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