comparison mercurial/bdiff.c @ 18551:d6fb7bbec16a

bdiff: simplify overflow checks

Rather than check that each delta start, end, and length is within 32
bits, we simply check that the input strings are under 4GB.

18550:db3a3a65e0db

	PyThreadState *_save;

	if (!PyArg_ParseTuple(args, "s#s#:bdiff", &sa, &la, &sb, &lb))
		return NULL;

	_save = PyEval_SaveThread();
	an = splitlines(sa, la, &al);
	bn = splitlines(sb, lb, &bl);
	if (!al || !bl)
		goto nomem;

	la = lb = 0;

	for (h = l.next; h; h = h->next) {
		if (h->a1 != la || h->b1 != lb) {
			len = bl[h->b1].l - bl[lb].l;

#define checkputbe32(__x, __c) \
	if (__x > UINT_MAX) { \
		PyErr_SetString(PyExc_ValueError, \
		                "bdiff: value too large for putbe32"); \
		goto nomem; \
	} \
	putbe32((uint32_t)(__x), __c);

			checkputbe32(al[la].l - al->l, rb);
			checkputbe32(al[h->a1].l - al->l, rb + 4);
			checkputbe32(len, rb + 8);
			memcpy(rb + 12, bl[lb].l, len);
			rb += 12 + len;
		}
		la = h->a2;
		lb = h->b2;

18551:d6fb7bbec16a

	PyThreadState *_save;

	if (!PyArg_ParseTuple(args, "s#s#:bdiff", &sa, &la, &sb, &lb))
		return NULL;

	if (la > UINT_MAX || lb > UINT_MAX) {
		PyErr_SetString(PyExc_ValueError, "bdiff inputs too large");
		return NULL;
	}

	_save = PyEval_SaveThread();
	an = splitlines(sa, la, &al);
	bn = splitlines(sb, lb, &bl);
	if (!al || !bl)
		goto nomem;

	la = lb = 0;

	for (h = l.next; h; h = h->next) {
		if (h->a1 != la || h->b1 != lb) {
			len = bl[h->b1].l - bl[lb].l;
			putbe32((uint32_t)(al[la].l - al->l), rb);
			putbe32((uint32_t)(al[h->a1].l - al->l), rb + 4);
			putbe32((uint32_t)len, rb + 8);
			memcpy(rb + 12, bl[lb].l, len);
			rb += 12 + len;
		}
		la = h->a2;
		lb = h->b2;