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#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include "memblockq.h"
struct memblock_list {
struct memblock_list *next;
struct memchunk chunk;
};
struct memblockq {
struct memblock_list *blocks, *blocks_tail;
unsigned n_blocks;
size_t total_length;
size_t maxlength;
size_t base;
size_t prebuf;
};
struct memblockq* memblockq_new(size_t maxlength, size_t base, size_t prebuf) {
struct memblockq* bq;
assert(maxlength && base);
bq = malloc(sizeof(struct memblockq));
assert(bq);
bq->blocks = bq->blocks_tail = 0;
bq->n_blocks = 0;
bq->total_length = 0;
bq->base = base;
bq->maxlength = ((maxlength+base-1)/base)*base;
bq->prebuf = prebuf == (size_t) -1 ? bq->maxlength/2 : prebuf;
if (bq->prebuf > bq->maxlength)
bq->prebuf = bq->maxlength;
assert(bq->maxlength >= base);
return bq;
}
void memblockq_free(struct memblockq* bq) {
struct memblock_list *l;
assert(bq);
while ((l = bq->blocks)) {
bq->blocks = l->next;
memblock_unref(l->chunk.memblock);
free(l);
}
free(bq);
}
void memblockq_push(struct memblockq* bq, struct memchunk *chunk, size_t delta) {
struct memblock_list *q;
assert(bq && chunk && chunk->memblock && chunk->length);
q = malloc(sizeof(struct memblock_list));
assert(q);
q->chunk = *chunk;
memblock_ref(q->chunk.memblock);
assert(q->chunk.index+q->chunk.length <= q->chunk.memblock->length);
q->next = NULL;
if (bq->blocks_tail)
bq->blocks_tail->next = q;
else
bq->blocks = q;
bq->blocks_tail = q;
bq->n_blocks++;
bq->total_length += chunk->length;
memblockq_shorten(bq, bq->maxlength);
}
int memblockq_peek(struct memblockq* bq, struct memchunk *chunk) {
assert(bq && chunk);
if (!bq->blocks || bq->total_length < bq->prebuf)
return -1;
bq->prebuf = 0;
*chunk = bq->blocks->chunk;
memblock_ref(chunk->memblock);
return 0;
}
int memblockq_pop(struct memblockq* bq, struct memchunk *chunk) {
struct memblock_list *q;
assert(bq && chunk);
if (!bq->blocks || bq->total_length < bq->prebuf)
return -1;
bq->prebuf = 0;
q = bq->blocks;
bq->blocks = bq->blocks->next;
*chunk = q->chunk;
bq->n_blocks--;
bq->total_length -= chunk->length;
free(q);
return 0;
}
void memblockq_drop(struct memblockq *bq, size_t length) {
assert(bq);
while (length > 0) {
size_t l = length;
assert(bq->blocks && bq->total_length >= length);
if (l > bq->blocks->chunk.length)
l = bq->blocks->chunk.length;
bq->blocks->chunk.index += l;
bq->blocks->chunk.length -= l;
bq->total_length -= l;
if (bq->blocks->chunk.length == 0) {
struct memblock_list *q;
q = bq->blocks;
bq->blocks = bq->blocks->next;
if (bq->blocks == NULL)
bq->blocks_tail = NULL;
memblock_unref(q->chunk.memblock);
free(q);
bq->n_blocks--;
}
length -= l;
}
}
void memblockq_shorten(struct memblockq *bq, size_t length) {
size_t l;
assert(bq);
if (bq->total_length <= length)
return;
fprintf(stderr, "Warning! memblockq_shorten()\n");
l = bq->total_length - length;
l /= bq->base;
l *= bq->base;
memblockq_drop(bq, l);
}
void memblockq_empty(struct memblockq *bq) {
assert(bq);
memblockq_shorten(bq, 0);
}
int memblockq_is_readable(struct memblockq *bq) {
assert(bq);
return bq->total_length >= bq->prebuf;
}
int memblockq_is_writable(struct memblockq *bq, size_t length) {
assert(bq);
assert(length <= bq->maxlength);
return bq->total_length + length <= bq->maxlength;
}
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