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// See settings.js, CORRUPTION_CHECK
var CorruptionChecker = {
BUFFER_FACTOR: {{{ CORRUPTION_CHECK }}},
ptrs: {},
init: function() {
this.realMalloc = _malloc;
_malloc = Module['_malloc'] = this.malloc;
this.realFree = _free;
_free = Module['_free'] = this.free;
},
malloc: function(size) {
assert(size > 0); // some mallocs accept zero - fix your code if you want to use this tool
var allocation = CorruptionChecker.realMalloc(size*(1+2*CorruptionChecker.BUFFER_FACTOR));
var ptr = allocation + size*CorruptionChecker.BUFFER_FACTOR;
assert(!CorruptionChecker.ptrs[ptr]);
CorruptionChecker.ptrs[ptr] = size;
CorruptionChecker.fillBuffer(allocation, size*CorruptionChecker.BUFFER_FACTOR);
CorruptionChecker.fillBuffer(allocation + size*(1+CorruptionChecker.BUFFER_FACTOR), size*CorruptionChecker.BUFFER_FACTOR);
return ptr;
},
free: function(ptr) {
CorruptionChecker.checkPtr(ptr, true);
},
canary: function(x) {
return (x + (x << 3) + (x&75) - (x&47))&255;
},
fillBuffer: function(allocation, size) {
for (var x = allocation; x < allocation + size; x++) {
{{{ makeSetValue('x', 0, 'CorruptionChecker.canary(x)', 'i8') }}};
}
},
checkBuffer: function(allocation, size) {
for (var x = allocation; x < allocation + size; x++) {
assert(({{{ makeGetValue('x', 0, 'i8') }}}&255) == CorruptionChecker.canary(x), 'Heap corruption detected!');
}
},
checkPtr: function(ptr, free) {
var size = CorruptionChecker.ptrs[ptr];
assert(size);
var allocation = ptr - size*CorruptionChecker.BUFFER_FACTOR;
CorruptionChecker.checkBuffer(allocation, size*CorruptionChecker.BUFFER_FACTOR);
CorruptionChecker.checkBuffer(allocation + size*(1+CorruptionChecker.BUFFER_FACTOR), size*CorruptionChecker.BUFFER_FACTOR);
if (free) {
delete CorruptionChecker.ptrs[ptr];
CorruptionChecker.realFree(allocation);
}
},
checkAll: function() {
for (var ptr in CorruptionChecker.ptrs) {
CorruptionChecker.checkPtr(ptr, false);
}
},
};
CorruptionChecker.init();
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