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Revision 1.31, Thu Apr 2 22:48:17 2015 UTC (8 years, 11 months ago) by schwarze
Branch: MAIN
Changes since 1.30: +4 -4 lines

Second step towards parser unification:
Replace struct mdoc_node and struct man_node by a unified struct roff_node.
To be able to use the tok member for both mdoc(7) and man(7) without
defining all the macros in roff.h, sacrifice a tiny bit of type safety
and make tok an int rather than an enum.
Almost mechanical, no functional change.
Written on the Eurostar from Bruxelles to London on the way to p2k15.

/*	$Id: man_hash.c,v 1.31 2015/04/02 22:48:17 schwarze Exp $ */
/*
 * Copyright (c) 2008, 2009, 2010 Kristaps Dzonsons <kristaps@bsd.lv>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include "config.h"

#include <sys/types.h>

#include <assert.h>
#include <ctype.h>
#include <limits.h>
#include <string.h>

#include "roff.h"
#include "man.h"
#include "libman.h"

#define	HASH_DEPTH	 6

#define	HASH_ROW(x) do { \
		if (isupper((unsigned char)(x))) \
			(x) -= 65; \
		else \
			(x) -= 97; \
		(x) *= HASH_DEPTH; \
	} while (/* CONSTCOND */ 0)

/*
 * Lookup table is indexed first by lower-case first letter (plus one
 * for the period, which is stored in the last row), then by lower or
 * uppercase second letter.  Buckets correspond to the index of the
 * macro (the integer value of the enum stored as a char to save a bit
 * of space).
 */
static	unsigned char	 table[26 * HASH_DEPTH];


/*
 * XXX - this hash has global scope, so if intended for use as a library
 * with multiple callers, it will need re-invocation protection.
 */
void
man_hash_init(void)
{
	int		 i, j, x;

	memset(table, UCHAR_MAX, sizeof(table));

	assert(MAN_MAX < UCHAR_MAX);

	for (i = 0; i < (int)MAN_MAX; i++) {
		x = man_macronames[i][0];

		assert(isalpha((unsigned char)x));

		HASH_ROW(x);

		for (j = 0; j < HASH_DEPTH; j++)
			if (UCHAR_MAX == table[x + j]) {
				table[x + j] = (unsigned char)i;
				break;
			}

		assert(j < HASH_DEPTH);
	}
}

int
man_hash_find(const char *tmp)
{
	int		 x, y, i;
	int		 tok;

	if ('\0' == (x = tmp[0]))
		return(MAN_MAX);
	if ( ! (isalpha((unsigned char)x)))
		return(MAN_MAX);

	HASH_ROW(x);

	for (i = 0; i < HASH_DEPTH; i++) {
		if (UCHAR_MAX == (y = table[x + i]))
			return(MAN_MAX);

		tok = y;
		if (0 == strcmp(tmp, man_macronames[tok]))
			return(tok);
	}

	return(MAN_MAX);
}