| /*- |
| * 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). |
| */ |
| enum ber_dec_rval_code_e { |
| RC_OK, /* Decoded successfully */ |
| RC_WMORE, /* More data expected, call again */ |
| RC_FAIL, /* Failure to decode data */ |
| }; |
| typedef struct ber_dec_rval_s { |
| enum ber_dec_rval_code_e code; /* Result 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_ */ |