Utility functions to encode strings. More...

#include <inttypes.h>
#include <stdio.h>

Macros
#define	ESID_MAXLEN 10
	Maximum number of characters that can be encoded. More...

#define	ESID_SHIFT 32
	Number used to translate ASCII character values. More...

#define	ESID_SHIFTPOS 60
	Encoded string ID LEN LSB position from LSB [ -—0000 00111111 22222233 33334444 44555555 66666677 77778888 88999999 ]. More...

#define	ESID_CHARBIT 6
	Number of bit used to encode a char. More...

#define	ESID_NUMPOS 27
	Number of bit used to encode a number in the srting_num encoding. More...

#define	ESID_MAXPAD 7
	Max number of padding zero digits. More...

Functions
static uint64_t	esid_encode_char (int c)

static uint8_t	esid_decode_char (uint64_t esid, size_t pos)

static uint64_t	encode_string_id (const char *str, size_t size, size_t start)

static uint64_t	encode_string_num_id (const char *str, size_t size, char sep)

static size_t	esid_decode_string_id (size_t size, uint64_t esid, char *str)

static size_t	esid_decode_string_num_id (size_t size, uint64_t esid, char *str)

static size_t	decode_string_id (uint64_t esid, char *str)

static uint64_t	muxhash64 (uint64_t k, uint64_t h)

static uint64_t	hash_string_id (const char *str, size_t size)

Detailed Description

Utility functions to encode strings.

Macro Definition Documentation

#define ESID_CHARBIT 6

#define ESID_MAXLEN 10

#define ESID_MAXPAD 7

#define ESID_NUMPOS 27

#define ESID_SHIFT 32

#define ESID_SHIFTPOS 60

Function Documentation

static size_t decode_string_id	(	uint64_t	esid,
		char *	str
	)

inlinestatic

Decode the encoded string ID. This function is the reverse of encode_string_id. The string is always returned in uppercase mode.

Parameters

esid	Encoded string ID code.
str	String buffer to be returned. Its size should be enough to contain the results (at least 11 bytes).

Returns: The total number of characters excluding the null-character appended at the end of the string.

static uint64_t encode_string_id	(	const char *	str,
		size_t	size,
		size_t	start
	)

inlinestatic

Encode maximum 10 characters of a string into a 64 bit unsigned integer. This function can be used to convert generic string IDs to numeric IDs.

Parameters

str	The string to encode. It must be maximum 10 characters long and support ASCII characters from '!' to 'z'.
size	Length of the string, excluding the terminating null byte.
start	First character to encode, starting from 0. To encode the last 10 characters, set this value at (size - 10).

Returns: Encoded string ID.

static uint64_t encode_string_num_id	(	const char *	str,
		size_t	size,
		char	sep
	)

inlinestatic

Encode a string composed by a character section followed by a separator character and a numerical section into a 64 bit unsigned integer. For example: "ABCDE:0001234". Encodes up to 5 characters in uppercase, a number up to 2^27, and up to 7 zero padding digits. If the string is 10 character or less, then the encode_string_id() is used.

Parameters

str	The string to encode. Support ASCII characters from '!' to 'z'.
size	Length of the string, excluding the terminating null byte.
sep	Separator character between string and number.

Returns: Encoded string ID.

static uint8_t esid_decode_char	(	uint64_t	esid,
		size_t	pos
	)

inlinestatic

static size_t esid_decode_string_id	(	size_t	size,
		uint64_t	esid,
		char *	str
	)

inlinestatic

static size_t esid_decode_string_num_id	(	size_t	size,
		uint64_t	esid,
		char *	str
	)

inlinestatic

static uint64_t esid_encode_char ( int c )

inlinestatic

static uint64_t hash_string_id	(	const char *	str,
		size_t	size
	)

inlinestatic

Hash the input string into a 64 bit unsigned integer. This function can be used to convert long string IDs into non-reversible numeric IDs.

Parameters

str	The string to encode.
size	Length of the string, excluding the terminating null byte.

Returns: Hash string ID.

static uint64_t muxhash64	(	uint64_t	k,
		uint64_t	h
	)

inlinestatic

Macros

Functions

Detailed Description

Macro Definition Documentation

Function Documentation