/*
 * Copyright (c) 2005-2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
 * Redistribution and modifications are permitted subject to BSD license.
 */
#ifndef ASN_BIT_DATA
#define ASN_BIT_DATA

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

#ifdef __cplusplus
extern "C" {
#endif

/*
 * This structure describes a position inside an incoming PER bit stream.
 */
typedef struct asn_bit_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_bit_data_s*);
  void* refill_key;
} asn_bit_data_t;

/*
 * Create a contiguous non-refillable bit data structure.
 * Can be freed by FREEMEM().
 */
asn_bit_data_t* asn_bit_data_new_contiguous(const void* data, size_t size_bits);

/*
 * 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 asn_get_few_bits(asn_bit_data_t*, int get_nbits);

/* Undo the immediately preceeding "get_few_bits" operation */
void asn_get_undo(asn_bit_data_t*, 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 asn_get_many_bits(
    asn_bit_data_t*, uint8_t* dst, int right_align, int get_nbits);

/* Non-thread-safe debugging function, don't use it */
char* asn_bit_data_string(asn_bit_data_t*);

/*
 * This structure supports forming bit output.
 */
typedef struct asn_bit_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 (*output)(const void* data, size_t size, void* op_key);
  void* op_key;         /* Key for (output) data callback */
  size_t flushed_bytes; /* Bytes already flushed through (output) */
} asn_bit_outp_t;

/* Output a small number of bits (<= 31) */
int asn_put_few_bits(asn_bit_outp_t*, uint32_t bits, int obits);

/* Output a large number of bits */
int asn_put_many_bits(asn_bit_outp_t*, const uint8_t* src, int put_nbits);

/*
 * Flush whole bytes (0 or more) through (outper) member.
 * The least significant bits which are not used are guaranteed to be set to 0.
 * Returns -1 if callback returns -1. Otherwise, 0.
 */
int asn_put_aligned_flush(asn_bit_outp_t*);

#ifdef __cplusplus
}
#endif

#endif /* ASN_BIT_DATA */
