First commit

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

1 files changed, 171 insertions, 0 deletions

diff --git a/libj2_ju_lsh_to_j2u.c b/libj2_ju_lsh_to_j2u.c
new file mode 100644
index 0000000..82aa61f
--- /dev/null
+++ b/libj2_ju_lsh_to_j2u.c
@@ -0,0 +1,171 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+extern inline void libj2_ju_lsh_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
+};
+
+
+PURE static size_t
+count_ones(const char *bits)
+{
+	size_t n = strlen(bits);
+	if (n > LIBJ2_J2U_BIT)
+		bits = &bits[n - LIBJ2_J2U_BIT];
+	n = 0;
+	while (*bits)
+		if (*bits++ == '1')
+			n += 1U;
+	return n;
+}
+
+
+static int
+set_j2u(struct libj2_j2u *a, const char *bits, size_t trailing_zeroes)
+{
+	size_t i, n;
+	char *all_bits, *p;
+
+	n = LIBJ2_J2U_BIT + strlen(bits) + trailing_zeroes;
+	EXPECT((all_bits = malloc(n + 1U)));
+	memset(all_bits, '0', LIBJ2_J2U_BIT);
+	p = stpcpy(&all_bits[LIBJ2_J2U_BIT], bits);
+	memset(p, '0', trailing_zeroes);
+	p = &p[trailing_zeroes];
+
+	n = 0;
+
+	a->low = 0;
+	for (i = 0; i < LIBJ2_JU_BIT; i++) {
+		if (*--p == '1') {
+			a->low |= (uintmax_t)1 << i;
+			n += 1U;
+		}
+	}
+
+	a->high = 0;
+	for (i = 0; i < LIBJ2_JU_BIT; i++) {
+		if (*--p == '1') {
+			a->high |= (uintmax_t)1 << i;
+			n += 1U;
+		}
+	}
+
+	free(all_bits);
+	return n < count_ones(bits);
+}
+
+
+static int
+set(struct libj2_j2u *a, const char *bits, size_t trailing_zeroes)
+{
+	size_t n = strlen(bits);
+	if (n > LIBJ2_JU_BIT)
+		bits = &bits[n - LIBJ2_JU_BIT];
+	return set_j2u(a, bits, trailing_zeroes);
+}
+
+
+static void
+self_check(void)
+{
+	struct libj2_j2u a = {111, 222};
+	char pattern[LIBJ2_J2U_BIT + 1U];
+	EXPECT(set(&a, "11", 8) == 0);
+	EXPECT(a.high == 0);
+	EXPECT(a.low == (3U << 8));
+	EXPECT(set(&a, "1101", LIBJ2_JU_BIT) == 0);
+	EXPECT(a.high == 13U);
+	EXPECT(a.low == 0);
+	EXPECT(set(&a, "1", LIBJ2_JU_BIT - 1) == 0);
+	EXPECT(a.high == 0);
+	EXPECT(a.low == (UINTMAX_MAX ^ (UINTMAX_MAX >> 1)));
+	EXPECT(set(&a, "111", LIBJ2_JU_BIT - 2) == 0);
+	EXPECT(a.high == 1);
+	EXPECT(a.low == (UINTMAX_MAX ^ (UINTMAX_MAX >> 2)));
+	EXPECT(set(&a, "1", LIBJ2_J2U_BIT) == 1);
+	EXPECT(a.high == 0);
+	EXPECT(a.low == 0);
+	memset(pattern, '1', LIBJ2_J2U_BIT);
+	pattern[LIBJ2_J2U_BIT] = '\0';
+	a = (struct libj2_j2u){111, 222};
+	EXPECT(set(&a, pattern, 0) == 0);
+	EXPECT(a.high == 0);
+	EXPECT(a.low == UINTMAX_MAX);
+}
+
+
+static void
+check(const char *pattern)
+{
+	struct libj2_j2u a, r, expected;
+	unsigned i;
+	int overflows;
+
+	set(&a, pattern, 0);
+	EXPECT(a.high == 0);
+	for (i = 0; i < LIBJ2_J2U_BIT + 8U; i++) {
+		overflows = set(&expected, pattern, i);
+
+		r = (struct libj2_j2u){111, 222};
+		libj2_ju_lsh_to_j2u(a.low, i, &r);
+		EXPECT(libj2_j2u_eq_j2u(&r, &expected));
+
+		r = (struct libj2_j2u){111, 222};
+		EXPECT(libj2_ju_lsh_to_j2u_overflow(a.low, i, &r) == overflows);
+		EXPECT(libj2_j2u_eq_j2u(&r, &expected));
+	}
+}
+
+
+int
+main(void)
+{
+	size_t i, j;
+	char pattern[LIBJ2_JU_BIT + 1U];
+
+	self_check();
+	srand((unsigned)time(NULL));
+
+	for (i = 0; patterns[i]; i++)
+		check(patterns[i]);
+
+	for (i = 0; i < 64; i++) {
+		for (j = 0; j < LIBJ2_JU_BIT; j++)
+			pattern[j] = '0' + (rand() < rand());
+		pattern[LIBJ2_JU_BIT] = '\0';
+		check(pattern);
+	}
+
+	return 0;
+}
+
+#endif