stringop.h File Reference

String operations. More...

#include "generic.h"

Data Structures
struct	VlEnumerator
	Member of an enumeration. More...

Enumerations
enum	{ VL_PROT_UNKNOWN = -1, VL_PROT_NONE = 0, VL_PROT_ASCII, VL_PROT_BINARY }
	File protocols. More...

Functions
vl_size	vl_string_copy (char *destination, vl_size destinationSize, char const *source)
	Copy string. More...
vl_size	vl_string_copy_sub (char *destination, vl_size destinationSize, char const *beginning, char const *end)
	Copy substring. More...
char *	vl_string_parse_protocol (char const *string, int *protocol)
	Extract the protocol prefix from a string. More...
char const *	vl_string_protocol_name (int prot)
	Get protocol name. More...
vl_size	vl_string_basename (char *destination, vl_size destinationSize, char const *source, vl_size maxNumStrippedExtension)
	Extract base of file name. More...
vl_size	vl_string_replace_wildcard (char *destination, vl_size destinationSize, char const *src, char wildcardChar, char escapeChar, char const *replacement)
	Replace wildcard characters by a string. More...
char *	vl_string_find_char_rev (char const *beginning, char const *end, char c)
	Search character in reversed order. More...
vl_size	vl_string_length (char const *string)
	Calculate string length. More...
int	vl_string_casei_cmp (const char *string1, const char *string2)
	Compare strings case-insensitive. More...
String enumerations
VlEnumerator *	vl_enumeration_get (VlEnumerator const *enumeration, char const *name)
	Get a member of an enumeration by name. More...
VlEnumerator *	vl_enumeration_get_casei (VlEnumerator const *enumeration, char const *name)
	Get a member of an enumeration by name (case insensitive) More...
VlEnumerator *	vl_enumeration_get_by_value (VlEnumerator const *enumeration, vl_index value)
	Get a member of an enumeration by value. More...

Detailed Description

Author

Andrea Vedaldi

stringop.h implements basic string operations. All functions that write to strings use range checking, which makes them safer than some standard POSIX equivalent (see Detecting overflow).

Enumerations

stringop.h defines a simple enumeration data type. This is given by an array of enumeration members, represented by instances of the VlEnumerator strucutre, each storing a name-value pair. The enumeration must end by a member whose name is set to NULL.

Use vl_enumeration_get and vl_enumeration_get_casei to retrieve an enumeration member by name.

File protocols

stringop.h defines a few file "protocols" and helps parsing them from URL-like formatted strings. The supported protocols are:

File protocols

Protocol	Code	URL prefix
ASCII	VL_PROT_ASCII	ascii://
BINARY	VL_PROT_BINARY	binary://

Detecting overflow

stringop.h functions that write a string to a character buffer take both the buffer and its size n as input. If n is not large enough, the output may be truncated but it is always a null terminated string (provided that n >= 1). Such functions also return the length of the string that would have been written r (which does not include the terminating null character) had the buffer been large enough. Hence an overflow can be detected by testing if r >= n, r can be used to re-allocate a buffer large enough to contain the result, and the operation can be repeated.

Author

Andrea Vedaldi

Enumeration Type Documentation

anonymous enum

anonymous enum

Enumerator
VL_PROT_UNKNOWN	unknown protocol
VL_PROT_NONE	no protocol
VL_PROT_ASCII	ASCII protocol
VL_PROT_BINARY	Binary protocol

Function Documentation

vl_enumeration_get()

VlEnumerator* vl_enumeration_get	(	VlEnumerator const *	enumeration,
		char const *	name
	)

Parameters

enumeration	array of VlEnumerator objects.
name	the name of the desired member.

Returns

enumerator matching name.

If name is not found in the enumeration, then the value NULL is returned.

See also

vl-stringop-enumeration

vl_enumeration_get_by_value()

VlEnumerator* vl_enumeration_get_by_value	(	VlEnumerator const *	enumeration,
		vl_index	value
	)

Parameters

enumeration	array of VlEnumerator objects.
value	value of the desired member.

Returns

enumerator matching value.

If value is not found in the enumeration, then the value NULL is returned.

See also

vl-stringop-enumeration

vl_enumeration_get_casei()

VlEnumerator* vl_enumeration_get_casei	(	VlEnumerator const *	enumeration,
		char const *	name
	)

Parameters

enumeration	array of VlEnumerator objects.
name	the name of the desired member.

Returns

enumerator matching name.

If name is not found in the enumeration, then the value NULL is returned. string is matched case insensitive.

See also

vl-stringop-enumeration

vl_string_basename()

vl_size vl_string_basename	(	char *	destination,
		vl_size	destinationSize,
		char const *	source,
		vl_size	maxNumStrippedExtensions
	)

Parameters

destination	destination buffer.
destinationSize	size of destination buffer.
source	input string.
maxNumStrippedExtensions	maximum number of extensions to strip.

Returns

length of the destination string.

The function removes the leading path and up to maxNumStrippedExtensions trailing extensions from the string source and writes the result to the buffer destination.

The leading path is the longest suffix that ends with either the \ or / characters. An extension is a string starting with the . character not containing it. For instance, the string file.png contains the extension .png and the string file.tar.gz contains two extensions (.tar and .gz).

See also

Detecting overflow.

vl_string_casei_cmp()

int vl_string_casei_cmp	(	const char *	string1,
		const char *	string2
	)

Parameters

string1	fisrt string.
string2	second string.

Returns

an integer =,<,> 0 if string1 =,<,> string2

vl_string_copy()

vl_size vl_string_copy	(	char *	destination,
		vl_size	destinationSize,
		char const *	source
	)

Parameters

destination	output buffer.
destinationSize	size of the output buffer.
source	string to copy.

Returns

length of the source string.

The function copies the string source to the buffer destination of size destinationSize.

See also

Detecting overflow.

vl_string_copy_sub()

vl_size vl_string_copy_sub	(	char *	destination,
		vl_size	destinationSize,
		char const *	beginning,
		char const *	end
	)

Parameters

destination	output buffer.
destinationSize	size of output buffer.
beginning	start of the substring.
end	end of the substring.

Returns

length of the destination string.

The function copies the substring from at beginning to end (not included) to the buffer destination of size destinationSize. If, however, the null character is found before end, the substring terminates there.

See also

Detecting overflow.

vl_string_find_char_rev()

char* vl_string_find_char_rev	(	char const *	beginning,
		char const *	end,
		char	c
	)

Parameters

beginning	pointer to the substring beginning.
end	pointer to the substring end.
c	character to search for.

Returns

pointer to last occurrence of c, or 0 if none.

The function searches for the last occurrence of the character c in the substring from beg to end (the latter not being included).

vl_string_length()

vl_size vl_string_length

(

char const *

string

)

Parameters

string

string.

Returns

string length.

vl_string_parse_protocol()

char* vl_string_parse_protocol	(	char const *	string,
		int *	protocol
	)

Parameters

string	string.
protocol	protocol code (output).

Returns

pointer to the first character after the protocol prefix.

The function extracts the prefix of the string string terminated by the first occurrence of the :// substring (if any). It then matches the suffix terminated by :// to the supported File protocols protocols. If protocol is not NULL, the corresponding protocol code is written to protocol

The function writes to protocol the value VL_PROT_NONE if no suffix is detected and VL_PROT_UNKNOWN if there is a suffix but it cannot be matched to any of the supported protocols.

vl_string_protocol_name()

char const* vl_string_protocol_name

(

int

protocol

)

Parameters

protocol

protocol code.

Returns

pointer protocol name string.

The function returns a pointer to a string containing the name of the protocol protocol (see the vl-file-protocols protocols list). If the protocol is unknown the function returns the empty string.

vl_string_replace_wildcard()

vl_size vl_string_replace_wildcard	(	char *	destination,
		vl_size	destinationSize,
		char const *	source,
		char	wildcardChar,
		char	escapeChar,
		char const *	replacement
	)

Parameters

destination	output buffer.
destinationSize	size of the output buffer.
source	input string.
wildcardChar	wildcard character.
escapeChar	escape character.
replacement	replacement string.

The function replaces the occurrence of the specified wildcard character wildcardChar by the string replacement. The result is written to the buffer destination of size destinationSize.

Wildcard characters may be escaped by preceding them by the esc character. More in general, anything following an occurrence of esc character is copied verbatim. To disable the escape characters simply set esc to 0.

Returns

length of the result.

See also

Detecting overflow.