From b8f8cb95823e0e56e0d8fd6ace5b38d9d57d03ff Mon Sep 17 00:00:00 2001
From: Feoramund <161657516+Feoramund@users.noreply.github.com>
Date: Tue, 3 Sep 2024 06:02:18 -0400
Subject: Add `bit_array.shrink`

---
 core/container/bit_array/bit_array.odin | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

(limited to 'core/container/bit_array/bit_array.odin')

diff --git a/core/container/bit_array/bit_array.odin b/core/container/bit_array/bit_array.odin
index 61119ef96..b1149e82e 100644
--- a/core/container/bit_array/bit_array.odin
+++ b/core/container/bit_array/bit_array.odin
@@ -1,5 +1,6 @@
 package container_dynamic_bit_array
 
+import "base:builtin"
 import "base:intrinsics"
 import "core:mem"
 
@@ -299,6 +300,35 @@ clear :: proc(ba: ^Bit_Array) {
 	mem.zero_slice(ba.bits[:])
 }
 /*
+Shrinks the Bit_Array's backing storage to the smallest possible size.
+
+Inputs:
+- ba: The target Bit_Array
+*/
+shrink :: proc(ba: ^Bit_Array) #no_bounds_check {
+	if ba == nil { return }
+	legs_needed := len(ba.bits)
+	for i := legs_needed - 1; i >= 0; i -= 1 {
+		if ba.bits[i] == 0 {
+			legs_needed -= 1
+		} else {
+			break
+		}
+	}
+	if legs_needed == len(ba.bits) {
+		return
+	}
+	ba.max_index = 0
+	if legs_needed > 0 {
+		if legs_needed > 1 {
+			ba.max_index = (legs_needed - 1) * NUM_BITS
+		}
+		ba.max_index += NUM_BITS - 1 - int(intrinsics.count_leading_zeros(ba.bits[legs_needed - 1]))
+	}
+	resize(&ba.bits, legs_needed)
+	builtin.shrink(&ba.bits)
+}
+/*
 Deallocates the Bit_Array and its backing storage
 
 Inputs:
-- 
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