/*
like realloc(r, newSize), resizeRegion will return a new region of size
newSize containing the old contents of r by:
1. checking if the present region has sufficient available space to
satisfy the request (if so, do nothing)
2. allocating a new region of sufficient size & copying the data
TODO: if the successor 's' to r's block is free, and there is sufficient space
in r + s, then just adjust sizes of r & s.
*/
void *resizeRegion(void *r, size_t newSize) {
int oldSize;
// int nextPSize;
// size_t oldAndNew;
BlockPrefix_t *p = regionToPrefix(r);
BlockPrefix_t *nextp = getNextPrefix(p);
int nextpNum = getNextPrefix(p);
BlockPrefix_t *nexts;
if (r != (void *)0){ /* old region existed */
oldSize = computeUsableSpace(regionToPrefix(r));
}
else
oldSize = 0; /* non-existant regions have size 0 */
if (oldSize >= newSize) /* old region is big enough */
return r;
// else if(nextpNum != 0){
// size_t nextPSize=computeUsableSpace(nextp);
// size_t oldAndNext=nextPSize+oldSize;
// if(oldAndNext>=align8(newSize)){
// // size_t asize = align8(newSize);
// // size_t availSize = computeUsableSpace(p);
// if (oldAndNext >= (align8(newSize) + prefixSize + suffixSize + 8)) { /* split block? */
// void *freeSliverStart = (void *)p + prefixSize + suffixSize + align8(newSize);
// void *freeSliverEnd = computeNextPrefixAddr(nextp);
// makeFreeBlock(freeSliverStart, freeSliverEnd - freeSliverStart);
// makeFreeBlock(p, freeSliverStart - (void *)p); /* piece being allocated */
// }
// p->allocated = 1; /* mark as allocated */
// return prefixToRegion(p); /* convert to *region */
// }
// }
else { /* allocate new region & copy old data */
char *o = (char *)r; /* treat both regions as char* */
char *n = (char *)nextFitAllocRegion(newSize);
int i;
for (i = 0; i < oldSize; i++) /* copy byte-by-byte, should use memcpy */
n[i] = o[i];
freeRegion(o); /* free old region */
return (void *)n;
}
}
void freeRegions( PStack desc ) {
while( !PStackIsEmpty(desc) ) freeRegion(PopPStack(desc));
FreePStack(desc);
}
