FastStringReader.java :  » OSGi » nucleus8583 » org » nucleus8583 » core » util » Java Open Source

package org.nucleus8583.core.util;

import java.io.IOException;
import java.io.Reader;

public class FastStringReader extends Reader {
  private String value;

  private int vlen;

  private int readIndex;

  private int remaining;

  public FastStringReader(String value) {
    this.value = value;
    this.vlen = value == null ? 0 : value.length();

    this.readIndex = 0;
    this.remaining = this.vlen;
  }

  public int read(char[] cbuf, int off, int len) throws IOException {
    if (remaining == 0) {
      return -1;
    }

    int actualLen = Math.min(len, remaining);
    if (actualLen > 0) {
      value.getChars(readIndex, readIndex + actualLen, cbuf, off);

      readIndex += actualLen;
      remaining -= actualLen;
    }

    return actualLen;
  }

  @Override
  public int read() throws IOException {
    if (remaining <= 0) {
      return -1;
    }

    char cc = value.charAt(readIndex);

    ++readIndex;
    --remaining;

    return cc;
  }

  @Override
  public int read(char[] cbuf) throws IOException {
    return read(cbuf, 0, cbuf.length);
  }

  @Override
  public long skip(long n) throws IOException {
    int actualN = Math.min(remaining, (int) n);

    readIndex += actualN;
    remaining -= actualN;

    return actualN;
  }

  @Override
  public boolean ready() throws IOException {
    return remaining > 0;
  }

  @Override
  public boolean markSupported() {
    return false;
  }

  @Override
  public void mark(int readAheadLimit) throws IOException {
    throw new IOException();
  }

  @Override
  public void reset() throws IOException {
    this.readIndex = 0;
    this.remaining = this.vlen;
  }

  public void close() throws IOException {
    this.readIndex = 0;
    this.remaining = 0;
    
    this.value = null;
    this.vlen = 0;
  }
}