Add Ring Buffer implementation

This commit is contained in:
Mathieu Maret 2021-05-26 00:32:25 +02:00
commit e4a531530e
4 changed files with 197 additions and 0 deletions

49
Makefile Normal file
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# Preproc options
# -MMD is used to generate .d files for user header dependencies (use -MD for system and user header instead)
CPPFLAGS = -MMD
# main compilation
CFLAGS ?= -Werror -Wall #$(shell pkg-config --cflags sdl)
# C++ flags
CXXFLAGS =
#Linker flags
LDFLAGS =
#Linker path
LDLIBS = #$(shell pkg-config --libs sdl)
ifneq ($(CROSS_COMPILE),)
CC :=$(CROSS_COMPILE)$(CC)
CXX :=$(CROSS_COMPILE)$(CXX)
LD :=$(CROSS_COMPILE)$(LD)
endif
bin = main
lib = libringbuffer.so
#Will be compiled with -fpic
lib_src = ringbuffer.c
lib_obj = $(lib_src:%.c=%.o)
lib_dep = $(lib_src:%.c=%.d)
sources = $(filter-out $(lib_src), $(wildcard *.c))
objects = $(sources:%.c=%.o)
depends = $(sources:%.c=%.d)
all: $(bin) $(lib)
$(bin): $(objects) $(lib)
$(lib): CFLAGS += -fpic
$(lib): $(lib_obj)
%.so:
$(LINK.c) -shared $^ $(LDLIBS) -o $@
.PHONY: clean
clean:
$(RM) $(bin) $(objects) $(depends) $(lib) $(lib_obj) $(lib_dep)
ifneq ($(MAKECMDGOALS),clean)
-include $(depends)
-include $(lib_dep)
endif

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main.c Normal file
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#include "ringbuffer.h"
#include <assert.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
ringbuffer_t inst = ringbuffer_create(4);
ringbuffer_debug(inst);
uint8_t item;
assert(ringbuffer_enqueue(inst, 1));
ringbuffer_debug(inst);
assert(ringbuffer_enqueue(inst, 2));
ringbuffer_debug(inst);
assert(ringbuffer_enqueue(inst, 3));
ringbuffer_debug(inst);
assert(ringbuffer_enqueue(inst, 4));
ringbuffer_debug(inst);
assert(ringbuffer_enqueue(inst, 5) == false);
ringbuffer_debug(inst);
assert(ringbuffer_dequeue(inst, &item));
assert(item == 1);
ringbuffer_debug(inst);
assert(ringbuffer_enqueue(inst, 5));
ringbuffer_debug(inst);
assert(ringbuffer_dequeue(inst, &item));
assert(item == 2);
ringbuffer_debug(inst);
assert(ringbuffer_dequeue(inst, &item));
assert(item == 3);
ringbuffer_debug(inst);
assert(ringbuffer_dequeue(inst, &item));
assert(item == 4);
ringbuffer_debug(inst);
assert(ringbuffer_dequeue(inst, &item));
assert(item == 5);
ringbuffer_debug(inst);
assert(ringbuffer_dequeue(inst, &item) == false);
ringbuffer_debug(inst);
return 0;
}

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ringbuffer.c Normal file
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#include "ringbuffer.h"
#include <stdio.h>
#include <stdlib.h>
struct ringbuffer_instance_t {
int32_t wr_pos;
int32_t rd_pos;
uint8_t *data;
uint32_t capacity;
bool full;
};
ringbuffer_t ringbuffer_create(uint32_t capacity)
{
ringbuffer_t inst = calloc(1, sizeof(struct ringbuffer_instance_t));
inst->data = calloc(capacity, sizeof(uint8_t));
inst->capacity = capacity;
inst->wr_pos = 0;
inst->rd_pos = 0;
inst->full = capacity == 0;
return inst;
}
uint32_t ringbuffer_capacity(ringbuffer_t instance)
{
return instance->capacity;
}
uint32_t ringbuffer_used(ringbuffer_t instance)
{
if (instance->full)
return instance->capacity;
return (instance->wr_pos - instance->rd_pos) % instance->capacity;
}
bool ringbuffer_empty(ringbuffer_t instance)
{
return (!instance->full && (instance->wr_pos == instance->rd_pos));
}
bool ringbuffer_full(ringbuffer_t instance)
{
return instance->full;
}
bool ringbuffer_enqueue(ringbuffer_t instance, uint8_t item)
{
if (ringbuffer_full(instance))
return false;
instance->data[instance->wr_pos] = item;
instance->wr_pos = (instance->wr_pos + 1) % instance->capacity;
if (instance->rd_pos == instance->wr_pos)
instance->full = true;
return true;
}
bool ringbuffer_dequeue(ringbuffer_t instance, uint8_t *item)
{
if (ringbuffer_empty(instance))
return false;
instance->full = false;
*item = instance->data[instance->rd_pos];
instance->rd_pos = (instance->rd_pos + 1) % instance->capacity;
return true;
}
void ringbuffer_destroy(ringbuffer_t instance)
{
if (instance) {
if (instance->data) {
free(instance->data);
}
free(instance);
}
}
void ringbuffer_debug(ringbuffer_t instance)
{
printf("%d/%d %d %d %s\n", ringbuffer_used(instance), ringbuffer_capacity(instance),
instance->wr_pos, instance->rd_pos, instance->full ? "(full)" : "");
}

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ringbuffer.h Normal file
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#pragma once
#include <stdint.h>
#include <stdbool.h>
typedef struct ringbuffer_instance_t* ringbuffer_t;
ringbuffer_t ringbuffer_create(uint32_t capacity);
uint32_t ringbuffer_capacity(ringbuffer_t instance);
uint32_t ringbuffer_used(ringbuffer_t instance);
bool ringbuffer_enqueue(ringbuffer_t instance, uint8_t item);
bool ringbuffer_dequeue(ringbuffer_t instance, uint8_t* item);
void ringbuffer_destroy(ringbuffer_t instance);
void ringbuffer_debug(ringbuffer_t instance);
bool ringbuffer_empty(ringbuffer_t instance);
bool ringbuffer_full(ringbuffer_t instance);