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Diffstat (limited to 'skeletons/ber_decoder.h')
-rw-r--r-- | skeletons/ber_decoder.h | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/skeletons/ber_decoder.h b/skeletons/ber_decoder.h new file mode 100644 index 00000000..8240270a --- /dev/null +++ b/skeletons/ber_decoder.h @@ -0,0 +1,77 @@ +/*- + * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved. + * Redistribution and modifications are permitted subject to BSD license. + */ +#ifndef _BER_DECODER_H_ +#define _BER_DECODER_H_ + +#include <constr_TYPE.h> + +struct asn1_TYPE_descriptor_s; /* Forward declaration */ + +/* + * This structure describes the return value common across the + * various BER decoders. + * + * Please note that the number of consumed bytes is ALWAYS meaningful, + * even if code!=RC_OK. This is so to indicate the number of successfully + * decoded bytes, hence provide a possibility, to fail with more diagnostics + * (i.e., print the offending remainder of the buffer). + */ +typedef struct ber_dec_rval_s { + enum { + RC_OK, /* Decoded successfully */ + RC_WMORE, /* More data expected, call again */ + RC_FAIL, /* Failure to decode data */ + } code; + + size_t consumed; /* Number of bytes consumed */ +} ber_dec_rval_t; + +/* + * A context for decoding BER across buffer boundaries. + */ +typedef struct ber_dec_ctx_s { + int phase; /* Decoding phase */ + int step; /* Elementary step of a phase */ + ber_tlv_len_t left; /* Number of bytes left, -1 for indefinite */ + void *ptr; /* Decoder-specific stuff */ +} ber_dec_ctx_t; + +/* + * The BER decoder of any type. + * This function may be invoked directly from the application. + */ +ber_dec_rval_t ber_decode(struct asn1_TYPE_descriptor_s *type_descriptor, + void **struct_ptr, /* Pointer to a target structure's pointer */ + void *buffer, /* Data to be decoded */ + size_t size /* Size of that buffer */ + ); + +/* + * Type of generic function which decodes the byte stream into the structure. + */ +typedef ber_dec_rval_t (ber_type_decoder_f)( + struct asn1_TYPE_descriptor_s *type_descriptor, + void **type_structure, void *buf_ptr, size_t size, + int tag_mode); + +/******************************* + * INTERNALLY USEFUL FUNCTIONS * + *******************************/ + +/* + * Check that all tags correspond to the type definition (as given in head). + * On return, last_length would contain either a non-negative length of the + * value part of the last TLV, or the negative number of expected + * "end of content" sequences. The number may only be negative if the + * head->last_tag_form is non-zero. + */ +ber_dec_rval_t ber_check_tags(struct asn1_TYPE_descriptor_s *type_dsc, + ber_dec_ctx_t *ctx, /* saved context */ + void *ptr, size_t size, + int tag_mode, /* {-1,0,1}: IMPLICIT, no, EXPLICIT */ + ber_tlv_len_t *last_length, + int *opt_tlv_form); + +#endif /* _BER_DECODER_H_ */ |