143 lines
3.9 KiB
C
143 lines
3.9 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2016 Paul Sokolovsky
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* Copyright (c) 2019 Jim Mussared
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "ringbuf.h"
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bool ringbuf_init(ringbuf_t *r, uint8_t *buf, size_t size) {
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r->buf = buf;
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r->size = size;
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r->used = 0;
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r->next_read = 0;
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r->next_write = 0;
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return r->buf != NULL;
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}
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// Dynamic initialization. This should be accessible from a root pointer..
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bool ringbuf_alloc(ringbuf_t *r, size_t size) {
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bool result = ringbuf_init(r, gc_alloc(size, false), size);
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return result;
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}
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void ringbuf_deinit(ringbuf_t *r) {
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// Free buf by doing nothing and letting gc take care of it. If the VM has finished already,
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// this will be safe.
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r->buf = (uint8_t *)NULL;
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r->size = 0;
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ringbuf_clear(r);
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}
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size_t ringbuf_size(ringbuf_t *r) {
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return r->size;
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}
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// Return -1 if buffer is empty, else return byte fetched.
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int ringbuf_get(ringbuf_t *r) {
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if (r->used < 1) {
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return -1;
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}
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uint8_t v = r->buf[r->next_read];
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r->next_read++;
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if (r->next_read >= r->size) {
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r->next_read = 0;
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}
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r->used--;
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return v;
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}
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int ringbuf_get16(ringbuf_t *r) {
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if (r->used < 2) {
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return -1;
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}
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int high_byte = ringbuf_get(r);
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int low_byte = ringbuf_get(r);
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return (high_byte << 8) | low_byte;
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}
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// Return -1 if no room in buffer, else return 0.
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int ringbuf_put(ringbuf_t *r, uint8_t v) {
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if (r->used >= r->size) {
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return -1;
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}
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r->buf[r->next_write] = v;
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r->next_write++;
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if (r->next_write >= r->size) {
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r->next_write = 0;
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}
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r->used++;
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return 0;
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}
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int ringbuf_put16(ringbuf_t *r, uint16_t v) {
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if (r->size - r->used < 2) {
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return -1;
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}
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ringbuf_put(r, (v >> 8) & 0xff);
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ringbuf_put(r, v & 0xff);
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return 0;
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}
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void ringbuf_clear(ringbuf_t *r) {
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r->next_write = 0;
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r->next_read = 0;
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r->used = 0;
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}
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// Number of free slots that can be written.
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size_t ringbuf_num_empty(ringbuf_t *r) {
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return r->size - r->used;
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}
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// Number of bytes available to read.
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size_t ringbuf_num_filled(ringbuf_t *r) {
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return r->used;
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}
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// If the ring buffer fills up, not all bytes will be written.
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// Returns how many bytes were successfully written.
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size_t ringbuf_put_n(ringbuf_t *r, const uint8_t *buf, size_t bufsize) {
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for (size_t i = 0; i < bufsize; i++) {
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if (ringbuf_put(r, buf[i]) < 0) {
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// If ringbuf is full, give up and return how many bytes
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// we wrote so far.
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return i;
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}
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}
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return bufsize;
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}
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// Returns how many bytes were fetched.
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size_t ringbuf_get_n(ringbuf_t *r, uint8_t *buf, size_t bufsize) {
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for (size_t i = 0; i < bufsize; i++) {
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int b = ringbuf_get(r);
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if (b < 0) {
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return i;
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}
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buf[i] = b;
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}
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return bufsize;
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}
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