How to decode HTML Entities in C?

Question

I'm interested in unescaping text for example: \ maps to in C. Does anyone know of a good library?

As reference the Wikipedia List of XML and HTML Character Entity References.

Answer 1

I had some free time today and wrote a decoder from scratch: entities.c, entities.h.

The only function with external linkage is

size_t decode_html_entities_utf8(char *dest, const char *src);

If src is a null pointer, the string will be taken from dest, ie the entities will be decoded in-place. Otherwise, the decoded string will be put in dest - which should point to a buffer big enough to hold strlen(src) + 1 characters - and src will be unchanged.

The function will return the length of the decoded string.

Please note that I haven't done any extensive testing, so there's a high probability of bugs...