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Extend UTF-8 code a bit

This commit is contained in:
Přemysl Eric Janouch 2015-05-07 08:34:10 +02:00
parent 70f12a8a7d
commit 99b92fdd6e
1 changed files with 47 additions and 8 deletions
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55
liberty.c
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@ -1843,9 +1843,8 @@ isspace_ascii (int c)
// --- UTF-8 -------------------------------------------------------------------
/// Return a pointer to the next UTF-8 character, or NULL on error
// TODO: decode the sequence while we're at it
static const char *
utf8_next (const char *s, size_t len)
utf8_next (const char *s, size_t len, int32_t *codepoint)
{
// End of string, we go no further
if (!len)
@ -1869,28 +1868,33 @@ utf8_next (const char *s, size_t len)
tail_len++;
}
p++;
// Check the rest of the sequence
if (tail_len > --len)
return NULL;
uint32_t cp = *p++ & ~mask;
while (tail_len--)
if ((*p++ & 0xC0) != 0x80)
{
if ((*p & 0xC0) != 0x80)
return NULL;
cp = cp << 6 | (*p++ & 0x3F);
}
if (codepoint)
*codepoint = cp;
return (const char *) p;
}
/// Very rough UTF-8 validation, just makes sure codepoints can be iterated
// TODO: also validate the codepoints
static bool
utf8_validate (const char *s, size_t len)
{
const char *next;
while (len)
{
if (!(next = utf8_next (s, len)))
int32_t codepoint;
// TODO: better validations
if (!(next = utf8_next (s, len, &codepoint))
|| codepoint > 0x10FFFF)
return false;
len -= next - s;
@ -1899,6 +1903,41 @@ utf8_validate (const char *s, size_t len)
return true;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
struct utf8_iter
{
const char *s; ///< String iterator
size_t len; ///< How many bytes remain
};
static void
utf8_iter_init (struct utf8_iter *self, const char *s)
{
self->len = strlen ((self->s = s));
}
static int32_t
utf8_iter_next (struct utf8_iter *self, size_t *len)
{
if (!self->len)
return -1;
const char *old = self->s;
int32_t codepoint;
if (!soft_assert ((self->s = utf8_next (old, self->len, &codepoint))))
{
// Invalid UTF-8
self->len = 0;
return -1;
}
size_t advance = self->s - old;
self->len -= advance;
if (len) *len = advance;
return codepoint;
}
// --- Base 64 -----------------------------------------------------------------
static uint8_t g_base64_table[256] =