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#include "FIFO.h"
#include <AK/StdLibExtras.h>
//#define FIFO_DEBUG
Retained<FIFO> FIFO::create()
{
return adopt(*new FIFO);
}
FIFO::FIFO()
{
}
void FIFO::open(Direction direction)
{
if (direction == Reader) {
++m_readers;
#ifdef FIFO_DEBUG
kprintf("open reader (%u)\n", m_readers);
#endif
} else if (direction == Writer) {
++m_writers;
#ifdef FIFO_DEBUG
kprintf("open writer (%u)\n", m_writers);
#endif
}
}
void FIFO::close(Direction direction)
{
if (direction == Reader) {
#ifdef FIFO_DEBUG
kprintf("close reader (%u - 1)\n", m_readers);
#endif
ASSERT(m_readers);
--m_readers;
} else if (direction == Writer) {
#ifdef FIFO_DEBUG
kprintf("close writer (%u - 1)\n", m_writers);
#endif
ASSERT(m_writers);
--m_writers;
}
}
bool FIFO::can_read() const
{
return !m_buffer.is_empty() || !m_writers;
}
bool FIFO::can_write() const
{
return m_buffer.bytes_in_write_buffer() < 4096;
}
ssize_t FIFO::read(byte* buffer, ssize_t size)
{
if (!m_writers && m_buffer.is_empty())
return 0;
#ifdef FIFO_DEBUG
dbgprintf("fifo: read(%u)\n",size);
#endif
ssize_t nread = m_buffer.read(buffer, size);
#ifdef FIFO_DEBUG
dbgprintf(" -> read (%c) %u\n", buffer[0], nread);
#endif
return nread;
}
ssize_t FIFO::write(const byte* buffer, ssize_t size)
{
if (!m_readers)
return 0;
#ifdef FIFO_DEBUG
dbgprintf("fifo: write(%p, %u)\n", buffer, size);
#endif
return m_buffer.write(buffer, size);
}
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