asn_codecs.h

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/*
 * Copyright (c) 2003-2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
 * Redistribution and modifications are permitted subject to BSD license.
 */
#ifndef ASN_CODECS_H
#define ASN_CODECS_H
 
#ifdef __cplusplus
extern "C" {
#endif
 
struct asn_TYPE_descriptor_s;   /* Forward declaration */
 
/*
 * This structure defines a set of parameters that may be passed
 * to every ASN.1 encoder or decoder function.
 * WARNING: if max_stack_size member is set, and you are calling the
 *   function pointers of the asn_TYPE_descriptor_t directly,
 *   this structure must be ALLOCATED ON THE STACK!
 *   If you can't always satisfy this requirement, use ber_decode(),
 *   xer_decode() and uper_decode() functions instead.
 */
typedef struct asn_codec_ctx_s {
        /*
         * Limit the decoder routines to use no (much) more stack than a given
         * number of bytes. Most of decoders are stack-based, and this
         * would protect against stack overflows if the number of nested
         * encodings is high.
         * The OCTET STRING, BIT STRING and ANY BER decoders are heap-based,
         * and are safe from this kind of overflow.
         * A value from getrlimit(RLIMIT_STACK) may be used to initialize
         * this variable. Be careful in multithreaded environments, as the
         * stack size is rather limited.
         */
        size_t  max_stack_size; /* 0 disables stack bounds checking */
} asn_codec_ctx_t;
 
/*
 * Type of the return value of the encoding functions (der_encode, xer_encode).
 */
typedef struct asn_enc_rval_s {
        /*
         * Number of bytes encoded.
         * -1 indicates failure to encode the structure.
         * In this case, the members below this one are meaningful.
         */
        ssize_t encoded;
 
        /*
         * Members meaningful when (encoded == -1), for post mortem analysis.
         */
 
        /* Type which cannot be encoded */
        const struct asn_TYPE_descriptor_s *failed_type;
 
        /* Pointer to the structure of that type */
        const void *structure_ptr;
} asn_enc_rval_t;
#define ASN__ENCODE_FAILED do {                                 \
        asn_enc_rval_t tmp_error;                               \
        tmp_error.encoded = -1;                                 \
        tmp_error.failed_type = td;                             \
        tmp_error.structure_ptr = sptr;                         \
        ASN_DEBUG("Failed to encode element %s", td ? td->name : "");   \
        return tmp_error;                                       \
} while(0)
#define ASN__ENCODED_OK(rval) do {                              \
        rval.structure_ptr = 0;                                 \
        rval.failed_type = 0;                                   \
        return rval;                                            \
} while(0)
 
/*
 * Type of the return value of the decoding functions (ber_decode, xer_decode)
 * 
 * Please note that the number of consumed bytes is ALWAYS meaningful,
 * even if code==RC_FAIL. This is to indicate the number of successfully
 * decoded bytes, hence providing a possibility to fail with more diagnostics
 * (i.e., print the offending remainder of the buffer).
 */
enum asn_dec_rval_code_e {
        RC_OK,          /* Decoded successfully */
        RC_WMORE,       /* More data expected, call again */
        RC_FAIL         /* Failure to decode data */
};
typedef struct asn_dec_rval_s {
        enum asn_dec_rval_code_e code;  /* Result code */
        size_t consumed;                /* Number of bytes consumed */
} asn_dec_rval_t;
#define ASN__DECODE_FAILED do {                                 \
        asn_dec_rval_t tmp_error;                               \
        tmp_error.code = RC_FAIL;                               \
        tmp_error.consumed = 0;                                 \
        ASN_DEBUG("Failed to decode element %s", td ? td->name : "");   \
        return tmp_error;                                       \
} while(0)
#define ASN__DECODE_STARVED do {                                \
        asn_dec_rval_t tmp_error;                               \
        tmp_error.code = RC_WMORE;                              \
        tmp_error.consumed = 0;                                 \
        return tmp_error;                                       \
} while(0)
 
#ifdef __cplusplus
}
#endif
 
#endif  /* ASN_CODECS_H */