From fc9430f56798a53f9393a697f4ccd6bf9981b970 Mon Sep 17 00:00:00 2001
From: Martin Wickham <spexguy070@gmail.com>
Date: Thu, 3 Jun 2021 15:39:26 -0500
Subject: Breaking hash map changes for 0.8.0

- hash/eql functions moved into a Context object
- *Context functions pass an explicit context
- *Adapted functions pass specialized keys and contexts
- new getPtr() function returns a pointer to value
- remove functions renamed to fetchRemove
- new remove functions return bool
- removeAssertDiscard deleted, use assert(remove(...)) instead
- Keys and values are stored in separate arrays
- Entry is now {*K, *V}, the new KV is {K, V}
- BufSet/BufMap functions renamed to match other set/map types
- fixed iterating-while-modifying bug in src/link/C.zig
---
 lib/std/math.zig | 51 +++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 47 insertions(+), 4 deletions(-)

(limited to 'lib/std/math.zig')

diff --git a/lib/std/math.zig b/lib/std/math.zig
index 4605c46970..ac28cbb4e2 100644
--- a/lib/std/math.zig
+++ b/lib/std/math.zig
@@ -380,12 +380,41 @@ test "math.min" {
     }
 }
 
+/// Finds the min of three numbers
+pub fn min3(x: anytype, y: anytype, z: anytype) @TypeOf(x, y, z) {
+    return min(x, min(y, z));
+}
+
+test "math.min3" {
+    try testing.expect(min3(@as(i32, 0), @as(i32, 1), @as(i32, 2)) == 0);
+    try testing.expect(min3(@as(i32, 0), @as(i32, 2), @as(i32, 1)) == 0);
+    try testing.expect(min3(@as(i32, 1), @as(i32, 0), @as(i32, 2)) == 0);
+    try testing.expect(min3(@as(i32, 1), @as(i32, 2), @as(i32, 0)) == 0);
+    try testing.expect(min3(@as(i32, 2), @as(i32, 0), @as(i32, 1)) == 0);
+    try testing.expect(min3(@as(i32, 2), @as(i32, 1), @as(i32, 0)) == 0);
+}
+
 pub fn max(x: anytype, y: anytype) @TypeOf(x, y) {
     return if (x > y) x else y;
 }
 
 test "math.max" {
     try testing.expect(max(@as(i32, -1), @as(i32, 2)) == 2);
+    try testing.expect(max(@as(i32, 2), @as(i32, -1)) == 2);
+}
+
+/// Finds the max of three numbers
+pub fn max3(x: anytype, y: anytype, z: anytype) @TypeOf(x, y, z) {
+    return max(x, max(y, z));
+}
+
+test "math.max3" {
+    try testing.expect(max3(@as(i32, 0), @as(i32, 1), @as(i32, 2)) == 2);
+    try testing.expect(max3(@as(i32, 0), @as(i32, 2), @as(i32, 1)) == 2);
+    try testing.expect(max3(@as(i32, 1), @as(i32, 0), @as(i32, 2)) == 2);
+    try testing.expect(max3(@as(i32, 1), @as(i32, 2), @as(i32, 0)) == 2);
+    try testing.expect(max3(@as(i32, 2), @as(i32, 0), @as(i32, 1)) == 2);
+    try testing.expect(max3(@as(i32, 2), @as(i32, 1), @as(i32, 0)) == 2);
 }
 
 pub fn clamp(val: anytype, lower: anytype, upper: anytype) @TypeOf(val, lower, upper) {
@@ -581,6 +610,17 @@ pub fn Log2Int(comptime T: type) type {
     return std.meta.Int(.unsigned, count);
 }
 
+pub fn Log2IntCeil(comptime T: type) type {
+    // comptime ceil log2
+    comptime var count = 0;
+    comptime var s = @typeInfo(T).Int.bits;
+    inline while (s != 0) : (s >>= 1) {
+        count += 1;
+    }
+
+    return std.meta.Int(.unsigned, count);
+}
+
 pub fn IntFittingRange(comptime from: comptime_int, comptime to: comptime_int) type {
     assert(from <= to);
     if (from == 0 and to == 0) {
@@ -1046,15 +1086,18 @@ fn testCeilPowerOfTwo() !void {
 }
 
 pub fn log2_int(comptime T: type, x: T) Log2Int(T) {
+    if (@typeInfo(T) != .Int or @typeInfo(T).Int.signedness != .unsigned)
+        @compileError("log2_int requires an unsigned integer, found "++@typeName(T));
     assert(x != 0);
     return @intCast(Log2Int(T), @typeInfo(T).Int.bits - 1 - @clz(T, x));
 }
 
-pub fn log2_int_ceil(comptime T: type, x: T) Log2Int(T) {
+pub fn log2_int_ceil(comptime T: type, x: T) Log2IntCeil(T) {
+    if (@typeInfo(T) != .Int or @typeInfo(T).Int.signedness != .unsigned)
+        @compileError("log2_int_ceil requires an unsigned integer, found "++@typeName(T));
     assert(x != 0);
-    const log2_val = log2_int(T, x);
-    if (@as(T, 1) << log2_val == x)
-        return log2_val;
+    if (x == 1) return 0;
+    const log2_val: Log2IntCeil(T) = log2_int(T, x - 1);
     return log2_val + 1;
 }
 
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