61 |
* |
* |
62 |
* @author Aaron M. Renn (arenn@urbanophile.com) |
* @author Aaron M. Renn (arenn@urbanophile.com) |
63 |
* @author Warren Levy <warrenl@cygnus.com> |
* @author Warren Levy <warrenl@cygnus.com> |
64 |
|
* @author Jeroen Frijters <jeroen@frijters.net> |
65 |
*/ |
*/ |
66 |
public class BufferedInputStream extends FilterInputStream |
public class BufferedInputStream extends FilterInputStream |
67 |
{ |
{ |
80 |
* The number of valid bytes currently in the buffer. It is also the index |
* The number of valid bytes currently in the buffer. It is also the index |
81 |
* of the buffer position one byte past the end of the valid data. |
* of the buffer position one byte past the end of the valid data. |
82 |
*/ |
*/ |
83 |
protected int count = 0; |
protected int count; |
84 |
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|
85 |
/** |
/** |
86 |
* The index of the next character that will by read from the buffer. |
* The index of the next character that will by read from the buffer. |
87 |
* When <code>pos == count</code>, the buffer is empty. |
* When <code>pos == count</code>, the buffer is empty. |
88 |
*/ |
*/ |
89 |
protected int pos = 0; |
protected int pos; |
90 |
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|
91 |
/** |
/** |
92 |
* The value of <code>pos</code> when the <code>mark()</code> method was |
* The value of <code>pos</code> when the <code>mark()</code> method was |
101 |
* After this may bytes are read, the <code>reset()</code> method |
* After this may bytes are read, the <code>reset()</code> method |
102 |
* may not be called successfully. |
* may not be called successfully. |
103 |
*/ |
*/ |
104 |
protected int marklimit = 0; |
protected int marklimit; |
105 |
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|
106 |
/** |
/** |
107 |
* This is the maximum size we have to allocate for the mark buffer. |
* This is the initial buffer size. When the buffer is grown because |
108 |
* This number may be huge (Integer.MAX_VALUE). The class will continue |
* of marking requirements, it will be grown by bufferSize increments. |
109 |
* to allocate new chunks (specified by <code>CHUNKSIZE</code>) until the |
* The underlying stream will be read in chunks of bufferSize. |
|
* the size specified by this field is achieved. |
|
110 |
*/ |
*/ |
111 |
private int marktarget = 0; |
private final int bufferSize; |
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|
|
|
/** |
|
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* This is the number of bytes to allocate to reach marktarget. |
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*/ |
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static final private int CHUNKSIZE = 1024; |
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112 |
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|
113 |
/** |
/** |
114 |
* This method initializes a new <code>BufferedInputStream</code> that will |
* This method initializes a new <code>BufferedInputStream</code> that will |
138 |
if (size <= 0) |
if (size <= 0) |
139 |
throw new IllegalArgumentException(); |
throw new IllegalArgumentException(); |
140 |
buf = new byte[size]; |
buf = new byte[size]; |
141 |
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// initialize pos & count to bufferSize, to prevent refill from |
142 |
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// allocating a new buffer (if the caller starts out by calling mark()). |
143 |
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pos = count = bufferSize = size; |
144 |
} |
} |
145 |
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|
146 |
/** |
/** |
171 |
{ |
{ |
172 |
// Free up the array memory. |
// Free up the array memory. |
173 |
buf = null; |
buf = null; |
174 |
|
pos = count = 0; |
175 |
|
markpos = -1; |
176 |
super.close(); |
super.close(); |
177 |
} |
} |
178 |
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|
196 |
*/ |
*/ |
197 |
public synchronized void mark(int readlimit) |
public synchronized void mark(int readlimit) |
198 |
{ |
{ |
199 |
marktarget = marklimit = readlimit; |
marklimit = readlimit; |
|
if (marklimit > CHUNKSIZE) |
|
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marklimit = CHUNKSIZE; |
|
200 |
markpos = pos; |
markpos = pos; |
201 |
} |
} |
202 |
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|
229 |
if (pos >= count && !refill()) |
if (pos >= count && !refill()) |
230 |
return -1; // EOF |
return -1; // EOF |
231 |
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|
232 |
if (markpos >= 0 && pos - markpos > marktarget) |
return buf[pos++] & 0xFF; |
|
markpos = -1; |
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|
|
|
|
return ((int) buf[pos++]) & 0xFF; |
|
233 |
} |
} |
234 |
|
|
235 |
/** |
/** |
236 |
* This method reads bytes from a stream and stores them into a caller |
* This method reads bytes from a stream and stores them into a caller |
237 |
* supplied buffer. It starts storing the data at index <code>off</code> |
* supplied buffer. It starts storing the data at index <code>off</code> |
238 |
* into the buffer and attempts to read <code>len</code> bytes. This method |
* into the buffer and attempts to read <code>len</code> bytes. This method |
239 |
* can return before reading the number of bytes requested. The actual |
* can return before reading the number of bytes requested, but it will try |
240 |
* number of bytes read is returned as an int. A -1 is returned to indicate |
* to read the requested number of bytes by repeatedly calling the underlying |
241 |
* the end of the stream. |
* stream as long as available() for this stream continues to return a |
242 |
|
* non-zero value (or until the requested number of bytes have been read). |
243 |
|
* The actual number of bytes read is returned as an int. A -1 is returned |
244 |
|
* to indicate the end of the stream. |
245 |
* <p> |
* <p> |
246 |
* This method will block until some data can be read. |
* This method will block until some data can be read. |
247 |
* |
* |
258 |
*/ |
*/ |
259 |
public synchronized int read(byte[] b, int off, int len) throws IOException |
public synchronized int read(byte[] b, int off, int len) throws IOException |
260 |
{ |
{ |
261 |
if (off < 0 || len < 0 || off + len > b.length) |
if (off < 0 || len < 0 || b.length - off < len) |
262 |
throw new IndexOutOfBoundsException(); |
throw new IndexOutOfBoundsException(); |
263 |
|
|
264 |
if (pos >= count && !refill()) |
if (pos >= count && !refill()) |
265 |
return -1; // No bytes were read before EOF. |
return -1; // No bytes were read before EOF. |
266 |
|
|
267 |
int remain = Math.min(count - pos, len); |
int totalBytesRead = Math.min(count - pos, len); |
268 |
System.arraycopy(buf, pos, b, off, remain); |
System.arraycopy(buf, pos, b, off, totalBytesRead); |
269 |
pos += remain; |
pos += totalBytesRead; |
270 |
|
off += totalBytesRead; |
271 |
|
len -= totalBytesRead; |
272 |
|
|
273 |
if (markpos >= 0 && pos - markpos > marktarget) |
while (len > 0 && super.available() > 0 && refill()) |
274 |
markpos = -1; |
{ |
275 |
|
int remain = Math.min(count - pos, len); |
276 |
|
System.arraycopy(buf, pos, b, off, remain); |
277 |
|
pos += remain; |
278 |
|
off += remain; |
279 |
|
len -= remain; |
280 |
|
totalBytesRead += remain; |
281 |
|
} |
282 |
|
|
283 |
return remain; |
return totalBytesRead; |
284 |
} |
} |
285 |
|
|
286 |
/** |
/** |
293 |
* passed when establishing the mark. |
* passed when establishing the mark. |
294 |
* |
* |
295 |
* @exception IOException If <code>mark()</code> was never called or more |
* @exception IOException If <code>mark()</code> was never called or more |
296 |
* then <code>markLimit</code> bytes were read since the last |
* then <code>marklimit</code> bytes were read since the last |
297 |
* call to <code>mark()</code> |
* call to <code>mark()</code> |
298 |
*/ |
*/ |
299 |
public synchronized void reset() throws IOException |
public synchronized void reset() throws IOException |
300 |
{ |
{ |
301 |
if (markpos < 0) |
if (markpos == -1) |
302 |
throw new IOException(); |
throw new IOException(buf == null ? "Stream closed." : "Invalid mark."); |
303 |
|
|
304 |
pos = markpos; |
pos = markpos; |
305 |
} |
} |
317 |
*/ |
*/ |
318 |
public synchronized long skip(long n) throws IOException |
public synchronized long skip(long n) throws IOException |
319 |
{ |
{ |
320 |
|
if (buf == null) |
321 |
|
throw new IOException("Stream closed."); |
322 |
|
|
323 |
final long origN = n; |
final long origN = n; |
324 |
|
|
325 |
while (n > 0L) |
while (n > 0L) |
333 |
int numread = (int) Math.min((long) (count - pos), n); |
int numread = (int) Math.min((long) (count - pos), n); |
334 |
pos += numread; |
pos += numread; |
335 |
n -= numread; |
n -= numread; |
|
|
|
|
if (markpos >= 0 && pos - markpos > marktarget) |
|
|
markpos = -1; |
|
336 |
} |
} |
337 |
|
|
338 |
return origN - n; |
return origN - n; |
339 |
} |
} |
340 |
|
|
341 |
/** |
/** |
342 |
* Called to refill the buffer (when count is equal or greater the pos). |
* Called to refill the buffer (when count is equal to pos). |
|
* Package local so BufferedReader can call it when needed. |
|
343 |
* |
* |
344 |
* @return <code>true</code> when <code>buf</code> can be (partly) refilled, |
* @return <code>true</code> when at least one additional byte was read |
345 |
* <code>false</code> otherwise. |
* into <code>buf</code>, <code>false</code> otherwise (at EOF). |
346 |
*/ |
*/ |
347 |
boolean refill() throws IOException |
private boolean refill() throws IOException |
348 |
{ |
{ |
349 |
if (markpos < 0) |
if (buf == null) |
350 |
count = pos = 0; |
throw new IOException("Stream closed."); |
351 |
else if (markpos > 0) |
|
352 |
|
if (markpos == -1 || count - markpos >= marklimit) |
353 |
{ |
{ |
354 |
// Shift the marked bytes (if any) to the beginning of the array |
markpos = -1; |
355 |
// but don't grow it. This saves space in case a reset is done |
pos = count = 0; |
|
// before we reach the max capacity of this array. |
|
|
System.arraycopy(buf, markpos, buf, 0, count - markpos); |
|
|
count -= markpos; |
|
|
pos -= markpos; |
|
|
markpos = 0; |
|
356 |
} |
} |
357 |
else if (marktarget >= buf.length && marklimit < marktarget) // BTW, markpos == 0 |
else |
358 |
{ |
{ |
359 |
// Need to grow the buffer now to have room for marklimit bytes. |
byte[] newbuf = buf; |
360 |
// Note that the new buffer is one greater than marklimit. |
if (markpos < bufferSize) |
361 |
// This is so that there will be one byte past marklimit to be read |
{ |
362 |
// before having to call refill again, thus allowing marklimit to be |
newbuf = new byte[count - markpos + bufferSize]; |
363 |
// invalidated. That way refill doesn't have to check marklimit. |
} |
364 |
marklimit += CHUNKSIZE; |
System.arraycopy(buf, markpos, newbuf, 0, count - markpos); |
|
if (marklimit >= marktarget) |
|
|
marklimit = marktarget; |
|
|
byte[] newbuf = new byte[marklimit + 1]; |
|
|
System.arraycopy(buf, 0, newbuf, 0, count); |
|
365 |
buf = newbuf; |
buf = newbuf; |
366 |
|
count -= markpos; |
367 |
|
pos -= markpos; |
368 |
|
markpos = 0; |
369 |
} |
} |
370 |
|
|
371 |
int numread = super.read(buf, count, buf.length - count); |
int numread = super.read(buf, count, bufferSize); |
372 |
|
|
373 |
if (numread < 0) // EOF |
if (numread <= 0) // EOF |
374 |
return false; |
return false; |
375 |
|
|
376 |
count += numread; |
count += numread; |
377 |
return true; |
return true; |