/*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <ctype.h>
typedef int boolean;
#define TRUE 1
#define FALSE 0
#define NIL 0
extern boolean l_onecase; /* true if upper and lower equivalent */
extern char *l_idchars; /* set of characters legal in identifiers
in addition to letters and digits */
extern char *strchr();
static void expconv(void);
#define isidchr(c) \
(isalnum(c) || ((c) != NIL && strchr(l_idchars, (c)) != NIL))
#define makelower(c) (isupper((c)) ? tolower((c)) : (c))
/* STRNCMP - like strncmp except that we convert the
* first string to lower case before comparing
* if l_onecase is set.
*/
int
STRNCMP(char *s1, char *s2, int len)
{
if (l_onecase) {
do
if (*s2 - makelower(*s1))
return (*s2 - makelower(*s1));
else {
s2++;
s1++;
}
while (--len);
} else {
do
if (*s2 - *s1)
return (*s2 - *s1);
else {
s2++;
s1++;
}
while (--len);
}
return(0);
}
/* The following routine converts an irregular expression to
* internal format.
*
* Either meta symbols (\a \d or \p) or character strings or
* operations ( alternation or parenthesizing ) can be
* specified. Each starts with a descriptor byte. The descriptor
* byte has STR set for strings, META set for meta symbols
* and OPER set for operations.
* The descriptor byte can also have the OPT bit set if the object
* defined is optional. Also ALT can be set to indicate an alternation.
*
* For metasymbols the byte following the descriptor byte identities
* the meta symbol (containing an ascii 'a', 'd', 'p', '|', or '('). For
* strings the byte after the descriptor is a character count for
* the string:
*
* meta symbols := descriptor
* symbol
*
* strings := descriptor
* character count
* the string
*
* operations := descriptor
* symbol
* character count
*/
/*
* handy macros for accessing parts of match blocks
*/
#define MSYM(A) (*(A+1)) /* symbol in a meta symbol block */
#define MNEXT(A) (A+2) /* character following a metasymbol block */
#define OSYM(A) (*(A+1)) /* symbol in an operation block */
#define OCNT(A) (*(A+2)) /* character count */
#define ONEXT(A) (A+3) /* next character after the operation */
#define OPTR(A) (A+*(A+2)) /* place pointed to by the operator */
#define SCNT(A) (*(A+1)) /* byte count of a string */
#define SSTR(A) (A+2) /* address of the string */
#define SNEXT(A) (A+2+*(A+1)) /* character following the string */
/*
* bit flags in the descriptor
*/
#define OPT 1
#define STR 2
#define META 4
#define ALT 8
#define OPER 16
char *ure; /* pointer current position in unconverted exp */
char *ccre; /* pointer to current position in converted exp*/
char *malloc();
char *
convexp(char *re)
/* re - unconverted irregular expression */
{
char *cre; /* pointer to converted regular expression */
/* allocate room for the converted expression */
if (re == NIL)
return (NIL);
if (*re == '\0')
return (NIL);
cre = malloc (4 * strlen(re) + 3);
ccre = cre;
ure = re;
/* start the conversion with a \a */
*cre = META | OPT;
MSYM(cre) = 'a';
ccre = MNEXT(cre);
/* start the conversion (its recursive) */
expconv ();
*ccre = 0;
return (cre);
}
static void
expconv(void)
{
char *cs; /* pointer to current symbol in converted exp */
char c; /* character being processed */
char *acs; /* pinter to last alternate */
int temp;
/* let the conversion begin */
acs = NIL;
cs = NIL;
while (*ure != NIL) {
switch (c = *ure++) {
case '\\':
switch (c = *ure++) {
/* escaped characters are just characters */
default:
if (cs == NIL || (*cs & STR) == 0) {
cs = ccre;
*cs = STR;
SCNT(cs) = 1;
ccre += 2;
} else
SCNT(cs)++;
*ccre++ = c;
break;
/* normal(?) metacharacters */
case 'a':
case 'd':
case 'e':
case 'p':
if (acs != NIL && acs != cs) {
do {
temp = OCNT(acs);
OCNT(acs) = ccre - acs;
acs -= temp;
} while (temp != 0);
acs = NIL;
}
cs = ccre;
*cs = META;
MSYM(cs) = c;
ccre = MNEXT(cs);
break;
}
break;
/* just put the symbol in */
case '^':
case '$':
if (acs != NIL && acs != cs) {
do {
temp = OCNT(acs);
OCNT(acs) = ccre - acs;
acs -= temp;
} while (temp != 0);
acs = NIL;
}
cs = ccre;
*cs = META;
MSYM(cs) = c;
ccre = MNEXT(cs);
break;
/* mark the last match sequence as optional */
case '?':
if (cs)
*cs = *cs | OPT;
break;
/* recurse and define a subexpression */
case '(':
if (acs != NIL && acs != cs) {
do {
temp = OCNT(acs);
OCNT(acs) = ccre - acs;
acs -= temp;
} while (temp != 0);
acs = NIL;
}
cs = ccre;
*cs = OPER;
OSYM(cs) = '(';
ccre = ONEXT(cs);
expconv ();
OCNT(cs) = ccre - cs; /* offset to next symbol */
break;
/* return from a recursion */
case ')':
if (acs != NIL) {
do {
temp = OCNT(acs);
OCNT(acs) = ccre - acs;
acs -= temp;
} while (temp != 0);
acs = NIL;
}
cs = ccre;
*cs = META;
MSYM(cs) = c;
ccre = MNEXT(cs);
return;
/* mark the last match sequence as having an alternate */
/* the third byte will contain an offset to jump over the */
/* alternate match in case the first did not fail */
case '|':
if (acs != NIL && acs != cs)
OCNT(ccre) = ccre - acs; /* make a back pointer */
else
OCNT(ccre) = 0;
*cs |= ALT;
cs = ccre;
*cs = OPER;
OSYM(cs) = '|';
ccre = ONEXT(cs);
acs = cs; /* remember that the pointer is to be filles */
break;
/* if its not a metasymbol just build a scharacter string */
default:
if (cs == NIL || (*cs & STR) == 0) {
cs = ccre;
*cs = STR;
SCNT(cs) = 1;
ccre = SSTR(cs);
} else
SCNT(cs)++;
*ccre++ = c;
break;
}
}
if (acs != NIL) {
do {
temp = OCNT(acs);
OCNT(acs) = ccre - acs;
acs -= temp;
} while (temp != 0);
acs = NIL;
}
}
/* end of convertre */
/*
* The following routine recognises an irregular expresion
* with the following special characters:
*
* \? - means last match was optional
* \a - matches any number of characters
* \d - matches any number of spaces and tabs
* \p - matches any number of alphanumeric
* characters. The
* characters matched will be copied into
* the area pointed to by 'name'.
* \| - alternation
* \( \) - grouping used mostly for alternation and
* optionality
*
* The irregular expression must be translated to internal form
* prior to calling this routine
*
* The value returned is the pointer to the first non \a
* character matched.
*/
boolean _escaped; /* true if we are currently _escaped */
char *Start; /* start of string */
char *
expmatch(char *s, char *re, char *mstring)
/* s - string to check for a match in */
/* re - a converted irregular expression */
/* mstring - where to put whatever matches a \p */
{
char *cs; /* the current symbol */
char *ptr, *s1; /* temporary pointer */
boolean matched; /* a temporary boolean */
/* initial conditions */
if (re == NIL)
return (NIL);
cs = re;
matched = FALSE;
/* loop till expression string is exhausted (or at least pretty tired) */
while (*cs) {
switch (*cs & (OPER | STR | META)) {
/* try to match a string */
case STR:
matched = !STRNCMP (s, SSTR(cs), SCNT(cs));
if (matched) {
/* hoorah it matches */
s += SCNT(cs);
cs = SNEXT(cs);
} else if (*cs & ALT) {
/* alternation, skip to next expression */
cs = SNEXT(cs);
} else if (*cs & OPT) {
/* the match is optional */
cs = SNEXT(cs);
matched = 1; /* indicate a successful match */
} else {
/* no match, error return */
return (NIL);
}
break;
/* an operator, do something fancy */
case OPER:
switch (OSYM(cs)) {
/* this is an alternation */
case '|':
if (matched)
/* last thing in the alternation was a match, skip ahead */
cs = OPTR(cs);
else
/* no match, keep trying */
cs = ONEXT(cs);
break;
/* this is a grouping, recurse */
case '(':
ptr = expmatch (s, ONEXT(cs), mstring);
if (ptr != NIL) {
/* the subexpression matched */
matched = 1;
s = ptr;
} else if (*cs & ALT) {
/* alternation, skip to next expression */
matched = 0;
} else if (*cs & OPT) {
/* the match is optional */
matched = 1; /* indicate a successful match */
} else {
/* no match, error return */
return (NIL);
}
cs = OPTR(cs);
break;
}
break;
/* try to match a metasymbol */
case META:
switch (MSYM(cs)) {
/* try to match anything and remember what was matched */
case 'p':
/*
* This is really the same as trying the match the
* remaining parts of the expression to any subset
* of the string.
*/
s1 = s;
do {
ptr = expmatch (s1, MNEXT(cs), mstring);
if (ptr != NIL && s1 != s) {
/* we have a match, remember the match */
strncpy (mstring, s, s1 - s);
mstring[s1 - s] = '\0';
return (ptr);
} else if (ptr != NIL && (*cs & OPT)) {
/* it was aoptional so no match is ok */
return (ptr);
} else if (ptr != NIL) {
/* not optional and we still matched */
return (NIL);
}
if (!isidchr(*s1))
return (NIL);
if (*s1 == '\\')
_escaped = _escaped ? FALSE : TRUE;
else
_escaped = FALSE;
} while (*s1++);
return (NIL);
/* try to match anything */
case 'a':
/*
* This is really the same as trying the match the
* remaining parts of the expression to any subset
* of the string.
*/
s1 = s;
do {
ptr = expmatch (s1, MNEXT(cs), mstring);
if (ptr != NIL && s1 != s) {
/* we have a match */
return (ptr);
} else if (ptr != NIL && (*cs & OPT)) {
/* it was aoptional so no match is ok */
return (ptr);
} else if (ptr != NIL) {
/* not optional and we still matched */
return (NIL);
}
if (*s1 == '\\')
_escaped = _escaped ? FALSE : TRUE;
else
_escaped = FALSE;
} while (*s1++);
return (NIL);
/* fail if we are currently _escaped */
case 'e':
if (_escaped)
return(NIL);
cs = MNEXT(cs);
break;
/* match any number of tabs and spaces */
case 'd':
ptr = s;
while (*s == ' ' || *s == '\t')
s++;
if (s != ptr || s == Start) {
/* match, be happy */
matched = 1;
cs = MNEXT(cs);
} else if (*s == '\n' || *s == '\0') {
/* match, be happy */
matched = 1;
cs = MNEXT(cs);
} else if (*cs & ALT) {
/* try the next part */
matched = 0;
cs = MNEXT(cs);
} else if (*cs & OPT) {
/* doesn't matter */
matched = 1;
cs = MNEXT(cs);
} else
/* no match, error return */
return (NIL);
break;
/* check for end of line */
case '$':
if (*s == '\0' || *s == '\n') {
/* match, be happy */
s++;
matched = 1;
cs = MNEXT(cs);
} else if (*cs & ALT) {
/* try the next part */
matched = 0;
cs = MNEXT(cs);
} else if (*cs & OPT) {
/* doesn't matter */
matched = 1;
cs = MNEXT(cs);
} else
/* no match, error return */
return (NIL);
break;
/* check for start of line */
case '^':
if (s == Start) {
/* match, be happy */
matched = 1;
cs = MNEXT(cs);
} else if (*cs & ALT) {
/* try the next part */
matched = 0;
cs = MNEXT(cs);
} else if (*cs & OPT) {
/* doesn't matter */
matched = 1;
cs = MNEXT(cs);
} else
/* no match, error return */
return (NIL);
break;
/* end of a subexpression, return success */
case ')':
return (s);
}
break;
}
}
return (s);
}