StringUtils.cxx File Reference

#include <cctype>
#include <cstdint>
#include <cmath>
#include <cstdlib>
#include <string>
#include <random>
#include <vector>
#include <list>
#include <memory>
#include <fstream>
#include <regex>
#include <map>
#include <functional>
#include <utility>
#include <sstream>
#include <istream>
#include <iomanip>
#include <iterator>
#include "DetectorsDCS/StringUtils.h"

Go to the source code of this file.

Functions
default_random_engine	gen (dev())
uniform_int_distribution< long long >	uniform_dist (32, 126)
geometric_distribution< long long >	geom_dist (0.1)
constexpr uint64_t	MODULO (13835058055282163729ULL)
uint8_t	lookup (const char input) noexcept
uint64_t	exp (uint64_t base, uint8_t exp) noexcept
char	to_alpha_numeric (const uint8_t c) noexcept

Variables
random_device	dev
constexpr char	ALPHABET [39]
constexpr uint64_t	PRIMES [52]

Function Documentation

exp()

uint64_t exp ( uint64_t  base, uint8_t  exp  )

noexcept

An all-integer exponent function. The orgiginal algorithm was submitted as an answer at StackOverflow, by Elias Yarrkow. The code was obtained from http://stackoverflow.com/a/101613 in 14 February 2017, 11:24, and modified to work with the unsigned C integer types. It is well-known that these kind of functions usually overflow, and overflows are ignored in this case.

Parameters

base	The base of the exponent function.
exp	The exponent.

Returns

The result.

Definition at line 192 of file StringUtils.cxx.

gen()

default_random_engine gen

(

dev()

)

geom_dist()

geometric_distribution< long long > geom_dist

(

0.

1

)

lookup()

uint8_t lookup ( const char  input )

noexcept

Transforms the given character into a 8-bit unsigned code symbol.

Parameters

input

Returns

Definition at line 71 of file StringUtils.cxx.

MODULO()

constexpr uint64_t MODULO ( 13835058055282163729ULL  )

constexpr

The modulo used in the hash function after calculating the sum. It is the prime number closest to 1.5 * 2^63.

to_alpha_numeric()

char to_alpha_numeric ( const uint8_t  c )

inlinenoexcept

Definition at line 272 of file StringUtils.cxx.

uniform_dist()

uniform_int_distribution< long long > uniform_dist	(	32	,
		126
	)

Variable Documentation

ALPHABET

constexpr char ALPHABET[39]

constexpr

Initial value:

{
  'E', 'T', 'A', 'O', 'I', '_', 'N', 'S', 'H', 'R',
  '/', 'D', 'L', '1', '2', 'C', 'U', 'M', 'W', '3',
  '4', '5', '6', '7', '8', '9', '0', 'F', 'G', 'Y',
  'P', 'B', 'V', 'K', 'J', 'X', 'Q', 'Z', '?'}

Definition at line 40 of file StringUtils.cxx.

dev

random_device dev

Definition at line 35 of file StringUtils.cxx.

PRIMES

constexpr uint64_t PRIMES[52]

constexpr

Initial value:

{
  2, 3, 5, 7, 11, 13, 17, 19, 23, 29,
  31, 37, 41, 43, 47, 53, 59, 61, 67, 71,
  73, 79, 83, 89, 97, 101, 103, 107, 109, 113,
  127, 131, 137, 139, 149, 151, 157, 163, 167, 173,
  179, 181, 191, 193, 197, 199, 211, 223, 227, 229,
  233, 239}

The first 52 prime numbers used for calculating the hash code. Each symbol of the alias will be multiplied (mod 256) with a prime of the same index and adding the obtained number to the sum that is the hash code.

Definition at line 51 of file StringUtils.cxx.