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/*
* shl - Dynamic Array
*
* Copyright (c) 2011-2012 David Herrmann <dh.herrmann@googlemail.com>
* Copyright (c) 2011 University of Tuebingen
*
* 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.
*/
/*
* A circular memory ring implementation
*/
#ifndef SHL_RING_H
#define SHL_RING_H
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#define SHL_RING_SIZE 512
struct shl_ring_entry {
struct shl_ring_entry *next;
size_t len;
char buf[];
};
struct shl_ring {
struct shl_ring_entry *first;
struct shl_ring_entry *last;
};
static inline int shl_ring_new(struct shl_ring **out)
{
struct shl_ring *ring;
if (!out)
return -EINVAL;
ring = malloc(sizeof(*ring));
if (!ring)
return -ENOMEM;
memset(ring, 0, sizeof(*ring));
*out = ring;
return 0;
}
static inline void shl_ring_free(struct shl_ring *ring)
{
struct shl_ring_entry *tmp;
if (!ring)
return;
while (ring->first) {
tmp = ring->first;
ring->first = tmp->next;
free(tmp);
}
free(ring);
}
static inline bool shl_ring_is_empty(struct shl_ring *ring)
{
if (!ring)
return true;
return ring->first == NULL;
}
static inline int shl_ring_write(struct shl_ring *ring, const char *val,
size_t len)
{
struct shl_ring_entry *ent;
size_t space, cp;
if (!ring || !val || !len)
return -EINVAL;
next:
ent = ring->last;
if (!ent || ent->len >= SHL_RING_SIZE) {
ent = malloc(sizeof(*ent) + SHL_RING_SIZE);
if (!ent)
return -ENOMEM;
ent->len = 0;
ent->next = NULL;
if (ring->last)
ring->last->next = ent;
else
ring->first = ent;
ring->last = ent;
}
space = SHL_RING_SIZE - ent->len;
if (len >= space)
cp = space;
else
cp = len;
memcpy(&ent->buf[ent->len], val, cp);
ent->len += cp;
val = &val[cp];
len -= cp;
if (len > 0)
goto next;
return 0;
}
static inline const char *shl_ring_peek(struct shl_ring *ring, size_t *len,
size_t offset)
{
struct shl_ring_entry *iter;
if (!ring || !ring->first || !len) {
if (len)
*len = 0;
return NULL;
}
iter = ring->first;
while (iter->len <= offset) {
if (!iter->next) {
*len = 0;
return NULL;
}
offset -= iter->len;
iter = iter->next;
}
*len = ring->first->len - offset;
return &ring->first->buf[offset];
}
static inline void shl_ring_drop(struct shl_ring *ring, size_t len)
{
struct shl_ring_entry *ent;
if (!ring || !len)
return;
next:
ent = ring->first;
if (!ent)
return;
if (len >= ent->len) {
len -= ent->len;
ring->first = ent->next;
free(ent);
if (!ring->first)
ring->last = NULL;
if (len)
goto next;
} else {
memmove(ent->buf, &ent->buf[len], ent->len - len);
ent->len -= len;
}
}
static inline void shl_ring_flush(struct shl_ring *ring)
{
struct shl_ring_entry *tmp;
if (!ring)
return;
while (ring->first) {
tmp = ring->first;
ring->first = tmp->next;
free(tmp);
}
ring->last = NULL;
}
#endif /* SHL_RING_H */
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