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System, Streams & Templates

#Markdown to HTML bstr Renderer

c
#define FIO_MD2HTML
#include "fio-stl.h"

A complete-document Markdown / GFM renderer that turns parser events into escaped HTML stored in an owned fio_bstr. Markdown goes in, tags come out. Implemented in ./103 md2html.h.

Defining FIO_MD2HTML automatically includes:

  • FIO_STR for fio_bstr
  • FIO_GFM for Markdown / GFM parsing

#Error Codes

#FIO_MD2HTML_ERR_ALLOC

c
#ifndef FIO_MD2HTML_ERR_ALLOC
#define FIO_MD2HTML_ERR_ALLOC 1
#endif

Internal renderer error used when output allocation fails. Override before inclusion only if you need a different non-zero value.

#Rendering

#fio_md2html

c
SFUNC char *fio_md2html(char *bstr_target, fio_buf_info_s source);

Renders a complete Markdown / GFM document into a fio_bstr.

Parameters:

  • bstr_target - existing fio_bstr to append to, or NULL to allocate a new one
  • source - Markdown bytes to parse

Returns: the output fio_bstr, or NULL on parser / allocation failure.

Ownership: the returned buffer is owned by the caller and should be released with fio_bstr_free. If bstr_target == NULL and rendering fails, the newly allocated output is freed. If bstr_target was provided, ownership stays with the caller.

#Rendering Behavior

From the implementation:

  • normal text, code, and attribute values are escaped
  • raw Markdown HTML blocks / inline HTML are preserved, with GFM tagfilter applied
  • blocked tag names include iframe, noembed, noframes, plaintext, style, textarea, title, and xmp; HTML blocks only filter textarea and xmp
  • fenced code info strings use the first word as class="language-..."
  • GFM tables render <table><thead>... and open <tbody> for body rows
  • table cell alignment uses align="left", align="right", or align="center"
  • GFM task list items render disabled checkbox inputs
  • autolinks add mailto: for bare email addresses and http:// for www. links
  • image alt text is escaped and strips nested link / emphasis markup

#Thread-Safety

The renderer uses caller-provided input and a local renderer state. It is thread-safe as long as separate calls do not mutate the same bstr_target at the same time.

#Example

c
#define FIO_MD2HTML
#include "fio-stl.h"
#include <stdio.h>

int main(void) {
  char md[] = "# Demo\n\nHello **world**.\n";
  char *html = fio_md2html(NULL, FIO_BUF_INFO1(md));
  if (!html)
    return 1;

  fwrite(html, 1, fio_bstr_len(html), stdout);
  fio_bstr_free(html);
  return 0;
}