Source code
Revision control
Copy as Markdown
Other Tools
/*
* Copyright © 2011,2012,2014 Google, Inc.
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* Google Author(s): Behdad Esfahbod
*/
#ifndef HB_UTF_HH
#define HB_UTF_HH
#include "hb.hh"
#include "hb-open-type.hh"
struct hb_utf8_t
{
typedef uint8_t codepoint_t;
static constexpr unsigned max_len = 4;
static const codepoint_t *
next (const codepoint_t *text,
const codepoint_t *end,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
/* Written to only accept well-formed sequences.
* Based on ideas from ICU's U8_NEXT.
* Generates one "replacement" for each ill-formed byte. */
hb_codepoint_t c = *text++;
if (c > 0x7Fu)
{
if (hb_in_range<hb_codepoint_t> (c, 0xC2u, 0xDFu)) /* Two-byte */
{
unsigned int t1;
if (likely (text < end &&
(t1 = text[0] - 0x80u) <= 0x3Fu))
{
c = ((c&0x1Fu)<<6) | t1;
text++;
}
else
goto error;
}
else if (hb_in_range<hb_codepoint_t> (c, 0xE0u, 0xEFu)) /* Three-byte */
{
unsigned int t1, t2;
if (likely (1 < end - text &&
(t1 = text[0] - 0x80u) <= 0x3Fu &&
(t2 = text[1] - 0x80u) <= 0x3Fu))
{
c = ((c&0xFu)<<12) | (t1<<6) | t2;
if (unlikely (c < 0x0800u || hb_in_range<hb_codepoint_t> (c, 0xD800u, 0xDFFFu)))
goto error;
text += 2;
}
else
goto error;
}
else if (hb_in_range<hb_codepoint_t> (c, 0xF0u, 0xF4u)) /* Four-byte */
{
unsigned int t1, t2, t3;
if (likely (2 < end - text &&
(t1 = text[0] - 0x80u) <= 0x3Fu &&
(t2 = text[1] - 0x80u) <= 0x3Fu &&
(t3 = text[2] - 0x80u) <= 0x3Fu))
{
c = ((c&0x7u)<<18) | (t1<<12) | (t2<<6) | t3;
if (unlikely (!hb_in_range<hb_codepoint_t> (c, 0x10000u, 0x10FFFFu)))
goto error;
text += 3;
}
else
goto error;
}
else
goto error;
}
*unicode = c;
return text;
error:
*unicode = replacement;
return text;
}
static const codepoint_t *
prev (const codepoint_t *text,
const codepoint_t *start,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
const codepoint_t *end = text--;
while (start < text && (*text & 0xc0) == 0x80 && end - text < 4)
text--;
if (likely (next (text, end, unicode, replacement) == end))
return text;
*unicode = replacement;
return end - 1;
}
static unsigned int
strlen (const codepoint_t *text)
{ return ::strlen ((const char *) text); }
static unsigned int
encode_len (hb_codepoint_t unicode)
{
if (unicode < 0x0080u) return 1;
if (unicode < 0x0800u) return 2;
if (unicode < 0x10000u) return 3;
if (unicode < 0x110000u) return 4;
return 3;
}
static codepoint_t *
encode (codepoint_t *text,
const codepoint_t *end,
hb_codepoint_t unicode)
{
if (unlikely (unicode >= 0xD800u && (unicode <= 0xDFFFu || unicode > 0x10FFFFu)))
unicode = 0xFFFDu;
if (unicode < 0x0080u)
*text++ = unicode;
else if (unicode < 0x0800u)
{
if (end - text >= 2)
{
*text++ = 0xC0u + (0x1Fu & (unicode >> 6));
*text++ = 0x80u + (0x3Fu & (unicode ));
}
}
else if (unicode < 0x10000u)
{
if (end - text >= 3)
{
*text++ = 0xE0u + (0x0Fu & (unicode >> 12));
*text++ = 0x80u + (0x3Fu & (unicode >> 6));
*text++ = 0x80u + (0x3Fu & (unicode ));
}
}
else
{
if (end - text >= 4)
{
*text++ = 0xF0u + (0x07u & (unicode >> 18));
*text++ = 0x80u + (0x3Fu & (unicode >> 12));
*text++ = 0x80u + (0x3Fu & (unicode >> 6));
*text++ = 0x80u + (0x3Fu & (unicode ));
}
}
return text;
}
};
template <typename TCodepoint>
struct hb_utf16_xe_t
{
static_assert (sizeof (TCodepoint) == 2, "");
typedef TCodepoint codepoint_t;
static constexpr unsigned max_len = 2;
static const codepoint_t *
next (const codepoint_t *text,
const codepoint_t *end,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
hb_codepoint_t c = *text++;
if (likely (!hb_in_range<hb_codepoint_t> (c, 0xD800u, 0xDFFFu)))
{
*unicode = c;
return text;
}
if (likely (c <= 0xDBFFu && text < end))
{
/* High-surrogate in c */
hb_codepoint_t l = *text;
if (likely (hb_in_range<hb_codepoint_t> (l, 0xDC00u, 0xDFFFu)))
{
/* Low-surrogate in l */
*unicode = (c << 10) + l - ((0xD800u << 10) - 0x10000u + 0xDC00u);
text++;
return text;
}
}
/* Lonely / out-of-order surrogate. */
*unicode = replacement;
return text;
}
static const codepoint_t *
prev (const codepoint_t *text,
const codepoint_t *start,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
hb_codepoint_t c = *--text;
if (likely (!hb_in_range<hb_codepoint_t> (c, 0xD800u, 0xDFFFu)))
{
*unicode = c;
return text;
}
if (likely (c >= 0xDC00u && start < text))
{
/* Low-surrogate in c */
hb_codepoint_t h = text[-1];
if (likely (hb_in_range<hb_codepoint_t> (h, 0xD800u, 0xDBFFu)))
{
/* High-surrogate in h */
*unicode = (h << 10) + c - ((0xD800u << 10) - 0x10000u + 0xDC00u);
text--;
return text;
}
}
/* Lonely / out-of-order surrogate. */
*unicode = replacement;
return text;
}
static unsigned int
strlen (const codepoint_t *text)
{
unsigned int l = 0;
while (*text++) l++;
return l;
}
static unsigned int
encode_len (hb_codepoint_t unicode)
{
return unicode < 0x10000 ? 1 : 2;
}
static codepoint_t *
encode (codepoint_t *text,
const codepoint_t *end,
hb_codepoint_t unicode)
{
if (unlikely (unicode >= 0xD800u && (unicode <= 0xDFFFu || unicode > 0x10FFFFu)))
unicode = 0xFFFDu;
if (unicode < 0x10000u)
*text++ = unicode;
else if (end - text >= 2)
{
unicode -= 0x10000u;
*text++ = 0xD800u + (unicode >> 10);
*text++ = 0xDC00u + (unicode & 0x03FFu);
}
return text;
}
};
typedef hb_utf16_xe_t<uint16_t> hb_utf16_t;
typedef hb_utf16_xe_t<OT::HBUINT16> hb_utf16_be_t;
template <typename TCodepoint, bool validate=true>
struct hb_utf32_xe_t
{
static_assert (sizeof (TCodepoint) == 4, "");
typedef TCodepoint codepoint_t;
static constexpr unsigned max_len = 1;
static const TCodepoint *
next (const TCodepoint *text,
const TCodepoint *end HB_UNUSED,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
hb_codepoint_t c = *unicode = *text++;
if (validate && unlikely (c >= 0xD800u && (c <= 0xDFFFu || c > 0x10FFFFu)))
*unicode = replacement;
return text;
}
static const TCodepoint *
prev (const TCodepoint *text,
const TCodepoint *start HB_UNUSED,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
hb_codepoint_t c = *unicode = *--text;
if (validate && unlikely (c >= 0xD800u && (c <= 0xDFFFu || c > 0x10FFFFu)))
*unicode = replacement;
return text;
}
static unsigned int
strlen (const TCodepoint *text)
{
unsigned int l = 0;
while (*text++) l++;
return l;
}
static unsigned int
encode_len (hb_codepoint_t unicode HB_UNUSED)
{
return 1;
}
static codepoint_t *
encode (codepoint_t *text,
const codepoint_t *end HB_UNUSED,
hb_codepoint_t unicode)
{
if (validate && unlikely (unicode >= 0xD800u && (unicode <= 0xDFFFu || unicode > 0x10FFFFu)))
unicode = 0xFFFDu;
*text++ = unicode;
return text;
}
};
typedef hb_utf32_xe_t<uint32_t> hb_utf32_t;
typedef hb_utf32_xe_t<uint32_t, false> hb_utf32_novalidate_t;
struct hb_latin1_t
{
typedef uint8_t codepoint_t;
static constexpr unsigned max_len = 1;
static const codepoint_t *
next (const codepoint_t *text,
const codepoint_t *end HB_UNUSED,
hb_codepoint_t *unicode,
hb_codepoint_t replacement HB_UNUSED)
{
*unicode = *text++;
return text;
}
static const codepoint_t *
prev (const codepoint_t *text,
const codepoint_t *start HB_UNUSED,
hb_codepoint_t *unicode,
hb_codepoint_t replacement HB_UNUSED)
{
*unicode = *--text;
return text;
}
static unsigned int
strlen (const codepoint_t *text)
{
unsigned int l = 0;
while (*text++) l++;
return l;
}
static unsigned int
encode_len (hb_codepoint_t unicode HB_UNUSED)
{
return 1;
}
static codepoint_t *
encode (codepoint_t *text,
const codepoint_t *end HB_UNUSED,
hb_codepoint_t unicode)
{
if (unlikely (unicode >= 0x0100u))
unicode = '?';
*text++ = unicode;
return text;
}
};
struct hb_ascii_t
{
typedef uint8_t codepoint_t;
static constexpr unsigned max_len = 1;
static const codepoint_t *
next (const codepoint_t *text,
const codepoint_t *end HB_UNUSED,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
*unicode = *text++;
if (*unicode >= 0x0080u)
*unicode = replacement;
return text;
}
static const codepoint_t *
prev (const codepoint_t *text,
const codepoint_t *start HB_UNUSED,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
*unicode = *--text;
if (*unicode >= 0x0080u)
*unicode = replacement;
return text;
}
static unsigned int
strlen (const codepoint_t *text)
{
unsigned int l = 0;
while (*text++) l++;
return l;
}
static unsigned int
encode_len (hb_codepoint_t unicode HB_UNUSED)
{
return 1;
}
static codepoint_t *
encode (codepoint_t *text,
const codepoint_t *end HB_UNUSED,
hb_codepoint_t unicode)
{
if (unlikely (unicode >= 0x0080u))
unicode = '?';
*text++ = unicode;
return text;
}
};
template <typename utf_t>
static inline const typename utf_t::codepoint_t *
hb_utf_offset_to_pointer (const typename utf_t::codepoint_t *start,
signed offset)
{
hb_codepoint_t unicode;
while (offset-- > 0)
start = utf_t::next (start,
start + utf_t::max_len,
&unicode,
HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT);
while (offset++ < 0)
start = utf_t::prev (start,
start - utf_t::max_len,
&unicode,
HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT);
return start;
}
#endif /* HB_UTF_HH */