Implement reading a number in the EixReader

1 files changed, 102 insertions, 14 deletions

diff --git a/portato/eix/libeix.pyx b/portato/eix/libeix.pyx
index 2b3ebb0..2a1c7df 100644
--- a/portato/eix/libeix.pyx
+++ b/portato/eix/libeix.pyx
@@ -1,14 +1,102 @@
-from portato.eix.eix_utils cimport File, fopen, fclose, ffree, fget
-
-def test (f):
-    cdef File* cf
-    cdef char* buf
-
-    print "Trying to open: ", f
-    cf = fopen(f, "r")
-    try:
-        buf = fget(cf, 20)
-        print "The first two chars:", buf[0], buf[1]
-        ffree(buf)
-    finally:
-        fclose(cf)
+class EixError (Exception):
+    message = "Unknown error."
+
+    def __str__ (self):
+        return self.message
+
+class EndOfFileException (EixError):
+
+    def __init__ (self, filename):
+        self.message = "End of file reached though it was not expected: '%s'" % filename
+
+class EixReaderClosed (EixError):
+    message = "EixReader is already closed."
+
+class UnsupportedVersionError (EixError):
+
+    def __init__ (self, version):
+        self.message = "Version '%s' is not supported." % version
+
+cdef class EixReader (object):
+    cdef object file
+    cdef char closed
+    
+    cdef readonly object filename
+    cdef readonly object version
+
+    supported_versions = (28, )
+
+    def __init__ (self, filename):
+        self.filename = filename
+        self.file = open(filename, "r")
+        self.closed = 0
+        
+        self.version = self._get_number()
+
+        if self.version not in self.supported_versions:
+            raise UnsupportedVersionError(self.version)
+
+    cdef unsigned long _get_number (self) except *:
+        cdef unsigned char n
+        cdef short count, i
+        cdef unsigned long value
+        cdef char* rest
+        cdef object orest
+
+        n = self._get_one_byte()
+
+        if n < 0xFF:
+            value = n
+        else:
+            count = 0
+
+            while (n == 0xFF):
+                count += 1
+                n = self._get_one_byte()
+
+            if n == 0:
+                n = 0xFF # 0xFF is encoded as 0xFF 0x00
+                count -= 1
+            
+            value = n << (count*8)
+
+            if count > 0:
+                orest = self.get_string(count)
+                rest = orest # cast to char*
+
+                for 0 <= i < count:
+                    value += (<unsigned char>rest[i]) << ((count - i - 1)*8)
+
+        return value
+
+    cdef unsigned char _get_one_byte (self) except? 0:
+        s = self.file.read(1)
+
+        if len(s) != 1:
+            raise EndOfFileException, self.filename
+        
+        return ord(s)
+
+    cdef object _get_string (self, length):
+        if self.closed:
+            raise EixReaderClosed
+
+        s = self.file.read(length)
+
+        if len(s) != length:
+            raise EndOfFileException, self.filename
+
+        return s
+
+    def get_number (self):
+        if self.closed:
+            raise EixReaderClosed
+        
+        return self._get_number()
+
+    def close (self):
+        if self.closed:
+            raise EixReaderClosed
+        
+        self.file.close()
+        self.closed = 1