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/*
* 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_PRIVATE_HH
#define HB_UTF_PRIVATE_HH
#include "hb-private.hh"
template <typename T, bool validate=true> struct hb_utf_t;
/* UTF-8 */
template <>
struct hb_utf_t<uint8_t, true>
{
static inline const uint8_t *
next (const uint8_t *text,
const uint8_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 (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 (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 (c, 0xD800u, 0xDFFFu)))
goto error;
text += 2;
}
else
goto error;
}
else if (hb_in_range (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 (c, 0x10000u, 0x10FFFFu)))
goto error;
text += 3;
}
else
goto error;
}
else
goto error;
}
*unicode = c;
return text;
error:
*unicode = replacement;
return text;
}
static inline const uint8_t *
prev (const uint8_t *text,
const uint8_t *start,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
const uint8_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 inline unsigned int
strlen (const uint8_t *text)
{
return ::strlen ((const char *) text);
}
};
/* UTF-16 */
template <>
struct hb_utf_t<uint16_t, true>
{
static inline const uint16_t *
next (const uint16_t *text,
const uint16_t *end,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
hb_codepoint_t c = *text++;
if (likely (!hb_in_range (c, 0xD800u, 0xDFFFu)))
{
*unicode = c;
return text;
}
if (likely (hb_in_range (c, 0xD800u, 0xDBFFu)))
{
/* High-surrogate in c */
hb_codepoint_t l;
if (text < end && ((l = *text), likely (hb_in_range (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 inline const uint16_t *
prev (const uint16_t *text,
const uint16_t *start,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
const uint16_t *end = text--;
hb_codepoint_t c = *text;
if (likely (!hb_in_range (c, 0xD800u, 0xDFFFu)))
{
*unicode = c;
return text;
}
if (likely (start < text && hb_in_range (c, 0xDC00u, 0xDFFFu)))
text--;
if (likely (next (text, end, unicode, replacement) == end))
return text;
*unicode = replacement;
return end - 1;
}
static inline unsigned int
strlen (const uint16_t *text)
{
unsigned int l = 0;
while (*text++) l++;
return l;
}
};
/* UTF-32 */
template <bool validate>
struct hb_utf_t<uint32_t, validate>
{
static inline const uint32_t *
next (const uint32_t *text,
const uint32_t *end HB_UNUSED,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
hb_codepoint_t c = *text++;
if (validate && unlikely (c > 0x10FFFFu || hb_in_range (c, 0xD800u, 0xDFFFu)))
goto error;
*unicode = c;
return text;
error:
*unicode = replacement;
return text;
}
static inline const uint32_t *
prev (const uint32_t *text,
const uint32_t *start HB_UNUSED,
hb_codepoint_t *unicode,
hb_codepoint_t replacement)
{
next (text - 1, text, unicode, replacement);
return text - 1;
}
static inline unsigned int
strlen (const uint32_t *text)
{
unsigned int l = 0;
while (*text++) l++;
return l;
}
};
#endif /* HB_UTF_PRIVATE_HH */
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