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/*
 * Copyright 2016 Carlos Ballesteros Velasco
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package java.io;

public class ByteArrayInputStream extends InputStream {
    protected byte buf[];
    protected int pos;
    protected int mark = 0;
    protected int count;

    public ByteArrayInputStream(byte data[]) {
        this.buf = data;
        this.pos = 0;
        this.count = data.length;
    }

    public ByteArrayInputStream(byte data[], int offset, int length) {
        this.buf = data;
        this.pos = offset;
        this.count = Math.min(offset + length, data.length);
        this.mark = offset;
    }

    public synchronized int read() {
        return (pos < count) ? (buf[pos++] & 0xff) : -1;
    }

    public synchronized int read(byte data[], int offset, int length) {
        if (data == null) throw new NullPointerException();
        if (offset < 0 || length < 0 || length > data.length - offset) throw new IndexOutOfBoundsException();

        if (pos >= count) return -1;
        int avail = count - pos;
        if (length > avail) length = avail;
        if (length <= 0) return 0;
        System.arraycopy(buf, pos, data, offset, length);
        pos += length;
        return length;
    }

    public synchronized long skip(long n) {
        long left = count - pos;
        if (n < left) left = n < 0 ? 0 : n;
        pos += left;
        return left;
    }

    public synchronized int available() {
        return count - pos;
    }

    public boolean markSupported() {
        return true;
    }

    public void mark(int readAheadLimit) {
        mark = pos;
    }

    public synchronized void reset() {
        pos = mark;
    }

    public void close() throws IOException {
    }
}