1 files changed, 148 insertions, 0 deletions
diff --git a/src/references.c b/src/references.c
new file mode 100644
index 0000000..04b9025
--- /dev/null
+++ b/src/references.c
@@ -0,0 +1,148 @@
+#include "cmark.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));
+}