dmmlib/LeaHeader.c

#include "LeaHeader.h"

//returns a pointer to the header of the block	
leaHdr * getHeader(const char * ptr) {
	return (leaHdr *) (ptr - HDR_SIZE);
}


unsigned int getSize (const char * ptr) {
	return (getHeader(ptr)->size >> 1);
}


unsigned int getPrevSize (const char * ptr) {
	unsigned int sz = getHeader(ptr)->prevSize;
	return sz >> 1;
}


void setSize (char * ptr, const unsigned int sz) {
	unsigned int size = getSize(ptr);
	size = ((size & 1) | (sz << 1));
	getHeader(ptr)->size = size;
}


void setPrevSize (char * ptr, const unsigned int sz) {
	unsigned int prevSize = getHeader(ptr)->prevSize;
	prevSize = (prevSize & 1) | (sz << 1);
	getHeader(ptr)->prevSize = prevSize;
}


//returns a pointer (that points) to the next block
char * getNext (const char * ptr) {
	return (char *)(ptr + HDR_SIZE + getSize(ptr));
}

char * getPrev (const char * ptr) {
	return (char *)(ptr - HDR_SIZE - getPrevSize(ptr));
}

void markPrevFree (char * ptr) {
	getHeader(ptr)->prevSize &= (~ 1);
}

void markPrevInUse (char * ptr) {
	getHeader(ptr)->prevSize |= 1;
}

unsigned int isPrevFree (char * ptr) {
	unsigned int free = ~(getHeader(ptr)->prevSize & 1);
	return (free & 1) ;
}

void markInUse (char * ptr) {
	markPrevInUse(getNext(ptr));
}

void markFree (char * ptr) {
	markPrevFree(getNext(ptr));
}
	

unsigned int isFree (char * ptr) {
	return isPrevFree(getNext(ptr));
}