lz4 zstack support

coro/zstack_lz4.pyx

+# -*- Mode: Cython -*-
+
+class Lz4Error (Exception):
+    "A problem with lz4"
+
+# at this time (Apr 2012) the lz4 distribution does not generate a library
+# something like the following steps will be necessary:
+#
+# $ cc -O3 lz4.c -o lz4.o -c
+# $ ar rvs liblz4.a lz4.o 
+# ar: creating archive liblz4.a
+# a - lz4.o
+# $ cp lz4.h /usr/local/include/
+# $ cp liblz4.a /usr/local/lib
+
+cimport lz4
+
+cdef class zstack:
+    cdef char * buffer
+    cdef int buffer_size
+    def __init__ (self, int size=1024*1024):
+        cdef int r
+        self.buffer = <char *>PyMem_Malloc (size)
+        if not self.buffer:
+            raise MemoryError
+        self.buffer_size = size
+    cdef size_t deflate (self, void * base, size_t size):
+        return lz4.LZ4_compress (<char*>base, self.buffer, size)
+    cdef size_t inflate (self, void * dst, size_t dsize, void * src, size_t ssize):
+        return lz4.LZ4_uncompress (<char*>src, <char*>dst, dsize)