MC100/Applications/libs/circle_buffer.c

#include <string.h>
#include "circle_buffer.h"

static int circle_get_write_space(c_buffer_t *cbuff);
static int circle_get_read_space(c_buffer_t *cbuff);
static c_buffer_t _g_cbuffer;
c_buffer_t *circle_buffer_init(u8 *buffer, int16_t max_len){
	c_buffer_t *cbuff = &_g_cbuffer;
	memset(cbuff, 0, sizeof(c_buffer_t));
	cbuff->buffer = buffer;
	cbuff->buffer_len = max_len;
	return cbuff;
}

void circle_reset(c_buffer_t *cbuff){
	cbuff->r_pos = cbuff->w_pos = 0;
}


int circle_put_data(c_buffer_t *cbuff, u8 *data, int16_t len){
	int16_t size = circle_get_write_space(cbuff);
	int16_t w_len = len;
	int16_t w1_len = len;
	if (size < 0){
		return size;
	}
	w_len = min(len, size);
	while(w_len > 0){
		//wrapper
		if (cbuff->w_pos + w_len > cbuff->buffer_len){
			w1_len = cbuff->buffer_len - cbuff->w_pos;
		}else{
			w1_len = w_len;
		}
		memcpy(cbuff->buffer + cbuff->w_pos, data, w1_len);
		cbuff->w_pos = (cbuff->w_pos + w1_len);
		if (cbuff->w_pos == cbuff->buffer_len){
			cbuff->w_pos = 0;
		}
		w_len -= w1_len;
		data += w1_len;
	}
	return min(len, size);
}

int circle_put_one_data(c_buffer_t *cbuff, u8 data){
	int16_t size = circle_get_write_space(cbuff);
	if (size < 0){
		return size;
	}
	cbuff->buffer[cbuff->w_pos] = data;
	cbuff->w_pos = cbuff->w_pos + 1;
	if (cbuff->w_pos == cbuff->buffer_len){
		cbuff->w_pos = 0;
	}
	return 1;
}

int circle_get_data(c_buffer_t *cbuff, u8 *data, int16_t len){
	int16_t size = circle_get_read_space(cbuff);
	int16_t r_len = len;
	int16_t r1_len = 0;
	if (size <= 0){
		return size;
	}

	r_len = min(size, len);

	while(r_len > 0){
		if (cbuff->r_pos + r_len > cbuff->buffer_len){
			r1_len = cbuff->buffer_len - cbuff->r_pos;
		}else{
			r1_len = r_len;
		}
		memcpy(data, cbuff->buffer + cbuff->r_pos, r1_len);
		cbuff->r_pos = (cbuff->r_pos + r1_len);
		if (cbuff->r_pos == cbuff->buffer_len){
			cbuff->r_pos = 0;
		}		
		r_len -= r1_len;
		data += r1_len;
	}
	return min(size, len);
}


int circle_get_one_data(c_buffer_t *cbuff, u8 *data){
	int16_t size = circle_get_read_space(cbuff);
	if (size <= 0){
		return size;
	}
	*data = cbuff->buffer[cbuff->r_pos];
	cbuff->r_pos = cbuff->r_pos + 1;
	if (cbuff->r_pos == cbuff->buffer_len){
		cbuff->r_pos = 0;
	}
	return 1;
}


static __inline__ int circle_get_write_space(c_buffer_t *cbuff){
	int16_t size = (cbuff->w_pos >= cbuff->r_pos)?(cbuff->buffer_len - cbuff->w_pos + cbuff->r_pos):(cbuff->r_pos - cbuff->w_pos);
	size -= 1;
	if (size <= 0){
		return CBUFF_FULL;
	}
	return size;
}

static __inline__ int circle_get_read_space(c_buffer_t *cbuff){
	int16_t size = (cbuff->r_pos > cbuff->w_pos) ? (cbuff->buffer_len - cbuff->r_pos + cbuff->w_pos) : (cbuff->w_pos - cbuff->r_pos);
	if (size <= 0){
		return CBUFF_EMPTY;
	}
	return size;
}