From 1eeda314beadd89b5308a7d8068cf1adec6575b6 Mon Sep 17 00:00:00 2001
From: mohanson <mohanson@outlook.com>
Date: Wed, 16 Oct 2024 19:35:10 +0800
Subject: [PATCH] Update leb128

---
 pywasm/leb128.py | 40 ++++++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 10 deletions(-)

diff --git a/pywasm/leb128.py b/pywasm/leb128.py
index 91d4fd63..5938bc34 100644
--- a/pywasm/leb128.py
+++ b/pywasm/leb128.py
@@ -1,9 +1,11 @@
-# https://en.wikipedia.org/wiki/LEB128
-#
-# LEB128 or Little Endian Base 128 is a form of variable-length code
-# compression used to store an arbitrarily large integer in a small number of
-# bytes. LEB128 is used in the DWARF debug file format and the WebAssembly
-# binary encoding for all integer literals.
+"""
+https://en.wikipedia.org/wiki/LEB128
+
+LEB128 or Little Endian Base 128 is a form of variable-length code
+compression used to store an arbitrarily large integer in a small number of
+bytes. LEB128 is used in the DWARF debug file format and the WebAssembly
+binary encoding for all integer literals.
+"""
 
 import typing
 
@@ -11,6 +13,7 @@
 class _U:
     @staticmethod
     def encode(i: int) -> bytearray:
+        """Encode the int i using unsigned leb128 and return the encoded bytearray."""
         assert i >= 0
         r = []
         while True:
@@ -23,16 +26,24 @@ def encode(i: int) -> bytearray:
 
     @staticmethod
     def decode(b: bytearray) -> int:
+        """Decode the unsigned leb128 encoded bytearray"""
         r = 0
         for i, e in enumerate(b):
             r = r + ((e & 0x7f) << (i * 7))
         return r
 
     @staticmethod
-    def decode_reader(r: typing.BinaryIO) -> (int, int):
+    def decode_reader(r: typing.BinaryIO) -> typing.Tuple[int, int]:
+        """
+        Decode the unsigned leb128 encoded from a reader, it will return two values, the actual number and the number
+        of bytes read.
+        """
         a = bytearray()
         while True:
-            b = ord(r.read(1))
+            b = r.read(1)
+            if len(b) != 1:
+                raise EOFError
+            b = ord(b)
             a.append(b)
             if (b & 0x80) == 0:
                 break
@@ -42,6 +53,7 @@ def decode_reader(r: typing.BinaryIO) -> (int, int):
 class _I:
     @staticmethod
     def encode(i: int) -> bytearray:
+        """Encode the int i using signed leb128 and return the encoded bytearray."""
         r = []
         while True:
             byte = i & 0x7f
@@ -53,6 +65,7 @@ def encode(i: int) -> bytearray:
 
     @staticmethod
     def decode(b: bytearray) -> int:
+        """Decode the signed leb128 encoded bytearray"""
         r = 0
         for i, e in enumerate(b):
             r = r + ((e & 0x7f) << (i * 7))
@@ -61,10 +74,17 @@ def decode(b: bytearray) -> int:
         return r
 
     @staticmethod
-    def decode_reader(r: typing.BinaryIO) -> (int, int):
+    def decode_reader(r: typing.BinaryIO) -> typing.Tuple[int, int]:
+        """
+        Decode the signed leb128 encoded from a reader, it will return two values, the actual number and the number
+        of bytes read.
+        """
         a = bytearray()
         while True:
-            b = ord(r.read(1))
+            b = r.read(1)
+            if len(b) != 1:
+                raise EOFError
+            b = ord(b)
             a.append(b)
             if (b & 0x80) == 0:
                 break