bufferedrandomaccessfile.java

来自「一个基于NetBeans平台开发的」· Java 代码 · 共 312 行

package com.sinpool.rivercrescent.io;

import java.io.RandomAccessFile;
import java.io.File;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.util.ResourceBundle;

/**
 * <p>Title: BufferedRandomAccessFile</p>
 ** <p>Description: 这个类提供了缓冲区读取数据和写数据的目的，是继承了RandomAccessFile类。</p>
 *
 * @version 1.0, 2002/10/12
 */

public class BufferedRandomAccessFile extends RandomAccessFile {

    static ResourceBundle res = ResourceBundle.getBundle("com.sinpool.rivercrescent.io.Res");
    private static final int DEFAULT_BUFFER_BIT_LEN = 10;
    private static final int DEFAULT_BUFFER_SIZE = 1 << DEFAULT_BUFFER_BIT_LEN;

    protected byte buf[];
    protected int bufbitlen;
    protected int bufsize;
    protected long bufmask;
    protected boolean bufdirty;
    protected int bufusedsize;
    protected long curpos;

    protected long bufstartpos;
    protected long bufendpos;
    protected long fileendpos;

    protected boolean append;
    protected String filename;
    protected long initfilelen;

    public BufferedRandomAccessFile(String name) throws  IOException {
        this(name, res.getString("r"), DEFAULT_BUFFER_BIT_LEN);
    }

    public BufferedRandomAccessFile(File file) throws IOException, FileNotFoundException {
        this(file.getPath(), res.getString("r"), DEFAULT_BUFFER_BIT_LEN);
    }

    public BufferedRandomAccessFile(String name, int bufbitlen) throws  IOException {
        this(name, res.getString("r"), bufbitlen);
    }

    public BufferedRandomAccessFile(File file, int bufbitlen) throws IOException, FileNotFoundException {
        this(file.getPath(), res.getString("r"), bufbitlen);
    }

    public BufferedRandomAccessFile(String name, String mode) throws IOException {
        this(name, mode, DEFAULT_BUFFER_BIT_LEN);
    }

    public BufferedRandomAccessFile(File file, String mode) throws IOException, FileNotFoundException {
        this(file.getPath(), mode, DEFAULT_BUFFER_BIT_LEN);
    }

    public BufferedRandomAccessFile(String name, String mode, int bufbitlen) throws IOException  {
        super(name, mode);
        this.init(name, mode, bufbitlen);
    }

    public BufferedRandomAccessFile(File file, String mode, int bufbitlen) throws IOException, FileNotFoundException {
        this(file.getPath(), mode, bufbitlen);
    }

    private void init(String name, String mode, int bufbitlen) throws IOException {
        if (mode.equals(res.getString("r")) == true) {
            this.append = false;
        } else {
            this.append = true;
        }

        this.filename = name;
        this.initfilelen = super.length();
        this.fileendpos = this.initfilelen - 1;
        this.curpos = super.getFilePointer();

        if (bufbitlen < 0) {
            throw new IllegalArgumentException(res.getString("bufbitlen_size_must_0"));
        }

        this.bufbitlen = bufbitlen;
        this.bufsize = 1 << bufbitlen;
        this.buf = new byte[this.bufsize];
        this.bufmask = ~((long)this.bufsize - 1L);
        this.bufdirty = false;
        this.bufusedsize = 0;
        this.bufstartpos = -1;
        this.bufendpos = -1;
    }

    private void flushbuf() throws IOException {
        if (this.bufdirty == true) {
            if (super.getFilePointer() != this.bufstartpos) {
                super.seek(this.bufstartpos);
            }
            super.write(this.buf, 0, this.bufusedsize);
            this.bufdirty = false;
        }
    }

    private int fillbuf() throws IOException {
        super.seek(this.bufstartpos);
        this.bufdirty = false;
        return super.read(this.buf);
    }

    public byte read(long pos) throws IOException {
        if (pos < this.bufstartpos || pos > this.bufendpos) {
            this.flushbuf();
            this.seek(pos);

            if ((pos < this.bufstartpos) || (pos > this.bufendpos)) {
                throw new IOException();
            }
        }
        this.curpos = pos;
        return this.buf[(int)(pos - this.bufstartpos)];
    }

    public boolean write(byte bw) throws IOException {
        return this.write(bw, this.curpos);
    }

    public boolean append(byte bw) throws IOException {
        return this.write(bw, this.fileendpos + 1);
    }

    public boolean write(byte bw, long pos) throws IOException {

        if ((pos >= this.bufstartpos) && (pos <= this.bufendpos)) { // write pos in buf
            this.buf[(int)(pos - this.bufstartpos)] = bw;
            this.bufdirty = true;

            if (pos == this.fileendpos + 1) { // write pos is append pos
                this.fileendpos++;
                this.bufusedsize++;
            }
        } else { // write pos not in buf
            this.seek(pos);

            if ((pos >= 0) && (pos <= this.fileendpos) && (this.fileendpos != 0)) { // write pos is modify file
                this.buf[(int)(pos - this.bufstartpos)] = bw;

            } else if (((pos == 0) && (this.fileendpos == 0)) || (pos == this.fileendpos + 1)) { // write pos is append pos
                this.buf[0] = bw;
                this.fileendpos++;
                this.bufusedsize = 1;
            } else {
                throw new IndexOutOfBoundsException();
            }
            this.bufdirty = true;
        }
        this.curpos = pos;
        return true;
    }

    public void write(byte b[], int off, int len) throws IOException {

        long writeendpos = this.curpos + len - 1;

        if (writeendpos <= this.bufendpos) { // b[] in cur buf
            System.arraycopy(b, off, this.buf, (int)(this.curpos - this.bufstartpos), len);
            this.bufdirty = true;
            this.bufusedsize = (int)(writeendpos - this.bufstartpos + 1);//(int)(this.curpos - this.bufstartpos + len - 1);

        } else { // b[] not in cur buf
            super.seek(this.curpos);
            super.write(b, off, len);
        }

        if (writeendpos > this.fileendpos)
            this.fileendpos = writeendpos;

        this.seek(writeendpos+1);
    }

    public int read(byte b[], int off, int len) throws IOException {

        long readendpos = this.curpos + len - 1;

        if (readendpos <= this.bufendpos && readendpos <= this.fileendpos ) { // read in buf
            System.arraycopy(this.buf, (int)(this.curpos - this.bufstartpos), b, off, len);
        } else { // read b[] size > buf[]

            if (readendpos > this.fileendpos) { // read b[] part in file
                len = (int)(this.length() - this.curpos + 1);
            }

            super.seek(this.curpos);
            len = super.read(b, off, len);
            readendpos = this.curpos + len - 1;
        }
        this.seek(readendpos + 1);
        return len;
    }

    public void write(byte b[]) throws IOException {
        this.write(b, 0, b.length);
    }

    public int read(byte b[]) throws IOException {
        return this.read(b, 0, b.length);
    }

    public void seek(long pos) throws IOException {

        if ((pos < this.bufstartpos) || (pos > this.bufendpos)) { // seek pos not in buf
            this.flushbuf();

            if ((pos >= 0) && (pos <= this.fileendpos) && (this.fileendpos != 0)) { // seek pos in file (file length > 0)
                this.bufstartpos =  pos & this.bufmask;
                this.bufusedsize = this.fillbuf();

            } else if (((pos == 0) && (this.fileendpos == 0)) || (pos == this.fileendpos + 1)) { // seek pos is append pos

                this.bufstartpos = pos;
                this.bufusedsize = 0;
            }
            this.bufendpos = this.bufstartpos + this.bufsize - 1;
        }
        this.curpos = pos;
    }

    public long length() throws IOException {
        return this.max(this.fileendpos + 1, this.initfilelen);
    }

    public void setLength(long newLength) throws IOException {
        if (newLength > 0) {
            this.fileendpos = newLength - 1;
        } else {
            this.fileendpos = 0;
        }
        super.setLength(newLength);
    }
    public long getFilePointer() throws IOException {
        return this.curpos;
    }

    private long max(long a, long b) {
        if (a > b) return a;
        return b;
    }

    public void close() throws IOException {
        this.flushbuf();
        super.close();
    }

    public static void main(String[] args) throws IOException {
        long readfilelen = 0;
        BufferedRandomAccessFile brafReadFile, brafWriteFile;

        brafReadFile = new BufferedRandomAccessFile("C:\\WINNT\\Fonts\\STKAITI.TTF");
        readfilelen = brafReadFile.initfilelen;
        brafWriteFile = new BufferedRandomAccessFile(".\\STKAITI.001", "rw", 10);

        byte buf[] = new byte[1024];
        int readcount;

        long start = System.currentTimeMillis();

        while((readcount = brafReadFile.read(buf)) != -1) {
            brafWriteFile.write(buf, 0, readcount);
        }

        brafWriteFile.close();
        brafReadFile.close();

        System.out.println("BufferedRandomAccessFile Copy & Write File: "
                           + brafReadFile.filename
                           + "    FileSize: "
                           + java.lang.Integer.toString((int)readfilelen >> 1024)
                           + " (KB)    "
                           + "Spend: "
                           +(double)(System.currentTimeMillis()-start) / 1000
                           + "(s)");

        java.io.FileInputStream fdin = new java.io.FileInputStream("C:\\WINNT\\Fonts\\STKAITI.TTF");
        java.io.BufferedInputStream bis = new java.io.BufferedInputStream(fdin, 1024);
        java.io.DataInputStream dis = new java.io.DataInputStream(bis);

        java.io.FileOutputStream fdout = new java.io.FileOutputStream(".\\STKAITI.002");
        java.io.BufferedOutputStream bos = new java.io.BufferedOutputStream(fdout, 1024);
        java.io.DataOutputStream dos = new java.io.DataOutputStream(bos);

        start = System.currentTimeMillis();

        for (int i = 0; i < readfilelen; i++) {
            dos.write(dis.readByte());
        }

        dos.close();
        dis.close();

        System.out.println("DataBufferedios Copy & Write File: "
                           + brafReadFile.filename
                           + "    FileSize: "
                           + java.lang.Integer.toString((int)readfilelen >> 1024)
                           + " (KB)    "
                           + "Spend: "
                           + (double)(System.currentTimeMillis()-start) / 1000
                           + "(s)");
    }
}