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<H2><A NAME="SECTION00081000000000000000">
Adding Hash Algorithms</A>
</H2>
<P>
The required constant definitions are as follows:
<P>
<PRE>
#define MODULE_NAME MD2 /* Name of algorithm */
#define DIGEST_SIZE 16 /* Size of resulting digest in bytes */
</PRE>
<P>
The C structure must be named hash_state:
<P>
<PRE>
typedef struct {
... whatever state variables you need ...
} hash_state;
</PRE>
<P>
There are four functions that need to be written: to initialize the
algorithm's state, to hash a string into the algorithm's state, to get
a digest from the current state, and to copy a state.
<P>
<UL>
<LI>void hash_init(hash_state *self);
</LI>
<LI>void hash_update(hash_state *self, unsigned char *buffer, int length);
</LI>
<LI>PyObject *hash_digest(hash_state *self);
</LI>
<LI>void hash_copy(hash_state *source, hash_state *dest);
</LI>
</UL>
<P>
Put #include "hash_template.c" at the end of the file to
include the actual implementation of the module.
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