circuitpython/py/ringbuf.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2019 Jim Mussared
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <string.h>
#include "ringbuf.h"
int ringbuf_get16(ringbuf_t *r) {
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int v = ringbuf_peek16(r);
if (v == -1) {
return v;
}
r->iget += 2;
if (r->iget >= r->size) {
r->iget -= r->size;
}
return v;
}
int ringbuf_peek16(ringbuf_t *r) {
if (r->iget == r->iput) {
return -1;
}
uint32_t iget_a = r->iget + 1;
if (iget_a == r->size) {
iget_a = 0;
}
if (iget_a == r->iput) {
return -1;
}
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return (r->buf[r->iget] << 8) | (r->buf[iget_a]);
}
int ringbuf_put16(ringbuf_t *r, uint16_t v) {
uint32_t iput_a = r->iput + 1;
if (iput_a == r->size) {
iput_a = 0;
}
if (iput_a == r->iget) {
return -1;
}
uint32_t iput_b = iput_a + 1;
if (iput_b == r->size) {
iput_b = 0;
}
if (iput_b == r->iget) {
return -1;
}
r->buf[r->iput] = (v >> 8) & 0xff;
r->buf[iput_a] = v & 0xff;
r->iput = iput_b;
return 0;
}
// Returns:
// 0: Success
// -1: Not enough data available to complete read (try again later)
// -2: Requested read is larger than buffer - will never succeed
int ringbuf_get_bytes(ringbuf_t *r, uint8_t *data, size_t data_len) {
if (ringbuf_avail(r) < data_len) {
return (r->size <= data_len) ? -2 : -1;
}
uint32_t iget = r->iget;
uint32_t iget_a = (iget + data_len) % r->size;
uint8_t *datap = data;
if (iget_a < iget) {
// Copy part of the data from the space left at the end of the buffer
memcpy(datap, r->buf + iget, r->size - iget);
datap += (r->size - iget);
iget = 0;
}
memcpy(datap, r->buf + iget, iget_a - iget);
r->iget = iget_a;
return 0;
}
// Returns:
// 0: Success
// -1: Not enough free space available to complete write (try again later)
// -2: Requested write is larger than buffer - will never succeed
int ringbuf_put_bytes(ringbuf_t *r, const uint8_t *data, size_t data_len) {
if (ringbuf_free(r) < data_len) {
return (r->size <= data_len) ? -2 : -1;
}
uint32_t iput = r->iput;
uint32_t iput_a = (iput + data_len) % r->size;
const uint8_t *datap = data;
if (iput_a < iput) {
// Copy part of the data to the end of the buffer
memcpy(r->buf + iput, datap, r->size - iput);
datap += (r->size - iput);
iput = 0;
}
memcpy(r->buf + iput, datap, iput_a - iput);
r->iput = iput_a;
return 0;
}