c2html

A tool to add HTML syntax highlighting to C code.

Installation and usage

c2html comes both as a C library and a command-line utility.

The library only exports one function

char *c2html(const char *str, long len, _Bool table_mode, 
             const char *class_prefix, const char **error);

which, given a string of C code, returns the version highlighted using HTML tags.

For example, lets consider the

/* .. include stdlib.h, string.h and stdio.h .. */
#include "c2html.h"

int main()
{
    // Table mode refers to the structure of the output HTML.
    // If table_mode is turned off, then the output lines are
    // separated by <br /> tags and there are no line numbers.
    // Using table mode, then the lines are represented as rows
    // of an HTML. The table has a first column with the line
    // numbers and the second with their content.
    _Bool table_mode = 0;
    const char *prefix = NULL;

    char *c = 
      "int main() {\n"
      "  int a = 5;\n"
      "  return 0;\n"
      "}\n";

    char *html = c2html(c, strlen(c), table_mode, prefix, NULL);
    printf("%s\n", html);
    free(html);
    return 0;
}

will output:

<div class="code">
  <div class="code-inner">
    <span class="kword kword-int">int</span> <span class="identifier fdeclname">main</span>() {<br />
    &emsp;&emsp;&emsp;&emsp;<span class="kword kword-int">int</span> <span class="identifier">a</span> <span class="operator">=</span> <span class="val-int">5</span>;<br />
    &emsp;&emsp;&emsp;&emsp;<span class="kword kword-return">return</span> <span class="val-int">0</span>;<br />
    }<br />
  </div>
</div>

if table_mode were 1, then the output would have been:

<div class="code">
  <div class="code-inner">
    <table>
      <tr><td>1</td><td><span class="kword kword-int">int</span> <span class="identifier fdeclname">main</span>() {</td></tr>
      <tr><td>2</td><td>&emsp;&emsp;<span class="kword kword-int">int</span> <span class="identifier">a</span> <span class="operator">=</span> <span class="val-int">5</span>;</td></tr>
      <tr><td>3</td><td>&emsp;&emsp;<span class="kword kword-return">return</span> <span class="val-int">0</span>;</td></tr>
      <tr><td>4</td><td>}</td></tr>
      <tr><td>5</td><td></td></tr>
    </table>
  </div>
</div>

the color doesn't come with the generated HTML, you need to add it yourself using CSS. There's an example CSS style provided in style.css, inspired by the Sublime Text color theme I use.

Since the generated class names of the HTML tags are pretty generic (identifier, operator, comment, ..), you can specify a prefix to be prepented to these names.