Author: sebb
Date: Sun Jul 11 14:24:19 2010
New Revision: 963079
URL: http://svn.apache.org/viewvc?rev=963079&view=rev
Log:
Document "magic" numbers -1 and -2
Modified:
commons/proper/net/branches/NET_2_0/src/main/java/org/apache/commons/net/telnet/TelnetInputStream.java
Modified:
commons/proper/net/branches/NET_2_0/src/main/java/org/apache/commons/net/telnet/TelnetInputStream.java
URL:
http://svn.apache.org/viewvc/commons/proper/net/branches/NET_2_0/src/main/java/org/apache/commons/net/telnet/TelnetInputStream.java?rev=963079&r1=963078&r2=963079&view=diff
==============================================================================
---
commons/proper/net/branches/NET_2_0/src/main/java/org/apache/commons/net/telnet/TelnetInputStream.java
(original)
+++
commons/proper/net/branches/NET_2_0/src/main/java/org/apache/commons/net/telnet/TelnetInputStream.java
Sun Jul 11 14:24:19 2010
@@ -35,6 +35,13 @@ import java.io.InterruptedIOException;
final class TelnetInputStream extends BufferedInputStream implements Runnable
{
+ /** End of file has been reached */
+ private static final int EOF = -1;
+
+ /** Read would block */
+ private static final int WOULD_BLOCK = -2;
+
+ // TODO should these be private enums?
static final int _STATE_DATA = 0, _STATE_IAC = 1, _STATE_WILL = 2,
_STATE_WONT = 3, _STATE_DO = 4, _STATE_DONT = 5,
_STATE_SB = 6, _STATE_SE = 7, _STATE_CR = 8,
_STATE_IAC_SB = 9;
@@ -106,6 +113,15 @@ final class TelnetInputStream extends Bu
// TelnetOutputStream writing through the telnet client at same time
// as a processDo/Will/etc. command invoked from TelnetInputStream
// tries to write.
+ /**
+ * Get the next byte of data.
+ * IAC commands are processed internally and do not return data.
+ *
+ * @param mayBlock true if method is allowed to block
+ * @return the next byte of data,
+ * or -1 (EOF) if end of stread reached,
+ * or -2 (WOULD_BLOCK) if mayBlock is false and there is no data available
+ */
private int __read(boolean mayBlock) throws IOException
{
int ch;
@@ -113,13 +129,13 @@ final class TelnetInputStream extends Bu
while (true)
{
- // If there is no more data AND we were told not to block, just
return -2. (More efficient than exception.)
+ // If there is no more data AND we were told not to block, just
return WOULD_BLOCK (-2). (More efficient than exception.)
if(!mayBlock && super.available() == 0)
- return -2;
+ return WOULD_BLOCK;
// Otherwise, exit only when we reach end of stream.
if ((ch = super.read()) < 0)
- return -1;
+ return EOF;
ch = (ch & 0xff);
@@ -341,9 +357,9 @@ final class TelnetInputStream extends Bu
if (__bytesAvailable == 0)
{
- // Return -1 if at end of file
+ // Return EOF if at end of file
if (__hasReachedEOF)
- return -1;
+ return EOF;
// Otherwise, we have to wait for queue to get something
if(__threaded)
@@ -371,9 +387,9 @@ final class TelnetInputStream extends Bu
{
try
{
- if ((ch = __read(mayBlock)) < 0)
- if(ch != -2)
- return (ch);
+ if ((ch = __read(mayBlock)) < 0) // EOF or
WOULD_BLOCK
+ if(ch != WOULD_BLOCK)
+ return (ch); // must be EOF
}
catch (InterruptedIOException e)
{
@@ -389,13 +405,13 @@ final class TelnetInputStream extends Bu
{
}
}
- return (-1);
+ return EOF;
}
try
{
- if(ch != -2)
+ if(ch != WOULD_BLOCK)
{
__processChar(ch);
}
@@ -403,7 +419,7 @@ final class TelnetInputStream extends Bu
catch (InterruptedException e)
{
if (__isClosed)
- return (-1);
+ return EOF;
}
// Reads should not block on subsequent
iterations. Potentially, this could happen if the
@@ -488,8 +504,8 @@ final class TelnetInputStream extends Bu
length = __bytesAvailable;
}
- if ((ch = read()) == -1)
- return -1;
+ if ((ch = read()) == EOF)
+ return EOF;
off = offset;
@@ -497,7 +513,7 @@ final class TelnetInputStream extends Bu
{
buffer[offset++] = (byte)ch;
}
- while (--length > 0 && (ch = read()) != -1);
+ while (--length > 0 && (ch = read()) != EOF);
//__client._spyRead(buffer, off, offset - off);
return (offset - off);
