| // © 2016 and later: Unicode, Inc. and others. |
| // License & terms of use: http://www.unicode.org/copyright.html |
| /* |
| ********************************************************************** |
| * Copyright (C) 2005-2016, International Business Machines |
| * Corporation and others. All Rights Reserved. |
| ********************************************************************** |
| */ |
| |
| #include "unicode/utypes.h" |
| |
| #if !UCONFIG_NO_CONVERSION |
| |
| #include "cmemory.h" |
| #include "cstring.h" |
| |
| #include "csr2022.h" |
| #include "csmatch.h" |
| |
| U_NAMESPACE_BEGIN |
| |
| /** |
| * Matching function shared among the 2022 detectors JP, CN and KR |
| * Counts up the number of legal and unrecognized escape sequences in |
| * the sample of text, and computes a score based on the total number & |
| * the proportion that fit the encoding. |
| * |
| * |
| * @param text the byte buffer containing text to analyse |
| * @param textLen the size of the text in the byte. |
| * @param escapeSequences the byte escape sequences to test for. |
| * @return match quality, in the range of 0-100. |
| */ |
| int32_t CharsetRecog_2022::match_2022(const uint8_t *text, int32_t textLen, const uint8_t escapeSequences[][5], int32_t escapeSequences_length) const |
| { |
| int32_t i, j; |
| int32_t escN; |
| int32_t hits = 0; |
| int32_t misses = 0; |
| int32_t shifts = 0; |
| int32_t quality; |
| |
| i = 0; |
| while(i < textLen) { |
| if(text[i] == 0x1B) { |
| escN = 0; |
| while(escN < escapeSequences_length) { |
| const uint8_t *seq = escapeSequences[escN]; |
| int32_t seq_length = (int32_t)uprv_strlen((const char *) seq); |
| |
| if (textLen-i >= seq_length) { |
| j = 1; |
| while(j < seq_length) { |
| if(seq[j] != text[i+j]) { |
| goto checkEscapes; |
| } |
| |
| j += 1; |
| } |
| |
| hits += 1; |
| i += seq_length-1; |
| goto scanInput; |
| } |
| // else we ran out of string to compare this time. |
| checkEscapes: |
| escN += 1; |
| } |
| |
| misses += 1; |
| } |
| |
| if( text[i]== 0x0e || text[i] == 0x0f){ |
| shifts += 1; |
| } |
| |
| scanInput: |
| i += 1; |
| } |
| |
| if (hits == 0) { |
| return 0; |
| } |
| |
| // |
| // Initial quality is based on relative proportion of recongized vs. |
| // unrecognized escape sequences. |
| // All good: quality = 100; |
| // half or less good: quality = 0; |
| // linear inbetween. |
| quality = (100*hits - 100*misses) / (hits + misses); |
| |
| // Back off quality if there were too few escape sequences seen. |
| // Include shifts in this computation, so that KR does not get penalized |
| // for having only a single Escape sequence, but many shifts. |
| if (hits+shifts < 5) { |
| quality -= (5-(hits+shifts))*10; |
| } |
| |
| if (quality < 0) { |
| quality = 0; |
| } |
| |
| return quality; |
| } |
| |
| |
| static const uint8_t escapeSequences_2022JP[][5] = { |
| {0x1b, 0x24, 0x28, 0x43, 0x00}, // KS X 1001:1992 |
| {0x1b, 0x24, 0x28, 0x44, 0x00}, // JIS X 212-1990 |
| {0x1b, 0x24, 0x40, 0x00, 0x00}, // JIS C 6226-1978 |
| {0x1b, 0x24, 0x41, 0x00, 0x00}, // GB 2312-80 |
| {0x1b, 0x24, 0x42, 0x00, 0x00}, // JIS X 208-1983 |
| {0x1b, 0x26, 0x40, 0x00, 0x00}, // JIS X 208 1990, 1997 |
| {0x1b, 0x28, 0x42, 0x00, 0x00}, // ASCII |
| {0x1b, 0x28, 0x48, 0x00, 0x00}, // JIS-Roman |
| {0x1b, 0x28, 0x49, 0x00, 0x00}, // Half-width katakana |
| {0x1b, 0x28, 0x4a, 0x00, 0x00}, // JIS-Roman |
| {0x1b, 0x2e, 0x41, 0x00, 0x00}, // ISO 8859-1 |
| {0x1b, 0x2e, 0x46, 0x00, 0x00} // ISO 8859-7 |
| }; |
| |
| #if !UCONFIG_ONLY_HTML_CONVERSION |
| static const uint8_t escapeSequences_2022KR[][5] = { |
| {0x1b, 0x24, 0x29, 0x43, 0x00} |
| }; |
| |
| static const uint8_t escapeSequences_2022CN[][5] = { |
| {0x1b, 0x24, 0x29, 0x41, 0x00}, // GB 2312-80 |
| {0x1b, 0x24, 0x29, 0x47, 0x00}, // CNS 11643-1992 Plane 1 |
| {0x1b, 0x24, 0x2A, 0x48, 0x00}, // CNS 11643-1992 Plane 2 |
| {0x1b, 0x24, 0x29, 0x45, 0x00}, // ISO-IR-165 |
| {0x1b, 0x24, 0x2B, 0x49, 0x00}, // CNS 11643-1992 Plane 3 |
| {0x1b, 0x24, 0x2B, 0x4A, 0x00}, // CNS 11643-1992 Plane 4 |
| {0x1b, 0x24, 0x2B, 0x4B, 0x00}, // CNS 11643-1992 Plane 5 |
| {0x1b, 0x24, 0x2B, 0x4C, 0x00}, // CNS 11643-1992 Plane 6 |
| {0x1b, 0x24, 0x2B, 0x4D, 0x00}, // CNS 11643-1992 Plane 7 |
| {0x1b, 0x4e, 0x00, 0x00, 0x00}, // SS2 |
| {0x1b, 0x4f, 0x00, 0x00, 0x00}, // SS3 |
| }; |
| #endif |
| |
| CharsetRecog_2022JP::~CharsetRecog_2022JP() {} |
| |
| const char *CharsetRecog_2022JP::getName() const { |
| return "ISO-2022-JP"; |
| } |
| |
| UBool CharsetRecog_2022JP::match(InputText *textIn, CharsetMatch *results) const { |
| int32_t confidence = match_2022(textIn->fInputBytes, |
| textIn->fInputLen, |
| escapeSequences_2022JP, |
| UPRV_LENGTHOF(escapeSequences_2022JP)); |
| results->set(textIn, this, confidence); |
| return (confidence > 0); |
| } |
| |
| #if !UCONFIG_ONLY_HTML_CONVERSION |
| CharsetRecog_2022KR::~CharsetRecog_2022KR() {} |
| |
| const char *CharsetRecog_2022KR::getName() const { |
| return "ISO-2022-KR"; |
| } |
| |
| UBool CharsetRecog_2022KR::match(InputText *textIn, CharsetMatch *results) const { |
| int32_t confidence = match_2022(textIn->fInputBytes, |
| textIn->fInputLen, |
| escapeSequences_2022KR, |
| UPRV_LENGTHOF(escapeSequences_2022KR)); |
| results->set(textIn, this, confidence); |
| return (confidence > 0); |
| } |
| |
| CharsetRecog_2022CN::~CharsetRecog_2022CN() {} |
| |
| const char *CharsetRecog_2022CN::getName() const { |
| return "ISO-2022-CN"; |
| } |
| |
| UBool CharsetRecog_2022CN::match(InputText *textIn, CharsetMatch *results) const { |
| int32_t confidence = match_2022(textIn->fInputBytes, |
| textIn->fInputLen, |
| escapeSequences_2022CN, |
| UPRV_LENGTHOF(escapeSequences_2022CN)); |
| results->set(textIn, this, confidence); |
| return (confidence > 0); |
| } |
| #endif |
| |
| CharsetRecog_2022::~CharsetRecog_2022() { |
| // nothing to do |
| } |
| |
| U_NAMESPACE_END |
| #endif |
