Yosokumo::Base64 Class Reference

Provides methods for converting bytes sequences to Base64 character strings and vice versa. More...

#include <Base64.h>

Static Public Member Functions
static void	encodeBytes (const std::vector< uint8_t > &source, std::string &dest)
	Convert a sequence of bytes to a Base64 string.
static uint8_t	decode64 (char c) throw (std::invalid_argument)
	Convert a 6-bit Base64 character to an 8-bit byte.
static void	decodeString (const std::string &source, std::vector< uint8_t > &dest) throw (std::invalid_argument)
	Convert a Base64 string to a sequence of bytes.
Static Private Member Functions
static void	map3to4 (uint8_t A, uint8_t B, uint8_t C, std::string &abcd)
	Convert a sequence of three bytes to a sequence of four characters.
static void	map4to3 (char a, char b, char c, char d, std::vector< uint8_t > &ABC, int j, int n) throw (std::invalid_argument)
	Convert a sequence of four characters to a sequence of three bytes.
Static Private Attributes
static char	encode64 []
	Base64 character set: A-Z, a-z, 0-9, +, /.

Detailed Description

Provides methods for converting bytes sequences to Base64 character strings and vice versa.

static void encodeBytes(const std::vector<uint8_t> &source, std::string &dest)
static void decodeString(const std::string &source, std::vector<uint8_t> &dest)

Be aware that there is not a one-to-one correspondence between byte sequences and Base64 character sequences. Given any character sequence C created by encodeBytes, the call decodeString(C) will return the original byte sequence. However, there exist character sequences which are never produced by encodeBytes, and, hence, applying decodeString to such character sequences produces byte sequences from which the original character sequences cannot be recovered. For example, decodeString converts both AA== and AB== to the single byte 0, and encodeBytes converts the single byte 0 to AA==. There does not exist a sequence of bytes which will cause encodeBytes to return AB==.

Author:: Roger House

Version:: 0.9

Definition at line 39 of file Base64.h.

Member Function Documentation

uint8_t Base64::decode64 ( char c ) throw (std::invalid_argument) [static]

Convert a 6-bit Base64 character to an 8-bit byte.

Parameters:

c

a 6-bit Base64 character.

Returns:: the 8-bit byte corresponding to the input character.

Exceptions:

std::invalid_argument

if the input character is not a Base64 character.

Definition at line 91 of file Base64.cpp.

void Base64::decodeString	(	const std::string &	source,
		std::vector< uint8_t > &	dest
	)			throw (std::invalid_argument) `[static]`

Convert a Base64 string to a sequence of bytes.

Parameters:

	source	is the input to this function, a string of zero or more 6-bit Base64 characters.
	dest	is the output from this function, a a byte sequence containing the 8-bit bytes corresponding to the input characters.

Exceptions:

	std::invalid_argument	if the length of the input string is not a multiple of four.
	std::invalid_argument	if the input string contains a character which is not a Base64 character.

Definition at line 154 of file Base64.cpp.

References ends_with().

void Base64::encodeBytes	(	const std::vector< uint8_t > &	source,
		std::string &	dest
	)			`[static]`

Convert a sequence of bytes to a Base64 string.

Parameters:

	source	is the input to this function, a sequence of zero or more 8-bit bytes.
	dest	is the output from this function, a string containing the Base64 representation of the input bytes, 6-bits per character.

Definition at line 63 of file Base64.cpp.

References map3to4().

void Base64::map3to4	(	uint8_t	A,
		uint8_t	B,
		uint8_t	C,
		std::string &	abcd
	)			`[static, private]`

Convert a sequence of three bytes to a sequence of four characters.

Map three 8-bit bytes to four 6-bit bytes:

       765432 10 7654 3210 76 543210 
      +---------+---------+---------+
      |AAAAAA AA|BBBB BBBB|CC CCCCCC|
      +------+-------+-------+------+
      |aaaaaa|bb bbbb|cccc cc|dddddd|
      +------+-------+-------+------+
       543210 54 3210 5432 10 543210
     *

Parameters:

	A	the first byte.
	B	the second byte.
	C	the third byte.
	abcd	the resulting four characters are appended to abcd.

Definition at line 22 of file Base64.cpp.

References encode64.

Referenced by encodeBytes().

void Base64::map4to3	(	char	a,
		char	b,
		char	c,
		char	d,
		std::vector< uint8_t > &	ABC,
		int	j,
		int	n
	)			throw (std::invalid_argument) `[static, private]`

Convert a sequence of four characters to a sequence of three bytes.

See the comment for map3to4 for the exact mapping.

Parameters:

	a	the first character.
	b	the second character.
	c	the third character.
	d	the fourth character.
	ABC	the resulting three bytes are stored here.
	j	an index to the first byte in ABC to change.
	n	1, 2, or 3, indicating how many bytes to store in ABC.

Exceptions:

std::invalid_argument

if any input character is not a Base64 character.

Definition at line 122 of file Base64.cpp.

Member Data Documentation

char Base64::encode64 [static, private]

Initial value:

 
{
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 
    'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
    'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 
    'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
    'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 
    'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
    'w', 'x', 'y', 'z', '0', '1', '2', '3', 
    '4', '5', '6', '7', '8', '9', '+', '/'
}

Base64 character set: A-Z, a-z, 0-9, +, /.

Definition at line 45 of file Base64.h.

Referenced by map3to4().

The documentation for this class was generated from the following files:

src/Base64.h
src/Base64.cpp

Yosokumo::Base64 Class Reference

Static Public Member Functions

Static Private Member Functions

Static Private Attributes

Detailed Description

Member Function Documentation

Member Data Documentation