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package sun.nio.cs.ext;

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CoderResult;

An abstract base class for subclasses which decode IBM double byte ebcdic host encodings such as ibm code pages 933, 935, 937,... etc
/** * An abstract base class for subclasses which decode * IBM double byte ebcdic host encodings such as ibm code * pages 933, 935, 937,... etc * */
public abstract class DBCS_IBM_EBCDIC_Decoder extends CharsetDecoder { private DBCSDecoderMapping decoderMapping; protected static final char REPLACE_CHAR='\uFFFD'; protected String singleByteToChar; protected short index1[]; protected String index2; protected int mask1; protected int mask2; protected int shift; private static final int SBCS = 0; private static final int DBCS = 1; private static final int SO = 0x0e; private static final int SI = 0x0f; private int currentState; protected DBCS_IBM_EBCDIC_Decoder(Charset cs) { super(cs, 0.5f, 1.0f); } protected void implReset() { currentState = SBCS; } private CoderResult decodeArrayLoop(ByteBuffer src, CharBuffer dst) { byte[] sa = src.array(); int sp = src.arrayOffset() + src.position(); int sl = src.arrayOffset() + src.limit(); assert (sp <= sl); sp = (sp <= sl ? sp : sl); char[] da = dst.array(); int dp = dst.arrayOffset() + dst.position(); int dl = dst.arrayOffset() + dst.limit(); assert (dp <= dl); dp = (dp <= dl ? dp : dl); try { while (sp < sl) { int b1, b2; b1 = sa[sp]; int inputSize = 1; int v = 0; char outputChar = REPLACE_CHAR; if (b1 < 0) b1 += 256; if (b1 == SO) { // Shift out // For SO characters - simply validate the state and if OK // update the state and go to the next byte if (currentState != SBCS) return CoderResult.malformedForLength(1); else currentState = DBCS; } else if (b1 == SI) { // For SI characters - simply validate the state and if OK // update the state and go to the next byte if (currentState != DBCS) { return CoderResult.malformedForLength(1); } else { currentState = SBCS; } } else { if (currentState == SBCS) { outputChar = singleByteToChar.charAt(b1); } else { if (sl - sp < 2) return CoderResult.UNDERFLOW; b2 = sa[sp + 1]; if (b2 < 0) b2 += 256; inputSize++; // Check validity of dbcs ebcdic byte pair values if ((b1 != 0x40 || b2 != 0x40) && (b2 < 0x41 || b2 > 0xfe)) { return CoderResult.malformedForLength(2); } // Lookup in the two level index v = b1 * 256 + b2; outputChar = index2.charAt(index1[((v & mask1) >> shift)] + (v & mask2)); } if (outputChar == '\uFFFD') return CoderResult.unmappableForLength(inputSize); if (dl - dp < 1) return CoderResult.OVERFLOW; da[dp++] = outputChar; } sp += inputSize; } return CoderResult.UNDERFLOW; } finally { src.position(sp - src.arrayOffset()); dst.position(dp - dst.arrayOffset()); } } private CoderResult decodeBufferLoop(ByteBuffer src, CharBuffer dst) { int mark = src.position(); try { while (src.hasRemaining()) { int b1, b2; int v = 0; b1 = src.get(); int inputSize = 1; char outputChar = REPLACE_CHAR; if (b1 < 0) b1 += 256; if (b1 == SO) { // Shift out // For SO characters - simply validate the state and if OK // update the state and go to the next byte if (currentState != SBCS) return CoderResult.malformedForLength(1); else currentState = DBCS; } else if (b1 == SI) { // For SI characters - simply validate the state and if OK // update the state and go to the next byte if (currentState != DBCS) { return CoderResult.malformedForLength(1); } else { currentState = SBCS; } } else { if (currentState == SBCS) { outputChar = singleByteToChar.charAt(b1); } else { if (src.remaining() < 1) return CoderResult.UNDERFLOW; b2 = src.get(); if (b2 < 0) b2 += 256; inputSize++; // Check validity of dbcs ebcdic byte pair values if ((b1 != 0x40 || b2 != 0x40) && (b2 < 0x41 || b2 > 0xfe)) { return CoderResult.malformedForLength(2); } // Lookup in the two level index v = b1 * 256 + b2; outputChar = index2.charAt(index1[((v & mask1) >> shift)] + (v & mask2)); } if (outputChar == REPLACE_CHAR) return CoderResult.unmappableForLength(inputSize); if (!dst.hasRemaining()) return CoderResult.OVERFLOW; dst.put(outputChar); } mark += inputSize; } return CoderResult.UNDERFLOW; } finally { src.position(mark); } } protected CoderResult decodeLoop(ByteBuffer src, CharBuffer dst) { if (src.hasArray() && dst.hasArray()) return decodeArrayLoop(src, dst); else return decodeBufferLoop(src, dst); } }