utils-std

tr_str.c (7500B)

// SPDX-License-Identifier: BSD-3-Clause
/*	$OpenBSD: str.c,v 1.15 2023/05/04 16:08:29 tb Exp $	*/
/*	$NetBSD: str.c,v 1.7 1995/08/31 22:13:47 jtc 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.
 */
#define _POSIX_C_SOURCE 202405L
#include "./tr_str.h"
#include "../libutils/err.h"
#include "../libutils/reallocarray.h"
#include <assert.h>
#include <ctype.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
static int backslash(STR *);
static int bracket(STR *);
static int c_class(const void *, const void *);
static void genclass(STR *);
static void genequiv(STR *);
static int genrange(STR *);
static void genseq(STR *);
int
next(STR *s)
{
	int ch;
	switch(s->state)
	{
	case EOS:
		return (0);
	case INFINITE:
		return (1);
	case NORMAL:
		switch(ch = *s->str)
		{
		case '\0':
			s->state = EOS;
			return (0);
		case '\\':
			s->lastch = backslash(s);
			break;
		case '[':
			if(bracket(s)) return (next(s));
			/* 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));
		return (1);
	case RANGE:
		if(s->cnt-- == 0)
		{
			s->state = NORMAL;
			return (next(s));
		}
		++s->lastch;
		return (1);
	case SEQUENCE:
		if(s->cnt-- == 0)
		{
			s->state = NORMAL;
			return (next(s));
		}
		return (1);
	case SET:
		if((s->lastch = s->set[s->cnt++]) == OOBCH)
		{
			s->state = NORMAL;
			return (next(s));
		}
		return (1);
	default:
		return 0;
	}
	/* NOTREACHED */
}
static int
bracket(STR *s)
{
	char *p;
	switch(s->str[1])
	{
	case ':': /* "[:class:]" */
		if((p = strstr((char *)s->str + 2, ":]")) == NULL) return (0);
		*p = '\0';
		s->str += 2;
		genclass(s);
		s->str = (unsigned char *)p + 2;
		return (1);
	case '=': /* "[=equiv=]" */
		if(strstr((char *)s->str + 2, "=]") == NULL) return (0);
		s->str += 2;
		genequiv(s);
		return (1);
	default: /* "[\###*n]" or "[#*n]" */
		if((p = strpbrk((char *)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);
	int *set;
} CLASS;
static CLASS classes[] = {
    /* clang-format off */
    { "alnum", isalnum, NULL, },
    { "alpha", isalpha, NULL, },
    { "blank", isblank, NULL, },
    { "cntrl", iscntrl, NULL, },
    { "digit", isdigit, NULL, },
    { "graph", isgraph, NULL, },
    { "lower", islower, NULL, },
    { "print", isprint, NULL, },
    { "punct", ispunct, NULL, },
    { "space", isspace, NULL, },
    { "upper", isupper, NULL, },
    { "xdigit", isxdigit, NULL, },
    /* clang-format on */
};
static void
genclass(STR *s)
{
	CLASS *cp, tmp;
	size_t len;
	int i;
	tmp.name = (char *)s->str;
	if((cp = (CLASS *)bsearch(
	        &tmp, classes, sizeof(classes) / sizeof(CLASS), sizeof(CLASS), c_class)) == NULL)
		utils_errx(1, "unknown class %s", s->str);
	/*
	 * Generate the set of characters in the class if we haven't
	 * already done so.
	 */
	if(cp->set == NULL)
	{
		len = NCHARS + 1;
		assert(len != 0);
		cp->set = utils_reallocarray(NULL, len, sizeof(*cp->set));
		if(cp->set == NULL) utils_err(1, NULL);
		len = 0;
		for(i = 0; i < NCHARS; i++)
		{
			if(cp->func(i)) cp->set[len++] = i;
		}
		cp->set[len++] = OOBCH;
		assert(len != 0);
		cp->set = utils_reallocarray(cp->set, len, sizeof(*cp->set));
		if(cp->set == NULL) utils_err(1, NULL);
	}
	s->cnt = 0;
	s->state = SET;
	s->set = cp->set;
}
static int
c_class(const void *a, const void *b)
{
	return (strcmp(((CLASS *)a)->name, ((CLASS *)b)->name));
}
/*
 * English doesn't have any equivalence classes, so for now
 * we just syntax check and grab the character.
 */
static void
genequiv(STR *s)
{
	if(*s->str == '\\')
	{
		s->equiv[0] = backslash(s);
		if(*s->str != '=') utils_errx(1, "misplaced equivalence equals sign");
	}
	else
	{
		s->equiv[0] = s->str[0];
		if(s->str[1] != '=') utils_errx(1, "misplaced equivalence equals sign");
	}
	s->str += 2;
	s->cnt = 0;
	s->state = SET;
	s->set = s->equiv;
}
static int
genrange(STR *s)
{
	int stopval;
	unsigned char *savestart;
	savestart = s->str;
	stopval = *++s->str == '\\' ? backslash(s) : *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) utils_errx(1, "sequences only valid in string2");
	if(*s->str == '\\')
		s->lastch = backslash(s);
	else
		s->lastch = *s->str++;
	if(*s->str != '*') utils_errx(1, "misplaced sequence asterisk");
	switch(*++s->str)
	{
	case '\\':
		s->cnt = backslash(s);
		break;
	case ']':
		s->cnt = 0;
		++s->str;
		break;
	default:
		if(isdigit(*s->str))
		{
			s->cnt = strtol((char *)s->str, &ep, 0);
			if(*ep == ']')
			{
				s->str = (unsigned char *)ep + 1;
				break;
			}
		}
		utils_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)
{
	size_t i;
	int ch, val;
	assert(*s->str == '\\');
	s->str++;
	/* Empty escapes become plain backslashes. */
	if(*s->str == '\0')
	{
		s->state = EOS;
		return ('\\');
	}
	val = 0;
	for(i = 0; i < 3; i++)
	{
		if(s->str[i] < '0' || '7' < s->str[i]) break;
		val = val * 8 + s->str[i] - '0';
	}
	if(i > 0)
	{
		if(val > UCHAR_MAX) utils_errx(1, "octal value out of range: %d", val);
		s->str += i;
		return (val);
	}
	ch = *s->str++;
	switch(ch)
	{
	case 'a': /* escape characters */
		return ('\7');
	case 'b':
		return ('\b');
	case 'f':
		return ('\f');
	case 'n':
		return ('\n');
	case 'r':
		return ('\r');
	case 't':
		return ('\t');
	case 'v':
		return ('\13');
	default: /* \x" -> x */
		return (ch);
	}
}