refactor: remove no-op randomness from key derivation

Author: zijievv

README.md

@@ -90,9 +90,7 @@ Expands to (simplified):
     @inline(__always)
     func $_deriveKey(_ u: [UInt8], _ i: UInt8) -> UInt8 {
         var h: UInt8 = i
-        let r = Int.random(in: 0 ... 16)
-        let s = r > 15 ? r : 16
-        for b in u[0 ..< s] {
+        for b in u {
             h = (h &+ (b &* 31)) ^ 0x5D
         }
         return h

Sources/ObfuStringMacros/ObfuscationAlgorithms/Obfuscation.swift

@@ -45,9 +45,7 @@ enum Obfuscation: CaseIterable {
         @inline(__always)
         func \(funcName)(_ u: [UInt8], _ i: UInt8) -> UInt8 {
             var h: UInt8 = i
-            let r = Int.random(in: 0...16)
-            let s = r > 15 ? r : 16
-            for b in u[0..<s] {
+            for b in u {
                 h = (h &+ (b &* 31)) ^ 0x5D
             }
             return h

Tests/ObfuStringTests/ObfuStringMacroTests.swift

@@ -30,9 +30,7 @@ final class ObfuStringMacroAlgoTests: XCTestCase {
                     @inline(__always)
                     func deriveKeyFn(_ u: [UInt8], _ i: UInt8) -> UInt8 {
                         var h: UInt8 = i
-                        let r = Int.random(in: 0 ... 16)
-                        let s = r > 15 ? r : 16
-                        for b in u[0 ..< s] {
+                        for b in u {
                             h = (h &+ (b &* 31)) ^ 0x5D
                         }
                         return h
@@ -80,9 +78,7 @@ final class ObfuStringMacroAlgoTests: XCTestCase {
                     @inline(__always)
                     func deriveKeyFn(_ u: [UInt8], _ i: UInt8) -> UInt8 {
                         var h: UInt8 = i
-                        let r = Int.random(in: 0 ... 16)
-                        let s = r > 15 ? r : 16
-                        for b in u[0 ..< s] {
+                        for b in u {
                             h = (h &+ (b &* 31)) ^ 0x5D
                         }
                         return h
@@ -127,9 +123,7 @@ final class ObfuStringMacroAlgoTests: XCTestCase {
                     @inline(__always)
                     func deriveKeyFn(_ u: [UInt8], _ i: UInt8) -> UInt8 {
                         var h: UInt8 = i
-                        let r = Int.random(in: 0 ... 16)
-                        let s = r > 15 ? r : 16
-                        for b in u[0 ..< s] {
+                        for b in u {
                             h = (h &+ (b &* 31)) ^ 0x5D
                         }
                         return h
@@ -175,9 +169,7 @@ final class ObfuStringMacroAlgoTests: XCTestCase {
                     @inline(__always)
                     func deriveKeyFn(_ u: [UInt8], _ i: UInt8) -> UInt8 {
                         var h: UInt8 = i
-                        let r = Int.random(in: 0 ... 16)
-                        let s = r > 15 ? r : 16
-                        for b in u[0 ..< s] {
+                        for b in u {
                             h = (h &+ (b &* 31)) ^ 0x5D
                         }
                         return h
@@ -230,9 +222,7 @@ final class ObfuStringMacroAlgoTests: XCTestCase {
                     @inline(__always)
                     func deriveKeyFn(_ u: [UInt8], _ i: UInt8) -> UInt8 {
                         var h: UInt8 = i
-                        let r = Int.random(in: 0 ... 16)
-                        let s = r > 15 ? r : 16
-                        for b in u[0 ..< s] {
+                        for b in u {
                             h = (h &+ (b &* 31)) ^ 0x5D
                         }
                         return h
@@ -259,9 +249,7 @@ final class ObfuStringMacroAlgoTests: XCTestCase {
                     @inline(__always)
                     func deriveKeyFn(_ u: [UInt8], _ i: UInt8) -> UInt8 {
                         var h: UInt8 = i
-                        let r = Int.random(in: 0 ... 16)
-                        let s = r > 15 ? r : 16
-                        for b in u[0 ..< s] {
+                        for b in u {
                             h = (h &+ (b &* 31)) ^ 0x5D
                         }
                         return h
@@ -310,9 +298,7 @@ final class ObfuStringMacroAlgoTests: XCTestCase {
                     @inline(__always)
                     func deriveKeyFn(_ u: [UInt8], _ i: UInt8) -> UInt8 {
                         var h: UInt8 = i
-                        let r = Int.random(in: 0 ... 16)
-                        let s = r > 15 ? r : 16
-                        for b in u[0 ..< s] {
+                        for b in u {
                             h = (h &+ (b &* 31)) ^ 0x5D
                         }
                         return h
@@ -358,9 +344,7 @@ final class ObfuStringMacroAlgoTests: XCTestCase {
                     @inline(__always)
                     func deriveKeyFn(_ u: [UInt8], _ i: UInt8) -> UInt8 {
                         var h: UInt8 = i
-                        let r = Int.random(in: 0 ... 16)
-                        let s = r > 15 ? r : 16
-                        for b in u[0 ..< s] {
+                        for b in u {
                             h = (h &+ (b &* 31)) ^ 0x5D
                         }
                         return h