package com.ctc.wstx.io;

import java.io.*;

import com.ctc.wstx.api.ReaderConfig;

Simple InputStream implementation that is used to "unwind" some data previously read from an input stream; so that as long as some of that data remains, it's returned; but as long as it's read, we'll just use data from the underlying original stream. This is similar to PushbackInputStream, but here there's only one implicit pushback, when instance is constructed.
/** * Simple {@link InputStream} implementation that is used to "unwind" some * data previously read from an input stream; so that as long as some of * that data remains, it's returned; but as long as it's read, we'll * just use data from the underlying original stream. * This is similar to {@link java.io.PushbackInputStream}, but here there's * only one implicit pushback, when instance is constructed. */
public final class MergedStream extends InputStream { final private ReaderConfig mConfig; final private InputStream mIn; private byte[] mData; private int mPtr; final private int mEnd; public MergedStream(ReaderConfig cfg, InputStream in, byte[] buf, int start, int end) { if (in == null) { throw new IllegalArgumentException("InputStream `in` should not be `null`"); } mConfig = cfg; mIn = in; mData = buf; mPtr = start; mEnd = end; } @Override public int available() throws IOException { if (mData != null) { return mEnd - mPtr; } return mIn.available(); } @Override public void close() throws IOException { freeMergedBuffer(); mIn.close(); } @Override public void mark(int readlimit) { if (mData == null) { mIn.mark(readlimit); } } @Override public boolean markSupported() { // Only supports marks past the initial rewindable section... return (mData == null) && mIn.markSupported(); } @Override public int read() throws IOException { if (mData != null) { int c = mData[mPtr++] & 0xFF; if (mPtr >= mEnd) { freeMergedBuffer(); } return c; } return mIn.read(); } @Override public int read(byte[] b) throws IOException { return read(b, 0, b.length); } @Override public int read(byte[] b, int off, int len) throws IOException { if (mData != null) { int avail = mEnd - mPtr; if (len > avail) { len = avail; } System.arraycopy(mData, mPtr, b, off, len); mPtr += len; if (mPtr >= mEnd) { freeMergedBuffer(); } return len; } return mIn.read(b, off, len); } @Override public void reset() throws IOException { if (mData == null) { mIn.reset(); } } @Override public long skip(long n) throws IOException { long count = 0L; if (mData != null) { int amount = mEnd - mPtr; if (amount > n) { // all in pushed back segment? mPtr += (int) n; return n; } freeMergedBuffer(); count += amount; n -= amount; } if (n > 0) { count += mIn.skip(n); } return count; } private void freeMergedBuffer() { if (mData != null) { byte[] data = mData; mData = null; if (mConfig != null) { mConfig.freeFullBBuffer(data); } } } }