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Added basic support for caller-specified character encoding

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git-svn-id: https://zxing.googlecode.com/svn/trunk@836 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
srowen 2009-01-31 00:40:04 +00:00
parent 89176baf0c
commit 807c1646b9
2 changed files with 69 additions and 37 deletions
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5
core/src/com/google/zxing/EncodeHintType.java
View file

@ -28,6 +28,11 @@ public final class EncodeHintType {
*/
public static final EncodeHintType ERROR_CORRECTION = new EncodeHintType();
/**
* Specifies what character encoding to use where applicable (type String)
*/
public static final EncodeHintType CHARACTER_SET = new EncodeHintType();
private EncodeHintType() {
}

101
core/src/com/google/zxing/qrcode/encoder/Encoder.java
View file

@ -17,6 +17,7 @@
package com.google.zxing.qrcode.encoder;
import com.google.zxing.WriterException;
import com.google.zxing.EncodeHintType;
import com.google.zxing.common.ByteArray;
import com.google.zxing.common.ByteMatrix;
import com.google.zxing.common.reedsolomon.GF256;
@ -26,6 +27,7 @@ import com.google.zxing.qrcode.decoder.Mode;
import com.google.zxing.qrcode.decoder.Version;
import java.util.Vector;
import java.util.Hashtable;
import java.io.UnsupportedEncodingException;
/**
@ -78,22 +80,36 @@ public final class Encoder {
}
// Encode "bytes" with the error correction level "getECLevel". The encoding mode will be chosen
// internally by chooseMode(). On success, store the result in "qrCode" and return true.
// We recommend you to use QRCode.EC_LEVEL_L (the lowest level) for
// "getECLevel" since our primary use is to show QR code on desktop screens. We don't need very
// strong error correction for this purpose.
//
// Note that there is no way to encode bytes in MODE_KANJI. We might want to add EncodeWithMode()
// with which clients can specify the encoding mode. For now, we don't need the functionality.
/**
* Encode "bytes" with the error correction level "ecLevel". The encoding mode will be chosen
* internally by chooseMode(). On success, store the result in "qrCode".
*
* We recommend you to use QRCode.EC_LEVEL_L (the lowest level) for
* "getECLevel" since our primary use is to show QR code on desktop screens. We don't need very
* strong error correction for this purpose.
*
* Note that there is no way to encode bytes in MODE_KANJI. We might want to add EncodeWithMode()
* with which clients can specify the encoding mode. For now, we don't need the functionality.
*/
public static void encode(String content, ErrorCorrectionLevel ecLevel, QRCode qrCode)
throws WriterException {
encode(content, ecLevel, null, qrCode);
}
public static void encode(String content, ErrorCorrectionLevel ecLevel, Hashtable hints, QRCode qrCode)
throws WriterException {
String characterEncoding = hints == null ? null : (String) hints.get(EncodeHintType.CHARACTER_SET);
if (characterEncoding == null) {
characterEncoding = "ISO-8859-1";
}
// Step 1: Choose the mode (encoding).
Mode mode = chooseMode(content);
// Step 2: Append "bytes" into "dataBits" in appropriate encoding.
BitVector dataBits = new BitVector();
appendBytes(content, mode, dataBits);
appendBytes(content, mode, dataBits, characterEncoding);
// Step 3: Initialize QR code that can contain "dataBits".
int numInputBytes = dataBits.sizeInBytes();
initQRCode(numInputBytes, ecLevel, mode, qrCode);
@ -127,8 +143,10 @@ public final class Encoder {
}
}
// Return the code point of the table used in alphanumeric mode. Return -1 if there is no
// corresponding code in the table.
/**
* @return the code point of the table used in alphanumeric mode or
* -1 if there is no corresponding code in the table.
*/
static int getAlphanumericCode(int code) {
if (code < ALPHANUMERIC_TABLE.length) {
return ALPHANUMERIC_TABLE[code];
@ -136,13 +154,13 @@ public final class Encoder {
return -1;
}
// Choose the best mode by examining the content.
//
// Note that this function does not return MODE_KANJI, as we cannot distinguish Shift_JIS from
// other encodings such as ISO-8859-1, from data bytes alone. For example "\xE0\xE0" can be
// interpreted as one character in Shift_JIS, but also two characters in ISO-8859-1.
//
// JAVAPORT: This MODE_KANJI limitation sounds like a problem for us.
/**
* Choose the best mode by examining the content.
*
* Note that this function does not return MODE_KANJI, as we cannot distinguish Shift_JIS from
* other encodings such as ISO-8859-1, from data bytes alone. For example "\xE0\xE0" can be
* interpreted as one character in Shift_JIS, but also two characters in ISO-8859-1.
*/
public static Mode chooseMode(String content) {
boolean hasNumeric = false;
boolean hasAlphanumeric = false;
@ -181,8 +199,9 @@ public final class Encoder {
return bestMaskPattern;
}
// Initialize "qrCode" according to "numInputBytes", "ecLevel", and "mode". On success, modify
// "qrCode".
/**
* Initialize "qrCode" according to "numInputBytes", "ecLevel", and "mode". On success, modify "qrCode".
*/
private static void initQRCode(int numInputBytes, ErrorCorrectionLevel ecLevel, Mode mode, QRCode qrCode)
throws WriterException {
qrCode.setECLevel(ecLevel);
@ -219,7 +238,9 @@ public final class Encoder {
throw new WriterException("Cannot find proper rs block info (input data too big?)");
}
// Terminate bits as described in 8.4.8 and 8.4.9 of JISX0510:2004 (p.24).
/**
* Terminate bits as described in 8.4.8 and 8.4.9 of JISX0510:2004 (p.24).
*/
static void terminateBits(int numDataBytes, BitVector bits) throws WriterException {
int capacity = numDataBytes << 3;
if (bits.size() > capacity) {
@ -255,9 +276,11 @@ public final class Encoder {
}
}
// Get number of data bytes and number of error correction bytes for block id "blockID". Store
// the result in "numDataBytesInBlock", and "numECBytesInBlock". See table 12 in 8.5.1 of
// JISX0510:2004 (p.30)
/**
* Get number of data bytes and number of error correction bytes for block id "blockID". Store
* the result in "numDataBytesInBlock", and "numECBytesInBlock". See table 12 in 8.5.1 of
* JISX0510:2004 (p.30)
*/
static void getNumDataBytesAndNumECBytesForBlockID(int numTotalBytes, int numDataBytes,
int numRSBlocks, int blockID, int[] numDataBytesInBlock,
int[] numECBytesInBlock) throws WriterException {
@ -307,9 +330,10 @@ public final class Encoder {
}
}
// Interleave "bits" with corresponding error correction bytes. On success, store the result in
// "result" and return true. The interleave rule is complicated. See 8.6
// of JISX0510:2004 (p.37) for details.
/**
* Interleave "bits" with corresponding error correction bytes. On success, store the result in
* "result". The interleave rule is complicated. See 8.6 of JISX0510:2004 (p.37) for details.
*/
static void interleaveWithECBytes(BitVector bits, int numTotalBytes,
int numDataBytes, int numRSBlocks, BitVector result) throws WriterException {
@ -386,15 +410,17 @@ public final class Encoder {
return ecBytes;
}
// Append mode info. On success, store the result in "bits" and return true. On error, return
// false.
/**
* Append mode info. On success, store the result in "bits".
*/
static void appendModeInfo(Mode mode, BitVector bits) {
bits.appendBits(mode.getBits(), 4);
}
// Append length info. On success, store the result in "bits" and return true. On error, return
// false.
/**
* Append length info. On success, store the result in "bits".
*/
static void appendLengthInfo(int numLetters, int version, Mode mode, BitVector bits) throws WriterException {
int numBits = mode.getCharacterCountBits(Version.getVersionForNumber(version));
if (numLetters > ((1 << numBits) - 1)) {
@ -403,15 +429,16 @@ public final class Encoder {
bits.appendBits(numLetters, numBits);
}
// Append "bytes" in "mode" mode (encoding) into "bits". On success, store the result in "bits"
// and return true.
static void appendBytes(String content, Mode mode, BitVector bits) throws WriterException {
/**
* Append "bytes" in "mode" mode (encoding) into "bits". On success, store the result in "bits".
*/
static void appendBytes(String content, Mode mode, BitVector bits, String encoding) throws WriterException {
if (mode.equals(Mode.NUMERIC)) {
appendNumericBytes(content, bits);
} else if (mode.equals(Mode.ALPHANUMERIC)) {
appendAlphanumericBytes(content, bits);
} else if (mode.equals(Mode.BYTE)) {
append8BitBytes(content, bits);
append8BitBytes(content, bits, encoding);
} else if (mode.equals(Mode.KANJI)) {
appendKanjiBytes(content, bits);
} else {
@ -467,10 +494,10 @@ public final class Encoder {
}
}
static void append8BitBytes(String content, BitVector bits) throws WriterException {
static void append8BitBytes(String content, BitVector bits, String encoding) throws WriterException {
byte[] bytes;
try {
bytes = content.getBytes("ISO-8859-1"); // TODO support specifying encoding?
bytes = content.getBytes(encoding);
} catch (UnsupportedEncodingException uee) {
throw new WriterException(uee.toString());
}