Documentation>C API
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
VlEnumeratorvl_enumeration_get (VlEnumerator const *enumeration, char const *name)
 Get a member of an enumeration by name. More...
 
VlEnumeratorvl_enumeration_get_casei (VlEnumerator const *enumeration, char const *name)
 Get a member of an enumeration by name (case insensitive) More...
 
VlEnumeratorvl_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
ProtocolCodeURL prefix
ASCIIVL_PROT_ASCIIascii://
BINARYVL_PROT_BINARYbinary://

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
enumerationarray of VlEnumerator objects.
namethe 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
enumerationarray of VlEnumerator objects.
valuevalue 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
enumerationarray of VlEnumerator objects.
namethe 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
destinationdestination buffer.
destinationSizesize of destination buffer.
sourceinput string.
maxNumStrippedExtensionsmaximum 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
string1fisrt string.
string2second 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
destinationoutput buffer.
destinationSizesize of the output buffer.
sourcestring 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
destinationoutput buffer.
destinationSizesize of output buffer.
beginningstart of the substring.
endend 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
beginningpointer to the substring beginning.
endpointer to the substring end.
ccharacter 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
stringstring.
Returns
string length.

◆ vl_string_parse_protocol()

char* vl_string_parse_protocol ( char const *  string,
int *  protocol 
)
Parameters
stringstring.
protocolprotocol 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
protocolprotocol 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
destinationoutput buffer.
destinationSizesize of the output buffer.
sourceinput string.
wildcardCharwildcard character.
escapeCharescape character.
replacementreplacement 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.