From e98c5b65e9b24e7020ef1dd1e9066ba318c91a31 Mon Sep 17 00:00:00 2001
From: Humza Shahid <humzasaur@gmail.com>
Date: Thu, 26 Dec 2024 15:10:33 +0000
Subject: [PATCH] add bin search function

---
 fcore/bin-search.sml | 23 +++++++++++++++++++++++
 oms.mlb              |  1 +
 2 files changed, 24 insertions(+)
 create mode 100644 fcore/bin-search.sml

diff --git a/fcore/bin-search.sml b/fcore/bin-search.sml
new file mode 100644
index 0000000..c752672
--- /dev/null
+++ b/fcore/bin-search.sml
@@ -0,0 +1,23 @@
+structure BinSearch =
+struct
+  local
+    fun helpFind (findNum, vec, low, high) =
+      if high >= low then
+        let
+          val mid = low + ((high - low) div 2)
+          val curNum = Vector.sub (vec, mid)
+        in
+          if curNum = findNum then
+            mid
+          else if curNum < findNum then
+            helpFind (findNum, vec, mid + 1, high)
+          else
+            helpFind (findNum, vec, low, mid - 1)
+        end
+      else
+        ~1
+  in
+    fun find (findNum, vec) =
+      helpFind (findNum, vec, 0, Vector.length vec - 1)
+  end
+end
diff --git a/oms.mlb b/oms.mlb
index 54ec3af..6c0ccdd 100644
--- a/oms.mlb
+++ b/oms.mlb
@@ -2,6 +2,7 @@ $(SML_LIB)/basis/basis.mlb
 
 (* fcore *)
 fcore/quad-tree.sml
+fcore/bin-search.sml
 
 ann
   "allowVectorExps true"