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memManager.cpp
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memManager.cpp
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#include "memManager.h"
memManager::memManager(void){
//clean the memory
memset((void *) memNext, 100000, maxMem*sizeof(uint32_t));
curFreeLoc = 0;
//intialize the whole memory as one free block
memInfoUsed[0] = FREE;
memNext[0] = maxMem-1;
memInfoUsed[maxMem-1] = FREE;
memNext[maxMem-1] = 0;
memAvail = maxMem;
};
void *memManager::memalloc(size_t size){
if(memAvail < size){
return NULL;
}
return findNext(size);
};
void memManager::free(void *ptr){
uint32_t curLoc = (unsigned char *)ptr - memBuff;
if(ptr == NULL || ((unsigned char *)ptr - memBuff) < 0){
return;
}
//curLoc = curLoc + 1;
setUpMem(curLoc, -1, FREE);
mregeUp(curLoc);
mregeDown(curLoc);
};//
void memManager::printMem(void){
cout << endl;
for(uint32_t i=0; i < maxMem; i++){
cout << memBuff[i];
}
cout << endl;
};
//findst the next free area
void *memManager::findNext(size_t size){
char flag = 0;
uint32_t tempLoc = 0;
tempLoc = curFreeLoc;
//check the top first
if(memInfoUsed[tempLoc]==FREE && ((memNext[tempLoc]-tempLoc+1) > size)){//if the memory is avialable and object fits in
flag = 1;
}
else{
//if the memory is availabe on the top good otherwise search from start
tempLoc = 0;
while(tempLoc < maxMem){
if(memInfoUsed[tempLoc]==FREE && ((memNext[tempLoc]-tempLoc+1) >= size)){//if the memory is avialable and object fits in
flag = 1;
break;
}
else
{tempLoc = memNext[tempLoc]+1;}
}//end of while
}//end of if on top
if(flag){
setUpMem(tempLoc, size,USED);
return (memBuff+tempLoc);
}
return NULL;
};
//sets up the memrory for the
void memManager::setUpMem(uint32_t tempLoc, size_t size, char setWhat){
if(setWhat == USED){//it is free set it up to used
uint32_t temp = memNext[tempLoc];
memNext[tempLoc] = tempLoc+size-1;
memNext[tempLoc+size-1] = tempLoc;
memInfoUsed[tempLoc] = USED;
memInfoUsed[tempLoc+size-1] = USED;
this->memAvail = memAvail-size;
//if allocated block is smaller than the current block, break it
if( (tempLoc+size-1) != temp){
memNext[tempLoc+size] = temp;
memNext[temp] = tempLoc+size;
memInfoUsed[tempLoc+size] = FREE;
memInfoUsed[temp] = FREE;
curFreeLoc = tempLoc+size;
}
}///if used
else{
uint32_t temp = memNext[tempLoc];
memInfoUsed[tempLoc] = FREE;
memInfoUsed[temp] = FREE;
memAvail = memAvail + temp-tempLoc+1;
}
};//end of setupMem
void memManager::mregeUp(uint32_t tempLoc){
//check the next block and if it is free merge it
uint32_t temp1 = memNext[tempLoc];
if(temp1+1< maxMem && memInfoUsed[temp1+1] == FREE){
memNext[tempLoc] = memNext[temp1+1];
memNext[memNext[temp1+1]] = tempLoc;
//setUpMem(tempLoc, -1, FREE);
}
};//end of mergeUp
void memManager::mregeDown(uint32_t tempLoc){
if(tempLoc>=0){
uint32_t prev = tempLoc-1;
uint32_t temp1 = memNext[tempLoc];
if(memInfoUsed[prev] == FREE){//check if previous is free
memNext[memNext[prev]] = temp1;//in the previous add the current
memNext[temp1] = memNext[prev]; // in the end of the current make it know the start of previous
//setUpMem(prev, -1, FREE);
}
}
};//end of mergeUp