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* X.509: Add simple ASN.1 grammar compilerDavid Howells2012-10-081-0/+87
Add a simple ASN.1 grammar compiler. This produces a bytecode output that can be fed to a decoder to inform the decoder how to interpret the ASN.1 stream it is trying to parse. Action functions can be specified in the grammar by interpolating: ({ foo }) after a type, for example: SubjectPublicKeyInfo ::= SEQUENCE { algorithm AlgorithmIdentifier, subjectPublicKey BIT STRING ({ do_key_data }) } The decoder is expected to call these after matching this type and parsing the contents if it is a constructed type. The grammar compiler does not currently support the SET type (though it does support SET OF) as I can't see a good way of tracking which members have been encountered yet without using up extra stack space. Currently, the grammar compiler will fail if more than 256 bytes of bytecode would be produced or more than 256 actions have been specified as it uses 8-bit jump values and action indices to keep space usage down. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>