rand: add missing i32 APIs, corresponding to the int ones

Author: spytheman

vlib/rand/rand.v

@@ -42,7 +42,13 @@ pub fn (mut rng PRNG) read(mut buf []u8) {
 	read_internal(mut rng, mut buf)
 }
 
-// u32n returns a uniformly distributed pseudorandom 32-bit signed positive `u32` in range `[0, max)`.
+// i32n returns a uniformly distributed pseudorandom 32-bit signed positive `i32` in range `[0, max)`.
+@[inline]
+pub fn (mut rng PRNG) i32n(max i32) !i32 {
+	return i32(rng.intn(max)!)
+}
+
+// u32n returns a uniformly distributed pseudorandom 32-bit unsigned positive `u32` in range `[0, max)`.
 @[inline]
 pub fn (mut rng PRNG) u32n(max u32) !u32 {
 	if max == 0 {
@@ -138,6 +144,12 @@ pub fn (mut rng PRNG) i16() i16 {
 	return i16(rng.u16())
 }
 
+// i32 returns a (possibly negative) pseudorandom 32-bit `i32`.
+@[inline]
+pub fn (mut rng PRNG) i32() i32 {
+	return i32(rng.u32())
+}
+
 // int returns a (possibly negative) pseudorandom 32-bit `int`.
 @[inline]
 pub fn (mut rng PRNG) int() int {
@@ -190,6 +202,16 @@ pub fn (mut rng PRNG) int_in_range(min int, max int) !int {
 	return min + rng.intn(max - min)!
 }
 
+// int_in_range returns a pseudorandom `int` in range `[min, max)`.
+@[inline]
+pub fn (mut rng PRNG) i32_in_range(min i32, max i32) !i32 {
+	if max <= min {
+		return error('max must be greater than min')
+	}
+	// This supports negative ranges like [-10, -5) because the difference is positive
+	return min + i32(rng.intn(max - min)!)
+}
+
 // i64_in_range returns a pseudorandom `i64` in range `[min, max)`.
 @[inline]
 pub fn (mut rng PRNG) i64_in_range(min i64, max i64) !i64 {
@@ -564,11 +586,21 @@ pub fn i16() i16 {
 	return default_rng.i16()
 }
 
+// i32 returns a uniformly distributed pseudorandom 32-bit signed (possibly negative) `i32`.
+pub fn i32() i32 {
+	return default_rng.i32()
+}
+
 // int returns a uniformly distributed pseudorandom 32-bit signed (possibly negative) `int`.
 pub fn int() int {
 	return default_rng.int()
 }
 
+// i32n returns a uniformly distributed pseudorandom 32-bit signed positive `i32` in range `[0, max)`.
+pub fn i32n(max i32) !i32 {
+	return default_rng.i32n(max)
+}
+
 // intn returns a uniformly distributed pseudorandom 32-bit signed positive `int` in range `[0, max)`.
 pub fn intn(max int) !int {
 	return default_rng.intn(max)
@@ -580,6 +612,12 @@ pub fn int_in_range(min int, max int) !int {
 	return default_rng.int_in_range(min, max)
 }
 
+// int_in_range returns a uniformly distributed pseudorandom  32-bit signed int in range `[min, max)`.
+// Both `min` and `max` can be negative, but we must have `min < max`.
+pub fn i32_in_range(min i32, max i32) !i32 {
+	return default_rng.i32_in_range(min, max)
+}
+
 // int31 returns a uniformly distributed pseudorandom 31-bit signed positive `int`.
 pub fn int31() int {
 	return default_rng.int31()

vlib/rand/random_numbers_test.v

@@ -71,6 +71,15 @@ fn test_rand_intn() {
 	}
 }
 
+fn test_rand_i32n() {
+	max := i32(2525642)
+	for _ in 0 .. rnd_count {
+		value := rand.i32n(max) or { panic("Couldn't obtain i32") }
+		assert value >= 0
+		assert value < max
+	}
+}
+
 fn test_rand_i64n() {
 	max := i64(3246727724653636)
 	for _ in 0 .. rnd_count {
@@ -90,6 +99,16 @@ fn test_rand_int_in_range() {
 	}
 }
 
+fn test_rand_i32_in_range() {
+	min := i32(-4252)
+	max := i32(23054962)
+	for _ in 0 .. rnd_count {
+		value := rand.i32_in_range(min, max) or { panic("Couldn't obtain i32 in range") }
+		assert value >= min
+		assert value < max
+	}
+}
+
 fn test_rand_i64_in_range() {
 	min := i64(-24095)
 	max := i64(324058)
@@ -324,7 +343,9 @@ fn test_rand_ascii() {
 fn ensure_same_output(mut rng rand.PRNG) {
 	for _ in 0 .. 100 {
 		assert rand.int() == rng.int()
+		assert rand.i32() == rng.i32()
 		assert rand.intn(45) or { 0 } == rng.intn(45) or { 0 }
+		assert rand.i32n(45) or { 0 } == rng.i32n(45) or { 0 }
 		assert rand.u64() == rng.u64()
 		assert rand.f64() == rng.f64()
 		assert rand.u32n(25) or { 0 } == rng.u32n(25) or { 0 }

vlib/rand/sys/system_rng_test.v

@@ -178,6 +178,20 @@ fn test_sys_rng_intn() {
 	}
 }
 
+fn test_sys_rng_i32n() {
+	max := i32(2525642)
+	for seed in seeds {
+		seed_data := [seed]
+		mut rng := &rand.PRNG(&sys.SysRNG{})
+		rng.seed(seed_data)
+		for _ in 0 .. range_limit {
+			value := rng.i32n(max) or { panic("Couldn't obtain i32") }
+			assert value >= 0
+			assert value < max
+		}
+	}
+}
+
 fn test_sys_rng_i64n() {
 	max := i64(3246727724653636)
 	for seed in seeds {
@@ -207,6 +221,21 @@ fn test_sys_rng_int_in_range() {
 	}
 }
 
+fn test_sys_rng_i32_in_range() {
+	min := i32(-4252)
+	max := i32(23054962)
+	for seed in seeds {
+		seed_data := [seed]
+		mut rng := &rand.PRNG(&sys.SysRNG{})
+		rng.seed(seed_data)
+		for _ in 0 .. range_limit {
+			value := rng.i32_in_range(min, max) or { panic("Couldn't obtain i32 in range") }
+			assert value >= min
+			assert value < max
+		}
+	}
+}
+
 fn test_sys_rng_i64_in_range() {
 	min := i64(-24095)
 	max := i64(324058)