e85d191b46
- merge v0.01 --> Añadido fileselector - Añadidas fuentes de Gem y Pure Data - pix2jpg incluído en Gem. Archivos de construcción de Gem modificados. - Añadido fichero ompiling.txt con instrucciones de compilación
311 lines
9 KiB
C
Executable file
311 lines
9 KiB
C
Executable file
/* pmutil.c -- some helpful utilities for building midi
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applications that use PortMidi
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*/
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#include "stdlib.h"
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#include "assert.h"
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#include "memory.h"
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#include "portmidi.h"
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#include "pmutil.h"
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#include "pminternal.h"
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#ifdef WIN32
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#define bzero(addr, siz) memset(addr, 0, siz)
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#endif
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// #define QUEUE_DEBUG 1
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#ifdef QUEUE_DEBUG
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#include "stdio.h"
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#endif
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/* code is based on 4-byte words -- it should work on a 64-bit machine
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as long as a "long" has 4 bytes. This code could be generalized to
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be independent of the size of "long" */
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typedef long int32;
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typedef struct {
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long head;
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long tail;
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long len;
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long msg_size; /* number of int32 in a message including extra word */
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long overflow;
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long peek_overflow;
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int32 *buffer;
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int32 *peek;
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int peek_flag;
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} PmQueueRep;
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PmQueue *Pm_QueueCreate(long num_msgs, long bytes_per_msg)
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{
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PmQueueRep *queue = (PmQueueRep *) pm_alloc(sizeof(PmQueueRep));
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int int32s_per_msg = ((bytes_per_msg + sizeof(int32) - 1) &
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~(sizeof(int32) - 1)) / sizeof(int32);
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/* arg checking */
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if (!queue)
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return NULL;
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/* need extra word per message for non-zero encoding */
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queue->len = num_msgs * (int32s_per_msg + 1);
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queue->buffer = (int32 *) pm_alloc(queue->len * sizeof(int32));
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bzero(queue->buffer, queue->len * sizeof(int32));
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if (!queue->buffer) {
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pm_free(queue);
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return NULL;
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} else { /* allocate the "peek" buffer */
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queue->peek = (int32 *) pm_alloc(int32s_per_msg * sizeof(int32));
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if (!queue->peek) {
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/* free everything allocated so far and return */
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pm_free(queue->buffer);
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pm_free(queue);
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return NULL;
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}
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}
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bzero(queue->buffer, queue->len * sizeof(int32));
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queue->head = 0;
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queue->tail = 0;
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/* msg_size is in words */
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queue->msg_size = int32s_per_msg + 1; /* note extra word is counted */
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queue->overflow = FALSE;
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queue->peek_overflow = FALSE;
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queue->peek_flag = FALSE;
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return queue;
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}
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PmError Pm_QueueDestroy(PmQueue *q)
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{
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PmQueueRep *queue = (PmQueueRep *) q;
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/* arg checking */
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if (!queue || !queue->buffer || !queue->peek)
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return pmBadPtr;
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pm_free(queue->peek);
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pm_free(queue->buffer);
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pm_free(queue);
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return pmNoError;
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}
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PmError Pm_Dequeue(PmQueue *q, void *msg)
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{
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long head;
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PmQueueRep *queue = (PmQueueRep *) q;
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int i;
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int32 *msg_as_int32 = (int32 *) msg;
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/* arg checking */
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if (!queue)
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return pmBadPtr;
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/* a previous peek operation encountered an overflow, but the overflow
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* has not yet been reported to client, so do it now. No message is
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* returned, but on the next call, we will return the peek buffer.
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*/
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if (queue->peek_overflow) {
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queue->peek_overflow = FALSE;
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return pmBufferOverflow;
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}
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if (queue->peek_flag) {
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#ifdef QUEUE_DEBUG
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printf("Pm_Dequeue returns peek msg:");
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for (i = 0; i < queue->msg_size - 1; i++) {
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printf(" %d", queue->peek[i]);
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}
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printf("\n");
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#endif
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memcpy(msg, queue->peek, (queue->msg_size - 1) * sizeof(int32));
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queue->peek_flag = FALSE;
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return 1;
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}
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head = queue->head;
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/* if writer overflows, it writes queue->overflow = tail+1 so that
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* when the reader gets to that position in the buffer, it can
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* return the overflow condition to the reader. The problem is that
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* at overflow, things have wrapped around, so tail == head, and the
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* reader will detect overflow immediately instead of waiting until
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* it reads everything in the buffer, wrapping around again to the
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* point where tail == head. So the condition also checks that
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* queue->buffer[head] is zero -- if so, then the buffer is now
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* empty, and we're at the point in the msg stream where overflow
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* occurred. It's time to signal overflow to the reader. If
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* queue->buffer[head] is non-zero, there's a message there and we
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* should read all the way around the buffer before signalling overflow.
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* There is a write-order dependency here, but to fail, the overflow
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* field would have to be written while an entire buffer full of
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* writes are still pending. I'm assuming out-of-order writes are
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* possible, but not that many.
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*/
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if (queue->overflow == head + 1 && !queue->buffer[head]) {
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queue->overflow = 0; /* non-overflow condition */
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return pmBufferOverflow;
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}
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/* test to see if there is data in the queue -- test from back
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* to front so if writer is simultaneously writing, we don't
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* waste time discovering the write is not finished
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*/
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for (i = queue->msg_size - 1; i >= 0; i--) {
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if (!queue->buffer[head + i]) {
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return 0;
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}
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}
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#ifdef QUEUE_DEBUG
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printf("Pm_Dequeue:");
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for (i = 0; i < queue->msg_size; i++) {
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printf(" %d", queue->buffer[head + i]);
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}
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printf("\n");
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#endif
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memcpy(msg, (char *) &queue->buffer[head + 1],
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sizeof(int32) * (queue->msg_size - 1));
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/* fix up zeros */
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i = queue->buffer[head];
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while (i < queue->msg_size) {
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int32 j;
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i--; /* msg does not have extra word so shift down */
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j = msg_as_int32[i];
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msg_as_int32[i] = 0;
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i = j;
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}
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/* signal that data has been removed by zeroing: */
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bzero((char *) &queue->buffer[head], sizeof(int32) * queue->msg_size);
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/* update head */
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head += queue->msg_size;
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if (head == queue->len) head = 0;
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queue->head = head;
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return 1; /* success */
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}
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PmError Pm_SetOverflow(PmQueue *q)
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{
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PmQueueRep *queue = (PmQueueRep *) q;
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long tail;
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/* no more enqueue until receiver acknowledges overflow */
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if (queue->overflow) return pmBufferOverflow;
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if (!queue)
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return pmBadPtr;
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tail = queue->tail;
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queue->overflow = tail + 1;
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return pmBufferOverflow;
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}
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PmError Pm_Enqueue(PmQueue *q, void *msg)
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{
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PmQueueRep *queue = (PmQueueRep *) q;
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long tail;
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int i;
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int32 *src = (int32 *) msg;
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int32 *ptr;
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int32 *dest;
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int rslt;
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/* no more enqueue until receiver acknowledges overflow */
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if (!queue) return pmBadPtr;
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if (queue->overflow) return pmBufferOverflow;
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rslt = Pm_QueueFull(q);
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/* already checked above: if (rslt == pmBadPtr) return rslt; */
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tail = queue->tail;
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if (rslt) {
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queue->overflow = tail + 1;
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return pmBufferOverflow;
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}
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/* queue is has room for message, and overflow flag is cleared */
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ptr = &queue->buffer[tail];
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dest = ptr + 1;
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for (i = 1; i < queue->msg_size; i++) {
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int32 j = src[i - 1];
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if (!j) {
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*ptr = i;
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ptr = dest;
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} else {
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*dest = j;
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}
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dest++;
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}
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*ptr = i;
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#ifdef QUEUE_DEBUG
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printf("Pm_Enqueue:");
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for (i = 0; i < queue->msg_size; i++) {
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printf(" %d", queue->buffer[tail + i]);
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}
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printf("\n");
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#endif
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tail += queue->msg_size;
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if (tail == queue->len) tail = 0;
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queue->tail = tail;
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return pmNoError;
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}
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int Pm_QueueEmpty(PmQueue *q)
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{
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PmQueueRep *queue = (PmQueueRep *) q;
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if (!queue) return TRUE;
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return (queue->buffer[queue->head] == 0);
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}
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int Pm_QueueFull(PmQueue *q)
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{
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PmQueueRep *queue = (PmQueueRep *) q;
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int tail;
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int i;
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/* arg checking */
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if (!queue)
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return pmBadPtr;
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tail = queue->tail;
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/* test to see if there is space in the queue */
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for (i = 0; i < queue->msg_size; i++) {
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if (queue->buffer[tail + i]) {
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return TRUE;
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}
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}
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return FALSE;
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}
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void *Pm_QueuePeek(PmQueue *q)
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{
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PmQueueRep *queue = (PmQueueRep *) q;
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PmError rslt;
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long temp;
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/* arg checking */
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if (!queue)
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return NULL;
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if (queue->peek_flag) {
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return queue->peek;
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}
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/* this is ugly: if peek_overflow is set, then Pm_Dequeue()
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* returns immediately with pmBufferOverflow, but here, we
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* want Pm_Dequeue() to really check for data. If data is
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* there, we can return it
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*/
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temp = queue->peek_overflow;
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queue->peek_overflow = FALSE;
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rslt = Pm_Dequeue(q, queue->peek);
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queue->peek_overflow = temp;
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if (rslt == 1) {
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queue->peek_flag = TRUE;
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return queue->peek;
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} else if (rslt == pmBufferOverflow) {
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/* when overflow is indicated, the queue is empty and the
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* first message that was dropped by Enqueue (signalling
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* pmBufferOverflow to its caller) would have been the next
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* message in the queue. Pm_QueuePeek will return NULL, but
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* remember that an overflow occurred. (see Pm_Dequeue)
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*/
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queue->peek_overflow = TRUE;
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}
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return NULL;
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}
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