Merge pull request #1 from cowgp/develop

Add methods for writing unsigned Int so it's possible to write a UInt64

Author: tsolomko

Sources/BitWriter.swift

@@ -54,7 +54,23 @@ public final class LsbBitWriter: BitWriter {
             mask <<= 1
         }
     }
+    
+    /**
+     Writes `number`, using and advancing by `bitsCount` BIT positions.
 
+     - Note: If `bitsCount` is smaller than the actual amount of `number`'s bits than the `number` will be truncated to
+     fit into `bitsCount` amount of bits.
+     - Note: Bits of `number` are processed using the same bit-numbering scheme as of the writer (i.e. "LSB 0").
+     - Note: This method is specifically useful when needing to write a UInt64 which can overflow and crash if converting to an Int when using the regular `write` method
+     */
+    public func write(unsignedNumber: UInt, bitsCount: Int) {
+        var mask: UInt = 1
+        for _ in 0..<bitsCount {
+            self.write(bit: unsignedNumber & mask > 0 ? 1 : 0)
+            mask <<= 1
+        }
+    }
+    
     /**
      Writes `byte`, advancing by one BYTE position.
 

Sources/LsbBitWriter.swift

@@ -54,6 +54,22 @@ public final class MsbBitWriter: BitWriter {
             mask >>= 1
         }
     }
+    
+    /**
+     Writes `number`, using and advancing by `bitsCount` BIT positions.
+
+     - Note: If `bitsCount` is smaller than the actual amount of `number`'s bits than the `number` will be truncated to
+     fit into `bitsCount` amount of bits.
+     - Note: Bits of `number` are processed using the same bit-numbering scheme as of the writer (i.e. "MSB 0").
+     - Note: This method is specifically useful when needing to write a UInt64 which can overflow and crash if converting to an Int when using the regular `write` method
+     */
+    public func write(unsignedNumber: UInt, bitsCount: Int) {
+        var mask: UInt = 1 << (UInt(truncatingIfNeeded: bitsCount) - 1)
+        for _ in 0..<bitsCount {
+            self.write(bit: unsignedNumber & mask > 0 ? 1 : 0)
+            mask >>= 1
+        }
+    }
 
     /**
      Writes `byte`, advancing by one BYTE position.

Sources/MsbBitWriter.swift

@@ -78,5 +78,13 @@ class LsbBitWriterTests: XCTestCase {
         let bitReader = LsbBitReader(data: bitWriter.data)
         XCTAssertEqual(bitReader.int(fromBits: 14), 14582)
     }
+    
+    func testUInt64() {
+        let bitWriter = LsbBitWriter()
+        bitWriter.write(unsignedNumber: UInt(UInt64.max), bitsCount: UInt64.bitWidth)
+        
+        let byteReader = ByteReader.init(data: bitWriter.data)
+        XCTAssertEqual(byteReader.uint64(), UInt64.max)
+    }
 
 }

Tests/BitByteDataTests/LsbBitWriterTests.swift

@@ -81,5 +81,13 @@ class MsbBitWriterTests: XCTestCase {
         let bitReader = MsbBitReader(data: bitWriter.data)
         XCTAssertEqual(bitReader.int(fromBits: 14), 14582)
     }
+    
+    func testUInt64() {
+        let bitWriter = MsbBitWriter()
+        bitWriter.write(unsignedNumber: UInt(UInt64.max), bitsCount: UInt64.bitWidth)
+        
+        let byteReader = ByteReader.init(data: bitWriter.data)
+        XCTAssertEqual(byteReader.uint64(), UInt64.max)
+    }
 
 }