1 files changed, 103 insertions, 0 deletions
diff --git a/src/blogc/toctree.c b/src/blogc/toctree.c
new file mode 100644
index 0000000..307c62c
--- /dev/null
+++ b/src/blogc/toctree.c
@@ -0,0 +1,103 @@
+/*
+ * blogc: A blog compiler.
+ * Copyright (C) 2014-2020 Rafael G. Martins <rafael@rafaelmartins.eng.br>
+ *
+ * This program can be distributed under the terms of the BSD License.
+ * See the file LICENSE.
+ */
+
+#include <stdlib.h>
+#include "../common/utils.h"
+#include "toctree.h"
+
+bc_slist_t*
+blogc_toctree_append(bc_slist_t *headers, size_t level, const char *slug, const char *text)
+{
+    if (level == 0)
+        return headers;
+
+    blogc_toctree_header_t *t = bc_malloc(sizeof(blogc_toctree_header_t));
+    t->level = level;
+    t->slug = bc_strdup(slug);
+    t->text = bc_strdup(text);
+    return bc_slist_append(headers, t);
+}
+
+
+char*
+blogc_toctree_render(bc_slist_t *headers, int maxdepth, const char *endl)
+{
+    if (headers == NULL || maxdepth == 0)
+        return NULL;
+
+    // find lower level
+    size_t lower_level = 0;
+    for (bc_slist_t *l = headers; l != NULL; l = l->next) {
+        size_t lv = ((blogc_toctree_header_t*) l->data)->level;
+        if (lower_level == 0 || lower_level > lv) {
+            lower_level = lv;
+        }
+    }
+
+    if (lower_level == 0)
+        return NULL;
+
+    // render
+    bc_string_t *rv = bc_string_new();
+    bc_string_append_printf(rv, "<ul>%s", endl == NULL ? "\n" : endl);
+    size_t spacing = 4;
+    size_t current_level = lower_level;
+    for (bc_slist_t *l = headers; l != NULL; l = l->next) {
+        blogc_toctree_header_t *t = l->data;
+        if (t->level - lower_level >= maxdepth) {
+            continue;
+        }
+        while (current_level > t->level) {
+            spacing -= 4;
+            bc_string_append_printf(rv, "%*s</ul>%s", spacing, "",
+                endl == NULL ? "\n" : endl);
+            current_level--;
+        }
+        while (current_level < t->level) {
+            bc_string_append_printf(rv, "%*s<ul>%s", spacing, "",
+                endl == NULL ? "\n" : endl);
+            current_level++;
+            spacing += 4;
+        }
+        bc_string_append_printf(rv, "%*s<li>", spacing, "");
+        if (t->slug != NULL) {
+            bc_string_append_printf(rv, "<a href=\"#%s\">%s</a>", t->slug,
+                t->text != NULL ? t->text : "");
+        }
+        else {
+            bc_string_append(rv, t->text);
+        }
+        bc_string_append_printf(rv, "</li>%s", endl == NULL ? "\n" : endl);
+    }
+
+    // close leftovers
+    while (current_level >= lower_level) {
+        spacing -= 4;
+        bc_string_append_printf(rv, "%*s</ul>%s", spacing, "",
+            endl == NULL ? "\n" : endl);
+        current_level--;
+    }
+
+    return bc_string_free(rv, false);
+}
+
+
+static void
+free_header(blogc_toctree_header_t *h)
+{
+    free(h->slug);
+    free(h->text);
+    free(h);
+}
+
+
+void
+blogc_toctree_free(bc_slist_t *l)
+{
+    bc_slist_free_full(l, (bc_free_func_t) free_header);
+}