From c45c6706234d5fb6e28f72e27dad7a9a23ad1c98 Mon Sep 17 00:00:00 2001
From: Cervenka Dusan <cervenka@acrios.com>
Date: Fri, 20 Dec 2019 08:29:51 +0100
Subject: [PATCH] Fixed VLA/VSA for all types.

Null termination removed.
---
 dissect/cstruct/cstruct.py | 40 ++++++++++++++++++++++++++------------
 1 file changed, 28 insertions(+), 12 deletions(-)

diff --git a/dissect/cstruct/cstruct.py b/dissect/cstruct/cstruct.py
index 3314e40..5c24ccd 100644
--- a/dissect/cstruct/cstruct.py
+++ b/dissect/cstruct/cstruct.py
@@ -985,7 +985,7 @@ class Array(BaseType):
         When using the default C-style parser, the following syntax is supported:
 
             x[3] -> 3 -> static length.
-            x[] -> None -> null-terminated.
+            x[] -> None -> length based on data buf length (to the end of buffer) (VLA/VSA).
             x[expr] -> expr -> dynamic length.
     """
 
@@ -1522,14 +1522,30 @@ def gen_struct_class(self, structure):
                         num = 'max(0, Expression(self.cstruct, "{expr}").evaluate(r))'.format(
                             expr=num.expr
                         )
-
-                    struct_read += (
-                        'r["{name}"] = []\n'
-                        'for _ in xrange({num}):\n'
-                        '    r["{name}"].append(self.cstruct.{struct_name}._read(stream))\n'.format(
-                            name=field.name, num=num, struct_name=ft.type.name
+                    if ft.dynamic:  #To the end of buffer
+                        struct_read += (
+                            'r["{name}"] = []\n'
+                            'while True:\n'
+                            '    bufSize = stream.getbuffer().nbytes\n'
+                            '    bufPos = stream.tell()\n'
+                            '    try:'
+                            '       a = self.cstruct.{struct_name}._read(stream)\n'
+                            '    except:\n'
+                            '       if bufSize == bufPos:\n'
+                            '           break;\n'
+                            '       raise EOFError()\n'
+                            '    r["{name}"].append(a)\n'.format(
+                                name=field.name, num=num, struct_name=ft.type.name
+                            )
+                        )
+                    else:
+                        struct_read += (
+                            'r["{name}"] = []\n'
+                            'for _ in xrange({num}):\n'
+                            '    r["{name}"].append(self.cstruct.{struct_name}._read(stream))\n'.format(
+                                name=field.name, num=num, struct_name=ft.type.name
+                            )
                         )
-                    )
                 else:
                     struct_read += 'r["{name}"] = self.cstruct.{struct_name}._read(stream)\n'.format(
                         name=field.name, struct_name=ft.name
@@ -1713,14 +1729,14 @@ def gen_dynamic_block(self, field):
         t = field.type.type
         reader = None
 
-        if not field.type.count:  # Null terminated
+        if not field.type.count:  #To the end of buffer
             if isinstance(t, PackedType):
                 reader = (
                     't = []\nwhile True:\n'
                     '    d = stream.read({size})\n'
+                    '    if len(d) == 0: break\n'
                     '    if len(d) != {size}: raise EOFError()\n'
                     '    v = struct.unpack(self.cstruct.endian + "{packchar}", d)[0]\n'
-                    '    if v == 0: break\n'
                     '    t.append(v)'.format(size=t.size, packchar=t.packchar)
                 )
 
@@ -1738,14 +1754,14 @@ def gen_dynamic_block(self, field):
 
                 if isinstance(t, WcharType):
                     reader += ".decode('utf-16-le' if self.cstruct.endian == '<' else 'utf-16-be')"
-            elif isinstance(t, BytesInteger):
+            elif isinstance(t, BytesInteger):  #To the end of buffer
                 reader = (
                     't = []\n'
                     'while True:\n'
                     '    d = stream.read({size})\n'
+                    '    if len(d) == 0: break\n'
                     '    if len(d) != {size}: raise EOFError()\n'
                     '    v = BytesInteger.parse(d, {size}, 1, {signed}, self.cstruct.endian)\n'
-                    '    if v == 0: break\n'
                     '    t.append(v)'.format(size=t.size, signed=t.signed)
                 )