diff options
Diffstat (limited to 'src/rt/sundown/html/houdini_href_e.c')
| -rw-r--r-- | src/rt/sundown/html/houdini_href_e.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/src/rt/sundown/html/houdini_href_e.c b/src/rt/sundown/html/houdini_href_e.c new file mode 100644 index 00000000000..981b3b17e41 --- /dev/null +++ b/src/rt/sundown/html/houdini_href_e.c @@ -0,0 +1,108 @@ +#include <assert.h> +#include <stdio.h> +#include <string.h> + +#include "houdini.h" + +#define ESCAPE_GROW_FACTOR(x) (((x) * 12) / 10) + +/* + * The following characters will not be escaped: + * + * -_.+!*'(),%#@?=;:/,+&$ alphanum + * + * Note that this character set is the addition of: + * + * - The characters which are safe to be in an URL + * - The characters which are *not* safe to be in + * an URL because they are RESERVED characters. + * + * We asume (lazily) that any RESERVED char that + * appears inside an URL is actually meant to + * have its native function (i.e. as an URL + * component/separator) and hence needs no escaping. + * + * There are two exceptions: the chacters & (amp) + * and ' (single quote) do not appear in the table. + * They are meant to appear in the URL as components, + * yet they require special HTML-entity escaping + * to generate valid HTML markup. + * + * All other characters will be escaped to %XX. + * + */ +static const char HREF_SAFE[] = { + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, + 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, +}; + +void +houdini_escape_href(struct buf *ob, const uint8_t *src, size_t size) +{ + static const char hex_chars[] = "0123456789ABCDEF"; + size_t i = 0, org; + char hex_str[3]; + + bufgrow(ob, ESCAPE_GROW_FACTOR(size)); + hex_str[0] = '%'; + + while (i < size) { + org = i; + while (i < size && HREF_SAFE[src[i]] != 0) + i++; + + if (i > org) + bufput(ob, src + org, i - org); + + /* escaping */ + if (i >= size) + break; + + switch (src[i]) { + /* amp appears all the time in URLs, but needs + * HTML-entity escaping to be inside an href */ + case '&': + BUFPUTSL(ob, "&"); + break; + + /* the single quote is a valid URL character + * according to the standard; it needs HTML + * entity escaping too */ + case '\'': + BUFPUTSL(ob, "'"); + break; + + /* the space can be escaped to %20 or a plus + * sign. we're going with the generic escape + * for now. the plus thing is more commonly seen + * when building GET strings */ +#if 0 + case ' ': + bufputc(ob, '+'); + break; +#endif + + /* every other character goes with a %XX escaping */ + default: + hex_str[1] = hex_chars[(src[i] >> 4) & 0xF]; + hex_str[2] = hex_chars[src[i] & 0xF]; + bufput(ob, hex_str, 3); + } + + i++; + } +} |