archo5/sgregex

Regular expression library

SGRegex [SRX] regular expression library v1.2

Simple regular expression library for C (ANSI characters only, limited feature set)

Usage:

• add sgregex.h and sgregex.c to your project

The library supports:

• . (dot)
• *, +, ? (simple quantifiers)
• *?, +?, ?? (lazy quantifiers)
• {<num>}, {<num1>,<num2>} (complex quantifiers)
• [...], [^...] (character classes)
• (...) (subexpressions/capture ranges)
• | (the "or" operator)
• ^, $ (beginning/end matchers)
• modifier m - multiline
• modifier i - case insensitive matcing
• modifier s - dot includes newlines

Change log:

• 1.2 - partial rewrite to fix engine design issues

API documentation:

srx_Create

	const rxChar* regex, // the regular expression
	const rxChar* mods // modifier char list

• creates a regular expression matcher from the specified expression and modifier list
• returns the regular expression matcher ("context")

srx_CreateExt

	const rxChar* regex, // the regular expression
	const rxChar* mods, // modifier char list (optional)
	int* errnpos, // pointer to an array of *two* int values: error code and error position (optional)
	srx_MemFunc memfn, // memory allocation function (optional)
	void* memctx // user pointer to pass to the allocation function (optional)

• creates a regular expression matcher from the specified expression and modifier list
• allows to specify custom memory allocation and error output
• returns the regular expression matcher ("context")

srx_Destroy

	srx_Context* R // the regex matcher context

• destroys the created matcher object

srx_DumpToFile

	srx_Context* R, // the regex matcher context
	FILE* fp // the file to dump the structure

• dumps the structure of the context to file

srx_DumpToStdout

	srx_Context* R // the regex matcher context

• dumps the structure of the context to standard output

srx_Match

	srx_Context* R, // the regex matcher context
	const rxChar* str, // the string to use for matching
	int offset // the starting point for matching

• searches for a match through the string
• offset is not "approached safely" (with a loop to check for a NUL-byte)
• returns whether a match was found

srx_MatchExt

	srx_Context* R, // the regex matcher context
	const rxChar* str, // the string to use for matching
	size_t size, // length of the string
	size_t offset // the starting point for matching

• searches for a match through the string
• string does not need to be null-terminated, size must be passed to size argument
• offset is not "approached safely" (with a loop to check for a NUL-byte)
• returns whether a match was found

srx_GetCaptureCount

	srx_Context* R // the regex matcher context

• returns the number of capture ranges that were found in the expression (there's always at least one - the whole match)
• the current upper limit is 10 (including the whole match)

srx_GetCaptured

	srx_Context* R, // the regex matcher context
	int which, // the capture range number
	int* pbeg, // pointer to output for start offset (optional)
	int* pend // pointer to output for end offset (optional)

• retrieves the offsets from the specified capture range
• returns if the capture range number is in range and if the last match included the capture range (which also means that data was written to specified pointers)

srx_GetCapturedPtrs

	srx_Context* R, // the regex matcher context
	int which, // the capture range number
	const rxChar** pbeg, // pointer to output for start offset pointer (optional)
	const rxChar** pend // pointer to output for end offset pointer (optional)

• retrieves the offset pointers from the specified capture range
• returns if the capture range number is in range and if the last match included the capture range (which also means that data was written to specified pointers)

srx_Replace

	srx_Context* R, // the regex matcher contex
	const rxChar* str, // the input string
	const rxChar* rep // the replacement string (supports capture ranges in the form of "\1")

• replaces occurrences of pattern in string str with string rep, returns the replaced string
• the returned string is allocated with the registered allocator

srx_ReplaceExt

	srx_Context* R, // the regex matcher contex
	const rxChar* str, // the input string
	size_t strsize, // the length of the input string
	const rxChar* rep, // the replacement string (supports capture ranges in the form of "\1")
	size_t repsize, // the length of the replacement string
	size_t* outsize // pointer to output for length of returned string (optional)

• replaces occurrences of pattern in string str with string rep, returns the replaced string
• the returned string is allocated with the registered allocator
• none of the strings involved need to be null-terminated

srx_FreeReplaced

	srx_Context* R,
	RX_Char* repstr

• frees the string returned by srx_Replace

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This library was created by Arvīds Kokins (snake5)