/* $NetBSD: str.c,v 1.30 2018/05/26 11:20:30 leot Exp $ */
/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/types.h>
#include <err.h>
#include <errno.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <assert.h>
#include "extern.h"
struct str {
enum { STRING1, STRING2 } which;
enum { EOS, INFINITE, NORMAL, RANGE, SEQUENCE, SET } state;
int cnt; /* character count */
int lastch; /* last character */
int equiv[2]; /* equivalence set */
int *set; /* set of characters */
const char *str; /* user's string */
};
static int backslash(STR *);
static int bracket(STR *);
static int c_class(const void *, const void *);
static int *genclass(const char *, size_t);
static void genequiv(STR *);
static int genrange(STR *);
static void genseq(STR *);
STR *
str_create(int whichstring, const char *txt)
{
STR *s;
s = malloc(sizeof(*s));
if (s == NULL) {
err(1, "Out of memory");
}
s->which = whichstring == 2 ? STRING2 : STRING1;
s->state = NORMAL;
s->cnt = 0;
s->lastch = OOBCH;
s->equiv[0] = 0;
s->equiv[1] = OOBCH;
s->set = NULL;
s->str = txt;
return s;
}
void
str_destroy(STR *s)
{
if (s->set != NULL && s->set != s->equiv) {
free(s->set);
}
free(s);
}
int
next(STR *s, int *ret)
{
int ch;
switch (s->state) {
case EOS:
*ret = s->lastch;
return 0;
case INFINITE:
*ret = s->lastch;
return 1;
case NORMAL:
ch = (unsigned char)s->str[0];
switch (ch) {
case '\0':
s->state = EOS;
*ret = s->lastch;
return 0;
case '\\':
s->lastch = backslash(s);
break;
case '[':
if (bracket(s)) {
return next(s, ret);
}
/* FALLTHROUGH */
default:
++s->str;
s->lastch = ch;
break;
}
/* We can start a range at any time. */
if (s->str[0] == '-' && genrange(s)) {
return next(s, ret);
}
*ret = s->lastch;
return 1;
case RANGE:
if (s->cnt == 0) {
s->state = NORMAL;
return next(s, ret);
}
s->cnt--;
++s->lastch;
*ret = s->lastch;
return 1;
case SEQUENCE:
if (s->cnt == 0) {
s->state = NORMAL;
return next(s, ret);
}
s->cnt--;
*ret = s->lastch;
return 1;
case SET:
s->lastch = s->set[s->cnt++];
if (s->lastch == OOBCH) {
s->state = NORMAL;
if (s->set != s->equiv) {
free(s->set);
}
s->set = NULL;
return next(s, ret);
}
*ret = s->lastch;
return 1;
}
/* NOTREACHED */
assert(0);
*ret = s->lastch;
return 0;
}
static int
bracket(STR *s)
{
const char *p;
int *q;
switch (s->str[1]) {
case ':': /* "[:class:]" */
if ((p = strstr(s->str + 2, ":]")) == NULL)
return 0;
s->str += 2;
q = genclass(s->str, p - s->str);
s->state = SET;
s->set = q;
s->cnt = 0;
s->str = p + 2;
return 1;
case '=': /* "[=equiv=]" */
if ((p = strstr(s->str + 2, "=]")) == NULL)
return 0;
s->str += 2;
genequiv(s);
s->str = p + 2;
return 1;
default: /* "[\###*n]" or "[#*n]" */
if ((p = strpbrk(s->str + 2, "*]")) == NULL)
return 0;
if (p[0] != '*' || strchr(p, ']') == NULL)
return 0;
s->str += 1;
genseq(s);
return 1;
}
/* NOTREACHED */
}
typedef struct {
const char *name;
int (*func)(int);
} CLASS;
static const CLASS classes[] = {
{ "alnum", isalnum },
{ "alpha", isalpha },
{ "blank", isblank },
{ "cntrl", iscntrl },
{ "digit", isdigit },
{ "graph", isgraph },
{ "lower", islower },
{ "print", isprint },
{ "punct", ispunct },
{ "space", isspace },
{ "upper", isupper },
{ "xdigit", isxdigit },
};
const int classes_len = 12;
typedef struct {
const char *name;
size_t len;
} CLASSKEY;
static int *
genclass(const char *class, size_t len)
{
int ch;
const CLASS *cp;
CLASSKEY key;
int *p;
unsigned pos, num;
/* Find the class */
key.name = class;
key.len = len;
cp = bsearch(&key, classes, classes_len, sizeof(classes[0]),
c_class);
if (cp == NULL) {
errx(1, "unknown class %.*s", (int)len, class);
}
/*
* Figure out what characters are in the class
*/
num = NCHARS + 1;
p = malloc(num * sizeof(*p));
if (p == NULL) {
err(1, "malloc");
}
pos = 0;
for (ch = 0; ch < NCHARS; ch++) {
if (cp->func(ch)) {
p[pos++] = ch;
}
}
p[pos++] = OOBCH;
for (; pos < num; pos++) {
p[pos] = 0;
}
return p;
}
static int
c_class(const void *av, const void *bv)
{
const CLASSKEY *a = av;
const CLASS *b = bv;
size_t blen;
int r;
blen = strlen(b->name);
r = strncmp(a->name, b->name, a->len);
if (r != 0) {
return r;
}
if (a->len < blen) {
/* someone gave us a prefix of the right name */
return -1;
}
assert(a-> len == blen);
return 0;
}
/*
* English doesn't have any equivalence classes, so for now
* we just syntax check and grab the character.
*/
static void
genequiv(STR *s)
{
int ch;
ch = (unsigned char)s->str[0];
if (ch == '\\') {
s->equiv[0] = backslash(s);
} else {
s->equiv[0] = ch;
s->str++;
}
if (s->str[0] != '=') {
errx(1, "Misplaced equivalence equals sign");
}
s->str++;
if (s->str[0] != ']') {
errx(1, "Misplaced equivalence right bracket");
}
s->str++;
s->cnt = 0;
s->state = SET;
s->set = s->equiv;
}
static int
genrange(STR *s)
{
int stopval;
const char *savestart;
savestart = s->str++;
stopval = s->str[0] == '\\' ? backslash(s) : (unsigned char)*s->str++;
if (stopval < (unsigned char)s->lastch) {
s->str = savestart;
return 0;
}
s->cnt = stopval - s->lastch + 1;
s->state = RANGE;
--s->lastch;
return 1;
}
static void
genseq(STR *s)
{
char *ep;
if (s->which == STRING1) {
errx(1, "Sequences only valid in string2");
}
if (*s->str == '\\') {
s->lastch = backslash(s);
} else {
s->lastch = (unsigned char)*s->str++;
}
if (*s->str != '*') {
errx(1, "Misplaced sequence asterisk");
}
s->str++;
switch (s->str[0]) {
case '\\':
s->cnt = backslash(s);
break;
case ']':
s->cnt = 0;
++s->str;
break;
default:
if (isdigit((unsigned char)s->str[0])) {
s->cnt = strtol(s->str, &ep, 0);
if (*ep == ']') {
s->str = ep + 1;
break;
}
}
errx(1, "illegal sequence count");
/* NOTREACHED */
}
s->state = s->cnt ? SEQUENCE : INFINITE;
}
/*
* Translate \??? into a character. Up to 3 octal digits, if no digits either
* an escape code or a literal character.
*/
static int
backslash(STR *s)
{
int ch, cnt, val;
cnt = val = 0;
for (;;) {
/* Consume the character we're already on. */
s->str++;
/* Look at the next character. */
ch = (unsigned char)s->str[0];
if (!isascii(ch) || !isdigit(ch)) {
break;
}
val = val * 8 + ch - '0';
if (++cnt == 3) {
/* Enough digits; consume this one and stop */
++s->str;
break;
}
}
if (cnt) {
/* We saw digits, so return their value */
if (val >= OOBCH)
errx(1, "Invalid octal character value");
return val;
}
if (ch == '\0') {
/* \<end> -> \ */
s->state = EOS;
return '\\';
}
/* Consume the escaped character */
s->str++;
switch (ch) {
case 'a': /* escape characters */
return '\7';
case 'b':
return '\b';
case 'e':
return '\033';
case 'f':
return '\f';
case 'n':
return '\n';
case 'r':
return '\r';
case 't':
return '\t';
case 'v':
return '\13';
default: /* \q -> q */
return ch;
}
}
