faset over fra Z3950 til google books

python/gdata/tlslite/utils/codec.py

@@ -0,0 +1,94 @@
+"""Classes for reading/writing binary data (such as TLS records)."""
+
+from compat import *
+
+class Writer:
+    def __init__(self, length=0):
+        #If length is zero, then this is just a "trial run" to determine length
+        self.index = 0
+        self.bytes = createByteArrayZeros(length)
+
+    def add(self, x, length):
+        if self.bytes:
+            newIndex = self.index+length-1
+            while newIndex >= self.index:
+                self.bytes[newIndex] = x & 0xFF
+                x >>= 8
+                newIndex -= 1
+        self.index += length
+
+    def addFixSeq(self, seq, length):
+        if self.bytes:
+            for e in seq:
+                self.add(e, length)
+        else:
+            self.index += len(seq)*length
+
+    def addVarSeq(self, seq, length, lengthLength):
+        if self.bytes:
+            self.add(len(seq)*length, lengthLength)
+            for e in seq:
+                self.add(e, length)
+        else:
+            self.index += lengthLength + (len(seq)*length)
+
+
+class Parser:
+    def __init__(self, bytes):
+        self.bytes = bytes
+        self.index = 0
+
+    def get(self, length):
+        if self.index + length > len(self.bytes):
+            raise SyntaxError()
+        x = 0
+        for count in range(length):
+            x <<= 8
+            x |= self.bytes[self.index]
+            self.index += 1
+        return x
+
+    def getFixBytes(self, lengthBytes):
+        bytes = self.bytes[self.index : self.index+lengthBytes]
+        self.index += lengthBytes
+        return bytes
+
+    def getVarBytes(self, lengthLength):
+        lengthBytes = self.get(lengthLength)
+        return self.getFixBytes(lengthBytes)
+
+    def getFixList(self, length, lengthList):
+        l = [0] * lengthList
+        for x in range(lengthList):
+            l[x] = self.get(length)
+        return l
+
+    def getVarList(self, length, lengthLength):
+        lengthList = self.get(lengthLength)
+        if lengthList % length != 0:
+            raise SyntaxError()
+        lengthList = int(lengthList/length)
+        l = [0] * lengthList
+        for x in range(lengthList):
+            l[x] = self.get(length)
+        return l
+
+    def startLengthCheck(self, lengthLength):
+        self.lengthCheck = self.get(lengthLength)
+        self.indexCheck = self.index
+
+    def setLengthCheck(self, length):
+        self.lengthCheck = length
+        self.indexCheck = self.index
+
+    def stopLengthCheck(self):
+        if (self.index - self.indexCheck) != self.lengthCheck:
+            raise SyntaxError()
+
+    def atLengthCheck(self):
+        if (self.index - self.indexCheck) < self.lengthCheck:
+            return False
+        elif (self.index - self.indexCheck) == self.lengthCheck:
+            return True
+        else:
+            raise SyntaxError()