1#include "circle-buffer.h"
  2
  3#include <stddef.h>	
  4#include <stdlib.h>
  5
  6void CircleBufferInit(struct CircleBuffer* buffer, unsigned capacity) {
  7	buffer->data = malloc(capacity);
  8	buffer->capacity = capacity;
  9	buffer->size = 0;
 10	buffer->readPtr = buffer->data;
 11	buffer->writePtr = buffer->data;
 12}
 13
 14void CircleBufferDeinit(struct CircleBuffer* buffer) {
 15	free(buffer->data);
 16	buffer->data = 0;
 17}
 18
 19unsigned CircleBufferSize(const struct CircleBuffer* buffer) {
 20	return buffer->size;
 21}
 22
 23int CircleBufferWrite8(struct CircleBuffer* buffer, int8_t value) {
 24	int8_t* data = buffer->writePtr;
 25	if (buffer->size + sizeof(int8_t) > buffer->capacity) {
 26		return 0;
 27	}
 28	*data = value;
 29	++data;
 30	size_t size = (int8_t*) data - (int8_t*) buffer->data;
 31	if (size < buffer->capacity) {
 32		buffer->writePtr = data;
 33	} else {
 34		buffer->writePtr = buffer->data;
 35	}
 36	buffer->size += sizeof(int8_t);
 37	return 1;
 38}
 39
 40int CircleBufferWrite32(struct CircleBuffer* buffer, int32_t value) {
 41	int32_t* data = buffer->writePtr;
 42	if (buffer->size + sizeof(int32_t) > buffer->capacity) {
 43		return 0;
 44	}
 45	*data = value;
 46	++data;
 47	size_t size = (int8_t*) data - (int8_t*) buffer->data;
 48	if (size < buffer->capacity) {
 49		buffer->writePtr = data;
 50	} else {
 51		buffer->writePtr = buffer->data;
 52	}
 53	buffer->size += sizeof(int32_t);
 54	return 1;
 55}
 56
 57int CircleBufferRead8(struct CircleBuffer* buffer, int8_t* value) {
 58	int8_t* data = buffer->readPtr;
 59	if (buffer->size < sizeof(int8_t)) {
 60		return 0;
 61	}
 62	*value = *data;
 63	++data;
 64	size_t size = (int8_t*) data - (int8_t*) buffer->data;
 65	if (size < buffer->capacity) {
 66		buffer->readPtr = data;
 67	} else {
 68		buffer->readPtr = buffer->data;
 69	}
 70	buffer->size -= sizeof(int8_t);
 71	return 1;
 72}
 73
 74int CircleBufferRead32(struct CircleBuffer* buffer, int32_t* value) {
 75	int32_t* data = buffer->readPtr;
 76	if (buffer->size < sizeof(int32_t)) {
 77		return 0;
 78	}
 79	*value = *data;
 80	++data;
 81	size_t size = (int8_t*) data - (int8_t*) buffer->data;
 82	if (size < buffer->capacity) {
 83		buffer->readPtr = data;
 84	} else {
 85		buffer->readPtr = buffer->data;
 86	}
 87	buffer->size -= sizeof(int32_t);
 88	return 1;
 89}
 90
 91int CircleBufferRead(struct CircleBuffer* buffer, void* output, size_t length) {
 92	int8_t* data = buffer->readPtr;
 93	if (buffer->size == 0) {
 94		return 0;
 95	}
 96	if (length > buffer->size) {
 97		length = buffer->size;
 98	}
 99	size_t remaining = buffer->capacity - ((int8_t*) data - (int8_t*) buffer->data);
100	if (length <= remaining) {
101		memcpy(output, data, length);
102		if (length == remaining) {
103			buffer->readPtr = buffer->data;
104		} else {
105			buffer->readPtr = (int8_t*) data + length;
106		}
107	} else {
108		memcpy(output, data, remaining);
109		memcpy((int8_t*) output + remaining, buffer->data, length - remaining);
110		buffer->readPtr = (int8_t*) buffer->data + length - remaining;
111	}
112
113	buffer->size -= length;
114	return length;
115}