text: /*
   * Copyright (c) 2005, 2006, 2007 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);
  
  /* 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);
  
  /*
   * 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_ */
  