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Binary search mapped blocks

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This commit is contained in:
Aurimas Blažulionis
2021-06-25 21:49:10 +01:00
parent 91451aa2f5
commit 160045a910
2 changed files with 72 additions and 23 deletions
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73
uc.c
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@ -765,26 +765,52 @@ uc_err uc_emu_stop(uc_engine *uc)
return UC_ERR_OK;
}
// return target index where a memory region at the address exists, or could be inserted
//
// address either is inside the mapping at the returned index, or is in free space before
// the next mapping.
//
// if there is overlap, between regions, ending address will be higher than the starting
// address of the mapping at returned index
static int bsearch_mapped_blocks(const uc_engine *uc, uint64_t address) {
int left, right, mid;
MemoryRegion *mapping;
left = 0;
right = uc->mapped_block_count;
while (left < right) {
mid = left + (right - left) / 2;
mapping = uc->mapped_blocks[mid];
if (mapping->end - 1 < address) {
left = mid + 1;
} else if (mapping->addr > address) {
right = mid;
} else {
return mid;
}
}
return left;
}
// find if a memory range overlaps with existing mapped regions
static bool memory_overlap(struct uc_struct *uc, uint64_t begin, size_t size)
{
unsigned int i;
uint64_t end = begin + size - 1;
for(i = 0; i < uc->mapped_block_count; i++) {
// begin address falls inside this region?
if (begin >= uc->mapped_blocks[i]->addr && begin <= uc->mapped_blocks[i]->end - 1) {
return true;
}
// end address falls inside this region?
if (end >= uc->mapped_blocks[i]->addr && end <= uc->mapped_blocks[i]->end - 1) {
return true;
}
// this region falls totally inside this range?
if (begin < uc->mapped_blocks[i]->addr && end > uc->mapped_blocks[i]->end - 1) {
return true;
}
}
i = bsearch_mapped_blocks(uc, begin);
// is this the highest region with no possible overlap?
if (i >= uc->mapped_block_count)
return false;
// end address overlaps this region?
if (end >= uc->mapped_blocks[i]->addr)
return true;
// not found
return false;
@ -794,6 +820,7 @@ static bool memory_overlap(struct uc_struct *uc, uint64_t begin, size_t size)
static uc_err mem_map(uc_engine *uc, uint64_t address, size_t size, uint32_t perms, MemoryRegion *block)
{
MemoryRegion **regions;
int pos;
if (block == NULL) {
return UC_ERR_NOMEM;
@ -808,7 +835,12 @@ static uc_err mem_map(uc_engine *uc, uint64_t address, size_t size, uint32_t per
uc->mapped_blocks = regions;
}
uc->mapped_blocks[uc->mapped_block_count] = block;
pos = bsearch_mapped_blocks(uc, block->addr);
// shift the array right to give space for the new pointer
memmove(&uc->mapped_blocks[pos + 1], &uc->mapped_blocks[pos], sizeof(MemoryRegion*) * (uc->mapped_block_count - pos));
uc->mapped_blocks[pos] = block;
uc->mapped_block_count++;
return UC_ERR_OK;
@ -1225,13 +1257,10 @@ MemoryRegion *memory_mapping(struct uc_struct* uc, uint64_t address)
return uc->mapped_blocks[i];
}
for(i = 0; i < uc->mapped_block_count; i++) {
if (address >= uc->mapped_blocks[i]->addr && address <= uc->mapped_blocks[i]->end - 1) {
// cache this index for the next query
uc->mapped_block_cache_index = i;
return uc->mapped_blocks[i];
}
}
i = bsearch_mapped_blocks(uc, address);
if (i < uc->mapped_block_count && address >= uc->mapped_blocks[i]->addr && address <= uc->mapped_blocks[i]->end - 1)
return uc->mapped_blocks[i];
// not found
return NULL;