Sort map keys in CBOR encoder

2026-03-22 17:41:44 +01:00
parent 98ba43bea9
commit 21fa1e08b8
1 changed files with 14 additions and 3 deletions
@@ -13,7 +13,7 @@ class CborEncoder {
        val map = CborMapEncoder()
        map.block()
        writeHeader(5, map.entries.size)
-        map.entries.forEach { out.addAll(it) }
+        sortCanonical(map.entries).forEach { out.addAll(it) }
    }

    fun toByteArray(): ByteArray = out.toByteArray()
@@ -39,7 +39,7 @@ class CborMapEncoder {
        nested.block()
        val bytes = mutableListOf<Byte>()
        bytes.addAll(encodeHeader(5, nested.entries.size))
-        nested.entries.forEach { bytes.addAll(it) }
+        sortCanonical(nested.entries).forEach { bytes.addAll(it) }
        return CborRaw(bytes)
    }

@@ -67,7 +67,7 @@ class CborArrayEncoder {
        nested.block()
        val bytes = mutableListOf<Byte>()
        bytes.addAll(encodeHeader(5, nested.entries.size))
-        nested.entries.forEach { bytes.addAll(it) }
+        sortCanonical(nested.entries).forEach { bytes.addAll(it) }
        items.add(bytes)
    }
 }
@@ -75,6 +75,17 @@ class CborArrayEncoder {
@JvmInline
 value class CborRaw(val bytes: List<Byte>)

+private fun sortCanonical(entries: List<List<Byte>>): List<List<Byte>> {
+    return entries.sortedWith { a, b ->
+        val ka = CborDecoder.measureFirstValue(a.toByteArray())
+        val kb = CborDecoder.measureFirstValue(b.toByteArray())
+        if (ka != kb) ka - kb
+        else (0 until ka).map {
+            (a[it].toInt() and 0xFF) - (b[it].toInt() and 0xFF)
+        }.firstOrNull { it != 0 } ?: 0
+    }
+}
+
 private fun encodeValue(value: Any?): List<Byte> = when (value) {
    null -> listOf(0xF6.toByte())
    is Boolean -> listOf(if (value) 0xF5.toByte() else 0xF4.toByte())