www.pudn.com > MyPlayerbylqh.rar > RingBuffer.cpp

 
#include "RingBuffer.h" 
 
 
 
MediaRingBuffer::MediaRingBuffer() 
{ 
	this->ring = (char *) new char[RING_SIZE]; 
 
	this->read_pos  = 0; 
	this->write_pos = 0; 
} 
 
MediaRingBuffer::~MediaRingBuffer() 
{ 
	free(this->ring); 
} 
 
 
void MediaRingBuffer::Init() 
{ 
	this->read_pos  = 0; 
	this->write_pos = 0; 
} 
 
 
void MediaRingBuffer::Read(char *outData, unsigned int size) 
{ 
	if(write_pos <= read_pos) { 
     
	    if(read_pos + size < RING_SIZE) { 
			memcpy(outData, ring + read_pos, size); 
			read_pos += size; 
		} 
		else { 
			 
			if(read_pos + size < RING_SIZE + write_pos) { 
	 
				unsigned int before, after; 
	 
				before = (RING_SIZE - 1) - read_pos; 
				after = size - before; 
	 
				memcpy(outData, ring + read_pos, before); 
				memcpy(outData + before, ring, after); 
	 
				read_pos = after; 
			} 
			else { 
			} 
		} 
	} 
	else { 
		 
		if(read_pos + size <= write_pos) { 
			 
			memcpy(outData, ring + read_pos, size); 
			read_pos += size; 
		} 
		else { 
		} 
	}  
} 
 
void MediaRingBuffer::Write(char *inData, unsigned int size) 
{ 
	if(write_pos >= read_pos) { 
     
		if(write_pos + size < RING_SIZE) { 
			 
			memcpy(ring + write_pos, inData, size); 
			write_pos += size; 
		} 
		else { 
		 
			if(write_pos + size < RING_SIZE + read_pos) { 
	 
				unsigned int before, after; 
 
				before = (RING_SIZE - 1) - write_pos; 
				after = size - before; 
 
				memcpy(ring + write_pos, inData, before); 
				memcpy(ring, inData + before, after); 
 
				write_pos = after; 
			} 
		} 
	} 
	else { 
     
		if(write_pos + size <= read_pos) { 
			 
			memcpy(ring + write_pos, inData, size); 
			write_pos += size; 
		} 
	} 
} 
 
int  MediaRingBuffer::IsFullFor(unsigned int size) 
{ 
	if(write_pos == read_pos) 
		return 0; 
 
	if(write_pos > read_pos) { 
 
		if(write_pos + size < read_pos + RING_SIZE) 
			return 0; 
 
		return 1; 
	} 
	else { 
 
		if(write_pos + size < read_pos) 
			return 0; 
 
		return 1; 
	} 
}