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1
10
11 package com.go.trove.io;
12
13 import java.io.*;
14
15
21
25 public class FastBufferedInputStream extends FilterInputStream {
26 private byte[] mBuffer;
29 private int mCount;
30 private int mPos;
31 private int mMarkPos = -1;
32 private int mMarkLimit;
33
34 private void ensureOpen() throws IOException {
35 if (in == null) {
36 throw new IOException("Stream closed");
37 }
38 }
39
40 public FastBufferedInputStream(InputStream in) {
41 this(in, 2048);
42 }
43
44 public FastBufferedInputStream(InputStream in, int size) {
45 super(in);
46 if (size <= 0) {
47 throw new IllegalArgumentException  ("Buffer size <= 0");
48 }
49 mBuffer = new byte[size];
50 }
51
52 private void fill() throws IOException {
53 if (mMarkPos < 0) {
54 mPos = 0;
55 }
56 else if (mPos >= mBuffer.length) {
57 if (mMarkPos > 0) {
58 int sz = mPos - mMarkPos;
59 System.arraycopy(mBuffer, mMarkPos, mBuffer, 0, sz);
60 mPos = sz;
61 mMarkPos = 0;
62 }
63 else if (mBuffer.length >= mMarkLimit) {
64 mMarkPos = -1;
65 mPos = 0;
66 }
67 else {
68 int nsz = mPos * 2;
69 if (nsz > mMarkLimit) {
70 nsz = mMarkLimit;
71 }
72 byte nbuf[] = new byte[nsz];
73 System.arraycopy(mBuffer, 0, nbuf, 0, mPos);
74 mBuffer = nbuf;
75 }
76 }
77 mCount = mPos;
78 int n = in.read(mBuffer, mPos, mBuffer.length - mPos);
79 if (n > 0) {
80 mCount = n + mPos;
81 }
82 }
83
84 public int read() throws IOException {
85 ensureOpen();
86 if (mPos >= mCount) {
87 fill();
88 if (mPos >= mCount) {
89 return -1;
90 }
91 }
92 return mBuffer[mPos++] & 0xff;
93 }
94
95 private int read1(byte[] b, int off, int len) throws IOException {
96 int avail = mCount - mPos;
97 if (avail <= 0) {
98 if (len >= mBuffer.length && mMarkPos < 0) {
99 return in.read(b, off, len);
100 }
101 fill();
102 avail = mCount - mPos;
103 if (avail <= 0) {
104 return -1;
105 }
106 }
107 int cnt = (avail < len) ? avail : len;
108 System.arraycopy(mBuffer, mPos, b, off, cnt);
109 mPos += cnt;
110 return cnt;
111 }
112
113 public int read(byte b[], int off, int len) throws IOException {
114 ensureOpen();
115 if ((off | len | (off + len) | (b.length - (off + len))) < 0) {
116 throw new IndexOutOfBoundsException ();
117 }
118 else if (len == 0) {
119 return 0;
120 }
121
122 int n = read1(b, off, len);
123 if (n <= 0) {
124 return n;
125 }
126 while ((n < len) && (in.available() > 0)) {
127 int n1 = read1(b, off + n, len - n);
128 if (n1 <= 0) {
129 break;
130 }
131 n += n1;
132 }
133 return n;
134 }
135
136 public long skip(long n) throws IOException {
137 ensureOpen();
138 if (n <= 0) {
139 return 0;
140 }
141 long avail = mCount - mPos;
142
143 if (avail <= 0) {
144 if (mMarkPos <0) {
145 return in.skip(n);
146 }
147
148 fill();
149 avail = mCount - mPos;
150 if (avail <= 0) {
151 return 0;
152 }
153 }
154
155 long skipped = (avail < n) ? avail : n;
156 mPos += skipped;
157 return skipped;
158 }
159
160 public int available() throws IOException {
161 ensureOpen();
162 return (mCount - mPos) + in.available();
163 }
164
165 public void mark(int readlimit) {
166 mMarkLimit = readlimit;
167 mMarkPos = mPos;
168 }
169
170 public void reset() throws IOException {
171 ensureOpen();
172 if (mMarkPos < 0) {
173 throw new IOException("Resetting to invalid mark");
174 }
175 mPos = mMarkPos;
176 }
177
178 public boolean markSupported() {
179 return true;
180 }
181
182 public void close() throws IOException {
183 if (in != null) {
184 in.close();
185 in = null;
186 mBuffer = null;
187 }
188 }
189 }
190 |
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