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git-svn-id: https://zxing.googlecode.com/svn/trunk@1839 59b500cc-1b3d-0410-9834-0bbf25fbcc57
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smparkes@smparkes.net 2011-06-28 16:02:20 +00:00
parent 0d4ae9fef6
commit 395cdb0f24
1 changed files with 298 additions and 297 deletions
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cpp/core/src/zxing/qrcode/decoder/DecodedBitStreamParser.cpp
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@ -1,4 +1,5 @@
/* /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* DecodedBitStreamParser.cpp * DecodedBitStreamParser.cpp
* zxing * zxing
* *
@ -37,317 +38,317 @@
using namespace zxing; using namespace zxing;
namespace zxing { namespace zxing {
namespace qrcode { namespace qrcode {
using namespace std; using namespace std;
const char DecodedBitStreamParser::ALPHANUMERIC_CHARS[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', const char DecodedBitStreamParser::ALPHANUMERIC_CHARS[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B',
'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', ' ', '$', '%', '*', '+', '-', '.', '/', ':' 'Y', 'Z', ' ', '$', '%', '*', '+', '-', '.', '/', ':'
}; };
const char *DecodedBitStreamParser::ASCII = "ASCII"; const char *DecodedBitStreamParser::ASCII = "ASCII";
const char *DecodedBitStreamParser::ISO88591 = "ISO-8859-1"; const char *DecodedBitStreamParser::ISO88591 = "ISO-8859-1";
const char *DecodedBitStreamParser::UTF8 = "UTF-8"; const char *DecodedBitStreamParser::UTF8 = "UTF-8";
const char *DecodedBitStreamParser::SHIFT_JIS = "SHIFT_JIS"; const char *DecodedBitStreamParser::SHIFT_JIS = "SHIFT_JIS";
const char *DecodedBitStreamParser::EUC_JP = "EUC-JP"; const char *DecodedBitStreamParser::EUC_JP = "EUC-JP";
void DecodedBitStreamParser::append(std::string &result, const unsigned char *bufIn, size_t nIn, const char *src) { void DecodedBitStreamParser::append(std::string &result, const unsigned char *bufIn, size_t nIn, const char *src) {
#ifndef NO_ICONV #ifndef NO_ICONV
if (nIn == 0) { if (nIn == 0) {
return; return;
} }
iconv_t cd = iconv_open(UTF8, src); iconv_t cd = iconv_open(UTF8, src);
const int maxOut = 4 * nIn + 1; const int maxOut = 4 * nIn + 1;
unsigned char* bufOut = new unsigned char[maxOut]; unsigned char* bufOut = new unsigned char[maxOut];
ICONV_CONST char *fromPtr = (ICONV_CONST char *)bufIn; ICONV_CONST char *fromPtr = (ICONV_CONST char *)bufIn;
size_t nFrom = nIn; size_t nFrom = nIn;
char *toPtr = (char *)bufOut; char *toPtr = (char *)bufOut;
size_t nTo = maxOut; size_t nTo = maxOut;
while (nFrom > 0) { while (nFrom > 0) {
size_t oneway = iconv(cd, &fromPtr, &nFrom, &toPtr, &nTo); size_t oneway = iconv(cd, &fromPtr, &nFrom, &toPtr, &nTo);
if (oneway == (size_t)(-1)) { if (oneway == (size_t)(-1)) {
iconv_close(cd); iconv_close(cd);
delete[] bufOut; delete[] bufOut;
throw ReaderException("error converting characters"); throw ReaderException("error converting characters");
} }
} }
iconv_close(cd); iconv_close(cd);
int nResult = maxOut - nTo; int nResult = maxOut - nTo;
bufOut[nResult] = '\0'; bufOut[nResult] = '\0';
result.append((const char *)bufOut); result.append((const char *)bufOut);
delete[] bufOut; delete[] bufOut;
#else #else
result.append((const char *)bufIn, nIn); result.append((const char *)bufIn, nIn);
#endif #endif
} }
void DecodedBitStreamParser::decodeKanjiSegment(Ref<BitSource> bits, std::string &result, int count) { void DecodedBitStreamParser::decodeKanjiSegment(Ref<BitSource> bits, std::string &result, int count) {
// Each character will require 2 bytes. Read the characters as 2-byte pairs // Each character will require 2 bytes. Read the characters as 2-byte pairs
// and decode as Shift_JIS afterwards // and decode as Shift_JIS afterwards
size_t nBytes = 2 * count; size_t nBytes = 2 * count;
unsigned char* buffer = new unsigned char[nBytes]; unsigned char* buffer = new unsigned char[nBytes];
int offset = 0; int offset = 0;
while (count > 0) { while (count > 0) {
// Each 13 bits encodes a 2-byte character // Each 13 bits encodes a 2-byte character
int twoBytes = bits->readBits(13); int twoBytes = bits->readBits(13);
int assembledTwoBytes = ((twoBytes / 0x0C0) << 8) | (twoBytes % 0x0C0); int assembledTwoBytes = ((twoBytes / 0x0C0) << 8) | (twoBytes % 0x0C0);
if (assembledTwoBytes < 0x01F00) { if (assembledTwoBytes < 0x01F00) {
// In the 0x8140 to 0x9FFC range // In the 0x8140 to 0x9FFC range
assembledTwoBytes += 0x08140; assembledTwoBytes += 0x08140;
} else { } else {
// In the 0xE040 to 0xEBBF range // In the 0xE040 to 0xEBBF range
assembledTwoBytes += 0x0C140; assembledTwoBytes += 0x0C140;
} }
buffer[offset] = (unsigned char)(assembledTwoBytes >> 8); buffer[offset] = (unsigned char)(assembledTwoBytes >> 8);
buffer[offset + 1] = (unsigned char)assembledTwoBytes; buffer[offset + 1] = (unsigned char)assembledTwoBytes;
offset += 2; offset += 2;
count--; count--;
} }
append(result, buffer, nBytes, SHIFT_JIS); append(result, buffer, nBytes, SHIFT_JIS);
delete[] buffer; delete[] buffer;
} }
void DecodedBitStreamParser::decodeByteSegment(Ref<BitSource> bits, std::string &result, int count) { void DecodedBitStreamParser::decodeByteSegment(Ref<BitSource> bits, std::string &result, int count) {
int nBytes = count; int nBytes = count;
unsigned char* readBytes = new unsigned char[nBytes]; unsigned char* readBytes = new unsigned char[nBytes];
if (count << 3 > bits->available()) { if (count << 3 > bits->available()) {
ostringstream s; ostringstream s;
s << "Count too large: " << count; s << "Count too large: " << count;
delete[] readBytes; delete[] readBytes;
throw ReaderException(s.str().c_str()); throw ReaderException(s.str().c_str());
} }
for (int i = 0; i < count; i++) { for (int i = 0; i < count; i++) {
readBytes[i] = (unsigned char)bits->readBits(8); readBytes[i] = (unsigned char)bits->readBits(8);
} }
// The spec isn't clear on this mode; see // The spec isn't clear on this mode; see
// section 6.4.5: t does not say which encoding to assuming // section 6.4.5: t does not say which encoding to assuming
// upon decoding. I have seen ISO-8859-1 used as well as // upon decoding. I have seen ISO-8859-1 used as well as
// Shift_JIS -- without anything like an ECI designator to // Shift_JIS -- without anything like an ECI designator to
// give a hint. // give a hint.
const char *encoding = guessEncoding(readBytes, nBytes); const char *encoding = guessEncoding(readBytes, nBytes);
append(result, readBytes, nBytes, encoding); append(result, readBytes, nBytes, encoding);
delete[] readBytes; delete[] readBytes;
} }
void DecodedBitStreamParser::decodeNumericSegment(Ref<BitSource> bits, std::string &result, int count) { void DecodedBitStreamParser::decodeNumericSegment(Ref<BitSource> bits, std::string &result, int count) {
int nBytes = count; int nBytes = count;
unsigned char* bytes = new unsigned char[nBytes]; unsigned char* bytes = new unsigned char[nBytes];
int i = 0; int i = 0;
// Read three digits at a time // Read three digits at a time
while (count >= 3) { while (count >= 3) {
// Each 10 bits encodes three digits // Each 10 bits encodes three digits
int threeDigitsBits = bits->readBits(10); int threeDigitsBits = bits->readBits(10);
if (threeDigitsBits >= 1000) { if (threeDigitsBits >= 1000) {
ostringstream s; ostringstream s;
s << "Illegal value for 3-digit unit: " << threeDigitsBits; s << "Illegal value for 3-digit unit: " << threeDigitsBits;
delete[] bytes; delete[] bytes;
throw ReaderException(s.str().c_str()); throw ReaderException(s.str().c_str());
} }
bytes[i++] = ALPHANUMERIC_CHARS[threeDigitsBits / 100]; bytes[i++] = ALPHANUMERIC_CHARS[threeDigitsBits / 100];
bytes[i++] = ALPHANUMERIC_CHARS[(threeDigitsBits / 10) % 10]; bytes[i++] = ALPHANUMERIC_CHARS[(threeDigitsBits / 10) % 10];
bytes[i++] = ALPHANUMERIC_CHARS[threeDigitsBits % 10]; bytes[i++] = ALPHANUMERIC_CHARS[threeDigitsBits % 10];
count -= 3; count -= 3;
} }
if (count == 2) { if (count == 2) {
// Two digits left over to read, encoded in 7 bits // Two digits left over to read, encoded in 7 bits
int twoDigitsBits = bits->readBits(7); int twoDigitsBits = bits->readBits(7);
if (twoDigitsBits >= 100) { if (twoDigitsBits >= 100) {
ostringstream s; ostringstream s;
s << "Illegal value for 2-digit unit: " << twoDigitsBits; s << "Illegal value for 2-digit unit: " << twoDigitsBits;
delete[] bytes; delete[] bytes;
throw ReaderException(s.str().c_str()); throw ReaderException(s.str().c_str());
} }
bytes[i++] = ALPHANUMERIC_CHARS[twoDigitsBits / 10]; bytes[i++] = ALPHANUMERIC_CHARS[twoDigitsBits / 10];
bytes[i++] = ALPHANUMERIC_CHARS[twoDigitsBits % 10]; bytes[i++] = ALPHANUMERIC_CHARS[twoDigitsBits % 10];
} else if (count == 1) { } else if (count == 1) {
// One digit left over to read // One digit left over to read
int digitBits = bits->readBits(4); int digitBits = bits->readBits(4);
if (digitBits >= 10) { if (digitBits >= 10) {
ostringstream s; ostringstream s;
s << "Illegal value for digit unit: " << digitBits; s << "Illegal value for digit unit: " << digitBits;
delete[] bytes; delete[] bytes;
throw ReaderException(s.str().c_str()); throw ReaderException(s.str().c_str());
} }
bytes[i++] = ALPHANUMERIC_CHARS[digitBits]; bytes[i++] = ALPHANUMERIC_CHARS[digitBits];
} }
append(result, bytes, nBytes, ASCII); append(result, bytes, nBytes, ASCII);
delete[] bytes; delete[] bytes;
} }
void DecodedBitStreamParser::decodeAlphanumericSegment(Ref<BitSource> bits, std::string &result, int count) { void DecodedBitStreamParser::decodeAlphanumericSegment(Ref<BitSource> bits, std::string &result, int count) {
int nBytes = count; int nBytes = count;
unsigned char* bytes = new unsigned char[nBytes]; unsigned char* bytes = new unsigned char[nBytes];
int i = 0; int i = 0;
// Read two characters at a time // Read two characters at a time
while (count > 1) { while (count > 1) {
int nextTwoCharsBits = bits->readBits(11); int nextTwoCharsBits = bits->readBits(11);
bytes[i++] = ALPHANUMERIC_CHARS[nextTwoCharsBits / 45]; bytes[i++] = ALPHANUMERIC_CHARS[nextTwoCharsBits / 45];
bytes[i++] = ALPHANUMERIC_CHARS[nextTwoCharsBits % 45]; bytes[i++] = ALPHANUMERIC_CHARS[nextTwoCharsBits % 45];
count -= 2; count -= 2;
} }
if (count == 1) { if (count == 1) {
bytes[i++] = ALPHANUMERIC_CHARS[bits->readBits(6)]; bytes[i++] = ALPHANUMERIC_CHARS[bits->readBits(6)];
} }
append(result, bytes, nBytes, ASCII); append(result, bytes, nBytes, ASCII);
delete[] bytes; delete[] bytes;
} }
const char * const char *
DecodedBitStreamParser::guessEncoding(unsigned char *bytes, int length) { DecodedBitStreamParser::guessEncoding(unsigned char *bytes, int length) {
const bool ASSUME_SHIFT_JIS = false; const bool ASSUME_SHIFT_JIS = false;
char const* const PLATFORM_DEFAULT_ENCODING="UTF-8"; char const* const PLATFORM_DEFAULT_ENCODING="UTF-8";
// Does it start with the UTF-8 byte order mark? then guess it's UTF-8 // Does it start with the UTF-8 byte order mark? then guess it's UTF-8
if (length > 3 && bytes[0] == (unsigned char)0xEF && bytes[1] == (unsigned char)0xBB && bytes[2] if (length > 3 && bytes[0] == (unsigned char)0xEF && bytes[1] == (unsigned char)0xBB && bytes[2]
== (unsigned char)0xBF) { == (unsigned char)0xBF) {
return UTF8; return UTF8;
} }
// For now, merely tries to distinguish ISO-8859-1, UTF-8 and Shift_JIS, // For now, merely tries to distinguish ISO-8859-1, UTF-8 and Shift_JIS,
// which should be by far the most common encodings. ISO-8859-1 // which should be by far the most common encodings. ISO-8859-1
// should not have bytes in the 0x80 - 0x9F range, while Shift_JIS // should not have bytes in the 0x80 - 0x9F range, while Shift_JIS
// uses this as a first byte of a two-byte character. If we see this // uses this as a first byte of a two-byte character. If we see this
// followed by a valid second byte in Shift_JIS, assume it is Shift_JIS. // followed by a valid second byte in Shift_JIS, assume it is Shift_JIS.
// If we see something else in that second byte, we'll make the risky guess // If we see something else in that second byte, we'll make the risky guess
// that it's UTF-8. // that it's UTF-8.
bool canBeISO88591 = true; bool canBeISO88591 = true;
bool canBeShiftJIS = true; bool canBeShiftJIS = true;
bool canBeUTF8 = true; bool canBeUTF8 = true;
int utf8BytesLeft = 0; int utf8BytesLeft = 0;
int maybeDoubleByteCount = 0; int maybeDoubleByteCount = 0;
int maybeSingleByteKatakanaCount = 0; int maybeSingleByteKatakanaCount = 0;
bool sawLatin1Supplement = false; bool sawLatin1Supplement = false;
bool sawUTF8Start = false; bool sawUTF8Start = false;
bool lastWasPossibleDoubleByteStart = false; bool lastWasPossibleDoubleByteStart = false;
for (int i = 0; for (int i = 0;
i < length && (canBeISO88591 || canBeShiftJIS || canBeUTF8); i < length && (canBeISO88591 || canBeShiftJIS || canBeUTF8);
i++) { i++) {
int value = bytes[i] & 0xFF; int value = bytes[i] & 0xFF;
// UTF-8 stuff // UTF-8 stuff
if (value >= 0x80 && value <= 0xBF) { if (value >= 0x80 && value <= 0xBF) {
if (utf8BytesLeft > 0) { if (utf8BytesLeft > 0) {
utf8BytesLeft--; utf8BytesLeft--;
}
} else {
if (utf8BytesLeft > 0) {
canBeUTF8 = false;
}
if (value >= 0xC0 && value <= 0xFD) {
sawUTF8Start = true;
int valueCopy = value;
while ((valueCopy & 0x40) != 0) {
utf8BytesLeft++;
valueCopy <<= 1;
}
}
}
// Shift_JIS stuff
if (value >= 0xA1 && value <= 0xDF) {
// count the number of characters that might be a Shift_JIS single-byte Katakana character
if (!lastWasPossibleDoubleByteStart) {
maybeSingleByteKatakanaCount++;
}
}
if (!lastWasPossibleDoubleByteStart &&
((value >= 0xF0 && value <= 0xFF) || value == 0x80 || value == 0xA0)) {
canBeShiftJIS = false;
}
if (((value >= 0x81 && value <= 0x9F) || (value >= 0xE0 && value <= 0xEF))) {
// These start double-byte characters in Shift_JIS. Let's see if it's followed by a valid
// second byte.
if (lastWasPossibleDoubleByteStart) {
// If we just checked this and the last byte for being a valid double-byte
// char, don't check starting on this byte. If this and the last byte
// formed a valid pair, then this shouldn't be checked to see if it starts
// a double byte pair of course.
lastWasPossibleDoubleByteStart = false;
} else {
// ... otherwise do check to see if this plus the next byte form a valid
// double byte pair encoding a character.
lastWasPossibleDoubleByteStart = true;
if (i >= length - 1) {
canBeShiftJIS = false;
} else {
int nextValue = bytes[i + 1] & 0xFF;
if (nextValue < 0x40 || nextValue > 0xFC) {
canBeShiftJIS = false;
} else {
maybeDoubleByteCount++;
}
// There is some conflicting information out there about which bytes can follow which in
// double-byte Shift_JIS characters. The rule above seems to be the one that matches practice.
}
}
} else {
lastWasPossibleDoubleByteStart = false;
}
} }
} else {
if (utf8BytesLeft > 0) { if (utf8BytesLeft > 0) {
canBeUTF8 = false; canBeUTF8 = false;
} }
if (value >= 0xC0 && value <= 0xFD) {
sawUTF8Start = true; // Easy -- if assuming Shift_JIS and no evidence it can't be, done
int valueCopy = value; if (canBeShiftJIS && ASSUME_SHIFT_JIS) {
while ((valueCopy & 0x40) != 0) { return SHIFT_JIS;
utf8BytesLeft++;
valueCopy <<= 1;
}
} }
if (canBeUTF8 && sawUTF8Start) {
return UTF8;
}
// Distinguishing Shift_JIS and ISO-8859-1 can be a little tough. The crude heuristic is:
// - If we saw
// - at least 3 bytes that starts a double-byte value (bytes that are rare in ISO-8859-1), or
// - over 5% of bytes could be single-byte Katakana (also rare in ISO-8859-1),
// - and, saw no sequences that are invalid in Shift_JIS, then we conclude Shift_JIS
if (canBeShiftJIS && (maybeDoubleByteCount >= 3 || 20 * maybeSingleByteKatakanaCount > length)) {
return SHIFT_JIS;
}
// Otherwise, we default to ISO-8859-1 unless we know it can't be
if (!sawLatin1Supplement && canBeISO88591) {
return ISO88591;
}
// Otherwise, we take a wild guess with platform encoding
return PLATFORM_DEFAULT_ENCODING;
} }
// Shift_JIS stuff string DecodedBitStreamParser::decode(ArrayRef<unsigned char> bytes, Version *version) {
string result;
if (value >= 0xA1 && value <= 0xDF) { Ref<BitSource> bits(new BitSource(bytes));
// count the number of characters that might be a Shift_JIS single-byte Katakana character Mode *mode = &Mode::TERMINATOR;
if (!lastWasPossibleDoubleByteStart) { do {
maybeSingleByteKatakanaCount++; // While still another segment to read...
} if (bits->available() < 4) {
} // OK, assume we're done. Really, a TERMINATOR mode should have been recorded here
if (!lastWasPossibleDoubleByteStart && mode = &Mode::TERMINATOR;
((value >= 0xF0 && value <= 0xFF) || value == 0x80 || value == 0xA0)) {
canBeShiftJIS = false;
}
if (((value >= 0x81 && value <= 0x9F) || (value >= 0xE0 && value <= 0xEF))) {
// These start double-byte characters in Shift_JIS. Let's see if it's followed by a valid
// second byte.
if (lastWasPossibleDoubleByteStart) {
// If we just checked this and the last byte for being a valid double-byte
// char, don't check starting on this byte. If this and the last byte
// formed a valid pair, then this shouldn't be checked to see if it starts
// a double byte pair of course.
lastWasPossibleDoubleByteStart = false;
} else {
// ... otherwise do check to see if this plus the next byte form a valid
// double byte pair encoding a character.
lastWasPossibleDoubleByteStart = true;
if (i >= length - 1) {
canBeShiftJIS = false;
} else { } else {
int nextValue = bytes[i + 1] & 0xFF; mode = &Mode::forBits(bits->readBits(4)); // mode is encoded by 4 bits
if (nextValue < 0x40 || nextValue > 0xFC) {
canBeShiftJIS = false;
} else {
maybeDoubleByteCount++;
}
// There is some conflicting information out there about which bytes can follow which in
// double-byte Shift_JIS characters. The rule above seems to be the one that matches practice.
} }
} if (mode != &Mode::TERMINATOR) {
} else { // How many characters will follow, encoded in this mode?
lastWasPossibleDoubleByteStart = false; int count = bits->readBits(mode->getCharacterCountBits(version));
if (mode == &Mode::NUMERIC) {
decodeNumericSegment(bits, result, count);
} else if (mode == &Mode::ALPHANUMERIC) {
decodeAlphanumericSegment(bits, result, count);
} else if (mode == &Mode::BYTE) {
decodeByteSegment(bits, result, count);
} else if (mode == &Mode::KANJI) {
decodeKanjiSegment(bits, result, count);
} else {
throw ReaderException("Unsupported mode indicator");
}
}
} while (mode != &Mode::TERMINATOR);
return result;
} }
}
if (utf8BytesLeft > 0) {
canBeUTF8 = false;
}
// Easy -- if assuming Shift_JIS and no evidence it can't be, done
if (canBeShiftJIS && ASSUME_SHIFT_JIS) {
return SHIFT_JIS;
} }
if (canBeUTF8 && sawUTF8Start) {
return UTF8;
}
// Distinguishing Shift_JIS and ISO-8859-1 can be a little tough. The crude heuristic is:
// - If we saw
// - at least 3 bytes that starts a double-byte value (bytes that are rare in ISO-8859-1), or
// - over 5% of bytes could be single-byte Katakana (also rare in ISO-8859-1),
// - and, saw no sequences that are invalid in Shift_JIS, then we conclude Shift_JIS
if (canBeShiftJIS && (maybeDoubleByteCount >= 3 || 20 * maybeSingleByteKatakanaCount > length)) {
return SHIFT_JIS;
}
// Otherwise, we default to ISO-8859-1 unless we know it can't be
if (!sawLatin1Supplement && canBeISO88591) {
return ISO88591;
}
// Otherwise, we take a wild guess with platform encoding
return PLATFORM_DEFAULT_ENCODING;
}
string DecodedBitStreamParser::decode(ArrayRef<unsigned char> bytes, Version *version) {
string result;
Ref<BitSource> bits(new BitSource(bytes));
Mode *mode = &Mode::TERMINATOR;
do {
// While still another segment to read...
if (bits->available() < 4) {
// OK, assume we're done. Really, a TERMINATOR mode should have been recorded here
mode = &Mode::TERMINATOR;
} else {
mode = &Mode::forBits(bits->readBits(4)); // mode is encoded by 4 bits
}
if (mode != &Mode::TERMINATOR) {
// How many characters will follow, encoded in this mode?
int count = bits->readBits(mode->getCharacterCountBits(version));
if (mode == &Mode::NUMERIC) {
decodeNumericSegment(bits, result, count);
} else if (mode == &Mode::ALPHANUMERIC) {
decodeAlphanumericSegment(bits, result, count);
} else if (mode == &Mode::BYTE) {
decodeByteSegment(bits, result, count);
} else if (mode == &Mode::KANJI) {
decodeKanjiSegment(bits, result, count);
} else {
throw ReaderException("Unsupported mode indicator");
}
}
} while (mode != &Mode::TERMINATOR);
return result;
}
}
} }