mystrtok.c

[詳解]

/*++
/* NAME
/*  mystrtok 3
/* SUMMARY
/*  safe tokenizer
/* SYNOPSIS
/*  #include <stringops.h>
/*
/*  char    *mystrtok(bufp, delimiters)
/*  char    **bufp;
/*  const char *delimiters;
/*
/*  char    *mystrtokq(bufp, delimiters, parens)
/*  char    **bufp;
/*  const char *delimiters;
/*  const char *parens;
/* DESCRIPTION
/*  mystrtok() splits a buffer on the specified \fIdelimiters\fR.
/*  Tokens are delimited by runs of delimiters, so this routine
/*  cannot return zero-length tokens.
/*
/*  mystrtokq() is like mystrtok() but will not split text
/*  between balanced parentheses.  \fIparens\fR specifies the
/*  opening and closing parenthesis (one of each).  The set of
/*  \fIparens\fR must be distinct from the set of \fIdelimiters\fR.
/*
/*  The \fIbufp\fR argument specifies the start of the search; it
/*  is updated with each call. The input is destroyed.
/*
/*  The result value is the next token, or a null pointer when the
/*  end of the buffer was reached.
/* 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"

/* mystrtok - safe tokenizer */

char   *mystrtok(char **src, const char *sep)
{
    char   *start = *src;
    char   *end;

    /*
     * Skip over leading delimiters.
     */
    start += strspn(start, sep);
    if (*start == 0) {
    *src = start;
    return (0);
    }

    /*
     * Separate off one token.
     */
    end = start + strcspn(start, sep);
    if (*end != 0)
    *end++ = 0;
    *src = end;
    return (start);
}

/* mystrtokq - safe tokenizer with quoting support */

char   *mystrtokq(char **src, const char *sep, const char *parens)
{
    char   *start = *src;
    static char   *cp;
    int     ch;
    int     level;

    /*
     * Skip over leading delimiters.
     */
    start += strspn(start, sep);
    if (*start == 0) {
    *src = start;
    return (0);
    }

    /*
     * Parse out the next token.
     */
    for (level = 0, cp = start; (ch = *(unsigned char *) cp) != 0; cp++) {
    if (ch == parens[0]) {
        level++;
        } else if (level > 0 && ch == parens[1]) {
        level--;
    } else if (level == 0 && strchr(sep, ch) != 0) {
        *cp++ = 0;
        break;
    }
    }
    *src = cp;
    return (start);
}

#ifdef TEST

 /*
  * Test program: read lines from stdin, split on whitespace.
  */
#include "vstring.h"
#include "vstream.h"
#include "vstring_vstream.h"

int     main(void)
{
    VSTRING *vp = vstring_alloc(100);
    char   *start;
    char   *str;

    while (vstring_fgets(vp, VSTREAM_IN) && VSTRING_LEN(vp) > 0) {
    start = vstring_str(vp);
    if (strchr(start, CHARS_BRACE[0]) == 0) {
        while ((str = mystrtok(&start, CHARS_SPACE)) != 0)
        vstream_printf(">%s<\n", str);
    } else {
        while ((str = mystrtokq(&start, CHARS_SPACE, CHARS_BRACE)) != 0)
        vstream_printf(">%s<\n", str);
    }
    vstream_fflush(VSTREAM_OUT);
    }
    vstring_free(vp);
    return (0);
}

#endif