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/*
*
* Copyright: SPDX-License-Identifier: LGPL-3.0-only
*
* Author: Timotej Šiškovič <timotejs@gmail.com>
*
*/
#include "ringbuffer.h"
#include "ringbuffer_internal.h"
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#define MIN(a,b) (((a)<(b))?(a):(b))
#define MAX(a,b) (((a)>(b))?(a):(b))
// this allows user to use their own
// custom memory allocation functions
#ifdef RBUF_CUSTOM_MALLOC
#include "ringbuffer_pal.h"
#else
#define crbuf_malloc(...) malloc(__VA_ARGS__)
#define crbuf_free(...) free(__VA_ARGS__)
#endif
rbuf_t rbuf_create(size_t size)
{
rbuf_t buffer = crbuf_malloc(sizeof(struct rbuf_t) + size);
if (!buffer)
return NULL;
memset(buffer, 0, sizeof(struct rbuf_t));
buffer->data = ((char*)buffer) + sizeof(struct rbuf_t);
buffer->head = buffer->data;
buffer->tail = buffer->data;
buffer->size = size;
buffer->end = buffer->data + size;
return buffer;
}
void rbuf_free(rbuf_t buffer)
{
crbuf_free(buffer);
}
void rbuf_flush(rbuf_t buffer)
{
buffer->head = buffer->data;
buffer->tail = buffer->data;
buffer->size_data = 0;
}
char *rbuf_get_linear_insert_range(rbuf_t buffer, size_t *bytes)
{
*bytes = 0;
if (buffer->head == buffer->tail && buffer->size_data)
return NULL;
*bytes = ((buffer->head >= buffer->tail) ? buffer->end : buffer->tail) - buffer->head;
return buffer->head;
}
char *rbuf_get_linear_read_range(rbuf_t buffer, size_t *bytes)
{
*bytes = 0;
if(buffer->head == buffer->tail && !buffer->size_data)
return NULL;
*bytes = ((buffer->tail >= buffer->head) ? buffer->end : buffer->head) - buffer->tail;
return buffer->tail;
}
int rbuf_bump_head(rbuf_t buffer, size_t bytes)
{
size_t free_bytes = rbuf_bytes_free(buffer);
if (bytes > free_bytes)
return 0;
int i = buffer->head - buffer->data;
buffer->head = &buffer->data[(i + bytes) % buffer->size];
buffer->size_data += bytes;
return 1;
}
int rbuf_bump_tail(rbuf_t buffer, size_t bytes)
{
if(!rbuf_bump_tail_noopt(buffer, bytes))
return 0;
// if tail catched up with head
// start writing buffer from beggining
// this is not necessary (rbuf must work well without it)
// but helps to optimize big writes as rbuf_get_linear_insert_range
// will return bigger continuous region
if(buffer->tail == buffer->head) {
assert(buffer->size_data == 0);
rbuf_flush(buffer);
}
return 1;
}
size_t rbuf_get_capacity(rbuf_t buffer)
{
return buffer->size;
}
size_t rbuf_bytes_available(rbuf_t buffer)
{
return buffer->size_data;
}
size_t rbuf_bytes_free(rbuf_t buffer)
{
return buffer->size - buffer->size_data;
}
size_t rbuf_push(rbuf_t buffer, const char *data, size_t len)
{
size_t to_cpy;
char *w_ptr = rbuf_get_linear_insert_range(buffer, &to_cpy);
if(!to_cpy)
return to_cpy;
to_cpy = MIN(to_cpy, len);
memcpy(w_ptr, data, to_cpy);
rbuf_bump_head(buffer, to_cpy);
if(to_cpy < len)
to_cpy += rbuf_push(buffer, &data[to_cpy], len - to_cpy);
return to_cpy;
}
size_t rbuf_pop(rbuf_t buffer, char *data, size_t len)
{
size_t to_cpy;
const char *r_ptr = rbuf_get_linear_read_range(buffer, &to_cpy);
if(!to_cpy)
return to_cpy;
to_cpy = MIN(to_cpy, len);
memcpy(data, r_ptr, to_cpy);
rbuf_bump_tail(buffer, to_cpy);
if(to_cpy < len)
to_cpy += rbuf_pop(buffer, &data[to_cpy], len - to_cpy);
return to_cpy;
}
static inline void rbuf_ptr_inc(rbuf_t buffer, const char **ptr)
{
(*ptr)++;
if(*ptr >= buffer->end)
*ptr = buffer->data;
}
int rbuf_memcmp(rbuf_t buffer, const char *haystack, const char *needle, size_t needle_bytes)
{
const char *end = needle + needle_bytes;
// as head==tail can mean 2 things here
if (haystack == buffer->head && buffer->size_data) {
if (*haystack != *needle)
return (*haystack - *needle);
rbuf_ptr_inc(buffer, &haystack);
needle++;
}
while (haystack != buffer->head && needle != end) {
if (*haystack != *needle)
return (*haystack - *needle);
rbuf_ptr_inc(buffer, &haystack);
needle++;
}
return 0;
}
int rbuf_memcmp_n(rbuf_t buffer, const char *to_cmp, size_t to_cmp_bytes)
{
return rbuf_memcmp(buffer, buffer->tail, to_cmp, to_cmp_bytes);
}
char *rbuf_find_bytes(rbuf_t buffer, const char *needle, size_t needle_bytes, int *found_idx)
{
const char *ptr = buffer->tail;
*found_idx = 0;
if (!rbuf_bytes_available(buffer))
return NULL;
if (buffer->head == buffer->tail && buffer->size_data) {
if(!rbuf_memcmp(buffer, ptr, needle, needle_bytes))
return (char *)ptr;
rbuf_ptr_inc(buffer, &ptr);
(*found_idx)++;
}
while (ptr != buffer->head)
{
if(!rbuf_memcmp(buffer, ptr, needle, needle_bytes))
return (char *)ptr;
rbuf_ptr_inc(buffer, &ptr);
(*found_idx)++;
}
return NULL;
}
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