+/* 2^128 - 1 */
+#define U128_BASE_10_ARRAY_LEN sizeof("340282366920938463463374607431768211455")
+/* -2^127 */
+#define S128_BASE_10_ARRAY_LEN sizeof("-170141183460469231731687303715884105728")
+
+/*
+ * u128_tostring_base_10 is inspired from https://stackoverflow.com/a/4364365
+ */
+static
+void u128_tostring_base_10(union int_value v, char str[U128_BASE_10_ARRAY_LEN])
+{
+ int d[39] = {}, i, j, str_i = 0;
+
+ for (i = 63; i > -1; i--) {
+ if ((v.u[SIDE_INTEGER128_SPLIT_HIGH] >> i) & 1)
+ d[0]++;
+ for (j = 0; j < 39; j++)
+ d[j] *= 2;
+ for (j = 0; j < 38; j++) {
+ d[j + 1] += d[j] / 10;
+ d[j] %= 10;
+ }
+ }
+ for (i = 63; i > -1; i--) {
+ if ((v.u[SIDE_INTEGER128_SPLIT_LOW] >> i) & 1)
+ d[0]++;
+ if (i > 0) {
+ for (j = 0; j < 39; j++)
+ d[j] *= 2;
+ }
+ for (j = 0; j < 38; j++) {
+ d[j + 1] += d[j] / 10;
+ d[j] %= 10;
+ }
+ }
+ for (i = 38; i > 0; i--)
+ if (d[i] > 0)
+ break;
+ for (; i > -1; i--) {
+ str[str_i++] = '0' + d[i];
+ }
+ str[str_i] = '\0';
+}
+
+static
+void s128_tostring_base_10(union int_value v, char str[S128_BASE_10_ARRAY_LEN])
+{
+ uint64_t low, high, tmp;
+
+ if (v.s[SIDE_INTEGER128_SPLIT_HIGH] >= 0) {
+ /* Positive. */
+ v.u[SIDE_INTEGER128_SPLIT_LOW] = (uint64_t) v.s[SIDE_INTEGER128_SPLIT_LOW];
+ v.u[SIDE_INTEGER128_SPLIT_HIGH] = (uint64_t) v.s[SIDE_INTEGER128_SPLIT_HIGH];
+ u128_tostring_base_10(v, str);
+ return;
+ }
+
+ /* Negative. */
+
+ /* Special-case minimum value, which has no positive signed representation. */
+ if ((v.s[SIDE_INTEGER128_SPLIT_HIGH] == INT64_MIN) && (v.s[SIDE_INTEGER128_SPLIT_LOW] == 0)) {
+ memcpy(str, "-170141183460469231731687303715884105728", S128_BASE_10_ARRAY_LEN);
+ return;
+ }
+ /* Convert from two's complement. */
+ high = ~(uint64_t) v.s[SIDE_INTEGER128_SPLIT_HIGH];
+ low = ~(uint64_t) v.s[SIDE_INTEGER128_SPLIT_LOW];
+ tmp = low + 1;
+ if (tmp < low) {
+ high++;
+ /* Clear overflow to sign bit. */
+ high &= ~0x8000000000000000ULL;
+ }
+ v.u[SIDE_INTEGER128_SPLIT_LOW] = tmp;
+ v.u[SIDE_INTEGER128_SPLIT_HIGH] = high;
+ str[0] = '-';
+ u128_tostring_base_10(v, str + 1);
+}
+
+/* 2^128 - 1 */
+#define U128_BASE_8_ARRAY_LEN sizeof("3777777777777777777777777777777777777777777")
+
+static
+void u128_tostring_base_8(union int_value v, char str[U128_BASE_8_ARRAY_LEN])
+{
+ int d[43] = {}, i, j, str_i = 0;
+
+ for (i = 63; i > -1; i--) {
+ if ((v.u[SIDE_INTEGER128_SPLIT_HIGH] >> i) & 1)
+ d[0]++;
+ for (j = 0; j < 43; j++)
+ d[j] *= 2;
+ for (j = 0; j < 42; j++) {
+ d[j + 1] += d[j] / 8;
+ d[j] %= 8;
+ }
+ }
+ for (i = 63; i > -1; i--) {
+ if ((v.u[SIDE_INTEGER128_SPLIT_LOW] >> i) & 1)
+ d[0]++;
+ if (i > 0) {
+ for (j = 0; j < 43; j++)
+ d[j] *= 2;
+ }
+ for (j = 0; j < 42; j++) {
+ d[j + 1] += d[j] / 8;
+ d[j] %= 8;
+ }
+ }
+ for (i = 42; i > 0; i--)
+ if (d[i] > 0)
+ break;
+ for (; i > -1; i--) {
+ str[str_i++] = '0' + d[i];
+ }
+ str[str_i] = '\0';
+}
+