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/*
* Squeezelite - lightweight headless squeezebox emulator
*
* (c) Adrian Smith 2012-2015, triode1@btinternet.com
* Ralph Irving 2015-2021, ralph_irving@hotmail.com
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
// fifo bufffers
#define _GNU_SOURCE
#include "squeezelite.h"
// _* called with muxtex locked
inline unsigned _buf_used(struct buffer *buf) {
return buf->writep >= buf->readp ? buf->writep - buf->readp : buf->size - (buf->readp - buf->writep);
}
unsigned _buf_space(struct buffer *buf) {
return buf->size - _buf_used(buf) - 1; // reduce by one as full same as empty otherwise
}
unsigned _buf_cont_read(struct buffer *buf) {
return buf->writep >= buf->readp ? buf->writep - buf->readp : buf->wrap - buf->readp;
}
unsigned _buf_cont_write(struct buffer *buf) {
return buf->writep >= buf->readp ? buf->wrap - buf->writep : buf->readp - buf->writep;
}
void _buf_inc_readp(struct buffer *buf, unsigned by) {
buf->readp += by;
if (buf->readp >= buf->wrap) {
buf->readp -= buf->size;
}
}
void _buf_inc_writep(struct buffer *buf, unsigned by) {
buf->writep += by;
if (buf->writep >= buf->wrap) {
buf->writep -= buf->size;
}
}
void buf_flush(struct buffer *buf) {
mutex_lock(buf->mutex);
buf->readp = buf->buf;
buf->writep = buf->buf;
mutex_unlock(buf->mutex);
}
// adjust buffer to multiple of mod bytes so reading in multiple always wraps on frame boundary
void buf_adjust(struct buffer *buf, size_t mod) {
size_t size;
mutex_lock(buf->mutex);
size = ((unsigned)(buf->base_size / mod)) * mod;
buf->readp = buf->buf;
buf->writep = buf->buf;
buf->wrap = buf->buf + size;
buf->size = size;
mutex_unlock(buf->mutex);
}
// called with mutex locked to resize, does not retain contents, reverts to original size if fails
void _buf_resize(struct buffer *buf, size_t size) {
free(buf->buf);
buf->buf = malloc(size);
if (!buf->buf) {
size = buf->size;
buf->buf= malloc(size);
if (!buf->buf) {
size = 0;
}
}
buf->readp = buf->buf;
buf->writep = buf->buf;
buf->wrap = buf->buf + size;
buf->size = size;
buf->base_size = size;
}
void _buf_unwrap(struct buffer *buf, size_t cont) {
ssize_t len, by = cont - (buf->wrap - buf->readp);
size_t size;
u8_t *scratch;
// do nothing if we have enough space
if (by <= 0 || cont >= buf->size) return;
// buffer already unwrapped, just move it up
if (buf->writep >= buf->readp) {
memmove(buf->readp - by, buf->readp, buf->writep - buf->readp);
buf->readp -= by;
buf->writep -= by;
return;
}
// how much is overlapping
size = by - (buf->readp - buf->writep);
len = buf->writep - buf->buf;
// buffer is wrapped and enough free space to move data up directly
if (size <= 0) {
memmove(buf->readp - by, buf->readp, buf->wrap - buf->readp);
buf->readp -= by;
memcpy(buf->wrap - by, buf->buf, min(len, by));
if (len > by) {
memmove(buf->buf, buf->buf + by, len - by);
buf->writep -= by;
} else buf->writep += buf->size - by;
return;
}
scratch = malloc(size);
// buffer is wrapped but not enough free room => use scratch zone
if (scratch) {
memcpy(scratch, buf->writep - size, size);
memmove(buf->readp - by, buf->readp, buf->wrap - buf->readp);
buf->readp -= by;
memcpy(buf->wrap - by, buf->buf, by);
memmove(buf->buf, buf->buf + by, len - by - size);
buf->writep -= by;
memcpy(buf->writep - size, scratch, size);
free(scratch);
} else {
_buf_unwrap(buf, cont / 2);
_buf_unwrap(buf, cont - cont / 2);
}
}
void buf_init(struct buffer *buf, size_t size) {
buf->buf = malloc(size);
buf->readp = buf->buf;
buf->writep = buf->buf;
buf->wrap = buf->buf + size;
buf->size = size;
buf->base_size = size;
mutex_create_p(buf->mutex);
}
void buf_destroy(struct buffer *buf) {
if (buf->buf) {
free(buf->buf);
buf->buf = NULL;
buf->size = 0;
buf->base_size = 0;
mutex_destroy(buf->mutex);
}
}
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