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/*-
* 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_ */
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