PhoneticStringUtils.cpp revision 0b161e0ce405b617a85d0f1b717bd3d7df056ced 
1/*
2 * Copyright (C) 2009 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <stdio.h>
18#include <stdlib.h>
19
20#include "PhoneticStringUtils.h"
21#include <utils/Unicode.h>
22
23// We'd like 0 length string last of sorted list. So when input string is NULL
24// or 0 length string, we use these instead.
25#define CODEPOINT_FOR_NULL_STR 0xFFFD
26#define STR_FOR_NULL_STR "\xEF\xBF\xBD"
27
28// We assume that users will not notice strings not sorted properly when the
29// first 128 characters are the same.
30#define MAX_CODEPOINTS 128
31
32namespace android {
33
34// Get hiragana from halfwidth katakana.
35static int GetHiraganaFromHalfwidthKatakana(char32_t codepoint,
36                                            char32_t next_codepoint,
37                                            bool *next_is_consumed) {
38    if (codepoint < 0xFF66 || 0xFF9F < codepoint) {
39        return codepoint;
40    }
41
42    switch (codepoint) {
43        case 0xFF66: // wo
44            return 0x3092;
45        case 0xFF67: // xa
46            return 0x3041;
47        case 0xFF68: // xi
48            return 0x3043;
49        case 0xFF69: // xu
50            return 0x3045;
51        case 0xFF6A: // xe
52            return 0x3047;
53        case 0xFF6B: // xo
54            return 0x3049;
55        case 0xFF6C: // xya
56            return 0x3083;
57        case 0xFF6D: // xyu
58            return 0x3085;
59        case 0xFF6E: // xyo
60            return 0x3087;
61        case 0xFF6F: // xtsu
62            return 0x3063;
63        case 0xFF70: // -
64            return 0x30FC;
65        case 0xFF9C: // wa
66            return 0x308F;
67        case 0xFF9D: // n
68            return 0x3093;
69            break;
70        default:   {
71            if (0xFF71 <= codepoint && codepoint <= 0xFF75) {
72                // a, i, u, e, o
73                if (codepoint == 0xFF73 && next_codepoint == 0xFF9E) {
74                    if (next_is_consumed != NULL) {
75                        *next_is_consumed = true;
76                    }
77                    return 0x3094; // vu
78                } else {
79                    return 0x3042 + (codepoint - 0xFF71) * 2;
80                }
81            } else if (0xFF76 <= codepoint && codepoint <= 0xFF81) {
82                // ka - chi
83                if (next_codepoint == 0xFF9E) {
84                    // "dakuten" (voiced mark)
85                    if (next_is_consumed != NULL) {
86                        *next_is_consumed = true;
87                    }
88                    return 0x304B + (codepoint - 0xFF76) * 2 + 1;
89                } else {
90                    return 0x304B + (codepoint - 0xFF76) * 2;
91                }
92            } else if (0xFF82 <= codepoint && codepoint <= 0xFF84) {
93                // tsu, te, to (skip xtsu)
94                if (next_codepoint == 0xFF9E) {
95                    // "dakuten" (voiced mark)
96                    if (next_is_consumed != NULL) {
97                        *next_is_consumed = true;
98                    }
99                    return 0x3064 + (codepoint - 0xFF82) * 2 + 1;
100                } else {
101                    return 0x3064 + (codepoint - 0xFF82) * 2;
102                }
103            } else if (0xFF85 <= codepoint && codepoint <= 0xFF89) {
104                // na, ni, nu, ne, no
105                return 0x306A + (codepoint - 0xFF85);
106            } else if (0xFF8A <= codepoint && codepoint <= 0xFF8E) {
107                // ha, hi, hu, he, ho
108                if (next_codepoint == 0xFF9E) {
109                    // "dakuten" (voiced mark)
110                    if (next_is_consumed != NULL) {
111                        *next_is_consumed = true;
112                    }
113                    return 0x306F + (codepoint - 0xFF8A) * 3 + 1;
114                } else if (next_codepoint == 0xFF9F) {
115                    // "han-dakuten" (half voiced mark)
116                    if (next_is_consumed != NULL) {
117                        *next_is_consumed = true;
118                    }
119                    return 0x306F + (codepoint - 0xFF8A) * 3 + 2;
120                } else {
121                    return 0x306F + (codepoint - 0xFF8A) * 3;
122                }
123            } else if (0xFF8F <= codepoint && codepoint <= 0xFF93) {
124                // ma, mi, mu, me, mo
125                return 0x307E + (codepoint - 0xFF8F);
126            } else if (0xFF94 <= codepoint && codepoint <= 0xFF96) {
127                // ya, yu, yo
128                return 0x3084 + (codepoint - 0xFF94) * 2;
129            } else if (0xFF97 <= codepoint && codepoint <= 0xFF9B) {
130                // ra, ri, ru, re, ro
131                return 0x3089 + (codepoint - 0xFF97);
132            }
133            // Note: 0xFF9C, 0xFF9D are handled above
134        } // end of default
135    }
136
137    return codepoint;
138}
139
140// Assuming input is hiragana, convert the hiragana to "normalized" hiragana.
141static int GetNormalizedHiragana(int codepoint) {
142    if (codepoint < 0x3040 || 0x309F < codepoint) {
143        return codepoint;
144    }
145
146    // TODO: should care (semi-)voiced mark (0x3099, 0x309A).
147
148    // Trivial kana conversions.
149    // e.g. xa => a
150    switch (codepoint) {
151        case 0x3041:
152        case 0x3043:
153        case 0x3045:
154        case 0x3047:
155        case 0x3049:
156        case 0x308E: // xwa
157            return codepoint + 1;
158        case 0x3095: // xka
159            return 0x304B;
160        case 0x3096: // xku
161            return 0x304F;
162        default:
163            return codepoint;
164    }
165}
166
167static int GetNormalizedKana(char32_t codepoint,
168                             char32_t next_codepoint,
169                             bool *next_is_consumed) {
170    // First, convert fullwidth katakana and halfwidth katakana to hiragana.
171    if (0x30A1 <= codepoint && codepoint <= 0x30F6) {
172        // Make fullwidth katakana same as hiragana.
173        // 96 == 0x30A1 - 0x3041c
174        codepoint = codepoint - 96;
175    } else {
176        codepoint = GetHiraganaFromHalfwidthKatakana(
177                codepoint, next_codepoint, next_is_consumed);
178    }
179
180    // Normalize Hiragana.
181    return GetNormalizedHiragana(codepoint);
182}
183
184int GetNormalizedCodePoint(char32_t codepoint,
185                           char32_t next_codepoint,
186                           bool *next_is_consumed) {
187    if (next_is_consumed != NULL) {
188        *next_is_consumed = false;
189    }
190
191    if (codepoint <= 0x0020 || codepoint == 0x3000) {
192        // Whitespaces. Keep it as is.
193        return codepoint;
194    } else if ((0x0021 <= codepoint && codepoint <= 0x007E) ||
195               (0xFF01 <= codepoint && codepoint <= 0xFF5E)) {
196        // Ascii and fullwidth ascii. Keep it as is
197        return codepoint;
198    } else if (codepoint == 0x02DC || codepoint == 0x223C) {
199        // tilde
200        return 0xFF5E;
201    } else if (codepoint <= 0x3040 ||
202               (0x3100 <= codepoint && codepoint < 0xFF00) ||
203               codepoint == CODEPOINT_FOR_NULL_STR) {
204        // Keep it as is.
205        return codepoint;
206    }
207
208    // Below is Kana-related handling.
209
210    return GetNormalizedKana(codepoint, next_codepoint, next_is_consumed);
211}
212
213static bool GetExpectedString(
214    const char *src, char **dst, size_t *dst_len,
215    int (*get_codepoint_function)(char32_t, char32_t, bool*)) {
216    if (dst == NULL || dst_len == NULL) {
217        return false;
218    }
219
220    if (src == NULL || *src == '\0') {
221        src = STR_FOR_NULL_STR;
222    }
223
224    char32_t codepoints[MAX_CODEPOINTS]; // if array size is changed the for loop needs to be changed
225
226    ssize_t src_len = utf8_length(src);
227    if (src_len <= 0) {
228        return false;
229    }
230
231    bool next_is_consumed;
232    size_t j = 0;
233    for (size_t i = 0; i < (size_t)src_len && j < MAX_CODEPOINTS;) {
234        int32_t ret = utf32_from_utf8_at(src, src_len, i, &i);
235        if (ret < 0) {
236            // failed to parse UTF-8
237            return false;
238        }
239        ret = get_codepoint_function(
240                static_cast<char32_t>(ret),
241                i + 1 < (size_t)src_len ? src[i + 1] : 0,
242                &next_is_consumed);
243        if (ret > 0) {
244            codepoints[j] = static_cast<char32_t>(ret);
245            j++;
246        }
247        if (next_is_consumed) {
248            i++;
249        }
250    }
251    size_t length = j;
252
253    if (length == 0) {
254        // If all of codepoints are invalid, we place the string at the end of
255        // the list.
256        codepoints[0] = 0x10000 + CODEPOINT_FOR_NULL_STR;
257        length = 1;
258    }
259
260    ssize_t new_len = utf32_to_utf8_length(codepoints, length);
261    if (new_len < 0) {
262        return false;
263    }
264
265    *dst = static_cast<char *>(malloc(new_len + 1));
266    if (*dst == NULL) {
267        return false;
268    }
269
270    utf32_to_utf8(codepoints, length, *dst);
271
272    *dst_len = new_len;
273    return true;
274}
275
276bool GetNormalizedString(const char *src, char **dst, size_t *len) {
277    return GetExpectedString(src, dst, len, GetNormalizedCodePoint);
278}
279
280}  // namespace android
281