michael@0: /*
michael@0:  **********************************************************************
michael@0:  *   Copyright (C) 2005-2012, International Business Machines
michael@0:  *   Corporation and others.  All Rights Reserved.
michael@0:  **********************************************************************
michael@0:  */
michael@0: 
michael@0: #include "unicode/utypes.h"
michael@0: 
michael@0: #if !UCONFIG_NO_CONVERSION
michael@0: 
michael@0: #include "csmatch.h"
michael@0: #include "csrmbcs.h"
michael@0: 
michael@0: #include <math.h>
michael@0: 
michael@0: U_NAMESPACE_BEGIN
michael@0: 
michael@0: #define ARRAY_SIZE(array) (sizeof array / sizeof array[0])
michael@0: 
michael@0: #define min(x,y) (((x)<(y))?(x):(y))
michael@0: 
michael@0: static const uint16_t commonChars_sjis [] = {
michael@0: // TODO:  This set of data comes from the character frequency-
michael@0: //        of-occurence analysis tool.  The data needs to be moved
michael@0: //        into a resource and loaded from there.
michael@0: 0x8140, 0x8141, 0x8142, 0x8145, 0x815b, 0x8169, 0x816a, 0x8175, 0x8176, 0x82a0,
michael@0: 0x82a2, 0x82a4, 0x82a9, 0x82aa, 0x82ab, 0x82ad, 0x82af, 0x82b1, 0x82b3, 0x82b5,
michael@0: 0x82b7, 0x82bd, 0x82be, 0x82c1, 0x82c4, 0x82c5, 0x82c6, 0x82c8, 0x82c9, 0x82cc,
michael@0: 0x82cd, 0x82dc, 0x82e0, 0x82e7, 0x82e8, 0x82e9, 0x82ea, 0x82f0, 0x82f1, 0x8341,
michael@0: 0x8343, 0x834e, 0x834f, 0x8358, 0x835e, 0x8362, 0x8367, 0x8375, 0x8376, 0x8389,
michael@0: 0x838a, 0x838b, 0x838d, 0x8393, 0x8e96, 0x93fa, 0x95aa};
michael@0: 
michael@0: static const uint16_t commonChars_euc_jp[] = {
michael@0: // TODO:  This set of data comes from the character frequency-
michael@0: //        of-occurence analysis tool.  The data needs to be moved
michael@0: //        into a resource and loaded from there.
michael@0: 0xa1a1, 0xa1a2, 0xa1a3, 0xa1a6, 0xa1bc, 0xa1ca, 0xa1cb, 0xa1d6, 0xa1d7, 0xa4a2,
michael@0: 0xa4a4, 0xa4a6, 0xa4a8, 0xa4aa, 0xa4ab, 0xa4ac, 0xa4ad, 0xa4af, 0xa4b1, 0xa4b3,
michael@0: 0xa4b5, 0xa4b7, 0xa4b9, 0xa4bb, 0xa4bd, 0xa4bf, 0xa4c0, 0xa4c1, 0xa4c3, 0xa4c4,
michael@0: 0xa4c6, 0xa4c7, 0xa4c8, 0xa4c9, 0xa4ca, 0xa4cb, 0xa4ce, 0xa4cf, 0xa4d0, 0xa4de,
michael@0: 0xa4df, 0xa4e1, 0xa4e2, 0xa4e4, 0xa4e8, 0xa4e9, 0xa4ea, 0xa4eb, 0xa4ec, 0xa4ef,
michael@0: 0xa4f2, 0xa4f3, 0xa5a2, 0xa5a3, 0xa5a4, 0xa5a6, 0xa5a7, 0xa5aa, 0xa5ad, 0xa5af,
michael@0: 0xa5b0, 0xa5b3, 0xa5b5, 0xa5b7, 0xa5b8, 0xa5b9, 0xa5bf, 0xa5c3, 0xa5c6, 0xa5c7,
michael@0: 0xa5c8, 0xa5c9, 0xa5cb, 0xa5d0, 0xa5d5, 0xa5d6, 0xa5d7, 0xa5de, 0xa5e0, 0xa5e1,
michael@0: 0xa5e5, 0xa5e9, 0xa5ea, 0xa5eb, 0xa5ec, 0xa5ed, 0xa5f3, 0xb8a9, 0xb9d4, 0xbaee,
michael@0: 0xbbc8, 0xbef0, 0xbfb7, 0xc4ea, 0xc6fc, 0xc7bd, 0xcab8, 0xcaf3, 0xcbdc, 0xcdd1};
michael@0: 
michael@0: static const uint16_t commonChars_euc_kr[] = {
michael@0: // TODO:  This set of data comes from the character frequency-
michael@0: //        of-occurence analysis tool.  The data needs to be moved
michael@0: //        into a resource and loaded from there.
michael@0: 0xb0a1, 0xb0b3, 0xb0c5, 0xb0cd, 0xb0d4, 0xb0e6, 0xb0ed, 0xb0f8, 0xb0fa, 0xb0fc,
michael@0: 0xb1b8, 0xb1b9, 0xb1c7, 0xb1d7, 0xb1e2, 0xb3aa, 0xb3bb, 0xb4c2, 0xb4cf, 0xb4d9,
michael@0: 0xb4eb, 0xb5a5, 0xb5b5, 0xb5bf, 0xb5c7, 0xb5e9, 0xb6f3, 0xb7af, 0xb7c2, 0xb7ce,
michael@0: 0xb8a6, 0xb8ae, 0xb8b6, 0xb8b8, 0xb8bb, 0xb8e9, 0xb9ab, 0xb9ae, 0xb9cc, 0xb9ce,
michael@0: 0xb9fd, 0xbab8, 0xbace, 0xbad0, 0xbaf1, 0xbbe7, 0xbbf3, 0xbbfd, 0xbcad, 0xbcba,
michael@0: 0xbcd2, 0xbcf6, 0xbdba, 0xbdc0, 0xbdc3, 0xbdc5, 0xbec6, 0xbec8, 0xbedf, 0xbeee,
michael@0: 0xbef8, 0xbefa, 0xbfa1, 0xbfa9, 0xbfc0, 0xbfe4, 0xbfeb, 0xbfec, 0xbff8, 0xc0a7,
michael@0: 0xc0af, 0xc0b8, 0xc0ba, 0xc0bb, 0xc0bd, 0xc0c7, 0xc0cc, 0xc0ce, 0xc0cf, 0xc0d6,
michael@0: 0xc0da, 0xc0e5, 0xc0fb, 0xc0fc, 0xc1a4, 0xc1a6, 0xc1b6, 0xc1d6, 0xc1df, 0xc1f6,
michael@0: 0xc1f8, 0xc4a1, 0xc5cd, 0xc6ae, 0xc7cf, 0xc7d1, 0xc7d2, 0xc7d8, 0xc7e5, 0xc8ad};
michael@0: 
michael@0: static const uint16_t commonChars_big5[] = {
michael@0: // TODO:  This set of data comes from the character frequency-
michael@0: //        of-occurence analysis tool.  The data needs to be moved
michael@0: //        into a resource and loaded from there.
michael@0: 0xa140, 0xa141, 0xa142, 0xa143, 0xa147, 0xa149, 0xa175, 0xa176, 0xa440, 0xa446,
michael@0: 0xa447, 0xa448, 0xa451, 0xa454, 0xa457, 0xa464, 0xa46a, 0xa46c, 0xa477, 0xa4a3,
michael@0: 0xa4a4, 0xa4a7, 0xa4c1, 0xa4ce, 0xa4d1, 0xa4df, 0xa4e8, 0xa4fd, 0xa540, 0xa548,
michael@0: 0xa558, 0xa569, 0xa5cd, 0xa5e7, 0xa657, 0xa661, 0xa662, 0xa668, 0xa670, 0xa6a8,
michael@0: 0xa6b3, 0xa6b9, 0xa6d3, 0xa6db, 0xa6e6, 0xa6f2, 0xa740, 0xa751, 0xa759, 0xa7da,
michael@0: 0xa8a3, 0xa8a5, 0xa8ad, 0xa8d1, 0xa8d3, 0xa8e4, 0xa8fc, 0xa9c0, 0xa9d2, 0xa9f3,
michael@0: 0xaa6b, 0xaaba, 0xaabe, 0xaacc, 0xaafc, 0xac47, 0xac4f, 0xacb0, 0xacd2, 0xad59,
michael@0: 0xaec9, 0xafe0, 0xb0ea, 0xb16f, 0xb2b3, 0xb2c4, 0xb36f, 0xb44c, 0xb44e, 0xb54c,
michael@0: 0xb5a5, 0xb5bd, 0xb5d0, 0xb5d8, 0xb671, 0xb7ed, 0xb867, 0xb944, 0xbad8, 0xbb44,
michael@0: 0xbba1, 0xbdd1, 0xc2c4, 0xc3b9, 0xc440, 0xc45f};
michael@0: 
michael@0: static const uint16_t commonChars_gb_18030[] = {
michael@0: // TODO:  This set of data comes from the character frequency-
michael@0: //        of-occurence analysis tool.  The data needs to be moved
michael@0: //        into a resource and loaded from there.
michael@0: 0xa1a1, 0xa1a2, 0xa1a3, 0xa1a4, 0xa1b0, 0xa1b1, 0xa1f1, 0xa1f3, 0xa3a1, 0xa3ac,
michael@0: 0xa3ba, 0xb1a8, 0xb1b8, 0xb1be, 0xb2bb, 0xb3c9, 0xb3f6, 0xb4f3, 0xb5bd, 0xb5c4,
michael@0: 0xb5e3, 0xb6af, 0xb6d4, 0xb6e0, 0xb7a2, 0xb7a8, 0xb7bd, 0xb7d6, 0xb7dd, 0xb8b4,
michael@0: 0xb8df, 0xb8f6, 0xb9ab, 0xb9c9, 0xb9d8, 0xb9fa, 0xb9fd, 0xbacd, 0xbba7, 0xbbd6,
michael@0: 0xbbe1, 0xbbfa, 0xbcbc, 0xbcdb, 0xbcfe, 0xbdcc, 0xbecd, 0xbedd, 0xbfb4, 0xbfc6,
michael@0: 0xbfc9, 0xc0b4, 0xc0ed, 0xc1cb, 0xc2db, 0xc3c7, 0xc4dc, 0xc4ea, 0xc5cc, 0xc6f7,
michael@0: 0xc7f8, 0xc8ab, 0xc8cb, 0xc8d5, 0xc8e7, 0xc9cf, 0xc9fa, 0xcab1, 0xcab5, 0xcac7,
michael@0: 0xcad0, 0xcad6, 0xcaf5, 0xcafd, 0xccec, 0xcdf8, 0xceaa, 0xcec4, 0xced2, 0xcee5,
michael@0: 0xcfb5, 0xcfc2, 0xcfd6, 0xd0c2, 0xd0c5, 0xd0d0, 0xd0d4, 0xd1a7, 0xd2aa, 0xd2b2,
michael@0: 0xd2b5, 0xd2bb, 0xd2d4, 0xd3c3, 0xd3d0, 0xd3fd, 0xd4c2, 0xd4da, 0xd5e2, 0xd6d0};
michael@0: 
michael@0: static int32_t binarySearch(const uint16_t *array, int32_t len, uint16_t value)
michael@0: {
michael@0:     int32_t start = 0, end = len-1;
michael@0:     int32_t mid = (start+end)/2;
michael@0: 
michael@0:     while(start <= end) {
michael@0:         if(array[mid] == value) {
michael@0:             return mid;
michael@0:         }
michael@0: 
michael@0:         if(array[mid] < value){
michael@0:             start = mid+1;
michael@0:         } else {
michael@0:             end = mid-1;
michael@0:         }
michael@0: 
michael@0:         mid = (start+end)/2;
michael@0:     }
michael@0: 
michael@0:     return -1;
michael@0: }
michael@0: 
michael@0: IteratedChar::IteratedChar() : 
michael@0: charValue(0), index(-1), nextIndex(0), error(FALSE), done(FALSE)
michael@0: {
michael@0:     // nothing else to do.
michael@0: }
michael@0: 
michael@0: /*void IteratedChar::reset()
michael@0: {
michael@0:     charValue = 0;
michael@0:     index     = -1;
michael@0:     nextIndex = 0;
michael@0:     error     = FALSE;
michael@0:     done      = FALSE;
michael@0: }*/
michael@0: 
michael@0: int32_t IteratedChar::nextByte(InputText *det)
michael@0: {
michael@0:     if (nextIndex >= det->fRawLength) {
michael@0:         done = TRUE;
michael@0: 
michael@0:         return -1;
michael@0:     }
michael@0: 
michael@0:     return det->fRawInput[nextIndex++];
michael@0: }
michael@0: 
michael@0: CharsetRecog_mbcs::~CharsetRecog_mbcs()
michael@0: {
michael@0:     // nothing to do.
michael@0: }
michael@0: 
michael@0: int32_t CharsetRecog_mbcs::match_mbcs(InputText *det, const uint16_t commonChars[], int32_t commonCharsLen) const {
michael@0:     int32_t singleByteCharCount = 0;
michael@0:     int32_t doubleByteCharCount = 0;
michael@0:     int32_t commonCharCount     = 0;
michael@0:     int32_t badCharCount        = 0;
michael@0:     int32_t totalCharCount      = 0;
michael@0:     int32_t confidence          = 0;
michael@0:     IteratedChar iter;
michael@0: 
michael@0:     while (nextChar(&iter, det)) {
michael@0:         totalCharCount++;
michael@0: 
michael@0:         if (iter.error) {
michael@0:             badCharCount++;
michael@0:         } else {
michael@0:             if (iter.charValue <= 0xFF) {
michael@0:                 singleByteCharCount++;
michael@0:             } else {
michael@0:                 doubleByteCharCount++;
michael@0: 
michael@0:                 if (commonChars != 0) {
michael@0:                     if (binarySearch(commonChars, commonCharsLen, iter.charValue) >= 0){
michael@0:                         commonCharCount += 1;
michael@0:                     }
michael@0:                 }
michael@0:             }
michael@0:         }
michael@0: 
michael@0: 
michael@0:         if (badCharCount >= 2 && badCharCount*5 >= doubleByteCharCount) {
michael@0:             // Bail out early if the byte data is not matching the encoding scheme.
michael@0:             // break detectBlock;
michael@0:             return confidence;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     if (doubleByteCharCount <= 10 && badCharCount == 0) {
michael@0:         // Not many multi-byte chars.
michael@0:         if (doubleByteCharCount == 0 && totalCharCount < 10) {
michael@0:             // There weren't any multibyte sequences, and there was a low density of non-ASCII single bytes.
michael@0:             // We don't have enough data to have any confidence.
michael@0:             // Statistical analysis of single byte non-ASCII charcters would probably help here.
michael@0:             confidence = 0;
michael@0:         }
michael@0:         else {
michael@0:             //   ASCII or ISO file?  It's probably not our encoding,
michael@0:             //   but is not incompatible with our encoding, so don't give it a zero.
michael@0:             confidence = 10;
michael@0:         }
michael@0: 
michael@0:         return confidence;
michael@0:     }
michael@0: 
michael@0:     //
michael@0:     //  No match if there are too many characters that don't fit the encoding scheme.
michael@0:     //    (should we have zero tolerance for these?)
michael@0:     //
michael@0:     if (doubleByteCharCount < 20*badCharCount) {
michael@0:         confidence = 0;
michael@0: 
michael@0:         return confidence;
michael@0:     }
michael@0: 
michael@0:     if (commonChars == 0) {
michael@0:         // We have no statistics on frequently occuring characters.
michael@0:         //  Assess confidence purely on having a reasonable number of
michael@0:         //  multi-byte characters (the more the better)
michael@0:         confidence = 30 + doubleByteCharCount - 20*badCharCount;
michael@0: 
michael@0:         if (confidence > 100) {
michael@0:             confidence = 100;
michael@0:         }
michael@0:     } else {
michael@0:         //
michael@0:         // Frequency of occurence statistics exist.
michael@0:         //
michael@0: 
michael@0:         double maxVal = log((double)doubleByteCharCount / 4); /*(float)?*/
michael@0:         double scaleFactor = 90.0 / maxVal;
michael@0:         confidence = (int32_t)(log((double)commonCharCount+1) * scaleFactor + 10.0);
michael@0: 
michael@0:         confidence = min(confidence, 100);
michael@0:     }
michael@0: 
michael@0:     if (confidence < 0) {
michael@0:         confidence = 0;
michael@0:     }
michael@0: 
michael@0:     return confidence;
michael@0: }
michael@0: 
michael@0: CharsetRecog_sjis::~CharsetRecog_sjis()
michael@0: {
michael@0:     // nothing to do
michael@0: }
michael@0: 
michael@0: UBool CharsetRecog_sjis::nextChar(IteratedChar* it, InputText* det) const {
michael@0:     it->index = it->nextIndex;
michael@0:     it->error = FALSE;
michael@0: 
michael@0:     int32_t firstByte = it->charValue = it->nextByte(det);
michael@0: 
michael@0:     if (firstByte < 0) {
michael@0:         return FALSE;
michael@0:     }
michael@0: 
michael@0:     if (firstByte <= 0x7F || (firstByte > 0xA0 && firstByte <= 0xDF)) {
michael@0:         return TRUE;
michael@0:     }
michael@0: 
michael@0:     int32_t secondByte = it->nextByte(det);
michael@0:     if (secondByte >= 0) {
michael@0:         it->charValue = (firstByte << 8) | secondByte;
michael@0:     }
michael@0:     // else we'll handle the error later.
michael@0: 
michael@0:     if (! ((secondByte >= 0x40 && secondByte <= 0x7F) || (secondByte >= 0x80 && secondByte <= 0xFE))) {
michael@0:         // Illegal second byte value.
michael@0:         it->error = TRUE;
michael@0:     }
michael@0: 
michael@0:     return TRUE;
michael@0: }
michael@0: 
michael@0: UBool CharsetRecog_sjis::match(InputText* det, CharsetMatch *results) const {
michael@0:     int32_t confidence = match_mbcs(det, commonChars_sjis, ARRAY_SIZE(commonChars_sjis));
michael@0:     results->set(det, this, confidence);
michael@0:     return (confidence > 0);
michael@0: }
michael@0: 
michael@0: const char *CharsetRecog_sjis::getName() const
michael@0: {
michael@0:     return "Shift_JIS";
michael@0: }
michael@0: 
michael@0: const char *CharsetRecog_sjis::getLanguage() const
michael@0: {
michael@0:     return "ja";
michael@0: }
michael@0: 
michael@0: CharsetRecog_euc::~CharsetRecog_euc()
michael@0: {
michael@0:     // nothing to do
michael@0: }
michael@0: 
michael@0: UBool CharsetRecog_euc::nextChar(IteratedChar* it, InputText* det) const {
michael@0:     int32_t firstByte  = 0;
michael@0:     int32_t secondByte = 0;
michael@0:     int32_t thirdByte  = 0;
michael@0: 
michael@0:     it->index = it->nextIndex;
michael@0:     it->error = FALSE;
michael@0:     firstByte = it->charValue = it->nextByte(det);
michael@0: 
michael@0:     if (firstByte < 0) {
michael@0:         // Ran off the end of the input data
michael@0:         return FALSE;
michael@0:     }
michael@0: 
michael@0:     if (firstByte <= 0x8D) {
michael@0:         // single byte char
michael@0:         return TRUE;
michael@0:     }
michael@0: 
michael@0:     secondByte = it->nextByte(det);
michael@0:     if (secondByte >= 0) {
michael@0:         it->charValue = (it->charValue << 8) | secondByte;
michael@0:     }
michael@0:     // else we'll handle the error later.
michael@0: 
michael@0:     if (firstByte >= 0xA1 && firstByte <= 0xFE) {
michael@0:         // Two byte Char
michael@0:         if (secondByte < 0xA1) {
michael@0:             it->error = TRUE;
michael@0:         }
michael@0: 
michael@0:         return TRUE;
michael@0:     }
michael@0: 
michael@0:     if (firstByte == 0x8E) {
michael@0:         // Code Set 2.
michael@0:         //   In EUC-JP, total char size is 2 bytes, only one byte of actual char value.
michael@0:         //   In EUC-TW, total char size is 4 bytes, three bytes contribute to char value.
michael@0:         // We don't know which we've got.
michael@0:         // Treat it like EUC-JP.  If the data really was EUC-TW, the following two
michael@0:         //   bytes will look like a well formed 2 byte char.
michael@0:         if (secondByte < 0xA1) {
michael@0:             it->error = TRUE;
michael@0:         }
michael@0: 
michael@0:         return TRUE;
michael@0:     }
michael@0: 
michael@0:     if (firstByte == 0x8F) {
michael@0:         // Code set 3.
michael@0:         // Three byte total char size, two bytes of actual char value.
michael@0:         thirdByte    = it->nextByte(det);
michael@0:         it->charValue = (it->charValue << 8) | thirdByte;
michael@0: 
michael@0:         if (thirdByte < 0xa1) {
michael@0:             // Bad second byte or ran off the end of the input data with a non-ASCII first byte.
michael@0:             it->error = TRUE;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     return TRUE;
michael@0: 
michael@0: }
michael@0: 
michael@0: CharsetRecog_euc_jp::~CharsetRecog_euc_jp()
michael@0: {
michael@0:     // nothing to do
michael@0: }
michael@0: 
michael@0: const char *CharsetRecog_euc_jp::getName() const
michael@0: {
michael@0:     return "EUC-JP";
michael@0: }
michael@0: 
michael@0: const char *CharsetRecog_euc_jp::getLanguage() const
michael@0: {
michael@0:     return "ja";
michael@0: }
michael@0: 
michael@0: UBool CharsetRecog_euc_jp::match(InputText *det, CharsetMatch *results) const
michael@0: {
michael@0:     int32_t confidence = match_mbcs(det, commonChars_euc_jp, ARRAY_SIZE(commonChars_euc_jp));
michael@0:     results->set(det, this, confidence);
michael@0:     return (confidence > 0);
michael@0: }
michael@0: 
michael@0: CharsetRecog_euc_kr::~CharsetRecog_euc_kr()
michael@0: {
michael@0:     // nothing to do
michael@0: }
michael@0: 
michael@0: const char *CharsetRecog_euc_kr::getName() const
michael@0: {
michael@0:     return "EUC-KR";
michael@0: }
michael@0: 
michael@0: const char *CharsetRecog_euc_kr::getLanguage() const
michael@0: {
michael@0:     return "ko";
michael@0: }
michael@0: 
michael@0: UBool CharsetRecog_euc_kr::match(InputText *det, CharsetMatch *results) const
michael@0: {
michael@0:     int32_t confidence =  match_mbcs(det, commonChars_euc_kr, ARRAY_SIZE(commonChars_euc_kr));
michael@0:     results->set(det, this, confidence);
michael@0:     return (confidence > 0);
michael@0: }
michael@0: 
michael@0: CharsetRecog_big5::~CharsetRecog_big5()
michael@0: {
michael@0:     // nothing to do
michael@0: }
michael@0: 
michael@0: UBool CharsetRecog_big5::nextChar(IteratedChar* it, InputText* det) const
michael@0: {
michael@0:     int32_t firstByte;
michael@0: 
michael@0:     it->index = it->nextIndex;
michael@0:     it->error = FALSE;
michael@0:     firstByte = it->charValue = it->nextByte(det);
michael@0: 
michael@0:     if (firstByte < 0) {
michael@0:         return FALSE;
michael@0:     }
michael@0: 
michael@0:     if (firstByte <= 0x7F || firstByte == 0xFF) {
michael@0:         // single byte character.
michael@0:         return TRUE;
michael@0:     }
michael@0: 
michael@0:     int32_t secondByte = it->nextByte(det);
michael@0:     if (secondByte >= 0)  {
michael@0:         it->charValue = (it->charValue << 8) | secondByte;
michael@0:     }
michael@0:     // else we'll handle the error later.
michael@0: 
michael@0:     if (secondByte < 0x40 || secondByte == 0x7F || secondByte == 0xFF) {
michael@0:         it->error = TRUE;
michael@0:     }
michael@0: 
michael@0:     return TRUE;
michael@0: }
michael@0: 
michael@0: const char *CharsetRecog_big5::getName() const
michael@0: {
michael@0:     return "Big5";
michael@0: }
michael@0: 
michael@0: const char *CharsetRecog_big5::getLanguage() const
michael@0: {
michael@0:     return "zh";
michael@0: }
michael@0: 
michael@0: UBool CharsetRecog_big5::match(InputText *det, CharsetMatch *results) const
michael@0: {
michael@0:     int32_t confidence = match_mbcs(det, commonChars_big5, ARRAY_SIZE(commonChars_big5));
michael@0:     results->set(det, this, confidence);
michael@0:     return (confidence > 0);
michael@0: }
michael@0: 
michael@0: CharsetRecog_gb_18030::~CharsetRecog_gb_18030()
michael@0: {
michael@0:     // nothing to do
michael@0: }
michael@0: 
michael@0: UBool CharsetRecog_gb_18030::nextChar(IteratedChar* it, InputText* det) const {
michael@0:     int32_t firstByte  = 0;
michael@0:     int32_t secondByte = 0;
michael@0:     int32_t thirdByte  = 0;
michael@0:     int32_t fourthByte = 0;
michael@0: 
michael@0:     it->index = it->nextIndex;
michael@0:     it->error = FALSE;
michael@0:     firstByte = it->charValue = it->nextByte(det);
michael@0: 
michael@0:     if (firstByte < 0) {
michael@0:         // Ran off the end of the input data
michael@0:         return FALSE;
michael@0:     }
michael@0: 
michael@0:     if (firstByte <= 0x80) {
michael@0:         // single byte char
michael@0:         return TRUE;
michael@0:     }
michael@0: 
michael@0:     secondByte = it->nextByte(det);
michael@0:     if (secondByte >= 0) {
michael@0:         it->charValue = (it->charValue << 8) | secondByte;
michael@0:     }
michael@0:     // else we'll handle the error later.
michael@0: 
michael@0:     if (firstByte >= 0x81 && firstByte <= 0xFE) {
michael@0:         // Two byte Char
michael@0:         if ((secondByte >= 0x40 && secondByte <= 0x7E) || (secondByte >=80 && secondByte <= 0xFE)) {
michael@0:             return TRUE;
michael@0:         }
michael@0: 
michael@0:         // Four byte char
michael@0:         if (secondByte >= 0x30 && secondByte <= 0x39) {
michael@0:             thirdByte = it->nextByte(det);
michael@0: 
michael@0:             if (thirdByte >= 0x81 && thirdByte <= 0xFE) {
michael@0:                 fourthByte = it->nextByte(det);
michael@0: 
michael@0:                 if (fourthByte >= 0x30 && fourthByte <= 0x39) {
michael@0:                     it->charValue = (it->charValue << 16) | (thirdByte << 8) | fourthByte;
michael@0: 
michael@0:                     return TRUE;
michael@0:                 }
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         // Something wasn't valid, or we ran out of data (-1).
michael@0:         it->error = TRUE;
michael@0:     }
michael@0: 
michael@0:     return TRUE;
michael@0: }
michael@0: 
michael@0: const char *CharsetRecog_gb_18030::getName() const
michael@0: {
michael@0:     return "GB18030";
michael@0: }
michael@0: 
michael@0: const char *CharsetRecog_gb_18030::getLanguage() const
michael@0: {
michael@0:     return "zh";
michael@0: }
michael@0: 
michael@0: UBool CharsetRecog_gb_18030::match(InputText *det, CharsetMatch *results) const
michael@0: {
michael@0:     int32_t confidence = match_mbcs(det, commonChars_gb_18030, ARRAY_SIZE(commonChars_gb_18030));
michael@0:     results->set(det, this, confidence);
michael@0:     return (confidence > 0);
michael@0: }
michael@0: 
michael@0: U_NAMESPACE_END
michael@0: #endif