From 39e5c3736135f9a49daceee1fe4da9fbdbb96eab Mon Sep 17 00:00:00 2001
From: Karsten Schmidt <k@postspectacular.com>
Date: Thu, 21 Jan 2021 11:26:23 +0000
Subject: [PATCH] fix(arrays): fixed-length binarySearch2/4/8/16/32

- add binarySearch2()
- fix results for not-found values, make compatible w/ binarySearch()
---
 packages/arrays/src/binary-search.ts | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/packages/arrays/src/binary-search.ts b/packages/arrays/src/binary-search.ts
index 5ee840af47..bda59bb75d 100644
--- a/packages/arrays/src/binary-search.ts
+++ b/packages/arrays/src/binary-search.ts
@@ -86,6 +86,11 @@ export const binarySearchNumeric = (
     return -low - 1;
 };
 
+export const binarySearch2 = (buf: ArrayLike<number>, x: number) => {
+    let idx = buf[1] <= x ? 1 : 0;
+    return buf[idx] === x ? idx : buf[0] < x ? -idx - 2 : -1;
+};
+
 /**
  * Non-recursive, optimized binary search for fixed size numeric arrays of 4
  * values. Returns index of `x` or `-index-1` if not found.
@@ -96,7 +101,7 @@ export const binarySearchNumeric = (
 export const binarySearch4 = (buf: ArrayLike<number>, x: number) => {
     let idx = buf[2] <= x ? 2 : 0;
     idx |= buf[idx + 1] <= x ? 1 : 0;
-    return buf[idx] === x ? idx : -idx - 1;
+    return buf[idx] === x ? idx : buf[0] < x ? -idx - 2 : -1;
 };
 
 /**
@@ -110,7 +115,7 @@ export const binarySearch8 = (buf: ArrayLike<number>, x: number) => {
     let idx = buf[4] <= x ? 4 : 0;
     idx |= buf[idx + 2] <= x ? 2 : 0;
     idx |= buf[idx + 1] <= x ? 1 : 0;
-    return buf[idx] === x ? idx : -idx - 1;
+    return buf[idx] === x ? idx : buf[0] < x ? -idx - 2 : -1;
 };
 
 /**
@@ -125,7 +130,7 @@ export const binarySearch16 = (buf: ArrayLike<number>, x: number) => {
     idx |= buf[idx + 4] <= x ? 4 : 0;
     idx |= buf[idx + 2] <= x ? 2 : 0;
     idx |= buf[idx + 1] <= x ? 1 : 0;
-    return buf[idx] === x ? idx : -idx - 1;
+    return buf[idx] === x ? idx : buf[0] < x ? -idx - 2 : -1;
 };
 
 /**
@@ -141,7 +146,7 @@ export const binarySearch32 = (buf: ArrayLike<number>, x: number) => {
     idx |= buf[idx + 4] <= x ? 4 : 0;
     idx |= buf[idx + 2] <= x ? 2 : 0;
     idx |= buf[idx + 1] <= x ? 1 : 0;
-    return buf[idx] === x ? idx : -idx - 1;
+    return buf[idx] === x ? idx : buf[0] < x ? -idx - 2 : -1;
 };
 
 /**