First commit

Signed-off-by: Mattias Andrée <m@maandree.se>

1 files changed, 121 insertions, 0 deletions

diff --git a/libj2_ju_rsh_to_j2u.c b/libj2_ju_rsh_to_j2u.c
new file mode 100644
index 0000000..7c5913f
--- /dev/null
+++ b/libj2_ju_rsh_to_j2u.c
@@ -0,0 +1,121 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+extern inline void libj2_ju_rsh_to_j2u(uintmax_t a, unsigned b, struct libj2_j2u *res);
+/* TODO Add man page */
+
+
+#else
+
+static const char *patterns[] = {
+	"0",
+	"1111111111111111111111111111111111111111111111111111111111111111",
+	"1111111111111111111111111111111111111111111111111111111111111111"
+	"1111111111111111111111111111111111111111111111111111111111111111",
+	"1111111111111111111111111111111111111111111111111111111111111111"
+	"1111111111111111111111111111111111111111111111111111111111111111"
+	"1111111111111111111111111111111111111111111111111111111111111111"
+	"1111111111111111111111111111111111111111111111111111111111111111",
+	"1111111111111111111111111111111111111111111111111111111111111111"
+	"1111111111111111111111111111111111111111111111111111111111111111"
+	"1111111111111111111111111111111111111111111111111111111111111111"
+	"1111111111111111111111111111111111111111111111111111111111111111"
+	"1111111111111111111111111111111111111111111111111111111111111111"
+	"1111111111111111111111111111111111111111111111111111111111111111"
+	"1111111111111111111111111111111111111111111111111111111111111111"
+	"1111111111111111111111111111111111111111111111111111111111111111",
+	"1010101010101001010100100010101010101011000101101011101001000110",
+	"1110100100100010000010111111011101101001000010001000011110101010",
+	"11111111111100001001011",
+	"0010011011001",
+	"110010001011110100101001010011010111101",
+	NULL
+};
+
+
+static int
+set_j2u(struct libj2_j2u *a, const char *bits, size_t leading_zeroes)
+{
+	size_t i, n;
+	int underflow = 0;
+
+	a->high = 0;
+	a->low = 0;
+
+	n = strlen(bits);
+	if (n > LIBJ2_J2U_BIT) {
+		bits = &bits[n - LIBJ2_J2U_BIT];
+		n = LIBJ2_J2U_BIT;
+	}
+
+	while (n && leading_zeroes--)
+		underflow |= bits[--n] == '1';
+
+	for (i = 0; n && i < LIBJ2_JU_BIT; i++)
+		if (bits[--n] == '1')
+			a->low |= (uintmax_t)1 << i;
+
+	for (i = 0; n && i < LIBJ2_JU_BIT; i++)
+		if (bits[--n] == '1')
+			a->high |= (uintmax_t)1 << i;
+
+	return underflow;
+}
+
+
+static int
+set(struct libj2_j2u *a, const char *bits, size_t leading_zeroes)
+{
+	size_t n = strlen(bits);
+	if (n > LIBJ2_JU_BIT)
+		bits = &bits[n - LIBJ2_JU_BIT];
+	return set_j2u(a, bits, leading_zeroes);
+}
+
+
+static void
+check(const char *pattern)
+{
+	struct libj2_j2u a, r, expected;
+	unsigned i;
+	int underflows;
+
+	set(&a, pattern, 0);
+	EXPECT(a.high == 0);
+	for (i = 0; i < LIBJ2_J2U_BIT + 8U; i++) {
+		underflows = set(&expected, pattern, i);
+
+		r = (struct libj2_j2u){111, 222};
+		libj2_ju_rsh_to_j2u(a.low, i, &r);
+		EXPECT(libj2_j2u_eq_j2u(&r, &expected));
+
+		r = (struct libj2_j2u){111, 222};
+		EXPECT(libj2_ju_rsh_to_j2u_underflow(a.low, i, &r) == underflows);
+		EXPECT(libj2_j2u_eq_j2u(&r, &expected));
+	}
+}
+
+
+int
+main(void)
+{
+	size_t i, j;
+	char pattern[LIBJ2_J2U_BIT + 1U];
+
+	srand((unsigned)time(NULL));
+
+	for (i = 0; patterns[i]; i++)
+		check(patterns[i]);
+
+	for (i = 0; i < 64; i++) {
+		for (j = 0; j < LIBJ2_J2U_BIT; j++)
+			pattern[j] = '0' + (rand() < rand());
+		pattern[LIBJ2_J2U_BIT] = '\0';
+		check(pattern);
+	}
+
+	return 0;
+}
+
+#endif