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Tiny-Rex a tiny regular expression library.

This library has been optimized for smaller footprint and binary size compared to the original author's work. For AVR microcontroller binary format, the binary size is under 8K.

Copyright (C) 2014 Oscar Martinez
Copyright (C) 2003-2006 Alberto Demichelis

This software is provided 'as-is', without any express 
or implied warranty. In no event will the authors be held 
liable for any damages arising from the use of this software.

Permission is granted to anyone to use this software for 
any purpose, including commercial applications, and to alter
it and redistribute it freely, subject to the following restrictions:

	1. The origin of this software must not be misrepresented;
	you must not claim that you wrote the original software.
	If you use this software in a product, an acknowledgment
	in the product documentation would be appreciated but
	is not required.

	2. Altered source versions must be plainly marked as such,
	and must not be misrepresented as being the original software.

	3. This notice may not be removed or altered from any
	source distribution.

    \  Quote the next metacharacter
    ^  Match the beginning of the string
    .  Match any character
    $  Match the end of the string
    |  Alternation
    ()	Grouping (creates a capture)
    []	Character class  

GREEDY CLOSURES

    *      Match 0 or more times
    +	     Match 1 or more times
    ?	     Match 1 or 0 times
    {n}    Match exactly n times
    {n,}   Match at least n times
    {n,m}  Match at least n but not more than m times  

ESCAPE CHARACTERS

    \t		tab                   (HT, TAB)
    \n		newline               (LF, NL)
    \r		return                (CR)
    \f		form feed             (FF)

PREDEFINED CLASSES

    \l		lowercase next char
    \u		uppercase next char
    \a		letters
    \A		non letters
    \w		alphanimeric [0-9a-zA-Z]
    \W		non alphanimeric
    \s		space
    \S		non space
    \d		digits
    \D		non nondigits
    \x		exadecimal digits
    \X		non exadecimal digits
    \c		control charactrs
    \C		non control charactrs
    \p		punctation
    \P		non punctation
    \b		word boundary
    \B		non word boundary

TRex *trex_compile(const TRexChar *pattern)

Compiles an expression and returns a pointer to the compiled version. in case of failure returns NULL.The returned object has to be deleted through the function trex_free().

• pattern: a pointer to a zero terminated string containing the pattern that has to be compiled.

void trex_free(TRex *exp)

Deletes a expression structure created with trex_compile()

• exp: the expression structure that has to be deleted

TRexBool trex_match(TRex* exp,const TRexChar* text)

Returns TRex_True if the string specified in the parameter text is an exact match of the expression, otherwise returns TRex_False.

• exp: the compiled expression
• text: the string that has to be tested

TRexBool trex_search(TRex* exp,const TRexChar* text, const TRexChar** out_begin, const TRexChar** out_end)

Searches the first match of the expressin in the string specified in the parameter text. if the match is found returns TRex_True and the sets out_begin to the beginning of the match and out_end at the end of the match; otherwise returns TRex_False.

• exp: the compiled expression
• text: the string that has to be tested
• out_begin: a pointer to a string pointer that will be set with the beginning of the match
• out_end: a pointer to a string pointer that will be set with the end of the match

TREX_API TRexBool trex_searchrange(TRex* exp,const TRexChar* text_begin,const TRexChar* text_end,const TRexChar** out_begin, const TRexChar** out_end)

Searches the first match of the expression in the string delimited by the parameter text_begin and text_end. If the match is found returns TRex_True and the sets out_begin to the beginning of the match and out_end at the end of the match; otherwise returns TRex_False.

• exp: the compiled expression
• text_begin: a pointer to the beginnning of the string that has to be tested
• text_end: a pointer to the end of the string that has to be tested
• out_begin: a pointer to a string pointer that will be set with the beginning of the match
• out_end: a pointer to a string pointer that will be set with the end of the match

int trex_getsubexpcount(TRex* exp)

Returns the number of sub expressions matched by the expression

• exp: the compiled expression

TRexBool trex_getsubexp(TRex* exp, int n, TRexMatch *submatch)

Retrieve the begin and and pointer to the length of the sub expression indexed by n. The result is passed trhough the struct TRexMatch:

typedef struct {
	const TRexChar *begin;
	int len;
} TRexMatch;

The function returns TRex_True if n is valid index otherwise TRex_False.

• exp: the compiled expression
• n: the index of the submatch
• submatch: a pointer to structure that will store the result

This function works also after a match operation has been performed.