translit.c

[詳解]

/*++
/* NAME
/*  translit 3
/* SUMMARY
/*  transliterate characters
/* SYNOPSIS
/*  #include <stringops.h>
/*
/*  char    *translit(buf, original, replacement)
/*  char    *buf;
/*  char    *original;
/*  char    *replacement;
/* DESCRIPTION
/*  translit() takes a null-terminated string, and replaces characters
/*  given in its \fIoriginal\fR argument by the corresponding characters
/*  in the \fIreplacement\fR string. The result value is the \fIbuf\fR
/*  argument.
/* BUGS
/*  Cannot replace null characters.
/* LICENSE
/* .ad
/* .fi
/*  The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/*  Wietse Venema
/*  IBM T.J. Watson Research
/*  P.O. Box 704
/*  Yorktown Heights, NY 10598, USA
/*--*/

/* System library. */

#include "sys_defs.h"
#include <string.h>

/* Utility library. */

#include "stringops.h"

char   *translit(char *string, const char *original, const char *replacement)
{
    char   *cp;
    const char *op;

    /*
     * For large inputs, should use a lookup table.
     */
    for (cp = string; *cp != 0; cp++) {
    for (op = original; *op != 0; op++) {
        if (*cp == *op) {
        *cp = replacement[op - original];
        break;
        }
    }
    }
    return (string);
}

#ifdef TEST

 /*
  * Usage: translit string1 string2
  * 
  * test program to perform the most basic operation of the UNIX tr command.
  */
#include <msg.h>
#include <vstring.h>
#include <vstream.h>
#include <vstring_vstream.h>

#define STR vstring_str

int     main(int argc, char **argv)
{
    VSTRING *buf = vstring_alloc(100);

    if (argc != 3)
    msg_fatal("usage: %s string1 string2", argv[0]);
    while (vstring_fgets(buf, VSTREAM_IN))
    vstream_fputs(translit(STR(buf), argv[1], argv[2]), VSTREAM_OUT);
    vstream_fflush(VSTREAM_OUT);
    vstring_free(buf);
    return (0);
}

#endif