NAME

STRCASE, strcase, strcase_tolower - Multiway branch (switch) for short strings

SYNOPSIS

#include <strcase.h>
STRCASE(...)
static inline uint64_t strcase(const char *s);
static inline uint64_t strcase_tolower(const char *s);

DESCRIPTION

strcase.h provides two inline functions strcase, strcase_tolower and a macro STRCASE, all of them convert a string in a uint64_t integer value. Only the first 8 characters are significative.

strcase_tolower works like strcase but it converts uppercase letters as if they were lowercase.

strcase or strcase_tolower can be used in the expression of a switch statement to convert a string to an integer type, STRCASE generates at compile time the integer constants for the case stanzas of the switch.

Actually STRCASE (C language):

• requires the string to be specified as comma separated characters,
• supports "strings" using only literals, digits and underscore. Other symbols can appear using their name, as in:

  STRCASE(slash, e, t, c)

Regardless of its limitations this macro library is quite useful to write switch statements in C language using strings (almost) as if it were integers (as in the example below). Although STRCASE needs commas between characters the string is still readable, and it is simple to add cases or change the tags.

When the string contains only one char, the value of strcase is the code of the character (e.g. the value of strcase("a") as well as the value of STRCASE(a) is 'a')

Strcase is a portable alternative to multi-character constants in C.

Strcase is available for C++ users, too. STRCASE argument in C++ is a short string.

EXAMPLE

The following C program shows the use of strcase:

     #include <stdio.h>


     #include <strcase.h>


     int yes_or_not(const char *s) {


       switch (strcase_tolower(s)) {


         case STRCASE(y,e,s):


         case 'y':


             return 1;


         case STRCASE(n,o):


         case 'n':


             return 0;


         default:


             return -1;


       }


     }


     int main(int argc,char *argv[]) {


       for(argc--, argv++; argc > 0; argc--, argv++)


         printf("%s %d\n", *argv, yes_or_not(*argv));


     }

The same example can be translated in C++ as follows:

     #include <iostream>


     #include <strcase.h>


     using namespace std;


     int yes_or_not(const char *s) {


       switch (strcase_tolower(s)) {


         case STRCASE("yes"):


         case 'y':


             return 1;


         case STRCASE("no"):


         case 'n':


             return 0;


         default:


             return -1;


       }


     }


     int main(int argc,char *argv[]) {


       for(argc--, argv++; argc > 0; argc--, argv++)


         cout << *argv << " " << yes_or_not(*argv) << endl;


     }

BUGS

Bug reports should be addressed to <info@virtualsquare.org>

AUTHORS

Renzo Davoli <renzo@cs.unibo.it>