more cleanup to used pack/unpack, compatibility sjis

kaitaistruct.lua

@@ -1,6 +1,6 @@
 local class = require("class")
 local stringstream = require("string_stream")
-local struct = string.unpack and string or require("struct")
+local lunpack = require("struct").unpack
 
 local function try_require(name)
     local success, mod = pcall(require, name)
@@ -83,79 +83,79 @@ end
 -------------------------------------------------------------------------------
 
 function KaitaiStream:read_s1()
-    return struct.unpack('b', self._io:read(1))
+    return lunpack('b', self._io:read(1))
 end
 
 --.............................................................................
 -- Big-endian
 --.............................................................................
 
 function KaitaiStream:read_s2be()
-    return struct.unpack('>h', self._io:read(2))
+    return lunpack('>h', self._io:read(2))
 end
 
 function KaitaiStream:read_s4be()
-    return struct.unpack('>i', self._io:read(4))
+    return lunpack('>i', self._io:read(4))
 end
 
 function KaitaiStream:read_s8be()
-    return struct.unpack('>l', self._io:read(8))
+    return lunpack('>l', self._io:read(8))
 end
 
 --.............................................................................
 -- Little-endian
 --.............................................................................
 
 function KaitaiStream:read_s2le()
-    return struct.unpack('<h', self._io:read(2))
+    return lunpack('<h', self._io:read(2))
 end
 
 function KaitaiStream:read_s4le()
-    return struct.unpack('<i', self._io:read(4))
+    return lunpack('<i', self._io:read(4))
 end
 
 function KaitaiStream:read_s8le()
-    return struct.unpack('<l', self._io:read(8))
+    return lunpack('<l', self._io:read(8))
 end
 
 -------------------------------------------------------------------------------
 -- Unsigned
 -------------------------------------------------------------------------------
 
 function KaitaiStream:read_u1()
-    return struct.unpack('B', self._io:read(1))
+    return lunpack('B', self._io:read(1))
 end
 
 --.............................................................................
 -- Big-endian
 --.............................................................................
 
 function KaitaiStream:read_u2be()
-    return struct.unpack('>H', self._io:read(2))
+    return lunpack('>H', self._io:read(2))
 end
 
 function KaitaiStream:read_u4be()
-    return struct.unpack('>I', self._io:read(4))
+    return lunpack('>I', self._io:read(4))
 end
 
 function KaitaiStream:read_u8be()
-    return struct.unpack('>L', self._io:read(8))
+    return lunpack('>L', self._io:read(8))
 end
 
 --.............................................................................
 -- Little-endian
 --.............................................................................
 
 function KaitaiStream:read_u2le()
-    return struct.unpack('<H', self._io:read(2))
+    return lunpack('<H', self._io:read(2))
 end
 
 function KaitaiStream:read_u4le()
-    return struct.unpack('<I', self._io:read(4))
+    return lunpack('<I', self._io:read(4))
 end
 
 function KaitaiStream:read_u8le()
-    return struct.unpack('<L', self._io:read(8))
+    return lunpack('<L', self._io:read(8))
 end
 
 --=============================================================================
@@ -167,23 +167,23 @@ end
 -------------------------------------------------------------------------------
 
 function KaitaiStream:read_f4be()
-    return struct.unpack('>f', self._io:read(4))
+    return lunpack('>f', self._io:read(4))
 end
 
 function KaitaiStream:read_f8be()
-    return struct.unpack('>d', self._io:read(8))
+    return lunpack('>d', self._io:read(8))
 end
 
 -------------------------------------------------------------------------------
 -- Little-endian
 -------------------------------------------------------------------------------
 
 function KaitaiStream:read_f4le()
-    return struct.unpack('<f', self._io:read(4))
+    return lunpack('<f', self._io:read(4))
 end
 
 function KaitaiStream:read_f8le()
-    return struct.unpack('<d', self._io:read(8))
+    return lunpack('<d', self._io:read(8))
 end
 
 --=============================================================================

string_decode.lua

@@ -2,7 +2,6 @@
 -- String decoder functions
 --
 
-local unpack = rawget(_G, 'unpack') or table.unpack
 local lunicode = require(".unicode")
 
 local stringdecode = {}

unicode.lua

@@ -20,12 +20,8 @@ local bit = try_require('bit') or try_require('bit32') or error[[no bitwise libr
 -- over every char of a string
 local byte = string.byte
 local char = string.char
-local utf8char = string.char
-if rawget(_G, 'utf8') ~= nil then
-  utf8char = utf8.char
-end
-local lunpack = string.unpack or require("struct").unpack
-local lpack = string.pack or require("struct").pack
+local lunpack = require("struct").unpack
+local lpack = require("struct").pack
 local concat = table.concat
 
 local unicode = {}
@@ -3820,20 +3816,16 @@ function unicode.sjis_dec(buf, pos, bigendian)
   end
 
   local cp = lunpack(fmt, buf, pos)
-  local utf16cp = unicode.sjis_decode[cp]
+  local utf8cp = unicode.sjis_decode[cp]
 
   local ret = nil
 
-  if utf16cp == nil then
+  if utf8cp == nil then
     error(string.format("sjis missing cp %x", cp))
   else
-    if pcall(function() ret = utf8char(utf16cp) end) ~= true then
-      _, b1, b2, b3 = lunpack("BBBB", lpack(">I", utf16cp))
-      ret = utf8char(b1) .. utf8char(b2) .. utf8char(b3)
-    end
+    _, b1, b2, b3 = lunpack("BBBB", lpack(">I", utf8cp))
+    return pos + 2, char(b1) .. char(b2) .. char(b3)
   end
-
-  return pos + 2, ret
 end