From b0e649090003cb27d58d6dedd650ffe7884e0b70 Mon Sep 17 00:00:00 2001
From: Artem Baguinski <artm@escargot.(none)>
Date: Wed, 2 Apr 2008 14:34:46 +0200
Subject: [PATCH] [u]int24 conversions inside packer classes

---
 shuffle.py | 75 ++++++++++++++++++--------------------------------------------
 1 file changed, 22 insertions(+), 53 deletions(-)

diff --git a/shuffle.py b/shuffle.py
index 8c3d3cf..6680ae2 100644
--- a/shuffle.py
+++ b/shuffle.py
@@ -15,35 +15,6 @@ LITTLE_ENDIAN = False
 READ = 'rb'
 WRITE = 'w+b'
 
-def pack_uint24(i,bigendian):
-    "Pack an unsigned integer to a string of three bytes"
-    if bigendian:
-        return struct.pack(">I",i)[1:4]
-    else:
-        return struct.pack("<I",i)[0:3]
-
-def unpack_uint24(s,bigendian):
-    "Unpack an unsigned integer from first three bytes of a string"
-    if bigendian:
-         return struct.unpack('>I','\x00' + s[0:3])[0]
-    else:
-        return struct.unpack('<I',s[0:3] + '\x00')[0]
-
-def pack_int24(i,bigendian):
-    "Pack a signed integer to a string of three bytes"
-    if bigendian:
-        return struct.pack(">i",i)[1:4]
-    else:
-        return struct.pack("<i",i)[0:3]
-
-def unpack_int24(s,bigendian):
-    "Unpack a signed integer from first three bytes of a string"
-    u = unpack_uint24(s,bigendian)
-    if (u & 0x800) != 0:
-        return - ((~u + 1) & 0xfff)
-    else:
-        return u
-
 class Skip(object):
     def __init__(self, n): 
         self.size = n
@@ -134,19 +105,32 @@ class Uint24:
     def __init__(self, bigendian = LITTLE_ENDIAN):
         self.size = 3
         self.bigendian = bigendian
-    def pack(self, val):
-        return pack_uint24(val, self.bigendian)
-    def unpack(self, str):
-        return unpack_uint24(str, self.bigendian)
+    def pack(self, i):
+        if self.bigendian:
+            return struct.pack(">I",i)[1:4]
+        else:
+            return struct.pack("<I",i)[0:3]
+    def unpack(self, s):
+        if self.bigendian:
+             return struct.unpack('>I','\x00' + s[0:3])[0]
+        else:
+            return struct.unpack('<I',s[0:3] + '\x00')[0]
 
-class Int24:
+class Int24(Uint24):
     def __init__(self, bigendian = LITTLE_ENDIAN):
         self.size = 3
         self.bigendian = bigendian
-    def pack(self, val):
-        return pack_int24(val, self.bigendian)
-    def unpack(self, str):
-        return unpack_int24(str, self.bigendian)
+    def pack(self, i):
+        if self.bigendian:
+            return struct.pack(">i",i)[1:4]
+        else:
+            return struct.pack("<i",i)[0:3]
+    def unpack(self, s):
+        u = Uint24.unpack(self,s)
+        if (u & 0x800) != 0:
+            return - ((~u + 1) & 0xfff)
+        else:
+            return u
 
 class Bool24(Int24):
     def __init__(self): Int24.__init__(self)
@@ -383,21 +367,6 @@ class ShuffleDB:
 
 #####################################################################
 if __name__ == '__main__':
-    # try conversions
-    b100 = pack_uint24(100,True)
-    l100 = pack_uint24(100,False)
-    print b100 == '\x00\x00d'
-    print l100 == 'd\x00\x00'
-    print unpack_uint24(b100,True) == 100
-    print unpack_uint24(l100,False) == 100
-
-    b100 = pack_int24(-100,True)
-    l100 = pack_int24(-100,False)
-    print b100 == '\xff\xff\x9c'
-    print l100 == '\x9c\xff\xff'
-    print unpack_int24(b100,True) == -100
-    print unpack_int24(l100,False) == -100
-
     def print_list(xs):
         for x in xs:
             print x
-- 
2.11.4.GIT