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/* aKode: ByteBuffer
Copyright (C) 2004 Allan Sandfeld Jensen <kde@carewolf.com>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Steet, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include <string.h>
#include "bytebuffer.h"
namespace aKode {
ByteBuffer::ByteBuffer(unsigned int len)
: length(len)
, readPos(0)
, writePos(0)
, flushed(false)
, released(false)
, closed(false)
{
pthread_cond_init(¬_empty, 0);
pthread_cond_init(¬_full, 0);
pthread_mutex_init(&mutex, 0);
buffer = new char[length];
}
ByteBuffer::~ByteBuffer() {
delete[] buffer;
}
int ByteBuffer::write(char* buf, unsigned int len, bool blocking)
{
pthread_mutex_lock(&mutex);
if (released) len = 0;
flushed = closed = false;
while (space() < len) {
if (blocking) {
pthread_cond_wait(¬_full, &mutex);
if (flushed || released) len = 0;
}
else
len = space();
}
unsigned int base = len, rem = 0;
if (writePos+len > length) {
base = length-writePos;
rem = len-base;
}
memcpy(buffer+writePos, buf, base);
memcpy(buffer, buf+base, rem);
writePos = (writePos+len) % length;
pthread_cond_signal(¬_empty);
pthread_mutex_unlock(&mutex);
return len;
}
int ByteBuffer::read(char* buf, unsigned int len, bool blocking)
{
pthread_mutex_lock(&mutex);
if (released) len = 0;
if (closed) blocking = false;
while (content() < len) {
if (blocking) {
pthread_cond_wait(¬_empty, &mutex);
if (released)
len = 0;
else if (closed)
len = content();
}
else
len = content();
}
unsigned int base = len, rem = 0;
if (readPos+len > length) {
base = length-readPos;
rem = len-base;
}
memcpy(buf, buffer+readPos, base);
memcpy(buf+base, buffer, rem);
readPos = (readPos+len) % length;
pthread_cond_signal(¬_full);
pthread_mutex_unlock(&mutex);
return len;
}
void ByteBuffer::close() {
pthread_mutex_lock(&mutex);
closed = true;
pthread_cond_signal(¬_empty);
pthread_mutex_unlock(&mutex);
}
bool ByteBuffer::eof() {
return empty() && closed;
}
bool ByteBuffer::empty() {
return (readPos == writePos);
}
bool ByteBuffer::full() {
return (readPos == (writePos+1) % length);
}
unsigned int ByteBuffer::content() {
unsigned int cn;
if (readPos <= writePos)
cn=writePos-readPos;
else
cn=writePos+length-readPos;
return cn;
}
unsigned int ByteBuffer::space() {
unsigned int sp = length - content() - 1;
return sp;
}
void ByteBuffer::reset() {
// We assume all processes have been released at this point
readPos = writePos = 0;
flushed = released = closed = false;
}
void ByteBuffer::flush() {
pthread_mutex_lock(&mutex);
readPos = writePos = 0;
flushed = true;
pthread_cond_signal(¬_full);
pthread_mutex_unlock(&mutex);
}
void ByteBuffer::release() {
pthread_mutex_lock(&mutex);
released = true;
pthread_cond_signal(¬_empty);
pthread_cond_signal(¬_full);
pthread_mutex_unlock(&mutex);
}
} // namespace
|
