buffer.c

来自「实现功能ATmega单片机上处理GSM模块的数据」· C语言 代码 · 共 73 行

#include "buffer.h"


void bufferInit(cBuffer* buffer, unsigned char *start, unsigned short size)
{
	buffer->dataptr = start;
	buffer->size = size;
	buffer->dataindex = 0;
	buffer->datalength = 0;
}

unsigned char  bufferGetFromFront(cBuffer* buffer)
{
	unsigned char data = 0;
	
	if(buffer->datalength)
	{
		data = buffer->dataptr[buffer->dataindex];
		buffer->dataindex++;
		if(buffer->dataindex >= buffer->size)
		{
			buffer->dataindex %= buffer->size;
		}
		buffer->datalength--;
	}
	return data;
}

void bufferDumpFromFront(cBuffer* buffer, unsigned short numbytes)
{
	if(numbytes < buffer->datalength)
	{
		buffer->dataindex += numbytes;
		if(buffer->dataindex >= buffer->size)
		{
			buffer->dataindex %= buffer->size;
		}
		buffer->datalength -= numbytes;
	}
	else
	{
		buffer->datalength = 0;
	}
}

unsigned char bufferGetAtIndex(cBuffer* buffer, unsigned short index)
{
	return buffer->dataptr[(buffer->dataindex+index)%(buffer->size)];
}

unsigned char bufferAddToEnd(cBuffer* buffer, unsigned char data)
{
	if(buffer->datalength < buffer->size)
	{
		buffer->dataptr[(buffer->dataindex + buffer->datalength) % buffer->size] = data;
		buffer->datalength++;
		return -1;
	}
	else return 0;
}

unsigned char bufferIsNotFull(cBuffer* buffer)
{
	return (buffer->datalength < buffer->size);
}

void bufferFlush(cBuffer* buffer)
{
	buffer->datalength = 0;
}