Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2013 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 | //#define LOG_NDEBUG 0 |
| 18 | #define LOG_TAG "CharacterEncodingDector" |
| 19 | #include <utils/Log.h> |
| 20 | |
Pawin Vongmasa | 255735a | 2017-07-19 11:24:56 -0700 | [diff] [blame^] | 21 | #include <media/CharacterEncodingDetector.h> |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 22 | #include "CharacterEncodingDetectorTables.h" |
| 23 | |
Pawin Vongmasa | 255735a | 2017-07-19 11:24:56 -0700 | [diff] [blame^] | 24 | #include <utils/Vector.h> |
| 25 | #include <media/StringArray.h> |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 26 | |
Pawin Vongmasa | 255735a | 2017-07-19 11:24:56 -0700 | [diff] [blame^] | 27 | #include <unicode/ucnv.h> |
| 28 | #include <unicode/ucsdet.h> |
| 29 | #include <unicode/ustring.h> |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 30 | |
| 31 | namespace android { |
| 32 | |
| 33 | CharacterEncodingDetector::CharacterEncodingDetector() { |
| 34 | |
| 35 | UErrorCode status = U_ZERO_ERROR; |
| 36 | mUtf8Conv = ucnv_open("UTF-8", &status); |
| 37 | if (U_FAILURE(status)) { |
| 38 | ALOGE("could not create UConverter for UTF-8"); |
| 39 | mUtf8Conv = NULL; |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | CharacterEncodingDetector::~CharacterEncodingDetector() { |
| 44 | ucnv_close(mUtf8Conv); |
| 45 | } |
| 46 | |
| 47 | void CharacterEncodingDetector::addTag(const char *name, const char *value) { |
| 48 | mNames.push_back(name); |
| 49 | mValues.push_back(value); |
| 50 | } |
| 51 | |
| 52 | size_t CharacterEncodingDetector::size() { |
| 53 | return mNames.size(); |
| 54 | } |
| 55 | |
| 56 | status_t CharacterEncodingDetector::getTag(int index, const char **name, const char**value) { |
| 57 | if (index >= mNames.size()) { |
| 58 | return BAD_VALUE; |
| 59 | } |
| 60 | |
| 61 | *name = mNames.getEntry(index); |
| 62 | *value = mValues.getEntry(index); |
| 63 | return OK; |
| 64 | } |
| 65 | |
| 66 | static bool isPrintableAscii(const char *value, size_t len) { |
| 67 | for (size_t i = 0; i < len; i++) { |
| 68 | if ((value[i] & 0x80) || value[i] < 0x20 || value[i] == 0x7f) { |
| 69 | return false; |
| 70 | } |
| 71 | } |
| 72 | return true; |
| 73 | } |
| 74 | |
| 75 | void CharacterEncodingDetector::detectAndConvert() { |
| 76 | |
| 77 | int size = mNames.size(); |
| 78 | ALOGV("%d tags before conversion", size); |
| 79 | for (int i = 0; i < size; i++) { |
| 80 | ALOGV("%s: %s", mNames.getEntry(i), mValues.getEntry(i)); |
| 81 | } |
| 82 | |
| 83 | if (size && mUtf8Conv) { |
| 84 | |
| 85 | UErrorCode status = U_ZERO_ERROR; |
| 86 | UCharsetDetector *csd = ucsdet_open(&status); |
| 87 | const UCharsetMatch *ucm; |
caozhiyuan | 4a2c17f | 2017-05-05 13:53:33 +0800 | [diff] [blame] | 88 | bool goodmatch = true; |
| 89 | int highest = 0; |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 90 | |
| 91 | // try combined detection of artist/album/title etc. |
| 92 | char buf[1024]; |
| 93 | buf[0] = 0; |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 94 | bool allprintable = true; |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 95 | for (int i = 0; i < size; i++) { |
| 96 | const char *name = mNames.getEntry(i); |
| 97 | const char *value = mValues.getEntry(i); |
| 98 | if (!isPrintableAscii(value, strlen(value)) && ( |
| 99 | !strcmp(name, "artist") || |
| 100 | !strcmp(name, "albumartist") || |
| 101 | !strcmp(name, "composer") || |
| 102 | !strcmp(name, "genre") || |
| 103 | !strcmp(name, "album") || |
| 104 | !strcmp(name, "title"))) { |
| 105 | strlcat(buf, value, sizeof(buf)); |
| 106 | // separate tags by space so ICU's ngram detector can do its job |
| 107 | strlcat(buf, " ", sizeof(buf)); |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 108 | allprintable = false; |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 109 | } |
| 110 | } |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 111 | |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 112 | const char *combinedenc = "UTF-8"; |
| 113 | if (allprintable) { |
| 114 | // since 'buf' is empty, ICU would return a UTF-8 matcher with low confidence, so |
| 115 | // no need to even call it |
Mark Salyzyn | 34fb296 | 2014-06-18 16:30:56 -0700 | [diff] [blame] | 116 | ALOGV("all tags are printable, assuming ascii (%zu)", strlen(buf)); |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 117 | } else { |
| 118 | ucsdet_setText(csd, buf, strlen(buf), &status); |
| 119 | int32_t matches; |
| 120 | const UCharsetMatch** ucma = ucsdet_detectAll(csd, &matches, &status); |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 121 | const UCharsetMatch* bestCombinedMatch = getPreferred(buf, strlen(buf), |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 122 | ucma, matches, &goodmatch, &highest); |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 123 | |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 124 | ALOGV("goodmatch: %s, highest: %d", goodmatch ? "true" : "false", highest); |
| 125 | if (!goodmatch && (highest < 15 || strlen(buf) < 20)) { |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 126 | ALOGV("not a good match, trying with more data"); |
| 127 | // This string might be too short for ICU to do anything useful with. |
| 128 | // (real world example: "Björk" in ISO-8859-1 might be detected as GB18030, because |
| 129 | // the ISO detector reports a confidence of 0, while the GB18030 detector reports |
| 130 | // a confidence of 10 with no invalid characters) |
| 131 | // Append artist, album and title if they were previously omitted because they |
| 132 | // were printable ascii. |
| 133 | bool added = false; |
| 134 | for (int i = 0; i < size; i++) { |
| 135 | const char *name = mNames.getEntry(i); |
| 136 | const char *value = mValues.getEntry(i); |
| 137 | if (isPrintableAscii(value, strlen(value)) && ( |
| 138 | !strcmp(name, "artist") || |
| 139 | !strcmp(name, "album") || |
| 140 | !strcmp(name, "title"))) { |
| 141 | strlcat(buf, value, sizeof(buf)); |
| 142 | strlcat(buf, " ", sizeof(buf)); |
| 143 | added = true; |
| 144 | } |
| 145 | } |
| 146 | if (added) { |
| 147 | ucsdet_setText(csd, buf, strlen(buf), &status); |
| 148 | ucma = ucsdet_detectAll(csd, &matches, &status); |
| 149 | bestCombinedMatch = getPreferred(buf, strlen(buf), |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 150 | ucma, matches, &goodmatch, &highest); |
| 151 | if (!goodmatch && highest <= 15) { |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 152 | ALOGV("still not a good match after adding printable tags"); |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 153 | bestCombinedMatch = NULL; |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 154 | } |
| 155 | } else { |
| 156 | ALOGV("no printable tags to add"); |
| 157 | } |
| 158 | } |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 159 | |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 160 | if (bestCombinedMatch != NULL) { |
| 161 | combinedenc = ucsdet_getName(bestCombinedMatch, &status); |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 162 | } else { |
| 163 | combinedenc = "ISO-8859-1"; |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 164 | } |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 165 | } |
| 166 | |
| 167 | for (int i = 0; i < size; i++) { |
| 168 | const char *name = mNames.getEntry(i); |
| 169 | uint8_t* src = (uint8_t *)mValues.getEntry(i); |
| 170 | int len = strlen((char *)src); |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 171 | |
| 172 | ALOGV("@@@ checking %s", name); |
| 173 | const char *s = mValues.getEntry(i); |
| 174 | int32_t inputLength = strlen(s); |
| 175 | const char *enc; |
| 176 | |
Glenn Kasten | 1392eb3 | 2014-03-25 11:49:08 -0700 | [diff] [blame] | 177 | if (!allprintable && (!strcmp(name, "artist") || |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 178 | !strcmp(name, "albumartist") || |
| 179 | !strcmp(name, "composer") || |
| 180 | !strcmp(name, "genre") || |
| 181 | !strcmp(name, "album") || |
Glenn Kasten | 1392eb3 | 2014-03-25 11:49:08 -0700 | [diff] [blame] | 182 | !strcmp(name, "title"))) { |
caozhiyuan | 4a2c17f | 2017-05-05 13:53:33 +0800 | [diff] [blame] | 183 | if (!goodmatch && highest < 0) { |
| 184 | // Give it one more chance if there is no good match. |
| 185 | ALOGV("Trying to detect %s separately", name); |
| 186 | int32_t matches; |
| 187 | bool goodmatchSingle = true; |
| 188 | int highestSingle = 0; |
| 189 | ucsdet_setText(csd, s, inputLength, &status); |
| 190 | const UCharsetMatch** ucma = ucsdet_detectAll(csd, &matches, &status); |
| 191 | const UCharsetMatch* bestSingleMatch = getPreferred(s, inputLength, |
| 192 | ucma, matches, &goodmatchSingle, &highestSingle); |
| 193 | if (goodmatchSingle || highestSingle > highest) |
| 194 | enc = ucsdet_getName(bestSingleMatch, &status); |
| 195 | else |
| 196 | enc = combinedenc; |
| 197 | } else { |
| 198 | // use encoding determined from the combination of artist/album/title etc. |
| 199 | enc = combinedenc; |
| 200 | } |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 201 | } else { |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 202 | if (isPrintableAscii(s, inputLength)) { |
| 203 | enc = "UTF-8"; |
| 204 | ALOGV("@@@@ %s is ascii", mNames.getEntry(i)); |
| 205 | } else { |
| 206 | ucsdet_setText(csd, s, inputLength, &status); |
| 207 | ucm = ucsdet_detect(csd, &status); |
| 208 | if (!ucm) { |
| 209 | mValues.setEntry(i, "???"); |
| 210 | continue; |
| 211 | } |
| 212 | enc = ucsdet_getName(ucm, &status); |
| 213 | ALOGV("@@@@ recognized charset: %s for %s confidence %d", |
| 214 | enc, mNames.getEntry(i), ucsdet_getConfidence(ucm, &status)); |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 215 | } |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 216 | } |
| 217 | |
| 218 | if (strcmp(enc,"UTF-8") != 0) { |
| 219 | // only convert if the source encoding isn't already UTF-8 |
| 220 | ALOGV("@@@ using converter %s for %s", enc, mNames.getEntry(i)); |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 221 | status = U_ZERO_ERROR; |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 222 | UConverter *conv = ucnv_open(enc, &status); |
| 223 | if (U_FAILURE(status)) { |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 224 | ALOGW("could not create UConverter for %s (%d), falling back to ISO-8859-1", |
| 225 | enc, status); |
| 226 | status = U_ZERO_ERROR; |
| 227 | conv = ucnv_open("ISO-8859-1", &status); |
| 228 | if (U_FAILURE(status)) { |
| 229 | ALOGW("could not create UConverter for ISO-8859-1 either"); |
| 230 | continue; |
| 231 | } |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 232 | } |
| 233 | |
| 234 | // convert from native encoding to UTF-8 |
| 235 | const char* source = mValues.getEntry(i); |
| 236 | int targetLength = len * 3 + 1; |
| 237 | char* buffer = new char[targetLength]; |
| 238 | // don't normally check for NULL, but in this case targetLength may be large |
| 239 | if (!buffer) |
| 240 | break; |
| 241 | char* target = buffer; |
| 242 | |
| 243 | ucnv_convertEx(mUtf8Conv, conv, &target, target + targetLength, |
| 244 | &source, source + strlen(source), |
| 245 | NULL, NULL, NULL, NULL, TRUE, TRUE, &status); |
| 246 | |
| 247 | if (U_FAILURE(status)) { |
| 248 | ALOGE("ucnv_convertEx failed: %d", status); |
| 249 | mValues.setEntry(i, "???"); |
| 250 | } else { |
| 251 | // zero terminate |
| 252 | *target = 0; |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 253 | // strip trailing spaces |
| 254 | while (--target > buffer && *target == ' ') { |
| 255 | *target = 0; |
| 256 | } |
| 257 | // skip leading spaces |
| 258 | char *start = buffer; |
| 259 | while (*start == ' ') { |
| 260 | start++; |
| 261 | } |
| 262 | mValues.setEntry(i, start); |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 263 | } |
| 264 | |
| 265 | delete[] buffer; |
| 266 | |
| 267 | ucnv_close(conv); |
| 268 | } |
| 269 | } |
| 270 | |
| 271 | for (int i = size - 1; i >= 0; --i) { |
| 272 | if (strlen(mValues.getEntry(i)) == 0) { |
| 273 | ALOGV("erasing %s because entry is empty", mNames.getEntry(i)); |
| 274 | mNames.erase(i); |
| 275 | mValues.erase(i); |
| 276 | } |
| 277 | } |
| 278 | |
| 279 | ucsdet_close(csd); |
| 280 | } |
| 281 | } |
| 282 | |
| 283 | /* |
| 284 | * When ICU detects multiple encoding matches, apply additional heuristics to determine |
| 285 | * which one is the best match, since ICU can't always be trusted to make the right choice. |
| 286 | * |
| 287 | * What this method does is: |
| 288 | * - decode the input using each of the matches found |
| 289 | * - recalculate the starting confidence level for multibyte encodings using a different |
| 290 | * algorithm and larger frequent character lists than ICU |
| 291 | * - devalue encoding where the conversion contains unlikely characters (symbols, reserved, etc) |
| 292 | * - pick the highest match |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 293 | * - signal to the caller whether this match is considered good: confidence > 15, and confidence |
| 294 | * delta with the next runner up > 15 |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 295 | */ |
| 296 | const UCharsetMatch *CharacterEncodingDetector::getPreferred( |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 297 | const char *input, size_t len, |
| 298 | const UCharsetMatch** ucma, size_t nummatches, |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 299 | bool *goodmatch, int *highestmatch) { |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 300 | |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 301 | *goodmatch = false; |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 302 | Vector<const UCharsetMatch*> matches; |
| 303 | UErrorCode status = U_ZERO_ERROR; |
| 304 | |
Mark Salyzyn | 34fb296 | 2014-06-18 16:30:56 -0700 | [diff] [blame] | 305 | ALOGV("%zu matches", nummatches); |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 306 | for (size_t i = 0; i < nummatches; i++) { |
| 307 | const char *encname = ucsdet_getName(ucma[i], &status); |
| 308 | int confidence = ucsdet_getConfidence(ucma[i], &status); |
Mark Salyzyn | 34fb296 | 2014-06-18 16:30:56 -0700 | [diff] [blame] | 309 | ALOGV("%zu: %s %d", i, encname, confidence); |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 310 | matches.push_back(ucma[i]); |
| 311 | } |
| 312 | |
| 313 | size_t num = matches.size(); |
| 314 | if (num == 0) { |
| 315 | return NULL; |
| 316 | } |
| 317 | if (num == 1) { |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 318 | int confidence = ucsdet_getConfidence(matches[0], &status); |
| 319 | if (confidence > 15) { |
| 320 | *goodmatch = true; |
| 321 | } |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 322 | return matches[0]; |
| 323 | } |
| 324 | |
Mark Salyzyn | 34fb296 | 2014-06-18 16:30:56 -0700 | [diff] [blame] | 325 | ALOGV("considering %zu matches", num); |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 326 | |
| 327 | // keep track of how many "special" characters result when converting the input using each |
| 328 | // encoding |
| 329 | Vector<int> newconfidence; |
| 330 | for (size_t i = 0; i < num; i++) { |
| 331 | const uint16_t *freqdata = NULL; |
| 332 | float freqcoverage = 0; |
| 333 | status = U_ZERO_ERROR; |
| 334 | const char *encname = ucsdet_getName(matches[i], &status); |
| 335 | int confidence = ucsdet_getConfidence(matches[i], &status); |
| 336 | if (!strcmp("GB18030", encname)) { |
| 337 | freqdata = frequent_zhCN; |
| 338 | freqcoverage = frequent_zhCN_coverage; |
| 339 | } else if (!strcmp("Big5", encname)) { |
| 340 | freqdata = frequent_zhTW; |
| 341 | freqcoverage = frequent_zhTW_coverage; |
| 342 | } else if (!strcmp("EUC-KR", encname)) { |
| 343 | freqdata = frequent_ko; |
| 344 | freqcoverage = frequent_ko_coverage; |
| 345 | } else if (!strcmp("EUC-JP", encname)) { |
| 346 | freqdata = frequent_ja; |
| 347 | freqcoverage = frequent_ja_coverage; |
| 348 | } else if (!strcmp("Shift_JIS", encname)) { |
| 349 | freqdata = frequent_ja; |
| 350 | freqcoverage = frequent_ja_coverage; |
| 351 | } |
| 352 | |
Mark Salyzyn | 34fb296 | 2014-06-18 16:30:56 -0700 | [diff] [blame] | 353 | ALOGV("%zu: %s %d", i, encname, confidence); |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 354 | status = U_ZERO_ERROR; |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 355 | UConverter *conv = ucnv_open(encname, &status); |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 356 | int demerit = 0; |
| 357 | if (U_FAILURE(status)) { |
| 358 | ALOGV("failed to open %s: %d", encname, status); |
| 359 | confidence = 0; |
| 360 | demerit += 1000; |
| 361 | } |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 362 | const char *source = input; |
| 363 | const char *sourceLimit = input + len; |
| 364 | status = U_ZERO_ERROR; |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 365 | int frequentchars = 0; |
| 366 | int totalchars = 0; |
| 367 | while (true) { |
| 368 | // demerit the current encoding for each "special" character found after conversion. |
| 369 | // The amount of demerit is somewhat arbitrarily chosen. |
| 370 | int inchar; |
| 371 | if (source != sourceLimit) { |
| 372 | inchar = (source[0] << 8) + source[1]; |
| 373 | } |
| 374 | UChar32 c = ucnv_getNextUChar(conv, &source, sourceLimit, &status); |
| 375 | if (!U_SUCCESS(status)) { |
| 376 | break; |
| 377 | } |
| 378 | if (c < 0x20 || (c >= 0x7f && c <= 0x009f)) { |
| 379 | ALOGV("control character %x", c); |
| 380 | demerit += 100; |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 381 | } else if ((c == 0xa0) // no-break space |
| 382 | || (c >= 0xa2 && c <= 0xbe) // symbols, superscripts |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 383 | || (c == 0xd7) || (c == 0xf7) // multiplication and division signs |
| 384 | || (c >= 0x2000 && c <= 0x209f)) { // punctuation, superscripts |
| 385 | ALOGV("unlikely character %x", c); |
| 386 | demerit += 10; |
| 387 | } else if (c >= 0xe000 && c <= 0xf8ff) { |
| 388 | ALOGV("private use character %x", c); |
| 389 | demerit += 30; |
| 390 | } else if (c >= 0x2190 && c <= 0x2bff) { |
| 391 | // this range comprises various symbol ranges that are unlikely to appear in |
| 392 | // music file metadata. |
| 393 | ALOGV("symbol %x", c); |
| 394 | demerit += 10; |
| 395 | } else if (c == 0xfffd) { |
| 396 | ALOGV("replacement character"); |
| 397 | demerit += 50; |
| 398 | } else if (c >= 0xfff0 && c <= 0xfffc) { |
| 399 | ALOGV("unicode special %x", c); |
| 400 | demerit += 50; |
| 401 | } else if (freqdata != NULL) { |
| 402 | totalchars++; |
| 403 | if (isFrequent(freqdata, c)) { |
| 404 | frequentchars++; |
| 405 | } |
| 406 | } |
| 407 | } |
| 408 | if (freqdata != NULL && totalchars != 0) { |
| 409 | int myconfidence = 10 + float((100 * frequentchars) / totalchars) / freqcoverage; |
| 410 | ALOGV("ICU confidence: %d, my confidence: %d (%d %d)", confidence, myconfidence, |
| 411 | totalchars, frequentchars); |
| 412 | if (myconfidence > 100) myconfidence = 100; |
| 413 | if (myconfidence < 0) myconfidence = 0; |
| 414 | confidence = myconfidence; |
| 415 | } |
| 416 | ALOGV("%d-%d=%d", confidence, demerit, confidence - demerit); |
| 417 | newconfidence.push_back(confidence - demerit); |
| 418 | ucnv_close(conv); |
| 419 | if (i == 0 && (confidence - demerit) == 100) { |
| 420 | // no need to check any further, we'll end up using this match anyway |
| 421 | break; |
| 422 | } |
| 423 | } |
| 424 | |
| 425 | // find match with highest confidence after adjusting for unlikely characters |
| 426 | int highest = newconfidence[0]; |
| 427 | size_t highestidx = 0; |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 428 | int runnerup = -10000; |
| 429 | int runnerupidx = -10000; |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 430 | num = newconfidence.size(); |
| 431 | for (size_t i = 1; i < num; i++) { |
| 432 | if (newconfidence[i] > highest) { |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 433 | runnerup = highest; |
| 434 | runnerupidx = highestidx; |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 435 | highest = newconfidence[i]; |
| 436 | highestidx = i; |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 437 | } else if (newconfidence[i] > runnerup){ |
| 438 | runnerup = newconfidence[i]; |
| 439 | runnerupidx = i; |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 440 | } |
| 441 | } |
| 442 | status = U_ZERO_ERROR; |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 443 | ALOGV("selecting: '%s' w/ %d confidence", |
| 444 | ucsdet_getName(matches[highestidx], &status), highest); |
| 445 | if (runnerupidx < 0) { |
| 446 | ALOGV("no runner up"); |
| 447 | if (highest > 15) { |
| 448 | *goodmatch = true; |
| 449 | } |
| 450 | } else { |
| 451 | ALOGV("runner up: '%s' w/ %d confidence", |
| 452 | ucsdet_getName(matches[runnerupidx], &status), runnerup); |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 453 | if (runnerup < 0) { |
| 454 | runnerup = 0; |
| 455 | } |
Marco Nelissen | bfd55f2 | 2014-03-18 14:00:39 -0700 | [diff] [blame] | 456 | if ((highest - runnerup) > 15) { |
| 457 | *goodmatch = true; |
| 458 | } |
| 459 | } |
Marco Nelissen | 34581f4 | 2014-08-29 16:00:28 -0700 | [diff] [blame] | 460 | *highestmatch = highest; |
Marco Nelissen | 544ad2b | 2013-11-13 14:18:21 -0800 | [diff] [blame] | 461 | return matches[highestidx]; |
| 462 | } |
| 463 | |
| 464 | |
| 465 | bool CharacterEncodingDetector::isFrequent(const uint16_t *values, uint32_t c) { |
| 466 | |
| 467 | int start = 0; |
| 468 | int end = 511; // All the tables have 512 entries |
| 469 | int mid = (start+end)/2; |
| 470 | |
| 471 | while(start <= end) { |
| 472 | if(c == values[mid]) { |
| 473 | return true; |
| 474 | } else if (c > values[mid]) { |
| 475 | start = mid + 1; |
| 476 | } else { |
| 477 | end = mid - 1; |
| 478 | } |
| 479 | |
| 480 | mid = (start + end) / 2; |
| 481 | } |
| 482 | |
| 483 | return false; |
| 484 | } |
| 485 | |
| 486 | |
| 487 | } // namespace android |