SIP-router core :: convert/decode to/from ascii using various bases. More...

#include "compiler_opt.h"
#include "endianness.h"

Include dependency graph for basex.h:

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Defines

#define ALIGN_POINTER(p, type) ((type*) ((long)((char*)(p)+sizeof(type)-1)&~(long)(sizeof(type)-1)))
aligns p to a type* pointer, type must have a 2^k size
#define base16_dec_len(b, l) base16_max_dec_len(l)
actual space needed for decoding a string b of size l
#define base16_dec_min_len() 2
minimum valid source len for decoding
#define base16_enc_len(l) (l*2)
lenght needed for encoding l bytes
#define base16_enc_min_len() 0
minimum valid source len for encoding
#define base16_max_dec_len(l) (l/2)
maximum lenght needed for decoding l bytes
#define base64_dec_len(b, l) (base64_max_dec_len(l)-((b)[(l)-2]=='=') -((b)[(l)-1]=='='))
actual space needed for decoding a string b of size l, l>=4
#define base64_dec_min_len() 4
minimum valid source len for decoding
#define base64_enc_len(l) (((l)+2)/3*4)
space needed for encoding l bytes
#define base64_enc_min_len() 0
minimum valid source len for encoding
#define base64_max_dec_len(l) ((l)/4*3)
maximum space needed for encoding l bytes
#define HEX_HI(h) _bx_hexdig_hi[(unsigned char)(h)]
returns the first 4 bits of c converted to a hex digit
#define HEX_LOW(h) _bx_hexdig_low[(unsigned char)(h)]
returns the low 4 bits of converted to a hex digit
#define UNHEX(h) _bx_unhexdig256[(h)]
converts hex_digit to a number (0..15); it might

Functions

static int base16_enc (unsigned char *src, int slen, unsigned char *dst, int dlen)
static int base64_dec (unsigned char *src, int slen, unsigned char *dst, int dlen)
static unsigned base64_dec_char (unsigned char v)
helper internal function: decodes a base64 "digit",
static int base64_enc (unsigned char *src, int slen, unsigned char *dst, int dlen)
static unsigned char base64_enc_char (unsigned char v)
helper internal function: encodes v (6 bits value)
int init_basex (void)
inits internal lookup tables
static int q_base64_dec (unsigned char *src, int slen, unsigned char *dst, int dlen)
same as base64_enc() but with a different alphabet, that allows simpler and faster enc/dec
static int q_base64_enc (unsigned char *src, int slen, unsigned char *dst, int dlen)
same as base64_enc() but with a different alphabet, that allows simpler and faster enc/dec

Variables

unsigned char _bx_hexdig_hi [256]
use large tables: 512 for lookup and 256 for decode

Detailed Description

Module: SIP-router core

Functions:

base16_enc(src, src_len, dst, dst_len) : encode to standard hex
base16_dec(src, src_len, dst, dst_len) : decode from standard hex
base16_enc_len(len) : length needed to encode len bytes (macro)
base16_max_dec_len(len) : length needed to decode a string of size len

base64_enc(src, src_len, dst, dst_len) : encode to base64, standard alphabet
base64_dec(src, src_len, dst, dst_len) : decode from base64, standard alphabet
base64_enc_len(len) : length needed to encode len bytes (macro)
base64_max_dec_len(len) : maximum length needed to decode len bytes (macro)
base64_dec_len(str, len) : size of the decoded str
q_base64_enc(src, src_len, dst, dst_len) : encode to special base64 alphabet (non standard)
q_base64_dec(src, src_len, dst, dst_len) - decode from special non-standard base64 alphabet

All the above functions return the size used (in dst) on success and 0 or a negative number (which is -1*size_needed) on error.

There are close to no checks for validity, an unexpected char will lead to a corrupted result, but the functions won't return error.

Notes: on a core2 duo the versions with lookup tables are way faster (see http://www.experts-exchange.com/Programming/Languages/CPP/Q_21988706.html for some interesting tests and ideeas).

Test results for 40 bytes (typical ser nounce) in average cpu cycles:

 *                    lookup   lookup_large lookup8k no-lookup
 *  base16_enc           211/231  218/199      -       1331
 *  base16_dec           252/251  236          -       1226
 *  base64_enc           209      186         156      1005
 *  base64_dec           208      207         207      1242
 *  q_base64_enc         -                              288
 *  q_base64_dec         -                              281
 *  (see test/basex.txt for more results)

Defines:

BASE64_LOOKUP_TABLE/NO_BASE64_LOOKUP_TABLE : use (default)/don't use small lookup tables for conversions (faster in general).
BASE64_LOOKUP_LARGE : use large lookup tables (2560 bytes for encoding and 256 bytes for decoding; without it 64 bytes are used for encoding and 85 bytes for decoding.
BASE64_LOOKUP_8K : use even larger lookup tables (8K for encoding and 256 for decoding); also try to write 2 bytes at a time (short) if the destination is 2 byte aligned

BASE16_LOOKUP_TABLE/NO_BASE16_LOOKUP_TABLE : use (default)/don't use small lookup tables for conversions (faster in general).
BASE16_LOOKUP_LARGE : use large lookup tables (512 bytes for encoding and 256 bytes for decoding
BASE16_READ_WHOLE_INTS : read an int at a time

History: -------- 2008-06-11 created by andrei

Definition in file basex.h.

Define Documentation

#define UNHEX ( h ) _bx_unhexdig256[(h)]

Returns:: 0xff for invalid digit (but with some compile option it won't check)

Definition at line 150 of file basex.h.

Function Documentation

static int base16_enc	(	unsigned char *	src,
		int	slen,
		unsigned char *	dst,
		int	dlen
	)			`[inline, static]`

Returns:: : size used from the output buffer (dst) on success, -size_needed on error

Note:: WARNING: the output string is not 0-term

Definition at line 460 of file basex.h.

References HEX_HI, and HEX_LOW.

static int base64_dec	(	unsigned char *	src,
		int	slen,
		unsigned char *	dst,
		int	dlen
	)			`[inline, static]`

Returns:: size used from the output buffer (dst) on success (max: slen/4*3) -size_needed on error or 0 on bad base64 encoded string

Note:: WARNING: the output string is not 0-term

Definition at line 661 of file basex.h.

static unsigned base64_dec_char ( unsigned char v ) [inline, static]

Returns:: value on success (0-63) and 0xff on error (invalid)

Definition at line 521 of file basex.h.

static int base64_enc	(	unsigned char *	src,
		int	slen,
		unsigned char *	dst,
		int	dlen
	)			`[inline, static]`

Returns:: : size used from the output buffer (dst) on success ((slen+2)/3*4) -size_needed on error

Note:: WARNING: the output string is not 0-term

Definition at line 563 of file basex.h.

static unsigned char base64_enc_char ( unsigned char v ) [inline, static]

Returns:: char ascii encoding on success and 0xff on error (value out of range)

Definition at line 501 of file basex.h.

static int q_base64_dec	(	unsigned char *	src,
		int	slen,
		unsigned char *	dst,
		int	dlen
	)			`[inline, static]`

Returns:: size used from the output buffer (dst) on success (max: slen/4*3) -size_needed on error or 0 on bad base64 encoded string

Note:: WARNING: the output string is not 0-term

Definition at line 777 of file basex.h.

static int q_base64_enc	(	unsigned char *	src,
		int	slen,
		unsigned char *	dst,
		int	dlen
	)			`[inline, static]`

Returns:: size used from the output buffer (dst) on success ((slen+2)/3*4) -size_needed on error

Note:: WARNING: the alphabet includes ":;<>?@[]\`", so it might not be suited in all cases (e.g. encoding something in a sip uri).

Definition at line 730 of file basex.h.