Fix bugs and add a randomised testing

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

8 files changed, 63 insertions, 48 deletions

diff --git a/src/zadd.c b/src/zadd.c
index 73e5b42..e7d5265 100644
--- a/src/zadd.c
+++ b/src/zadd.c
@@ -9,16 +9,20 @@ zadd_unsigned(z_t a, z_t b, z_t c)
 	uint32_t carry[] = {0, 0};
 	zahl_char_t *addend;
 
-	if (a == c) {
-		zadd_unsigned(a, c, b);
+	if (zzero(b)) {
+		zabs(a, c);
+		return;
+	} else if (zzero(c)) {
+		zabs(a, b);
 		return;
 	}
 
 	size = MAX(b->used, c->used);
+	n = b->used + c->used - size;
+
 	ENSURE_SIZE(a, size + 1);
 	a->chars[size] = 0;
 
-	n = b->used + c->used - size;
 	if (a == b) {
 		if (a->used < c->used) {
 			n = c->used;
@@ -56,7 +60,7 @@ zadd_unsigned(z_t a, z_t b, z_t c)
 
 	if (a->used < i)
 		a->used = i;
-	SET_SIGNUM(a, !zzero(b) | !zzero(c));
+	SET_SIGNUM(a, 1);
 }
 
 
diff --git a/src/zdivmod.c b/src/zdivmod.c
index e145c27..def98b5 100644
--- a/src/zdivmod.c
+++ b/src/zdivmod.c
@@ -32,8 +32,6 @@ zdivmod(z_t a, z_t b, z_t c, z_t d)
 			zseti(a, sign);
 			SET_SIGNUM(b, 0);
 			return;
-		} else if (sign < 0) {
-			zsub_unsigned(b, d, c);
 		} else {
 			SET(b, c);
 		}
diff --git a/src/zload.c b/src/zload.c
index a77ae57..3ab939d 100644
--- a/src/zload.c
+++ b/src/zload.c
@@ -8,12 +8,9 @@ zload(z_t a, const void *buffer)
 	const char *buf = buffer;
 	a->sign = *((const int *)buf),    buf += sizeof(int);
 	a->used = *((const size_t *)buf), buf += sizeof(size_t);
-	a->alloced = 0;
-	if (a->sign)
+	if (a->sign) {
 		ENSURE_SIZE(a, a->used);
-	else
-		a->chars = 0;
-	if (!zzero(a))
 		zmemcpy(a->chars, buf, a->used);
+	}
 	return sizeof(int) + sizeof(size_t) + (zzero(a) ? 0 : a->used * sizeof(zahl_char_t));
 }
diff --git a/src/znot.c b/src/znot.c
index bcb17e2..d0e52c0 100644
--- a/src/znot.c
+++ b/src/znot.c
@@ -18,12 +18,12 @@ znot(z_t a, z_t b)
 
 	for (n = a->used; n--;)
 		a->chars[n] = ~(a->chars[n]);
-	bits &= BITS_PER_CHAR - 1;
-	a->chars[a->used - 1] &= ((zahl_char_t)1 << bits) - 1;
+	bits = BITS_IN_LAST_CHAR(bits);
+	if (bits)
+		a->chars[a->used - 1] &= ((zahl_char_t)1 << bits) - 1;
 
-	for (; a->used; a->used--)
-		if (a->chars[a->used - 1])
-			break;
+	while (a->used && !a->chars[a->used - 1])
+		 a->used--;
 	if (!a->used)
 		SET_SIGNUM(a, 0);
 }
diff --git a/src/zor.c b/src/zor.c
index 240024e..c50f5f8 100644
--- a/src/zor.c
+++ b/src/zor.c
@@ -20,16 +20,17 @@ zor(z_t a, z_t b, z_t c)
 
 	m = MAX(b->used, c->used);
 	n = b->used + c->used - m;
-	a->used = m;
 
 	ENSURE_SIZE(a, m);
 
 	if (a == b) {
-		zmemcpy(a->chars + n, m == b->used ? b->chars : c->chars, m - n);
+		if (b->used < c->used)
+			zmemcpy(a->chars + n, c->chars + n, m - n);
 		while (n--)
 			a->chars[n] |= c->chars[n];
 	} else if (a == c) {
-		zmemcpy(a->chars + n, m == b->used ? b->chars : c->chars, m - n);
+		if (c->used < b->used)
+			zmemcpy(a->chars + n, b->chars + n, m - n);
 		while (n--)
 			a->chars[n] |= b->chars[n];
 	} else if (m == b->used) {
@@ -42,5 +43,6 @@ zor(z_t a, z_t b, z_t c)
 			a->chars[n] |= b->chars[n];
 	}
 
+	a->used = m;
 	SET_SIGNUM(a, (zsignum(b) > 0 && zsignum(c) > 0) * 2 - 1);
 }
diff --git a/src/zsplit.c b/src/zsplit.c
index 384c5d7..8f51721 100644
--- a/src/zsplit.c
+++ b/src/zsplit.c
@@ -5,27 +5,17 @@
 void
 zsplit(z_t high, z_t low, z_t a, size_t delim)
 {
-	size_t chars;
-
 	if (zzero(a)) {
 		SET_SIGNUM(high, 0);
 		SET_SIGNUM(low, 0);
 		return;
 	}
 
-	chars = FLOOR_BITS_TO_CHARS(delim);
-
 	if (high == a) {
-		if (a->used < chars)
-			SET_SIGNUM(low, 0);
-		else
-			ztrunc(low, a, delim);
+		ztrunc(low, a, delim);
 		zrsh(high, a, delim);
 	} else {
 		zrsh(high, a, delim);
-		if (a->used < chars)
-			SET_SIGNUM(low, 0);
-		else
-			ztrunc(low, a, delim);
+		ztrunc(low, a, delim);
 	}
 }
diff --git a/src/zsub.c b/src/zsub.c
index 8616542..5096eb0 100644
--- a/src/zsub.c
+++ b/src/zsub.c
@@ -5,28 +5,49 @@
 void
 zsub_unsigned(z_t a, z_t b, z_t c)
 {
-	int magcmp = zcmpmag(b, c);
-	z_t s;
-	size_t i, n;
 	zahl_char_t carry[] = {0, 0};
+	zahl_char_t *s;
+	size_t i, n;
+	int magcmp;
+
+	if (zzero(b)) {
+		zabs(a, c);
+		zneg(a, a);
+		return;
+	} else if (zzero(c)) {
+		zabs(a, b);
+		return;
+	} else if (a == b || a == c) {
+		/* TODO This should not be necessary. */
+		z_t tb, tc;
+		zinit(tb);
+		zinit(tc);
+		zset(tb, b);
+		zset(tc, c);
+		zsub_unsigned(a, tb, tc);
+		zfree(tb);
+		zfree(tc);
+		return;
+	}
 
+	magcmp = zcmpmag(b, c);
 	if (magcmp <= 0) {
 		if (magcmp == 0) {
 			SET_SIGNUM(a, 0);
 			return;
 		}
 		SET(a, c);
-		*s = *b;
+		n = MIN(a->used, b->used);
+		s = b->chars;
 	} else {
 		SET(a, b);
-		*s = *c;
+		n = MIN(a->used, c->used);
+		s = c->chars;
 	}
 
-	n = MIN(a->used, s->used);
-
 	for (i = 0; i < n; i++) {
-		carry[~i & 1] = carry[i & 1] ? (a->chars[i] <= s->chars[i]) : (a->chars[i] < s->chars[i]);
-		a->chars[i] -= s->chars[i];
+		carry[~i & 1] = carry[i & 1] ? (a->chars[i] <= s[i]) : (a->chars[i] < s[i]);
+		a->chars[i] -= s[i];
 		a->chars[i] -= carry[i & 1];
 	}
 
diff --git a/src/zxor.c b/src/zxor.c
index fcbb3ae..d152ed7 100644
--- a/src/zxor.c
+++ b/src/zxor.c
@@ -21,19 +21,16 @@ zxor(z_t a, z_t b, z_t c)
 	m = MAX(b->used, c->used);
 	n = b->used + c->used - m;
 
-	if (n == m && !zmemcmp(b->chars, c->chars, m)) {
-		SET_SIGNUM(a, 0);
-		return;
-	}
-
 	ENSURE_SIZE(a, m);
 
 	if (a == b) {
-		zmemcpy(a->chars + n, m == b->used ? b->chars : c->chars, m - n);
+		if (b->used < c->used)
+			zmemcpy(a->chars + n, c->chars + n, m - n);
 		while (n--)
 			a->chars[n] ^= c->chars[n];
 	} else if (a == c) {
-		zmemcpy(a->chars + n, m == b->used ? b->chars : c->chars, m - n);
+		if (c->used < b->used)
+			zmemcpy(a->chars + n, b->chars + n, m - n);
 		while (n--)
 			a->chars[n] ^= b->chars[n];
 	} else if (m == b->used) {
@@ -46,5 +43,11 @@ zxor(z_t a, z_t b, z_t c)
 			a->chars[n] ^= b->chars[n];
 	}
 
-	SET_SIGNUM(a, 1 - 2 * ((zsignum(b) ^ zsignum(c)) < 0));
+	a->used = m;
+	while (a->used && !a->chars[a->used - 1])
+		a->used--;
+	if (a->used)
+		SET_SIGNUM(a, 1 - 2 * ((zsignum(b) ^ zsignum(c)) < 0));
+	else
+		SET_SIGNUM(a, 0);
 }