// A simple (TCP) socket server and a buffered socket connection
// (C)2007 Simon Urbanek
// Dual-license: GPL v2 and AT&T Proprietary
//
// this implementation is based on regular unix sockets

#import "BufferedConnection.h"

@implementation BufferedConnection

- (id) initWithConnection: (id <Connection>) aConnection bufferSize: (NSUInteger) bufSize
{
	self = [super init];
	if (self != nil) {
		connection = [aConnection retain];
		nbs = bufSize;
		netbuf = (unsigned char*) malloc(nbs);
		nbp = nbl = 0;
	}
	return self;
}

- (void) dealloc
{
	[connection release];
	free(netbuf);
	[super dealloc];
}

- (void) setInputBufferSize: (NSUInteger) size
{
	if (size < nbs)
		return; /* FIXME: we don't allow reduction of the buffer size */	
	unsigned char *newbuf = realloc(netbuf, size);
	if (!newbuf) {
		// FIXME: we should throw an exception
		return;
	}
	netbuf = newbuf;
	nbs = size;
}

- (NSError*) lastError {
	return [connection lastError];
}
	
- (int) _readNext
{
	int n;
	if (nbp > 0) { /* consolidate buffer */
		if (nbp < nbl)
			memmove(netbuf, netbuf+nbp, nbl-nbp);
		nbl -= nbp;
		nbp = 0;
	}
	n = [connection read:netbuf+nbl maxLength:nbs-nbl-1]; /* leave the last byte for termination */
#ifdef TALK_DEBUG
	NSLog(@"BufferedConnection._readNext: n=%d", n);
#endif
	if (n < 1)
		return n;
	nbl += n;
	return n;
}

- (char *) _readLineCString
{
	int i;
#ifdef TALK_DEBUG
	NSLog(@"BufferedConnection._readLineCString: npb=%d, nbl=%d", nbp, nbl);
#endif
	if (nbp >= nbl) {
		int n = [self _readNext];
		if (n < 1) return 0;
	}
	while (1) {
		i = nbp;
		while (i < nbl) {
			if (netbuf[i] == '\n' || netbuf[i] == '\r') {
				unsigned char *r = netbuf+nbp;
				if (i+1 < nbl && ( /* take CRLF or LFCR as one */
								  (netbuf[i]=='\r' && netbuf[i+1]=='\n') ||
								  (netbuf[i]=='\n' && netbuf[i+1]=='\r'))) netbuf[i++]=0;
				netbuf[i] = 0;
				nbp = i+1;
				return (char*) r;
			}
			i++;
		}
		if (nbp == 0 && nbl >= nbs - 1) { /* used all buffer space */
			netbuf[nbl] = 0; /* terminate and return the truncated string */
			return (char*) netbuf;
		}
		{
			int n = [self _readNext];
			if (n < 1) return 0;
		}
	}
	return 0;
}

- (NSString *) readLine
{
	char *ln = [self _readLineCString];
	return ln?[NSString stringWithUTF8String: ln]:nil;
}

- (NSInteger) read: (unsigned char *) buf maxLength: (NSUInteger) maxLength;
{
	int length = maxLength;
	while (length > 0) {
		if (nbp < nbl) { /* if there is data in the buffer, use as much as possible */
			int nxt = (length < nbl-nbp) ? length : (nbl-nbp);
			memcpy(buf, netbuf+nbp, nxt);
			length -= nxt;
			buf += nxt;
			nbp += nxt;
			if (!length) break;
		}
		/* we land here if more is needed than what the buffer holds */
		nbl = nbp = 0;
		/* we do not need to use the buffer - especially good for large data */
		int n = [connection read: buf maxLength: length];
#if TALK_DEBUG
		NSLog(@"BufferedConnection read:maxLength:%d (length=%d) called read with result %d", maxLength, length, n);
#endif
		if (n > 0) {
			length -= n;
			buf += n;
		} else
			break;
	}
	return maxLength - length;
}

- (NSInteger) write: (const unsigned char*) buf maxLength: (NSUInteger) len
{
	return [connection write:buf maxLength: len];
}

- (BOOL) close
{
	return [connection close];
}

- (BOOL) hasBytesAvailable
{
	/* bytes in the buffer? answer right away */
	if (nbp < nbl) return YES;
	/* otherwise ask the connection */
	return [connection hasBytesAvailable];
}

@end