per_support.h

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/*
 * Copyright (c) 2005-2014 Lev Walkin <vlm@lionet.info>.
 * All rights reserved.
 * Redistribution and modifications are permitted subject to BSD license.
 */
#ifndef _PER_SUPPORT_H_
#define _PER_SUPPORT_H_

#include <asn_system.h>     /* Platform-specific types */

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Pre-computed PER constraints.
 */
typedef struct asn_per_constraint_s {
    enum asn_per_constraint_flags {
        APC_UNCONSTRAINED   = 0x0,  /* No PER visible constraints */
        APC_SEMI_CONSTRAINED    = 0x1,  /* Constrained at "lb" */
        APC_CONSTRAINED     = 0x2,  /* Fully constrained */
        APC_EXTENSIBLE      = 0x4   /* May have extension */
    } flags;
    int  range_bits;        /* Full number of bits in the range */
    int  effective_bits;        /* Effective bits */
    long lower_bound;       /* "lb" value */
    long upper_bound;       /* "ub" value */
} asn_per_constraint_t;
typedef struct asn_per_constraints_s {
    asn_per_constraint_t value;
    asn_per_constraint_t size;
    int (*value2code)(unsigned int value);
    int (*code2value)(unsigned int code);
} asn_per_constraints_t;

/*
 * This structure describes a position inside an incoming PER bit stream.
 */
typedef struct asn_per_data_s {
  const uint8_t *buffer;  /* Pointer to the octet stream */
         size_t  nboff;   /* Bit offset to the meaningful bit */
         size_t  nbits;   /* Number of bits in the stream */
         size_t  moved;   /* Number of bits moved through this bit stream */
  int (*refill)(struct asn_per_data_s *);
  void *refill_key;
} asn_per_data_t;

/*
 * Extract a small number of bits (<= 31) from the specified PER data pointer.
 * This function returns -1 if the specified number of bits could not be
 * extracted due to EOD or other conditions.
 */
int32_t per_get_few_bits(asn_per_data_t *per_data, int get_nbits);

/* Undo the immediately preceeding "get_few_bits" operation */
void per_get_undo(asn_per_data_t *per_data, int get_nbits);

/*
 * Extract a large number of bits from the specified PER data pointer.
 * This function returns -1 if the specified number of bits could not be
 * extracted due to EOD or other conditions.
 */
int per_get_many_bits(asn_per_data_t *pd, uint8_t *dst, int right_align,
            int get_nbits);

/*
 * Get the length "n" from the Unaligned PER stream.
 */
ssize_t uper_get_length(asn_per_data_t *pd,
            int effective_bound_bits,
            int *repeat);

/*
 * Get the normally small length "n".
 */
ssize_t uper_get_nslength(asn_per_data_t *pd);

/*
 * Get the normally small non-negative whole number.
 */
ssize_t uper_get_nsnnwn(asn_per_data_t *pd);

/* X.691-2008/11, #11.5.6 */
int uper_get_constrained_whole_number(asn_per_data_t *pd, unsigned long *v, int nbits);

/* Non-thread-safe debugging function, don't use it */
char *per_data_string(asn_per_data_t *pd);

/*
 * This structure supports forming PER output.
 */
typedef struct asn_per_outp_s {
    uint8_t *buffer;    /* Pointer into the (tmpspace) */
    size_t nboff;       /* Bit offset to the meaningful bit */
    size_t nbits;       /* Number of bits left in (tmpspace) */
    uint8_t tmpspace[32];   /* Preliminary storage to hold data */
    int (*outper)(const void *data, size_t size, void *op_key);
    void *op_key;       /* Key for (outper) data callback */
    size_t flushed_bytes;   /* Bytes already flushed through (outper) */
} asn_per_outp_t;

/* Output a small number of bits (<= 31) */
int per_put_few_bits(asn_per_outp_t *per_data, uint32_t bits, int obits);

/* Output a large number of bits */
int per_put_many_bits(asn_per_outp_t *po, const uint8_t *src, int put_nbits);

/* X.691-2008/11, #11.5 */
int uper_put_constrained_whole_number_s(asn_per_outp_t *po, long v, int nbits);
int uper_put_constrained_whole_number_u(asn_per_outp_t *po, unsigned long v, int nbits);

/*
 * Put the length "n" to the Unaligned PER stream.
 * This function returns the number of units which may be flushed
 * in the next units saving iteration.
 */
ssize_t uper_put_length(asn_per_outp_t *po, size_t whole_length);

/*
 * Put the normally small length "n" to the Unaligned PER stream.
 * Returns 0 or -1.
 */
int uper_put_nslength(asn_per_outp_t *po, size_t length);

/*
 * Put the normally small non-negative whole number.
 */
int uper_put_nsnnwn(asn_per_outp_t *po, int n);

#ifdef __cplusplus
}
#endif

#endif  /* _PER_SUPPORT_H_ */