maps serialization

lynglib/src/commonMain/kotlin/net/sergeych/lynon/LynonDecoder.kt

@@ -56,7 +56,7 @@ open class LynonDecoder(val bin: BitInput, val settings: LynonSettings = LynonSe
         } ?: scope.raiseSymbolNotFound("can't deserialize: not found type $className")
     }
 
-    suspend fun decodeAnyList(scope: Scope): MutableList<Obj> {
+    suspend fun decodeAnyList(scope: Scope,fixedSize: Int?=null): MutableList<Obj> {
         return if (bin.getBit() == 1) {
             // homogenous
             val type = LynonType.entries[getBitsAsInt(4)]
@@ -64,7 +64,7 @@ open class LynonDecoder(val bin: BitInput, val settings: LynonSettings = LynonSe
             val objClass = if (type == LynonType.Other)
                 decodeClassObj(scope).also { println("detected class obj: $it") }
             else type.objClass
-            val size = bin.unpackUnsigned().toInt()
+            val size = fixedSize ?: bin.unpackUnsigned().toInt()
             println("detected homogenous list type $type, $size items")
             for (i in 0..<size) {
                 list += decodeObject(scope, objClass, type).also {
@@ -73,7 +73,7 @@ open class LynonDecoder(val bin: BitInput, val settings: LynonSettings = LynonSe
             }
             list
         } else {
-            val size = unpackUnsigned().toInt()
+            val size = fixedSize ?: unpackUnsigned().toInt()
             (0..<size).map { decodeAny(scope) }.toMutableList()
         }
     }

lynglib/src/commonMain/kotlin/net/sergeych/lynon/LynonEncoder.kt

@@ -108,30 +108,38 @@ open class LynonEncoder(val bout: BitOutput, val settings: LynonSettings = Lynon
      * for each item.
      *
      */
-    suspend fun encodeAnyList(scope: Scope, list: List<Obj>) {
-        val objClass = list[0].objClass
-        var type = list[0].lynonType()
-        var isHomogeneous = true
-        for (i in list.drop(1))
-            if (i.objClass != objClass) {
-                isHomogeneous = false
-                break
-            } else {
-                // same class but type might need generalization
-                type = type.generalizeTo(i.lynonType())
-                    ?: scope.raiseError("inner error: can't generalize lynon type $type to ${i.lynonType()}")
-            }
-        if (isHomogeneous) {
-            putBit(1)
-            putTypeRecord(scope, list[0], type)
-            encodeUnsigned(list.size.toULong())
-            for (i in list) encodeObject(scope, i, type)
-        } else {
+    suspend fun encodeAnyList(scope: Scope, list: List<Obj>,fixedSize: Boolean = false) {
+        if( list.isEmpty()) {
+            // any-typed, empty, save space
             putBit(0)
-            encodeUnsigned(list.size.toULong())
-            for (i in list) encodeAny(scope, i)
+            encodeUnsigned(0u)
+        }
+        else {
+            val objClass = list[0].objClass
+            var type = list[0].lynonType()
+            var isHomogeneous = true
+            for (i in list.drop(1))
+                if (i.objClass != objClass) {
+                    isHomogeneous = false
+                    break
+                } else {
+                    // same class but type might need generalization
+                    type = type.generalizeTo(i.lynonType())
+                        ?: scope.raiseError("inner error: can't generalize lynon type $type to ${i.lynonType()}")
+                }
+            if (isHomogeneous) {
+                putBit(1)
+                putTypeRecord(scope, list[0], type)
+                if (!fixedSize)
+                    encodeUnsigned(list.size.toULong())
+                for (i in list) encodeObject(scope, i, type)
+            } else {
+                putBit(0)
+                if (!fixedSize)
+                    encodeUnsigned(list.size.toULong())
+                for (i in list) encodeAny(scope, i)
+            }
         }
-
     }
 
     /**