path: root/src/houdini_html_u.c

#include <assert.h>
#include <stdio.h>
#include <string.h>

#include "buffer.h"
#include "houdini.h"
#include "utf8.h"
#include "html_unescape.h"

size_t
houdini_unescape_ent(cmark_strbuf *ob, const uint8_t *src, size_t size)
{
    size_t i = 0;

    if (size > 3 && src[0] == '#') {
        int codepoint = 0;

        if (_isdigit(src[1])) {
            for (i = 1; i < size && _isdigit(src[i]); ++i) {
                int cp = (codepoint * 10) + (src[i] - '0');

                if (cp < codepoint)
                    return 0;

                codepoint = cp;
            }
        }

        else if (src[1] == 'x' || src[1] == 'X') {
            for (i = 2; i < size && _isxdigit(src[i]); ++i) {
                int cp = (codepoint * 16) + ((src[i] | 32) % 39 - 9);

                if (cp < codepoint)
                    return 0;

                codepoint = cp;
            }
        }

        if (i < size && src[i] == ';' && codepoint) {
            utf8proc_encode_char(codepoint, ob);
            return i + 1;
        }
    }

    else {
        if (size > MAX_WORD_LENGTH)
            size = MAX_WORD_LENGTH;

        for (i = MIN_WORD_LENGTH; i < size; ++i) {
            if (src[i] == ' ')
                break;

            if (src[i] == ';') {
                const struct html_ent *entity = find_entity((char *)src, i);

                if (entity != NULL) {
                    cmark_strbuf_put(ob, entity->utf8, entity->utf8_len);
                    return i + 1;
                }

                break;
            }
        }
    }

    return 0;
}

int
houdini_unescape_html(cmark_strbuf *ob, const uint8_t *src, size_t size)
{
    size_t  i = 0, org, ent;

    while (i < size) {
        org = i;
        while (i < size && src[i] != '&')
            i++;

        if (likely(i > org)) {
            if (unlikely(org == 0)) {
                if (i >= size)
                    return 0;

                cmark_strbuf_grow(ob, HOUDINI_UNESCAPED_SIZE(size));
            }

            cmark_strbuf_put(ob, src + org, i - org);
        }

        /* escaping */
        if (i >= size)
            break;

        i++;

        ent = houdini_unescape_ent(ob, src + i, size - i);
        i += ent;

        /* not really an entity */
        if (ent == 0)
            cmark_strbuf_putc(ob, '&');
    }

    return 1;
}

void houdini_unescape_html_f(cmark_strbuf *ob, const uint8_t *src, size_t size)
{
    if (!houdini_unescape_html(ob, src, size))
        cmark_strbuf_put(ob, src, size);
}