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/*
* Copyright (c) 1987, 1989 University of Maryland
* Department of Computer Science. All rights reserved.
* Permission to copy for any purpose is hereby granted
* so long as this copyright notice remains intact.
*/
#ifndef lint
static char rcsid[] = "$Header: /usr/src/local/tex/local/mctex/lib/RCS/split.c,v 3.1 89/08/22 21:59:36 chris Exp $";
#endif
#include <ctype.h>
/*
* Split a line into an array of words. This is destructive of
* the original line; the word pointers point to places within
* that line.
*
* The pound-sign character `#', at the beginning of the line or
* after white space, marks the end of the line.
*
* Return the number of words made, or -1 for overflow.
*/
/*
* The lexical states are much like `sh's, except that we also do
* C-style backslash-escapes.
*/
enum lexstate {
S_BLANK, /* outside a word */
S_WORD, /* inside a word, no quoting */
S_SQUOTE, /* inside a single quote */
S_DQUOTE, /* inside a double quote */
S_BKSL0, /* last char was \ */
S_BKSL1, /* last chars were \, [0-7] */
S_BKSL2 /* last chars were \, [0-7][0-7] */
};
int
split(s, w, nw)
register char *s, **w;
int nw;
{
register int c;
register char *canon = s;
register int wleft = nw;
enum lexstate state, prebkstate;
/*
* Start out in the `blank' state (outside a word). Handle
* quotes and things. Backslashes are handled by saving the
* `pre-backslash' state, doing the backslash, and restoring
* that state at the end of the backslash sequence.
*/
state = S_BLANK;
while ((c = *s++) != 0) {
reswitch:
switch (state) {
/*
* Blanks: spaces stay in blank state; '#' ends the line;
* anything else starts a word. However, quotes may put
* us into quote states, rather than word states.
*/
case S_BLANK:
if (isspace(c))
continue;
if (c == '#')
goto stopped_by_comment;
if (--wleft < 0)
return (-1);
*w++ = canon;
state = S_WORD;
/* FALLTHROUGH */
/*
* In a word. Spaces take us out (and end the
* current word). Quotes, however, put us into
* quote states.
*/
case S_WORD:
if (isspace(c)) {
*canon++ = 0;
state = S_BLANK;
break;
}
if (c == '\'') {
state = S_SQUOTE;
break;
}
if (c == '"') {
state = S_DQUOTE;
break;
}
if (c == '\\') {
prebkstate = S_WORD;
state = S_BKSL0;
break;
}
*canon++ = c;
break;
/*
* Inside a single quote, the only special character
* is another single quote. This matches the Bourne
* shell quoting convention exactly.
*/
case S_SQUOTE:
if (c == '\'')
state = S_WORD;
else
*canon++ = c;
break;
/*
* Inside a double quote, double quotes get us out,
* but backslashes must be interpreted.
*/
case S_DQUOTE:
if (c == '\\') {
prebkstate = S_DQUOTE;
state = S_BKSL0;
} else if (c == '"')
state = S_WORD;
else
*canon++ = c;
break;
/*
* If we are handling a backslash, we will either
* restore the state, or go to BKSL1 state. In
* the latter case, do not advance the canonicalisation
* pointer, since we might have more octal digits
* to insert.
*/
case S_BKSL0:
state = prebkstate; /* probably */
switch (c) {
case 'b':
*canon++ = '\b';
break;
case 'f':
*canon++ = '\f';
break;
case 'n':
*canon++ = '\n';
break;
case 'r':
*canon++ = '\r';
break;
case 't':
*canon++ = '\t';
break;
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
*canon = c - '0';
state = S_BKSL1;
break;
default:
*canon++ = c;
break;
}
break;
/*
* In BKSL1, we have seen backslash and one octal
* digit. There may be more (in which case just
* count them on in), or there might be something
* that requires we restore the state and try again.
*/
case S_BKSL1:
switch (c) {
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
*canon <<= 3;
*canon |= c - '0';
state = S_BKSL2;
break;
default:
canon++;
state = prebkstate;
goto reswitch;
}
break;
/*
* BKSL2 is like BKSL1, except that it cannot
* help but restore the original state, since
* there are no four-character octal sequences.
*/
case S_BKSL2:
state = prebkstate; /* assuredly */
switch (c) {
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
*canon <<= 3;
*canon++ |= c - '0';
break;
default:
canon++;
goto reswitch;
}
break;
}
}
stopped_by_comment:
#ifdef notdef
if (state != S_WORD && state != S_BLANK)
error(0, 0, "warning: unclosed quote");
#endif
if (state != S_BLANK)
*canon = 0;
return (nw - wleft);
}
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