Merge pull request #15 from tonkeeper/fixes/bitstring

Bitstring - fix incorrect bounds check

Example/Podfile

@@ -8,3 +8,11 @@ target 'ton-swift-example' do
   pod 'TonSwift', :path => '../', :testspecs => ['Tests'] 
 
 end
+
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    target.build_configurations.each do |config|
+      config.build_settings["IPHONEOS_DEPLOYMENT_TARGET"] = "11.0"
+    end
+  end
+end

Example/Podfile.lock

@@ -1,9 +1,9 @@
 PODS:
   - BigInt (5.2.0)
-  - TonSwift (0.0.1):
+  - TonSwift (1.0.3):
     - BigInt
     - TweetNacl
-  - TonSwift/Tests (0.0.1):
+  - TonSwift/Tests (1.0.3):
     - BigInt
     - TweetNacl
   - TweetNacl (1.0.2)
@@ -23,9 +23,9 @@ EXTERNAL SOURCES:
 
 SPEC CHECKSUMS:
   BigInt: f668a80089607f521586bbe29513d708491ef2f7
-  TonSwift: 72bbfc1d924a4eebac87c8651afea7d2323771c6
+  TonSwift: 8263886e6a34c81a721cde1674cc70229a1d0d44
   TweetNacl: 3abf4d1d2082b0114e7a67410e300892448951e6
 
-PODFILE CHECKSUM: 4414c00005d2c10cd52b412b3080f767ee316ec4
+PODFILE CHECKSUM: adb693e82e588cc090eb72c366a3aff89a95e709
 
-COCOAPODS: 1.12.0
+COCOAPODS: 1.15.2

Source/TonSwift/Cells/Bitstring.swift

@@ -71,7 +71,7 @@ public struct Bitstring: Hashable {
      - returns true if the bit is set, false otherwise
      */
     public func at(_ index: Int) throws -> Bit {
-        guard index <= _length && index >= 0 else {
+        guard index < _length && index >= 0 else {
             throw TonError.indexOutOfBounds(index)
         }
 

Source/TonSwift/Util/TonError.swift

@@ -1,6 +1,6 @@
 import Foundation
 
-public enum TonError: Error {
+public enum TonError: Error, Equatable {
     case indexOutOfBounds(Int)
     case offsetOutOfBounds(Int)
     case custom(String)

Tests/TonSwiftTests/Cells/BitStringTest.swift

@@ -105,4 +105,20 @@ final class BitStringTest: XCTestCase {
             XCTAssertEqual(r.toString(), hex)
         }
     }
+
+    func testCorrectBoundsCheckForBitAccess() throws {
+        let dataHexString = "00240000000054657374205152207369676e6572"
+        let offset = 16
+        let length = 144
+
+        let bitstring = try Bitstring(
+            data: Data(hex: dataHexString)!,
+            offset: offset,
+            length: length
+        )
+
+        XCTAssertThrowsError(try bitstring.at(144)) { error in
+            XCTAssertEqual(error as! TonError, TonError.indexOutOfBounds(144))
+        }
+    }
 }