ringbuf: add a generic ring-buffer data type

This commit is contained in:
Andrei Alexeyev 2024-04-20 13:34:45 +02:00
parent 34963e21a3
commit e3a4e9065e
No known key found for this signature in database
GPG key ID: 72D26128040B9690
3 changed files with 189 additions and 0 deletions

View file

@ -86,6 +86,7 @@ taisei_src = files(
'projectile.c',
'projectile_prototypes.c',
'random.c',
'ringbuf.c',
'stage.c',
'stagedraw.c',
'stageinfo.c',

59
src/ringbuf.c Normal file
View file

@ -0,0 +1,59 @@
/*
* This software is licensed under the terms of the MIT License.
* See COPYING for further information.
* ---
* Copyright (c) 2011-2019, Lukas Weber <laochailan@web.de>.
* Copyright (c) 2012-2019, Andrei Alexeyev <akari@taisei-project.org>.
*/
#include "taisei.h"
#include "ringbuf.h"
static void push_index(RingBuffer *rbuf, ringbuf_size_t *idx) {
++(*idx);
if(*idx == rbuf->capacity) {
*idx = 0;
}
}
ringbuf_size_t _ringbuf_prepare_push(RingBuffer *rbuf) {
ringbuf_size_t pidx = rbuf->head;
if(_ringbuf_is_full(rbuf)) {
push_index(rbuf, &rbuf->tail);
} else {
++rbuf->num_elements;
}
push_index(rbuf, &rbuf->head);
return pidx;
}
ringbuf_size_t _ringbuf_prepare_pop(RingBuffer *rbuf) {
ringbuf_size_t pidx = rbuf->tail;
if(_ringbuf_is_empty(rbuf)) {
return -1;
}
push_index(rbuf, &rbuf->tail);
--rbuf->num_elements;
return pidx;
}
ringbuf_size_t _ringbuf_prepare_peek(RingBuffer *rbuf, ringbuf_size_t ofs) {
if(ofs >= rbuf->num_elements || ofs < 0) {
return -1;
}
ringbuf_size_t pidx = rbuf->tail + ofs;
if(pidx >= rbuf->num_elements) {
pidx -= rbuf->num_elements;
}
return pidx;
}

129
src/ringbuf.h Normal file
View file

@ -0,0 +1,129 @@
/*
* This software is licensed under the terms of the MIT License.
* See COPYING for further information.
* ---
* Copyright (c) 2011-2019, Lukas Weber <laochailan@web.de>.
* Copyright (c) 2012-2019, Andrei Alexeyev <akari@taisei-project.org>.
*/
#pragma once
#include "taisei.h"
#include "util/compat.h"
#include "util/macrohax.h"
typedef int32_t ringbuf_size_t;
#define RING_BUFFER_BASE(elem_type) struct { \
elem_type *data; \
ringbuf_size_t head; \
ringbuf_size_t tail; \
ringbuf_size_t capacity; \
ringbuf_size_t num_elements; \
}
typedef RING_BUFFER_BASE(void) RingBuffer;
#define RING_BUFFER(elem_type) union { \
RING_BUFFER_BASE(elem_type); \
RingBuffer ring_buffer; \
}
#define RINGBUF_ASSERT_VALID(rbuf) do { \
static_assert( \
__builtin_types_compatible_p(RingBuffer, __typeof__((rbuf)->ring_buffer)), \
"x->ring_buffer must be of RingBuffer type"); \
static_assert( \
__builtin_offsetof(__typeof__(*(rbuf)), ring_buffer) == 0, \
"x->ring_buffer must be the first member in struct"); \
} while(0)
#define RBUF_ASSERT_CONSISTENT(rbuf) ({ \
RINGBUF_ASSERT_VALID(rbuf); \
auto _rbuf = rbuf; \
assert(_rbuf->data != NULL); \
assert(_rbuf->num_elements >= 0); \
assert(_rbuf->num_elements <= _rbuf->capacity); \
_rbuf; \
})
#define RINGBUF_CHECK_ELEMENT_TYPE(rbuf, elem) do { \
static_assert( \
__builtin_types_compatible_p(__typeof__(elem), __typeof__(*(rbuf)->data)), \
"Ring buffer element type mismatch" \
); \
} while(0)
#define RINGBUF_CAST_TO_BASE(rbuf) \
&RBUF_ASSERT_CONSISTENT(rbuf)->ring_buffer
#define RING_BUFFER_INIT(backbuffer, num_elements) \
{ .data = (backbuffer), .capacity = (num_elements), }
ringbuf_size_t _ringbuf_prepare_push(RingBuffer *rbuf) attr_nonnull_all attr_nodiscard;
ringbuf_size_t _ringbuf_prepare_pop(RingBuffer *rbuf) attr_nonnull_all attr_nodiscard;
ringbuf_size_t _ringbuf_prepare_peek(RingBuffer *rbuf, ringbuf_size_t ofs) attr_nonnull_all attr_nodiscard;
attr_nonnull_all
INLINE bool _ringbuf_is_full(RingBuffer *rbuf) {
return rbuf->num_elements == rbuf->capacity;
}
attr_nonnull_all
INLINE bool _ringbuf_is_empty(RingBuffer *rbuf) {
return rbuf->num_elements == 0;
}
#define ringbuf_is_full(rbuf) _ringbuf_is_full(RINGBUF_CAST_TO_BASE(rbuf))
#define ringbuf_is_empty(rbuf) _ringbuf_is_empty(RINGBUF_CAST_TO_BASE(rbuf))
#define ringbuf_push(rbuf, value) ({ \
auto _rbuf = RBUF_ASSERT_CONSISTENT(rbuf); \
RINGBUF_CHECK_ELEMENT_TYPE(_rbuf, value); \
auto _idx = _ringbuf_prepare_push(&_rbuf->ring_buffer); \
_rbuf->data[_idx] = value; \
})
#define ringbuf_pop(rbuf, default_value) ({ \
auto _rbuf = RBUF_ASSERT_CONSISTENT(rbuf); \
RINGBUF_CHECK_ELEMENT_TYPE(_rbuf, default_value); \
auto _return_value = default_value; \
auto _idx = _ringbuf_prepare_pop(&_rbuf->ring_buffer); \
if(_idx >= 0) _return_value = _rbuf->data[_idx]; \
_return_value; \
})
#define _ringbuf_peek_ptr(_rbuf, ofs) ({ \
typeof(_rbuf->data) _ptr = NULL; \
auto _idx = _ringbuf_prepare_peek(&_rbuf->ring_buffer, ofs); \
if(_idx >= 0) _ptr = _rbuf->data + _idx; \
_ptr; \
})
#define ringbuf_peek_ptr(rbuf, ofs) ({ \
auto _rbuf = RBUF_ASSERT_CONSISTENT(rbuf); \
_ringbuf_peek_ptr(_rbuf, ofs); \
})
#define _ringbuf_peek(_rbuf, ofs, default_value) ({ \
RINGBUF_CHECK_ELEMENT_TYPE(_rbuf, default_value); \
auto _ptr = _ringbuf_peek_ptr(_rbuf, ofs); \
auto _return_value = default_value; \
if(_ptr != NULL) _return_value = *_ptr; \
_return_value; \
})
#define ringbuf_peek(rbuf, ofs, default_value) ({ \
auto _rbuf = RBUF_ASSERT_CONSISTENT(rbuf); \
_ringbuf_peek(_rbuf, ofs, default_value); \
})
#define ringbuf_rpeek_ptr(rbuf, ofs) ({ \
auto _rbuf = RBUF_ASSERT_CONSISTENT(rbuf); \
_ringbuf_peek_ptr(_rbuf, _rbuf->num_elements - ((ofs) + 1)); \
})
#define ringbuf_rpeek(rbuf, ofs, default_value) ({ \
auto _rbuf = RBUF_ASSERT_CONSISTENT(rbuf); \
_ringbuf_peek(_rbuf, _rbuf->num_elements - ((ofs) + 1), default_value); \
})