Function fxBigintToString

xs/sources/xsBigInt.c:629–687

};

void fxBigintToString(txMachine* the, txSlot* slot, txU4 radix)
{
	static const char gxDigits[] ICACHE_FLASH_ATTR = "0123456789abcdefghijklmnopqrstuvwxyz";
	txSize length, offset;
	txSlot* result;
	txSlot* stack;
	if (0 == radix) radix = 10;
	const BaseChunk32 *bc = base_chunks32 + (radix - 2);

	if (mxBigIntIsNaN(&slot->value.bigint)) {
		fxStringX(the, slot, "NaN");
		return;
	}
	mxBigInt_meter(slot->value.bigint.size);

	mxPushUndefined();
	result = the->stack;
	
	mxPushSlot(slot);
	fxBigInt_dup(the, &the->stack->value.bigint);
	stack = the->stack;

	length = 1 + bc->k + (txSize)c_ceil((txNumber)(stack->value.bigint.size + 1) * 32 * c_log(2) / c_log(radix));
	if (stack->value.bigint.sign)
		length++;
	offset = length;
	result->value.string = fxNewChunk(the, length);
	result->kind = XS_STRING_KIND;

	result->value.string[--offset] = 0;
	int32_t nonZeroWords = stack->value.bigint.size;
	do {
		uint64_t carry = 0;
		for (uint32_t i = nonZeroWords - 1, count = nonZeroWords, base_to_k = bc->base_to_k; count > 0; --count) {
			carry = (carry << 32) | stack->value.bigint.data[i];
			stack->value.bigint.data[i--] = (uint32_t)(carry / base_to_k);
			carry %= base_to_k;
		}
		uint32_t remainder = (uint32_t)carry, k = bc->k;
		do {
			result->value.string[--offset] = c_read8(gxDigits + (remainder % radix));
			remainder /= radix;
		} while (--k);

		while (nonZeroWords && (0 == stack->value.bigint.data[nonZeroWords - 1]))
			nonZeroWords -= 1;
	} while (nonZeroWords);

	while (('0' == result->value.string[offset]) && result->value.string[offset + 1])
		offset++;

	if (stack->value.bigint.sign)
		result->value.string[--offset] = '-';
	c_memmove(result->value.string, result->value.string + offset, length - offset);

	mxPop();
	mxPop();
	mxPullSlot(slot);