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#include "stdafx.h"
#include "Pipe.h"
namespace storm {
Pipe::Pipe() {
init(1024 * 4);
}
Pipe::Pipe(Nat size) {
init(size);
}
void Pipe::init(Nat size) {
data = runtime::allocArray<Byte>(engine(), &byteArrayType, size);
readPos = 0;
filled = 0;
readClosed = false;
writeClosed = false;
lock = new (this) Lock();
waitRead = new (this) Event();
waitWrite = new (this) Event();
waitWrite->set();
waitRead->clear();
}
IStream *Pipe::input() {
return new (this) PipeIStream(this);
}
OStream *Pipe::output() {
return new (this) PipeOStream(this);
}
void Pipe::close() {
closeRead();
closeWrite();
}
void Pipe::closeRead() {
readClosed = true;
waitWrite->set();
}
void Pipe::closeWrite() {
writeClosed = true;
waitRead->set();
}
Bool Pipe::more() {
Lock::Guard z(lock);
return !writeClosed;
}
void Pipe::read(Buffer to) {
readCommon(to, true);
}
void Pipe::peek(Buffer to) {
readCommon(to, false);
}
void Pipe::readCommon(Buffer to, Bool updatePos) {
while (true) {
// Wait until we can read...
waitRead->wait();
Lock::Guard z(lock);
// Spurious wakeup or closed?
if (filled <= 0) {
if (writeClosed)
return;
// Make sure we wait.
waitRead->clear();
continue;
}
Nat toRead = min(to.free(), filled);
if (readPos + toRead > data->count) {
// Need two memcpy.
Nat first = Nat(data->count) - readPos;
memcpy(to.dataPtr() + to.filled(), data->v + readPos, first);
memcpy(to.dataPtr() + to.filled() + first, data->v, toRead - first);
} else {
// One is enough.
memcpy(to.dataPtr() + to.filled(), data->v + readPos, toRead);
}
to.filled(to.filled() + toRead);
if (updatePos) {
filled -= toRead;
readPos += toRead;
if (readPos >= data->count)
readPos -= Nat(data->count);
// Now we can write more data!
waitWrite->set();
// Maybe we can't read anymore.
if (filled == 0)
waitRead->clear();
}
// Done!
return;
}
}
Nat Pipe::write(Buffer from, Nat start) {
Nat consumed = 0;
while (from.filled() > start) {
waitWrite->wait();
Lock::Guard z(lock);
// If the read end is closed, just stop writing.
if (readClosed)
return consumed;
// Any room to write? If not, wait a bit more. It could be a spurious wakeup.
if (filled >= data->count) {
// Make sure we wait.
waitWrite->clear();
continue;
}
Nat toWrite = min(Nat(data->count) - filled, from.filled() - start);
Nat tail = readPos + filled;
if (tail >= data->count)
tail -= Nat(data->count);
// Take wrapping into account.
toWrite = min(Nat(data->count) - tail, toWrite);
memcpy(data->v + tail, from.dataPtr() + start, toWrite);
filled += toWrite;
start += toWrite;
consumed += toWrite;
// Update our state:
if (filled >= data->count)
waitWrite->clear();
// It is possible to read now, we put data there.
waitRead->set();
}
return consumed;
}
}
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