Fix big integer creation from byte array, there was an unneccessary d…

…owncast to int. Fixes #153
ionspin · Feb 9, 2021 · c7e0c99 · c7e0c99
1 parent 2c0dbc2
commit c7e0c99
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/...ommonMain/kotlin/com/ionspin/kotlin/bignum/integer/base63/array/BigInteger63Arithmetic.kt b/...ommonMain/kotlin/com/ionspin/kotlin/bignum/integer/base63/array/BigInteger63Arithmetic.kt
@@ -2204,7 +2204,7 @@ internal object BigInteger63Arithmetic : BigIntegerArithmetic {
                 ulongArray[ulongArray.size - 1] or
                     (trimmedSource[ulongsCount * 8 + i].toULong() shl ((ulongRest - 1) * 8 - i * 8))
         }
-        val result = convertFrom64BitRepresentation(ulongArray.dropLastWhile { it.toUInt() == 0U }.toULongArray())
+        val result = convertFrom64BitRepresentation(ulongArray.dropLastWhile { it == 0UL }.toULongArray())
         return result
     }
 

diff --git a/...um/src/jvmTest/kotlin/com/ionspin/kotlin/bignum/integer/base63/ByteArrayConversionTest.kt b/...um/src/jvmTest/kotlin/com/ionspin/kotlin/bignum/integer/base63/ByteArrayConversionTest.kt
@@ -4,12 +4,14 @@
 
 package com.ionspin.kotlin.bignum.integer.base63
 
+import com.ionspin.kotlin.bignum.integer.Sign
 import com.ionspin.kotlin.bignum.integer.util.fromTwosComplementByteArray
 import com.ionspin.kotlin.bignum.integer.util.hexColumsPrint
 import com.ionspin.kotlin.bignum.integer.util.toTwosComplementByteArray
 import java.math.BigInteger
 import kotlin.random.Random
 import kotlin.test.assertTrue
+import org.junit.Assert
 import org.junit.Test
 
 /**
@@ -807,4 +809,14 @@ class ByteArrayConversionTest {
                     .joinToString(separator = "U, 0x", prefix = "0x", postfix = "U") { it.toString(16) }
             })") { bigIntArray.contentEquals(javaBigIntArray) }
     }
+
+    @Test
+    fun reportedIssueTest() {
+        val bytes = byteArrayOf(-128, 0, 0, 0, 0, 0, 0, 0)
+        val javaBig = BigInteger(1, bytes)
+        val kotlinBig = IonSpinBigInteger.fromByteArray(bytes, Sign.POSITIVE)
+        val javaBackToByteArray = javaBig.toByteArray().dropWhile { it == 0.toByte() }.toByteArray() // Java adds a leading zero byte
+        val bignumBackToByteArray = kotlinBig.toByteArray()
+        Assert.assertArrayEquals(javaBackToByteArray, bignumBackToByteArray)
+    }
 }