From 870e63be7360b5a0097a27656048e853bc720464 Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Mon, 21 Jul 2014 22:29:16 -0700
Subject: Initial commit

---
 src/html.c | 276 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 276 insertions(+)
 create mode 100644 src/html.c

(limited to 'src/html.c')

diff --git a/src/html.c b/src/html.c
new file mode 100644
index 0000000..56d5dbb
--- /dev/null
+++ b/src/html.c
@@ -0,0 +1,276 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include "bstrlib.h"
+#include "stmd.h"
+#include "debug.h"
+#include "scanners.h"
+
+// Functions to convert block and inline lists to HTML strings.
+
+// Escape special characters in HTML.  More efficient than
+// three calls to bfindreplace.  If preserve_entities is set,
+// existing entities are left alone.
+static bstring escape_html(bstring inp, bool preserve_entities)
+{
+  int pos = 0;
+  int match;
+  char c;
+  bstring escapable = blk2bstr("&<>\"", 4);
+  bstring ent;
+  bstring s = bstrcpy(inp);
+  while ((pos = binchr(s, pos, escapable)) != BSTR_ERR) {
+    c = bchar(s,pos);
+    switch (c) {
+    case '<':
+      bdelete(s, pos, 1);
+      ent = blk2bstr("&lt;", 4);
+      binsert(s, pos, ent, ' ');
+      bdestroy(ent);
+      pos += 4;
+      break;
+    case '>':
+      bdelete(s, pos, 1);
+      ent = blk2bstr("&gt;", 4);
+      binsert(s, pos, ent, ' ');
+      bdestroy(ent);
+      pos += 4;
+      break;
+    case '&':
+      if (preserve_entities && (match = scan_entity(s, pos))) {
+        pos += match;
+      } else {
+        bdelete(s, pos, 1);
+        ent = blk2bstr("&amp;", 5);
+        binsert(s, pos, ent, ' ');
+        bdestroy(ent);
+        pos += 5;
+      }
+      break;
+    case '"':
+      bdelete(s, pos, 1);
+      ent = blk2bstr("&quot;", 6);
+      binsert(s, pos, ent, ' ');
+      bdestroy(ent);
+      pos += 6;
+      break;
+    default:
+      bdelete(s, pos, 1);
+      log_err("unexpected character %02x", c);
+    }
+  }
+  bdestroy(escapable);
+  return s;
+}
+
+static inline void cr(bstring buffer)
+{
+  int c = bchar(buffer, blength(buffer) - 1);
+  if (c != '\n' && c) {
+    bconchar(buffer, '\n');
+  }
+}
+
+// Convert a block list to HTML.  Returns 0 on success, and sets result.
+extern int blocks_to_html(block* b, bstring* result, bool tight)
+{
+  bstring contents = NULL;
+  bstring escaped, escaped2;
+  struct bstrList * info_words;
+  struct ListData * data;
+  bstring mbstart;
+  bstring html = blk2bstr("", 0);
+
+  while(b != NULL) {
+    switch(b->tag) {
+    case document:
+      check(blocks_to_html(b->children, &contents, false) == 0,
+            "error converting blocks to html");
+      bformata(html, "%s", contents->data);
+      bdestroy(contents);
+      break;
+    case paragraph:
+      check(inlines_to_html(b->inline_content, &contents) == 0,
+            "error converting inlines to html");
+      if (tight) {
+        bformata(html, "%s", contents->data);
+      } else {
+        cr(html);
+        bformata(html, "<p>%s</p>", contents->data);
+        cr(html);
+      }
+      bdestroy(contents);
+      break;
+    case block_quote:
+      check(blocks_to_html(b->children, &contents, false) == 0,
+            "error converting blocks to html");
+      cr(html);
+      bformata(html, "<blockquote>\n%s</blockquote>", contents->data);
+      cr(html);
+      bdestroy(contents);
+      break;
+    case list_item:
+      check(blocks_to_html(b->children, &contents, tight) == 0,
+            "error converting blocks to html");
+      brtrimws(contents);
+      cr(html);
+      bformata(html, "<li>%s</li>", contents->data);
+      cr(html);
+      bdestroy(contents);
+      break;
+    case list:
+      // make sure a list starts at the beginning of the line:
+      cr(html);
+      data = &(b->attributes.list_data);
+      check(blocks_to_html(b->children, &contents, data->tight) == 0,
+            "error converting blocks to html");
+      mbstart = bformat(" start=\"%d\"", data->start);
+      bformata(html, "<%s%s>\n%s</%s>",
+               data->list_type == bullet ? "ul" : "ol",
+               data->start == 1 ? "" : (char*) mbstart->data,
+               contents->data,
+               data->list_type == bullet ? "ul" : "ol");
+      cr(html);
+      bdestroy(contents);
+      bdestroy(mbstart);
+      break;
+    case atx_header:
+    case setext_header:
+      check(inlines_to_html(b->inline_content, &contents) == 0,
+            "error converting inlines to html");
+      cr(html);
+      bformata(html, "<h%d>%s</h%d>",
+               b->attributes.header_level,
+               contents->data,
+               b->attributes.header_level);
+      cr(html);
+      bdestroy(contents);
+      break;
+    case indented_code:
+      escaped = escape_html(b->string_content, false);
+      cr(html);
+      bformata(html, "<pre><code>%s</code></pre>", escaped->data);
+      cr(html);
+      bdestroy(escaped);
+      break;
+    case fenced_code:
+      escaped = escape_html(b->string_content, false);
+      cr(html);
+      bformata(html, "<pre");
+      if (blength(b->attributes.fenced_code_data.info) > 0) {
+        escaped2 = escape_html(b->attributes.fenced_code_data.info, true);
+        info_words = bsplit(escaped2, ' ');
+        bformata(html, " class=\"%s\"", info_words->entry[0]->data);
+        bdestroy(escaped2);
+        bstrListDestroy(info_words);
+      }
+      bformata(html, "><code>%s</code></pre>", escaped->data);
+      cr(html);
+      bdestroy(escaped);
+      break;
+    case html_block:
+      bformata(html, "%s", b->string_content->data);
+      break;
+    case hrule:
+      bformata(html, "<hr />");
+      cr(html);
+      break;
+    case reference_def:
+      break;
+    default:
+      log_warn("block type %d not implemented\n", b->tag);
+      break;
+    }
+    b = b->next;
+  }
+  *result = html;
+  return 0;
+ error:
+  return -1;
+}
+
+// Convert an inline list to HTML.  Returns 0 on success, and sets result.
+extern int inlines_to_html(inl* ils, bstring* result)
+{
+  bstring contents = NULL;
+  bstring html = blk2bstr("", 0);
+  bstring mbtitle, escaped, escaped2;
+
+  while(ils != NULL) {
+    switch(ils->tag) {
+    case str:
+      escaped = escape_html(ils->content.literal, false);
+      bformata(html, "%s", escaped->data);
+      bdestroy(escaped);
+      break;
+    case linebreak:
+      bformata(html, "<br />\n");
+      break;
+    case softbreak:
+      bformata(html, "\n");
+      break;
+    case code:
+      escaped = escape_html(ils->content.literal, false);
+      bformata(html, "<code>%s</code>", escaped->data);
+      bdestroy(escaped);
+      break;
+    case raw_html:
+    case entity:
+      bformata(html, "%s", ils->content.literal->data);
+      break;
+    case link:
+      check(inlines_to_html(ils->content.inlines, &contents) == 0,
+            "error converting inlines to html");
+      if (blength(ils->content.linkable.title) > 0) {
+        escaped = escape_html(ils->content.linkable.title, true);
+        mbtitle = bformat(" title=\"%s\"", escaped->data);
+        bdestroy(escaped);
+      } else {
+        mbtitle = blk2bstr("",0);
+      }
+      escaped = escape_html(ils->content.linkable.url, true);
+      bformata(html, "<a href=\"%s\"%s>%s</a>",
+               escaped->data,
+               mbtitle->data,
+               contents->data);
+      bdestroy(escaped);
+      bdestroy(mbtitle);
+      bdestroy(contents);
+      break;
+    case image:
+      check(inlines_to_html(ils->content.inlines, &contents) == 0,
+            "error converting inlines to html");
+      escaped  = escape_html(ils->content.linkable.url, true);
+      escaped2 = escape_html(contents, false);
+      bdestroy(contents);
+      bformata(html, "<img src=\"%s\" alt=\"%s\"",
+               escaped->data, escaped2->data);
+      bdestroy(escaped);
+      bdestroy(escaped2);
+      if (blength(ils->content.linkable.title) > 0) {
+        escaped = escape_html(ils->content.linkable.title, true);
+        bformata(html, " title=\"%s\"", escaped->data);
+        bdestroy(escaped);
+      }
+      bformata(html, " />");
+      break;
+    case strong:
+      check(inlines_to_html(ils->content.inlines, &contents) == 0,
+            "error converting inlines to html");
+      bformata(html, "<strong>%s</strong>", contents->data);
+      bdestroy(contents);
+      break;
+    case emph:
+      check(inlines_to_html(ils->content.inlines, &contents) == 0,
+            "error converting inlines to html");
+      bformata(html, "<em>%s</em>", contents->data);
+      bdestroy(contents);
+      break;
+    }
+    ils = ils->next;
+  }
+  *result = html;
+  return 0;
+ error:
+  return -1;
+}
-- 
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