenationLocale::SLOVENIAN;
}
return new Hyphenator(patternData, minPrefix, minSuffix, hyphenLocale);
}
Hyphenator::Hyphenator(const uint8_t* patternData, size_t minPrefix, size_t minSuffix,
HyphenationLocale hyphenLocale)
: mPatternData(patternData),
mMinPrefix(minPrefix),
mMinSuffix(minSuffix),
mHyphenationLocale(hyphenLocale) {}
void Hyphenator::hyphenate(const U16StringPiece& word, HyphenationType* out) const {
const size_t len = word.size();
const size_t paddedLen = len + 2; // start and stop code each count for 1
if (mPatternData != nullptr && len >= mMinPrefix + mMinSuffix &&
paddedLen <= MAX_HYPHENATED_SIZE) {
uint16_t alpha_codes[MAX_HYPHENATED_SIZE];
const HyphenationType hyphenValue = alphabetLookup(alpha_codes, word);
if (hyphenValue != HyphenationType::DONT_BREAK) {
hyphenateFromCodes(alpha_codes, paddedLen, hyphenValue, out);
return;
}
// TODO: try NFC normalization
// TODO: handle non-BMP Unicode (requires remapping of offsets)
}
// Note that we will always get here if the word contains a hyphen or a soft hyphen, because the
// alphabet is not expected to contain a hyphen or a soft hyphen character, so alphabetLookup
// would return DONT_BREAK.
hyphenateWithNoPatterns(word, out);
}
// This function determines whether a character is like U+2010 HYPHEN in
// line breaking and usage: a character immediately after which line breaks
// are allowed, but words containing it should not be automatically
// hyphenated using patterns. This is a curated set, created by manually
// inspecting all the characters that have the Unicode line breaking
// property of BA or HY and seeing which ones are hyphens.
bool Hyphenator::isLineBreakingHyphen(uint32_t c) {
return (c == 0x002D || // HYPHEN-MINUS
c == 0x058A || // ARMENIAN HYPHEN
c == 0x05BE || // HEBREW PUNCTUATION MAQAF
c == 0x1400 || // CANADIAN SYLLABICS HYPHEN
c == 0x2010 || // HYPHEN
c == 0x2013 || // EN DASH
c == 0x2027 || // HYPHENATION POINT
c == 0x2E17 || // DOUBLE OBLIQUE HYPHEN
c == 0x2E40); // DOUBLE HYPHEN
}
EndHyphenEdit editForThisLine(HyphenationType type) {
switch (type) {
case HyphenationType::BREAK_AND_INSERT_HYPHEN:
return EndHyphenEdit::INSERT_HYPHEN;
case HyphenationType::BREAK_AND_INSERT_ARMENIAN_HYPHEN:
return EndHyphenEdit::INSERT_ARMENIAN_HYPHEN;
case HyphenationType::BREAK_AND_INSERT_MAQAF:
return EndHyphenEdit::INSERT_MAQAF;
case HyphenationType::BREAK_AND_INSERT_UCAS_HYPHEN:
return EndHyphenEdit::INSERT_UCAS_HYPHEN;
case HyphenationType::BREAK_AND_REPLACE_WITH_HYPHEN:
return EndHyphenEdit::REPLACE_WITH_HYPHEN;
case HyphenationType::BREAK_AND_INSERT_HYPHEN_AND_ZWJ:
return EndHyphenEdit::INSERT_ZWJ_AND_HYPHEN;
case HyphenationType::DONT_BREAK: // Hyphen edit for non breaking case doesn't make sense.
default:
return EndHyphenEdit::NO_EDIT;
}
}
StartHyphenEdit editForNextLine(HyphenationType type) {
switch (type) {
case HyphenationType::BREAK_AND_INSERT_HYPHEN_AT_NEXT_LINE:
return StartHyphenEdit::INSERT_HYPHEN;
case HyphenationType::BREAK_AND_INSERT_HYPHEN_AND_ZWJ:
return StartHyphenEdit::INSERT_ZWJ;
case HyphenationType::DONT_BREAK: // Hyphen edit for non breaking case doesn't make sense.
default:
return StartHyphenEdit::NO_EDIT;
}
}
static UScriptCode getScript(uint32_t codePoint) {
UErrorCode errorCode = U_ZERO_ERROR;
const UScriptCode script = uscript_getScript(static_cast<UChar32>(codePoint), &errorCode);
if (U_SUCCESS(errorCode)) {
return script;
} else {
return USCRIPT_INVALID_CODE;
}
}
static HyphenationType hyphenationTypeBasedOnScript(uint32_t codePoint) {
// Note: It's not clear what the best hyphen for Hebrew is. While maqaf is the "correct" hyphen
// for Hebrew, modern practice may have shifted towards Western hyphens. We use normal hyphens
// for now to be safe. BREAK_AND_INSERT_MAQAF is already implemented, so if we want to switch
// to maqaf for Hebrew, we can simply add a condition here.
const UScriptCode script = getScript(codePoint);
if (script == USCRIPT_KANNADA || script == USCRIPT_MALAYALAM || script == USCRIPT_TAMIL ||
script == USCRIPT_TELUGU) {
// Grantha is not included, since we don't support non-BMP hyphenation yet.
return HyphenationType::BREAK_AND_DONT_INSERT_HYPHEN;
} else if (script == USCRIPT_ARMENIAN) {
return HyphenationType::BREAK_AND_INSERT_ARMENIAN_HYPHEN;
} else if (script == USCRIPT_CANADIAN_ABORIGINAL) {
return HyphenationType::BREAK_AND_INSERT_UCAS_HYPHEN;
} else {
return HyphenationType::BREAK_AND_INSERT_HYPHEN;
}
}
static inline int32_t getJoiningType(UChar32 codepoint) {
return u_getIntPropertyValue(codepoint, UCHAR_JOINING_TYPE);
}
// Assumption for caller: location must be >= 2 and word[location] == CHAR_SOFT_HYPHEN.
// This function decides if the letters before and after the hyphen should appear as joining.
static inline HyphenationType getHyphTypeForArabic(const U16StringPiece& word, size_t location) {
ssize_t i = location;
int32_t type = U_JT_NON_JOINING;
while (static_cast<size_t>(i) < word.size() &&
(type = getJoiningType(word[i])) == U_JT_TRANSPARENT) {
i++;
}
if (type == U_JT_DUAL_JOINING || type == U_JT_RIGHT_JOINING || type == U_JT_JOIN_CAUSING) {
// The next character is of the type that may join the last character. See if the last
// character is also of the right type.
i = location - 2; // Skip the soft hyphen
type = U_JT_NON_JOINING;
while (i >= 0 && (type = getJoiningType(word[i])) == U_JT_TRANSPARENT) {
i--;
}
if (type == U_JT_DUAL_JOINING || type == U_JT_LEFT_JOINING || type == U_JT_JOIN_CAUSING) {
return HyphenationType::BREAK_AND_INSERT_HYPHEN_AND_ZWJ;
}
}
return HyphenationType::BREAK_AND_INSERT_HYPHEN;
}
// Use various recommendations of UAX #14 Unicode Line Breaking Algorithm for hyphenating words
// that didn't match patterns, especially words that contain hyphens or soft hyphens (See sections
// 5.3, Use of Hyphen, and 5.4, Use of Soft Hyphen).
void Hyphenator::hyphenateWithNoPatterns(const U16StringPiece& word, HyphenationType* out) const {
out[0] = HyphenationType::DONT_BREAK;
for (size_t i = 1; i < word.size(); i++) {
const uint16_t prevChar = word[i - 1];
if (i > 1 && isLineBreakingHyphen(prevChar)) {
// Break after hyphens, but only if they don't start the word.
if ((prevChar == CHAR_HYPHEN_MINUS || prevChar == CHAR_HYPHEN) &&
(mHyphenationLocale == HyphenationLocale::POLISH ||
mHyphenationLocale == HyphenationLocale::SLOVENIAN) &&
getScript(word[i]) == USCRIPT_LATIN) {
// In Polish and Slovenian, hyphens get repeated at the next line. To be safe,
// we will do this only if the next character is Latin.
out[i] = HyphenationType::BREAK_AND_INSERT_HYPHEN_AT_NEXT_LINE;
} else {
out[i] = HyphenationType::BREAK_AND_DONT_INSERT_HYPHEN;
}
} else if (i > 1 && prevChar == CHAR_SOFT_HYPHEN) {
// Break after soft hyphens, but only if they don't start the word (a soft hyphen
// starting the word doesn't give any useful break opportunities). The type of the break
// is based on the script of the character we break on.
if (getScript(word[i]) == USCRIPT_ARABIC) {
// For Arabic, we need to look and see if the characters around the soft hyphen
// actually join. If they don't, we'll just insert a normal hyphen.
out[i] = getHyphTypeForArabic(word, i);
} else {
out[i] = hyphenationTypeBasedOnScript(word[i]);
}
} else if (prevChar == CHAR_MIDDLE_DOT && mMinPrefix < i && i <= word.size() - mMinSuffix &&
((word[i - 2] == 'l' && word[i] == 'l') ||
(word[i - 2] == 'L' && word[i] == 'L')) &&
mHyphenationLocale == HyphenationLocale::CATALAN) {
// In Catalan, "l·l" should break as "l-" on the first line
// and "l" on the next line.
out[i] = HyphenationType::BREAK_AND_REPLACE_WITH_HYPHEN;
} else {
out[i] = HyphenationType::DONT_BREAK;
}
}
}
HyphenationType Hyphenator::alphabetLookup(uint16_t* alpha_codes,
const U16StringPiece& word) const {
const Header* header = getHeader();
HyphenationType result = HyphenationType::BREAK_AND_INSERT_HYPHEN;
// TODO: check header magic
uint32_t alphabetVersion = header->alphabetVersion();
if (alphabetVersion == 0) {
const AlphabetTable0* alphabet = header->alphabetTable0();
uint32_t min_codepoint = alphabet->min_codepoint;
uint32_t max_codepoint = alphabet->max_codepoint;
alpha_codes[0] = 0; // word start
for (size_t i = 0; i < word.size(); i++) {
uint16_t c = word[i];
if (c < min_codepoint || c >= max_codepoint) {
return HyphenationType::DONT_BREAK;
}
uint8_t code = alphabet->data[c - min_codepoint];
if (code == 0) {
return HyphenationType::DONT_BREAK;
}
if (result == HyphenationType::BREAK_AND_INSERT_HYPHEN) {
result = hyphenationTypeBasedOnScript(c);
}
alpha_codes[i + 1] = code;
}
alpha_codes[word.size() + 1] = 0; // word termination
return result;
} else if (alphabetVersion == 1) {
const AlphabetTable1* alphabet = header->alphabetTable1();
size_t n_entries = alphabet->n_entries;
const uint32_t* begin = alphabet->data;
const uint32_t* end = begin + n_entries;
alpha_codes[0] = 0;
for (size_t i = 0; i < word.size(); i++) {
uint16_t c = word[i];
auto p = std::lower_bound(begin, end, c << 11);
if (p == end) {
return HyphenationType::DONT_BREAK;
}
uint32_t entry = *p;
if (AlphabetTable1::codepoint(entry) != c) {
return HyphenationType::DONT_BREAK;
}
if (result == HyphenationType::BREAK_AND_INSERT_HYPHEN) {
result = hyphenationTypeBasedOnScript(c);
}
alpha_codes[i + 1] = AlphabetTable1::value(entry);
}
alpha_codes[word.size() + 1] = 0;
return result;
}
return HyphenationType::DONT_BREAK;
}
/**
* Internal implementation, after conversion to codes. All case folding and normalization
* has been done by now, and all characters have been found in the alphabet.
* Note: len here is the padded length including 0 codes at start and end.
**/
void Hyphenator::hyphenateFromCodes(const uint16_t* codes, size_t len, HyphenationType hyphenValue,
HyphenationType* out) const {
static_assert(sizeof(HyphenationType) == sizeof(uint8_t), "HyphnationType must be uint8_t.");
// Reuse the result array as a buffer for calculating intermediate hyphenation numbers.
uint8_t* buffer = reinterpret_cast<uint8_t*>(out);
const Header* header = getHeader();
const Trie* trie = header->trieTable();
const Pattern* pattern = header->patternTable();
uint32_t char_mask = trie->char_mask;
uint32_t link_shift = trie->link_shift;
uint32_t link_mask = trie->link_mask;
uint32_t pattern_shift = trie->pattern_shift;
size_t maxOffset = len - mMinSuffix - 1;
for (size_t i = 0; i < len - 1; i++) {
uint32_t node = 0; // index into Trie table
for (size_t j = i; j < len; j++) {
uint16_t c = codes[j];
uint32_t entry = trie->data[node + c];
if ((entry & char_mask) == c) {
node = (entry & link_mask) >> link_shift;
} else {
break;
}
uint32_t pat_ix = trie->data[node] >> pattern_shift;
// pat_ix contains a 3-tuple of length, shift (number of trailing zeros), and an offset
// into the buf pool. This is the pattern for the substring (i..j) we just matched,
// which we combine (via point-wise max) into the buffer vector.
if (pat_ix != 0) {
uint32_t pat_entry = pattern->data[pat_ix];
int pat_len = Pattern::len(pat_entry);
int pat_shift = Pattern::shift(pat_entry);
const uint8_t* pat_buf = pattern->buf(pat_entry);
int offset = j + 1 - (pat_len + pat_shift);
// offset is the index within buffer that lines up with the start of pat_buf
int start = std::max((int)mMinPrefix - offset, 0);
int end = std::min(pat_len, (int)maxOffset - offset);
for (int k = start; k < end; k++) {
buffer[offset + k] = std::max(buffer[offset + k], pat_buf[k]);
}
}
}
}
// Since the above calculation does not modify values outside
// [mMinPrefix, len - mMinSuffix], they are left as 0 = DONT_BREAK.
for (size_t i = mMinPrefix; i < maxOffset; i++) {
// Hyphenation opportunities happen when the hyphenation numbers are odd.
out[i] = (buffer[i] & 1u) ? hyphenValue : HyphenationType::DONT_BREAK;
}
}
} // namespace minikin