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/*
circularbuffer.c:
Copyright (C) 2012 Victor Lazzarini
This file is part of Csound.
The Csound Library is free software; you can redistribute it
and/or modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
Csound 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with Csound; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include <csoundCore.h>
typedef struct _circular_buffer {
char *buffer;
int wp;
int rp;
int numelem;
int elemsize; /* in number of bytes */
} circular_buffer;
void *csoundCreateCircularBuffer(CSOUND *csound, int numelem, int elemsize){
circular_buffer *p;
if ((p = (circular_buffer *)
csound->Malloc(csound, sizeof(circular_buffer))) == NULL) {
return NULL;
}
p->numelem = numelem;
p->wp = p->rp = 0;
p->elemsize = elemsize;
if ((p->buffer = (char *) csound->Malloc(csound, numelem*elemsize)) == NULL) {
return NULL;
}
memset(p->buffer, 0, numelem*elemsize);
return (void *)p;
}
int checkspace(circular_buffer *p, int writeCheck){
int wp = p->wp, rp = p->rp, numelem = p->numelem;
if(writeCheck){
if (wp > rp) return rp - wp + numelem - 1;
else if (wp < rp) return rp - wp - 1;
else return numelem - 1;
}
else {
if (wp > rp) return wp - rp;
else if (wp < rp) return wp - rp + numelem;
else return 0;
}
}
int csoundReadCircularBuffer(CSOUND *csound, void *p, void *out, int items)
{
IGN(csound);
if (p == NULL) return 0;
{
int remaining;
int itemsread, numelem = ((circular_buffer *)p)->numelem;
int elemsize = ((circular_buffer *)p)->elemsize;
int i=0, rp = ((circular_buffer *)p)->rp;
char *buffer = ((circular_buffer *)p)->buffer;
if ((remaining = checkspace(p, 0)) == 0) {
return 0;
}
itemsread = items > remaining ? remaining : items;
for (i=0; i < itemsread; i++){
memcpy((char *) out + (i * elemsize),
&(buffer[elemsize * rp++]), elemsize);
if (rp == numelem) {
rp = 0;
}
}
#if defined(MSVC)
InterlockedExchange(&((circular_buffer *)p)->rp, rp);
#elif defined(HAVE_ATOMIC_BUILTIN)
__atomic_exchange_n(&((circular_buffer *)p)->rp,rp, __ATOMIC_SEQ_CST);
#else
((circular_buffer *)p)->rp = rp;
#endif
return itemsread;
}
}
int csoundPeekCircularBuffer(CSOUND *csound, void *p, void *out, int items)
{
IGN(csound);
if (p == NULL) return 0;
int remaining;
int itemsread, numelem = ((circular_buffer *)p)->numelem;
int elemsize = ((circular_buffer *)p)->elemsize;
int i=0, rp = ((circular_buffer *)p)->rp;
char *buffer = ((circular_buffer *)p)->buffer;
if ((remaining = checkspace(p, 0)) == 0) {
return 0;
}
itemsread = items > remaining ? remaining : items;
for(i=0; i < itemsread; i++){
memcpy((char *) out + (i * elemsize),
&(buffer[elemsize * rp++]), elemsize);
if (rp == numelem) {
rp = 0;
}
}
return itemsread;
}
void csoundFlushCircularBuffer(CSOUND *csound, void *p)
{
IGN(csound);
if (p == NULL) return;
int remaining;
int itemsread, numelem = ((circular_buffer *)p)->numelem;
int i=0, rp = ((circular_buffer *)p)->rp;
//MYFLT *buffer = ((circular_buffer *)p)->buffer;
if ((remaining = checkspace(p, 0)) == 0) {
return;
}
itemsread = numelem > remaining ? remaining: numelem;
for (i=0; i < itemsread; i++){
rp++;
if(rp == numelem) rp = 0;
}
#if defined(MSVC)
InterlockedExchange(&((circular_buffer *)p)->rp, rp);
#elif defined(HAVE_ATOMIC_BUILTIN)
__atomic_store_n(&((circular_buffer *)p)->rp,rp, __ATOMIC_SEQ_CST);
#else
((circular_buffer *)p)->rp = rp;
#endif
}
int csoundWriteCircularBuffer(CSOUND *csound, void *p, const void *in, int items)
{
IGN(csound);
if (p == NULL) return 0;
int remaining;
int itemswrite, numelem = ((circular_buffer *)p)->numelem;
int elemsize = ((circular_buffer *)p)->elemsize;
int i=0, wp = ((circular_buffer *)p)->wp;
char *buffer = ((circular_buffer *)p)->buffer;
if ((remaining = checkspace(p, 1)) == 0) {
return 0;
}
itemswrite = items > remaining ? remaining : items;
for(i=0; i < itemswrite; i++){
memcpy(&(buffer[elemsize * wp++]),
((char *) in) + (i * elemsize), elemsize);
if(wp == numelem) wp = 0;
}
#if defined(MSVC)
InterlockedExchange(&((circular_buffer *)p)->wp, wp);
#elif defined(HAVE_ATOMIC_BUILTIN)
__atomic_store_n(&((circular_buffer *)p)->wp,wp, __ATOMIC_SEQ_CST);
#else
((circular_buffer *)p)->wp = wp;
#endif
return itemswrite;
}
void csoundDestroyCircularBuffer(CSOUND *csound, void *p){
if(p == NULL) return;
csound->Free(csound, ((circular_buffer *)p)->buffer);
csound->Free(csound, p);
}
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