From 22532cdad44a343f219bcdf670ebe71aab0dbc17 Mon Sep 17 00:00:00 2001 From: Josef 'Jeff' Sipek Date: Thu, 29 Mar 2012 17:41:48 -0400 Subject: [PATCH] include: generic circular buffer code Signed-off-by: Josef 'Jeff' Sipek --- include/circbuf.h | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 include/circbuf.h diff --git a/include/circbuf.h b/include/circbuf.h new file mode 100644 index 0000000..e127186 --- /dev/null +++ b/include/circbuf.h @@ -0,0 +1,77 @@ +/* + * Copyright (c) 2012 Josef 'Jeff' Sipek + * + * 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. + */ + +#ifndef __CIRCBUF_H +#define __CIRCBUF_H + +struct circbuf { + u32 start; /* the oldest entry idx */ + u32 filled; /* the number of entries */ + u32 size; /* the size of each entry */ + u32 count; /* the max number of entries */ + u8 data[0]; +}; + +#define CIRCBUF(name, n, s) struct circbuf name; u8 __circbuf_##name[(n)*sizeof(s)] + +#define init_circbuf(c, t, n) __init_circbuf((c), sizeof(t), (n)) +static inline void __init_circbuf(struct circbuf *c, u32 size, u32 count) +{ + c->start = 0; + c->filled = 0; + c->size = size; + c->count = count; +} + +static inline void insert_circbuf(struct circbuf *c, void *data) +{ + u32 idx; + + if (c->filled == c->count) { + idx = c->start; + c->start = (c->start+1) % c->count; + } else { + idx = (c->start + c->filled) % c->count; + c->filled++; + } + + memcpy(c->data + (idx * c->size), data, c->size); +} + +static inline int remove_circbuf(struct circbuf *c, void *data) +{ + if (!c->filled) + return 0; + + memcpy(data, c->data + (c->start * c->size), c->size); + + c->start = (c->start+1) % c->count; + c->filled--; + return 1; +} + +static inline int pending_circbuf(struct circbuf *c) +{ + return c->filled != 0; +} + +#endif -- 2.11.4.GIT