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/*
* Pure Data Packet system implementation:
* code for allocation/deallocation/copying/...
* Copyright (c) by Tom Schouten <pdp@zzz.kotnet.org>
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include "pdp.h"
#include <stdio.h>
/* all symbols are C style */
#ifdef __cplusplus
extern "C"
{
#endif
/* this needs to be able to grow dynamically, think about it later */
#define PDP_OBJECT_ARRAY_SIZE 1024
static t_pdp* pdp_stack[PDP_OBJECT_ARRAY_SIZE];
/* some global vars */
static t_symbol* pdp_sym_register_rw;
static t_symbol* pdp_sym_register_ro;
static t_symbol* pdp_sym_process;
/* setup methods */
void
pdp_packet_setup(void)
{
bzero(pdp_stack, PDP_OBJECT_ARRAY_SIZE * sizeof(t_pdp *));
pdp_sym_register_rw = gensym("register_rw");
pdp_sym_register_ro = gensym("register_ro");
pdp_sym_process = gensym("process");
}
void
pdp_packet_destroy(void)
{
int i = 0;
/* dealloc all the data in object stack */
while ((i < PDP_OBJECT_ARRAY_SIZE) && (pdp_stack[i])) free(pdp_stack[i++]);
}
/* private pdp_mem methods */
/* public object manips */
/* alloc method: alloc time is linear in the number of used packets */
/* think about a better (tree) method when this number grows large */
int
pdp_packet_new(unsigned int datatype, unsigned int datasize /*without header*/)
{
unsigned int totalsize = datasize + PDP_HEADER_SIZE;
int i = 0;
unsigned int align;
t_pdp* p;
for (i=0; i < PDP_OBJECT_ARRAY_SIZE; i++){
p = pdp_stack[i];
/* check if we can reuse this one if it is already allocated */
if (p) {
/* remark: if p->size >= totalsize we can give away the packet */
/* but that would lead to unefficient use if we have a lot of packets */
/* of different sizes */
if ((p->users == 0) && (p->size == totalsize)){
//post("pdp_new_object: can reuse %d", i);
memset(p, 0, PDP_HEADER_SIZE); //initialize header to 0
p->type = datatype;
p->size = totalsize;
p->users = 1;
return i;
}
else{
//post("pdp_new_object: can't reuse %d, (%d users)", i, p->users);
//post("size:%d, newsize:%d, type:%d, newtype:%d", p->size, totalsize, p->type, datatype);
}
}
/* allocate new one */
else {
p = (t_pdp *)malloc(totalsize);
align = ((unsigned int)p) & (PDP_ALIGN - 1);
if (align) post("pdp_new_object: warning data misaligned by %x", align);
pdp_stack[i] = p;
memset(p, 0, PDP_HEADER_SIZE); //initialize header to 0
p->type = datatype;
p->size = totalsize;
p->users = 1;
//post("pdp_new_object: allocating new (%d)", i);
return i;
}
}
post("pdp_new_object: WARNING: out of memory");
return -1;
}
t_pdp*
pdp_packet_header(int handle)
{
if ((handle >= 0) && (handle < PDP_OBJECT_ARRAY_SIZE)) return pdp_stack[handle];
else return 0;
}
void*
pdp_packet_data(int handle)
{
if ((handle >= 0) && (handle < PDP_OBJECT_ARRAY_SIZE))
return (char *)(pdp_stack[handle]) + PDP_HEADER_SIZE;
else return 0;
}
int
pdp_packet_copy_ro(int handle)
{
int out_handle;
t_pdp* p;
if ((handle >= 0)
&& (handle < PDP_OBJECT_ARRAY_SIZE)
&& (p = pdp_stack[handle])){
/* increase the number of users and return */
p->users++;
out_handle = handle;
}
else out_handle = -1;
//post("pdp_copy_ro: outhandle:%d", out_handle);
return out_handle;
}
int
pdp_packet_copy_rw(int handle)
{
int out_handle;
t_pdp* p;
if ((handle >= 0)
&& (handle < PDP_OBJECT_ARRAY_SIZE)
&& (p = pdp_stack[handle])){
/* if there are other users, copy the object otherwize return the same handle */
if (p->users){
int new_handle = pdp_packet_new(p->type, p->size - PDP_HEADER_SIZE);
t_pdp* new_p = pdp_packet_header(new_handle);
memcpy(new_p, p, p->size);
new_p->users = 1;
out_handle = new_handle;
}
else {
p->users++;
out_handle = handle;
}
//post("pdp_copy_rw: inhandle:%d outhandle:%d", handle, out_handle);
}
else out_handle = -1;
return out_handle;
}
int
pdp_packet_clone_rw(int handle)
{
int out_handle;
t_pdp* p;
if ((handle >= 0)
&& (handle < PDP_OBJECT_ARRAY_SIZE)
&& (p = pdp_stack[handle])){
/* clone the packet header, don't copy the data */
int new_handle = pdp_packet_new(p->type, p->size - PDP_HEADER_SIZE);
t_pdp* new_p = pdp_packet_header(new_handle);
memcpy(new_p, p, PDP_HEADER_SIZE);
new_p->users = 1;
out_handle = new_handle;
}
else out_handle = -1;
return out_handle;
}
void
pdp_packet_mark_unused(int handle)
{
t_pdp* p;
if ((handle >= 0) && (handle < PDP_OBJECT_ARRAY_SIZE)){
if (p = pdp_stack[handle]) {
if (p->users) {
p->users--;
//post("pdp_mark_unused: handle %d, users left %d", handle, p->users);
}
else {
post("pdp_mark_unused: WARNING: handle %d has zero users (duplicate pdp_mark_unused ?)", handle);
}
}
else {
post("pdp_mark_unused: WARNING: invalid handle %d: no associated object", handle);
}
}
else {
/* -1 is the only invalid handle that doesn't trigger a warning */
if (handle != -1) post("pdp_mark_unused: WARNING: invalid handle %d: out of bound", handle);
}
}
/* remark. if an owner frees a rw copy, he can still pass it along to clients.
the first copy instruction revives the object. maybe free should not be called free but unregister.
as long as no new_object method is called, or no copy on another object is performed,
the "undead" copy can be revived. this smells a bit, i know...*/
#ifdef __cplusplus
}
#endif
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