/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
#define C_LUCY_STANDARDTOKENIZER
#define C_LUCY_TOKEN
#include "Lucy/Util/ToolSet.h"
#include "Lucy/Analysis/StandardTokenizer.h"
#include "Lucy/Analysis/Token.h"
#include "Lucy/Analysis/Inversion.h"
/*
* We use a modified version of the Word_Break property defined in UAX #29.
* CR, LF, Newline and all undefined characters map to 0. WB_ASingle
* designates characters that are Alphabetic but are excluded from ALetter.
* WB_Extend_Format includes characters in both Extend and Format. The other
* WB_* values correspond to the standard properties.
*
* The tables are in a compressed format that uses a three-stage lookup
* scheme. They're generated with the perl script gen_word_break_tables.pl
* in devel/bin.
*/
#define WB_ASingle 1
#define WB_ALetter 2
#define WB_Numeric 3
#define WB_Katakana 4
#define WB_ExtendNumLet 5
#define WB_Extend_Format 6
#define WB_MidNumLet 7
#define WB_MidLetter 8
#define WB_MidNum 9
#include "WordBreak.tab"
typedef struct lucy_StringIter {
size_t byte_pos;
size_t char_pos;
} lucy_StringIter;
static int
S_parse_single(const char *text, size_t len, lucy_StringIter *iter,
Inversion *inversion);
static int
S_parse_word(const char *text, size_t len, lucy_StringIter *iter,
int state, Inversion *inversion);
static int
S_wb_lookup(const char *ptr);
static void
S_iter_advance(const char *text, lucy_StringIter *iter);
static int
S_skip_extend_format(const char *text, size_t len, lucy_StringIter *iter);
StandardTokenizer*
StandardTokenizer_new() {
StandardTokenizer *self = (StandardTokenizer*)VTable_Make_Obj(STANDARDTOKENIZER);
return StandardTokenizer_init(self);
}
StandardTokenizer*
StandardTokenizer_init(StandardTokenizer *self) {
Analyzer_init((Analyzer*)self);
return self;
}
Inversion*
StandardTokenizer_transform(StandardTokenizer *self, Inversion *inversion) {
Inversion *new_inversion = Inversion_new(NULL);
Token *token;
while (NULL != (token = Inversion_Next(inversion))) {
StandardTokenizer_Tokenize_Str(self, token->text, token->len,
new_inversion);
}
return new_inversion;
}
Inversion*
StandardTokenizer_transform_text(StandardTokenizer *self, CharBuf *text) {
Inversion *new_inversion = Inversion_new(NULL);
StandardTokenizer_Tokenize_Str(self, (char*)CB_Get_Ptr8(text),
CB_Get_Size(text), new_inversion);
return new_inversion;
}
void
StandardTokenizer_tokenize_str(StandardTokenizer *self, const char *text,
size_t len, Inversion *inversion) {
if (len >= 1 && (uint8_t)text[len - 1] >= 0xC0
|| len >= 2 && (uint8_t)text[len - 2] >= 0xE0
|| len >= 3 && (uint8_t)text[len - 3] >= 0xF0) {
THROW(ERR, "Invalid UTF-8 sequence");
}
lucy_StringIter iter = { 0, 0 };
while (iter.byte_pos < len) {
int wb = S_wb_lookup(text + iter.byte_pos);
while (wb >= WB_ASingle && wb <= WB_ExtendNumLet) {
if (wb == WB_ASingle) {
wb = S_parse_single(text, len, &iter, inversion);
}
else {
wb = S_parse_word(text, len, &iter, wb, inversion);
}
if (iter.byte_pos >= len) return;
}
S_iter_advance(text, &iter);
}
}
/*
* Parse a word consisting of a single codepoint followed by extend or
* format characters. Used for Alphabetic characters that don't have the
* ALetter word break property: ideographs, Hiragana, and "complex content".
* Advances the iterator and returns the word break property of the current
* character.
*/
static int
S_parse_single(const char *text, size_t len, lucy_StringIter *iter,
Inversion *inversion) {
lucy_StringIter start = *iter;
int wb = S_skip_extend_format(text, len, iter);
Token *token = Token_new(text + start.byte_pos,
iter->byte_pos - start.byte_pos,
start.char_pos, iter->char_pos, 1.0f, 1);
Inversion_Append(inversion, token);
return wb;
}
/*
* Parse a word starting with an ALetter, Numeric or Katakana character.
* Advances the iterator and returns the word break property of the current
* character.
*/
static int
S_parse_word(const char *text, size_t len, lucy_StringIter *iter,
int state, Inversion *inversion) {
int wb = -1;
lucy_StringIter start = *iter;
S_iter_advance(text, iter);
lucy_StringIter end = *iter;
while (iter->byte_pos < len) {
wb = S_wb_lookup(text + iter->byte_pos);
switch (wb) {
case WB_ALetter:
case WB_Numeric:
if (state == WB_Katakana) { goto word_break; }
break;
case WB_Katakana:
if (state == WB_ALetter || state == WB_Numeric) {
goto word_break;
}
break;
case WB_ExtendNumLet:
break;
case WB_Extend_Format:
// keep state
wb = state;
break;
case WB_MidNumLet:
case WB_MidLetter:
case WB_MidNum:
if (state == WB_ALetter && wb != WB_MidNum
|| state == WB_Numeric && wb != WB_MidLetter) {
wb = S_skip_extend_format(text, len, iter);
if (wb == state) { break; }
}
goto word_break;
default:
goto word_break;
}
state = wb;
S_iter_advance(text, iter);
end = *iter;
}
Token *token;
word_break:
token = Token_new(text + start.byte_pos, end.byte_pos - start.byte_pos,
start.char_pos, end.char_pos, 1.0f, 1);
Inversion_Append(inversion, token);
return wb;
}
/*
* Conceptually, the word break property table is split into rows that
* contain 64 columns and planes that contain 64 rows (not to be confused
* the 65,536 character Unicode planes). So bits 0-5 of a code point contain
* the column index into a row, bits 6-11 contain the row index into a plane,
* and bits 12-20 contain the plane index.
*
* To save space, identical rows are merged so the row table contains only
* unique rows and the plane table contains row indices remapped to row ids.
* Then, identical planes are merged, and a plane map table is created with
* plane indices remapped to plane ids.
*
* The row and plane tables are simple one-dimensional arrays created by
* concatenating all unique rows and planes. So looking up an entry can be
* done by left shifting the id and ORing the index.
*/
#define WB_TABLE_LOOKUP(table, id, index) table [ ((id) << 6) | (index) ]
static int
S_wb_lookup(const char *ptr) {
uint8_t start = *(uint8_t*)ptr++;
if (start < 0x80) { return wb_ascii[start]; }
size_t plane_id, row_index;
if (start < 0xE0) {
if (start < 0xC0) {
THROW(ERR, "Invalid UTF-8 sequence");
}
// two byte sequence
// 110rrrrr 10cccccc
plane_id = 0;
row_index = start & 0x1F;
}
else {
size_t plane_index;
if (start < 0xF0) {
// three byte sequence
// 1110pppp 10rrrrrr 10cccccc
plane_index = start & 0x0F;
}
else {
// four byte sequence
// 11110ppp 10pppppp 10rrrrrr 10cccccc
plane_index = ((start & 0x07) << 6) | (*ptr++ & 0x3F);
}
if (plane_index >= WB_PLANE_MAP_SIZE) { return 0; }
plane_id = wb_plane_map[plane_index];
row_index = *ptr++ & 0x3F;
}
size_t row_id = WB_TABLE_LOOKUP(wb_planes, plane_id, row_index);
size_t column_index = *ptr++ & 0x3F;
return WB_TABLE_LOOKUP(wb_rows, row_id, column_index);
}
static void
S_iter_advance(const char *text, lucy_StringIter *iter) {
iter->byte_pos += StrHelp_UTF8_COUNT[*(uint8_t*)(text + iter->byte_pos)];
iter->char_pos += 1;
}
/*
* Advances the iterator skipping over Extend and Format characters.
* Returns the word break property of the current character.
*/
static int
S_skip_extend_format(const char *text, size_t len, lucy_StringIter *iter) {
int wb = -1;
do {
S_iter_advance(text, iter);
if (iter->byte_pos >= len) { break; }
wb = S_wb_lookup(text + iter->byte_pos);
} while (wb == WB_Extend_Format);
return wb;
}
bool_t
StandardTokenizer_equals(StandardTokenizer *self, Obj *other) {
StandardTokenizer *const twin = (StandardTokenizer*)other;
if (twin == self) { return true; }
if (!Obj_Is_A(other, STANDARDTOKENIZER)) { return false; }
return true;
}