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/*
Copyright (C) 2003-2008 Andrey Nazarov
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "shared/shared.h"
#include "common/fifo.h"
#include "common/msg.h"
size_t FIFO_Read(fifo_t *fifo, void *buffer, size_t len)
{
size_t wrapped, head = fifo->ay - fifo->ax;
if (head > len) {
if (buffer) {
memcpy(buffer, fifo->data + fifo->ax, len);
fifo->ax += len;
}
return len;
}
wrapped = len - head;
if (wrapped > fifo->bs) {
wrapped = fifo->bs;
}
if (buffer) {
memcpy(buffer, fifo->data + fifo->ax, head);
memcpy((byte *)buffer + head, fifo->data, wrapped);
fifo->ax = wrapped;
fifo->ay = fifo->bs;
fifo->bs = 0;
}
return head + wrapped;
}
size_t FIFO_Write(fifo_t *fifo, const void *buffer, size_t len)
{
size_t tail, wrapped, remaining;
if (fifo->bs) {
remaining = fifo->ax - fifo->bs;
if (len > remaining) {
len = remaining;
}
if (buffer) {
memcpy(fifo->data + fifo->bs, buffer, len);
fifo->bs += len;
}
return len;
}
tail = fifo->size - fifo->ay;
if (tail > len) {
if (buffer) {
memcpy(fifo->data + fifo->ay, buffer, len);
fifo->ay += len;
}
return len;
}
wrapped = len - tail;
if (wrapped > fifo->ax) {
wrapped = fifo->ax;
}
if (buffer) {
memcpy(fifo->data + fifo->ay, buffer, tail);
memcpy(fifo->data, (byte *)buffer + tail, wrapped);
fifo->ay = fifo->size;
fifo->bs = wrapped;
}
return tail + wrapped;
}
qboolean FIFO_ReadMessage(fifo_t *fifo, size_t msglen)
{
size_t len;
byte *data;
data = FIFO_Peek(fifo, &len);
if (len < msglen) {
// read in two chunks into message buffer
if (!FIFO_TryRead(fifo, msg_read_buffer, msglen)) {
return qfalse; // not yet available
}
SZ_Init(&msg_read, msg_read_buffer, sizeof(msg_read_buffer));
} else {
// read in a single block without copying any memory
SZ_Init(&msg_read, data, msglen);
FIFO_Decommit(fifo, msglen);
}
msg_read.cursize = msglen;
return qtrue;
}
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