summaryrefslogtreecommitdiff
path: root/src/references.c
blob: 0ae79615e231f0ee04c6c29689b210fff5a98bde (plain)
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
#include "stmd.h"
#include "utf8.h"
#include "references.h"
#include "inlines.h"

static unsigned int
refhash(const unsigned char *link_ref)
{
	unsigned int hash = 0;

	while (*link_ref)
		hash = (*link_ref++) + (hash << 6) + (hash << 16) - hash;

	return hash;
}

static void reference_free(reference *ref)
{
    if(ref != NULL) {
	    free(ref->label);
    	free(ref->url);
	    free(ref->title);
    	free(ref);
    }
}

// normalize reference:  collapse internal whitespace to single space,
// remove leading/trailing whitespace, case fold
// Return NULL if the reference name is actually empty (i.e. composed
// solely from whitespace)
static unsigned char *normalize_reference(chunk *ref)
{
	strbuf normalized = GH_BUF_INIT;
	unsigned char *result;

    if(ref == NULL)
        return NULL;

	if (ref->len == 0)
		return NULL;

	utf8proc_case_fold(&normalized, ref->data, ref->len);
	strbuf_trim(&normalized);
	strbuf_normalize_whitespace(&normalized);

	result = strbuf_detach(&normalized);
	assert(result);

	if (result[0] == '\0') {
		free(result);
		return NULL;
	}
	
	return result;
}

static void add_reference(reference_map *map, reference* ref)
{
	reference *t = ref->next = map->table[ref->hash % REFMAP_SIZE];

	while (t) {
		if (t->hash == ref->hash &&
			!strcmp((char *)t->label, (char *)ref->label)) {
			reference_free(ref);
			return;
		}

		t = t->next;
	}

	map->table[ref->hash % REFMAP_SIZE] = ref;
}

extern void reference_create(reference_map *map, chunk *label, chunk *url, chunk *title)
{
	reference *ref;
	unsigned char *reflabel = normalize_reference(label);

	/* empty reference name, or composed from only whitespace */
	if (reflabel == NULL)
		return;

	ref = calloc(1, sizeof(*ref));
    if(ref != NULL) {
        ref->label = reflabel;
        ref->hash = refhash(ref->label);
        ref->url = clean_url(url);
        ref->title = clean_title(title);
        ref->next = NULL;

        add_reference(map, ref);
    }
}

// Returns reference if refmap contains a reference with matching
// label, otherwise NULL.
reference* reference_lookup(reference_map *map, chunk *label)
{
	reference *ref = NULL;
	unsigned char *norm;
	unsigned int hash;
	
	if (map == NULL)
		return NULL;
	
	norm = normalize_reference(label);
	if (norm == NULL)
		return NULL;

	hash = refhash(norm);
	ref = map->table[hash % REFMAP_SIZE];

	while (ref) {
		if (ref->hash == hash &&
			!strcmp((char *)ref->label, (char *)norm))
			break;
		ref = ref->next;
	}

	free(norm);
	return ref;
}

void reference_map_free(reference_map *map)
{
	unsigned int i;

    if(map == NULL)
        return;

	for (i = 0; i < REFMAP_SIZE; ++i) {
		reference *ref = map->table[i];
		reference *next;

		while (ref) {
			next = ref->next;
			reference_free(ref);
			ref = next;
		}
	}

	free(map);
}

reference_map *reference_map_new(void)
{
    return calloc(1, sizeof(reference_map));
}