blob: 7b494a34367f9ff9bcc0d114752e1bd90d43b59f [file] [log] [blame]
/******************************************************************************
*
* Copyright (C) 2017 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
#include <assert.h>
#include <stdlib.h>
#include "ringbuffer.h"
struct ringbuffer_t {
size_t total;
size_t available;
uint8_t* base;
uint8_t* head;
uint8_t* tail;
};
ringbuffer_t* ringbuffer_init(const size_t size) {
if (size == 0) return nullptr;
ringbuffer_t* p = static_cast<ringbuffer_t*>(calloc(1, sizeof(ringbuffer_t)));
if (p == nullptr) return nullptr;
p->base = static_cast<uint8_t*>(calloc(size, sizeof(uint8_t)));
p->head = p->tail = p->base;
p->total = p->available = size;
return p;
}
void ringbuffer_free(ringbuffer_t* rb) {
if (rb != nullptr) free(rb->base);
free(rb);
}
size_t ringbuffer_available(const ringbuffer_t* rb) {
assert(rb);
return rb->available;
}
size_t ringbuffer_size(const ringbuffer_t* rb) {
assert(rb);
return rb->total - rb->available;
}
size_t ringbuffer_insert(ringbuffer_t* rb, const uint8_t* p, size_t length) {
assert(rb);
assert(p);
if (length > ringbuffer_available(rb)) length = ringbuffer_available(rb);
for (size_t i = 0; i != length; ++i) {
*rb->tail++ = *p++;
if (rb->tail >= (rb->base + rb->total)) rb->tail = rb->base;
}
rb->available -= length;
return length;
}
size_t ringbuffer_delete(ringbuffer_t* rb, size_t length) {
assert(rb);
if (length > ringbuffer_size(rb)) length = ringbuffer_size(rb);
rb->head += length;
if (rb->head >= (rb->base + rb->total)) rb->head -= rb->total;
rb->available += length;
return length;
}
size_t ringbuffer_peek(const ringbuffer_t* rb, off_t offset, uint8_t* p,
size_t length) {
assert(rb);
assert(p);
assert(offset >= 0);
assert((size_t)offset <= ringbuffer_size(rb));
uint8_t* b = ((rb->head - rb->base + offset) % rb->total) + rb->base;
const size_t bytes_to_copy = (offset + length > ringbuffer_size(rb))
? ringbuffer_size(rb) - offset
: length;
for (size_t copied = 0; copied < bytes_to_copy; ++copied) {
*p++ = *b++;
if (b >= (rb->base + rb->total)) b = rb->base;
}
return bytes_to_copy;
}
size_t ringbuffer_pop(ringbuffer_t* rb, uint8_t* p, size_t length) {
assert(rb);
assert(p);
const size_t copied = ringbuffer_peek(rb, 0, p, length);
rb->head += copied;
if (rb->head >= (rb->base + rb->total)) rb->head -= rb->total;
rb->available += copied;
return copied;
}