Hash Generator API

Prototype for a Key hashing function. More...

Functions
static size_t	gen_hash_string (union HashKey key, size_t num_elems)
	Generate a hash from a string - Implements hash_gen_hash_t -.
static size_t	gen_hash_case_string (union HashKey key, size_t num_elems)
	Generate a hash from a string (ignore the case) - Implements hash_gen_hash_t -.
static size_t	gen_hash_int (union HashKey key, size_t num_elems)
	Generate a hash from an integer - Implements hash_gen_hash_t -.

Detailed Description

Prototype for a Key hashing function.

Parameters

key	Key to hash
num_elems	Number of elements in the Hash Table

Turn a Key (a string or an integer) into a hash id. The hash id will be a number between 0 and (num_elems-1).

Function Documentation

gen_hash_string()

static size_t gen_hash_string ( union HashKey key, size_t num_elems )

static

Generate a hash from a string - Implements hash_gen_hash_t -.

Note

If the key is NULL or empty, the retval will be 0

Definition at line 46 of file hash.c.

{
  size_t hash = 0;
  const unsigned char *s = (const unsigned char *) key.strkey;
  if (!s)
    return 0;
 
  while (*s != '\0')
    hash += ((hash << 7) + *s++);
  hash = (hash * SOME_PRIME) % num_elems;
 
  return hash;
}

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gen_hash_case_string()

static size_t gen_hash_case_string ( union HashKey key, size_t num_elems )

static

Generate a hash from a string (ignore the case) - Implements hash_gen_hash_t -.

Note

If the key is NULL or empty, the retval will be 0

Definition at line 73 of file hash.c.

{
  size_t hash = 0;
  const unsigned char *s = (const unsigned char *) key.strkey;
  if (!s)
    return 0;
 
  while (*s != '\0')
    hash += ((hash << 7) + mutt_tolower(*s++));
  hash = (hash * SOME_PRIME) % num_elems;
 
  return hash;
}

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gen_hash_int()

static size_t gen_hash_int ( union HashKey key, size_t num_elems )

static

Generate a hash from an integer - Implements hash_gen_hash_t -.

Definition at line 98 of file hash.c.

{
  return (key.intkey % num_elems);
}

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