diff --git a/src/main/java/io/github/yezhihao/protostar/schema/CollectionSchema.java b/src/main/java/io/github/yezhihao/protostar/schema/CollectionSchema.java
index c99b57b..8bc54ae 100644
--- a/src/main/java/io/github/yezhihao/protostar/schema/CollectionSchema.java
+++ b/src/main/java/io/github/yezhihao/protostar/schema/CollectionSchema.java
@@ -37,7 +37,11 @@ public class CollectionSchema<T> implements Schema<List<T>> {
 
     @Override
     public List<T> readFrom(ByteBuf input, int length) {
-        return this.readFrom(input.readSlice(length));
+        int writerIndex = input.writerIndex();
+        input.writerIndex(input.readerIndex() + length);
+        List<T> result = this.readFrom(input);
+        input.writerIndex(writerIndex);
+        return result;
     }
 
     @Override
diff --git a/src/main/java/io/github/yezhihao/protostar/schema/ConvertSchema.java b/src/main/java/io/github/yezhihao/protostar/schema/ConvertSchema.java
index 9ae56c1..051c079 100644
--- a/src/main/java/io/github/yezhihao/protostar/schema/ConvertSchema.java
+++ b/src/main/java/io/github/yezhihao/protostar/schema/ConvertSchema.java
@@ -35,8 +35,13 @@ public class ConvertSchema<T> implements Schema<T> {
 
     @Override
     public T readFrom(ByteBuf input, int length) {
-        if (length > 0)
-            input = input.readSlice(length);
+        if (length > 0) {
+            int writerIndex = input.writerIndex();
+            input.writerIndex(input.readerIndex() + length);
+            T result = converter.convert(input);
+            input.writerIndex(writerIndex);
+            return result;
+        }
         return converter.convert(input);
     }
 
diff --git a/src/main/java/io/github/yezhihao/protostar/schema/ObjectSchema.java b/src/main/java/io/github/yezhihao/protostar/schema/ObjectSchema.java
index d29e820..9b6c6fb 100644
--- a/src/main/java/io/github/yezhihao/protostar/schema/ObjectSchema.java
+++ b/src/main/java/io/github/yezhihao/protostar/schema/ObjectSchema.java
@@ -25,8 +25,13 @@ public class ObjectSchema<T> implements Schema<T> {
 
     @Override
     public T readFrom(ByteBuf input, int length) {
-        if (length > 0)
-            input = input.readSlice(length);
+        if (length > 0) {
+            int writerIndex = input.writerIndex();
+            input.writerIndex(input.readerIndex() + length);
+            T result = schema.readFrom(input);
+            input.writerIndex(writerIndex);
+            return result;
+        }
         return schema.readFrom(input);
     }