queue.c

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#include "user_config.h"
 
#ifdef AVR
#include <stdlib.h>
#endif
 
#include "queue.h"
 
queue_t *queue_new(size_t size)
{
    queue_t *q = safecalloc( sizeof(queue_t),1);
    if(!q)
        return(NULL);
    q->buf = safecalloc(size+1,1);
    if(!q->buf)
    {
        safefree(q);
        return(NULL);
    }
    q->in = 0;
    q->out = 0;
    q->bytes = 0;
    q->size = size;
    q->flags = 0;
    return(q);
}
 
 
void queue_del(queue_t *q)
{
    if(!q)
        return;
    if(q->buf)
    {
        safefree(q->buf);
// This clear help prevents a freed pointer from being used by mistake
// can be removed in production
        q->buf = NULL;
        q->in = 0;
        q->out = 0;
        q->bytes = 0;
        q->size = 0;
        q->flags = 0;
    }
    safefree(q);
}
 
 
void queue_flush(queue_t *q)
{
    if(!q)
        return;
    q->in = 0;
    q->out = 0;
    q->bytes = 0;
    q->flags = 0;
}
 
 
size_t queue_used(queue_t *q)
{
    if(!q || !q->buf)
        return(0);
    return(q->bytes);
}
 
 
size_t queue_empty(queue_t *q)
{
    if(!q || !q->buf)
        return(1);
    if(!q->bytes)
        return(1);
    return(0);
}
 
 
size_t queue_space(queue_t *q)
{
    if(!q || !q->buf)
        return(0);
    return(q->size - q->bytes);
}
 
 
size_t queue_full(queue_t *q)
{
    if(!q || !q->buf)
        return(0);
    return(queue_space(q) ? 0 : 1);
}
 
 
size_t queue_push_buffer(queue_t *q, uint8_t *src, size_t size)
{
    size_t bytes = 0;
 
    if(!q || !q->buf)
        return(0);
 
    while(size && queue_space(q) )
    {
        if(q->in >= q->size)
            q->in = 0;
        q->buf[q->in++] = *src++;
        ++q->bytes;
        --size;
        ++bytes;
    }
    return(bytes);
}
 
 
size_t queue_pop_buffer(queue_t *q, uint8_t *dst, size_t size)
{
    size_t bytes = 0;
 
    if(!q || !q->buf)
        return(0);
 
    while(size && q->bytes)
    {
        *dst++ = q->buf[q->out++];
        if(q->out >= q->size)
            q->out = 0;
        --q->bytes;
        --size;
        ++bytes;
    }
    return(bytes);
}
 
 
int queue_pushc(queue_t *q, uint8_t c)
{
    if(!q || !q->buf)
        return(0);
 
    if(q->bytes >= q->size)
    {
        q->flags |= QUEUE_OVERRUN;
        return(0);
    }
    if(q->in >= q->size)
        q->in = 0;
 
    if(c == '\n')                                 // st EOL flasg when we see one
        q->flags |= QUEUE_EOL;
    q->buf[q->in++] = c;
    ++q->bytes;
    return(1);
}
 
 
int queue_popc(queue_t *q)
{
    uint8_t c;
    if(!q || !q->buf)
        return(0);
 
    if(q->bytes)
    {
        c = q->buf[q->out];
        if(c == '\n')                             // reset EOL flag after a read
            q->flags &= ~QUEUE_EOL;
        if(++q->out >= q->size)
            q->out = 0;
        q->bytes--;
        return(c);
    }
    return(0);
}