summaryrefslogtreecommitdiffstats
path: root/chars.c
blob: fc43b26b3c932dae9c7d5b6bf5deb7b1cd5c74c1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
/*	$Id$ */
/*
 * Copyright (c) 2009 Kristaps Dzonsons <kristaps@kth.se>
 *
 * 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 <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "chars.h"

#define	PRINT_HI	 126
#define	PRINT_LO	 32

struct	ln {
	struct ln	 *next;
	const char	 *code;
	const char	 *ascii;
	const char	 *html;
	size_t		  codesz;
	size_t		  asciisz;
	size_t		  htmlsz;
	int		  type;
#define	CHARS_CHAR	 (1 << 0)
#define	CHARS_STRING	 (1 << 1)
#define CHARS_BOTH	 (0x03)
};

#define	LINES_MAX	  351

#define CHAR(w, x, y, z, a, b) \
	{ NULL, (w), (y), (a), (x), (z), (b), CHARS_CHAR },
#define STRING(w, x, y, z, a, b) \
	{ NULL, (w), (y), (a), (x), (z), (b), CHARS_STRING },
#define BOTH(w, x, y, z, a, b) \
	{ NULL, (w), (y), (a), (x), (z), (b), CHARS_BOTH },

static	struct ln lines[LINES_MAX] = {
#include "chars.in"
};

struct	tbl {
	enum chars	  type;
	struct ln	**htab;
};

static	inline int	  match(const struct ln *,
				const char *, size_t, int);
static	const char	 *find(struct tbl *, const char *, 
				size_t, size_t *, int);


void
chars_free(void *arg)
{
	struct tbl	*tab;

	tab = (struct tbl *)arg;

	free(tab->htab);
	free(tab);
}


void *
chars_init(enum chars type)
{
	struct tbl	 *tab;
	struct ln	**htab;
	struct ln	 *pp;
	int		  i, hash;

	/*
	 * Constructs a very basic chaining hashtable.  The hash routine
	 * is simply the integral value of the first character.
	 * Subsequent entries are chained in the order they're processed
	 * (they're in-line re-ordered during lookup).
	 */

	tab = malloc(sizeof(struct tbl));
	if (NULL == tab) {
		fprintf(stderr, "memory exhausted\n");
		exit(EXIT_FAILURE);
	}

	htab = calloc(PRINT_HI - PRINT_LO + 1, sizeof(struct ln **));
	if (NULL == htab) {
		fprintf(stderr, "memory exhausted\n");
		exit(EXIT_FAILURE);
	}

	for (i = 0; i < LINES_MAX; i++) {
		hash = (int)lines[i].code[0] - PRINT_LO;

		if (NULL == (pp = htab[hash])) {
			htab[hash] = &lines[i];
			continue;
		}

		for ( ; pp->next; pp = pp->next)
			/* Scan ahead. */ ;
		pp->next = &lines[i];
	}

	tab->htab = htab;
	tab->type = type;
	return(tab);
}


const char *
chars_a2ascii(void *arg, const char *p, size_t sz, size_t *rsz)
{

	return(find((struct tbl *)arg, p, sz, rsz, CHARS_CHAR));
}


const char *
chars_a2res(void *arg, const char *p, size_t sz, size_t *rsz)
{

	return(find((struct tbl *)arg, p, sz, rsz, CHARS_STRING));
}


static const char *
find(struct tbl *tab, const char *p, size_t sz, size_t *rsz, int type)
{
	struct ln	 *pp, *prev;
	struct ln	**htab;
	int		  hash;

	assert(p);
	assert(sz > 0);

	if (p[0] < PRINT_LO || p[0] > PRINT_HI)
		return(NULL);

	/*
	 * Lookup the symbol in the symbol hash.  See ascii2htab for the
	 * hashtable specs.  This dynamically re-orders the hash chain
	 * to optimise for repeat hits.
	 */

	hash = (int)p[0] - PRINT_LO;
	htab = tab->htab;

	if (NULL == (pp = htab[hash]))
		return(NULL);

	if (NULL == pp->next) {
		if ( ! match(pp, p, sz, type)) 
			return(NULL);

		if (CHARS_HTML == tab->type) {
			*rsz = pp->htmlsz;
			return(pp->html);
		}
		*rsz = pp->asciisz;
		return(pp->ascii);
	}

	for (prev = NULL; pp; pp = pp->next) {
		if ( ! match(pp, p, sz, type)) {
			prev = pp;
			continue;
		}

		if (prev) {
			prev->next = pp->next;
			pp->next = htab[hash];
			htab[hash] = pp;
		}

		if (CHARS_HTML == tab->type) {
			*rsz = pp->htmlsz;
			return(pp->html);
		}
		*rsz = pp->asciisz;
		return(pp->ascii);
	}

	return(NULL);
}


static inline int
match(const struct ln *ln, const char *p, size_t sz, int type)
{

	if ( ! (ln->type & type))
		return(0);
	if (ln->codesz != sz)
		return(0);
	return(0 == strncmp(ln->code, p, sz));
}