Move Thai shaper into a separate file
This commit is contained in:
Behdad Esfahbod
parent
ba82325b7a
commit
43f04a7456
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@ -81,11 +81,12 @@ HBSOURCES += \
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hb-ot-shape-complex-arabic.cc \
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hb-ot-shape-complex-arabic-fallback.hh \
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hb-ot-shape-complex-arabic-table.hh \
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hb-ot-shape-complex-default.cc \
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hb-ot-shape-complex-indic.cc \
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hb-ot-shape-complex-indic-machine.hh \
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hb-ot-shape-complex-indic-private.hh \
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hb-ot-shape-complex-indic-table.hh \
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hb-ot-shape-complex-misc.cc \
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hb-ot-shape-complex-thai.cc \
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hb-ot-shape-complex-private.hh \
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hb-ot-shape-normalize-private.hh \
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hb-ot-shape-normalize.cc \
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@ -223,117 +223,3 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_default =
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true, /* zero_width_attached_marks */
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true, /* fallback_position */
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};
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/* Thai / Lao shaper */
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static void
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preprocess_text_thai (const hb_ot_shape_plan_t *plan HB_UNUSED,
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hb_buffer_t *buffer,
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hb_font_t *font HB_UNUSED)
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{
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/* The following is NOT specified in the MS OT Thai spec, however, it seems
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* to be what Uniscribe and other engines implement. According to Eric Muller:
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*
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* When you have a SARA AM, decompose it in NIKHAHIT + SARA AA, *and* move the
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* NIKHAHIT backwards over any tone mark (0E48-0E4B).
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*
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* <0E14, 0E4B, 0E33> -> <0E14, 0E4D, 0E4B, 0E32>
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*
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* This reordering is legit only when the NIKHAHIT comes from a SARA AM, not
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* when it's there to start with. The string <0E14, 0E4B, 0E4D> is probably
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* not what a user wanted, but the rendering is nevertheless nikhahit above
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* chattawa.
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*
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* Same for Lao.
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*
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* Note:
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*
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* Uniscribe also does so below-marks reordering. Namely, it positions U+0E3A
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* after U+0E38 and U+0E39. We do that by modifying the ccc for U+0E3A.
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* See unicode->modified_combining_class (). Lao does NOT have a U+0E3A
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* equivalent.
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*/
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/*
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* Here are the characters of significance:
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*
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* Thai Lao
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* SARA AM: U+0E33 U+0EB3
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* SARA AA: U+0E32 U+0EB2
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* Nikhahit: U+0E4D U+0ECD
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*
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* Testing shows that Uniscribe reorder the following marks:
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* Thai: <0E31,0E34..0E37,0E47..0E4E>
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* Lao: <0EB1,0EB4..0EB7,0EC7..0ECE>
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*
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* Note how the Lao versions are the same as Thai + 0x80.
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*/
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/* We only get one script at a time, so a script-agnostic implementation
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* is adequate here. */
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#define IS_SARA_AM(x) (((x) & ~0x0080) == 0x0E33)
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#define NIKHAHIT_FROM_SARA_AM(x) ((x) - 0xE33 + 0xE4D)
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#define SARA_AA_FROM_SARA_AM(x) ((x) - 1)
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#define IS_TONE_MARK(x) (hb_in_ranges<hb_codepoint_t> ((x) & ~0x0080, 0x0E34, 0x0E37, 0x0E47, 0x0E4E, 0x0E31, 0x0E31))
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buffer->clear_output ();
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unsigned int count = buffer->len;
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for (buffer->idx = 0; buffer->idx < count;)
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{
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hb_codepoint_t u = buffer->cur().codepoint;
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if (likely (!IS_SARA_AM (u))) {
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buffer->next_glyph ();
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continue;
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}
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/* Is SARA AM. Decompose and reorder. */
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hb_codepoint_t decomposed[2] = {hb_codepoint_t (NIKHAHIT_FROM_SARA_AM (u)),
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hb_codepoint_t (SARA_AA_FROM_SARA_AM (u))};
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buffer->replace_glyphs (1, 2, decomposed);
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if (unlikely (buffer->in_error))
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return;
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/* Ok, let's see... */
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unsigned int end = buffer->out_len;
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unsigned int start = end - 2;
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while (start > 0 && IS_TONE_MARK (buffer->out_info[start - 1].codepoint))
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start--;
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if (start + 2 < end)
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{
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/* Move Nikhahit (end-2) to the beginning */
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buffer->merge_out_clusters (start, end);
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hb_glyph_info_t t = buffer->out_info[end - 2];
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memmove (buffer->out_info + start + 1,
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buffer->out_info + start,
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sizeof (buffer->out_info[0]) * (end - start - 2));
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buffer->out_info[start] = t;
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}
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else
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{
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/* Since we decomposed, and NIKHAHIT is combining, merge clusters with the
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* previous cluster. */
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if (start)
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buffer->merge_out_clusters (start - 1, end);
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}
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}
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buffer->swap_buffers ();
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}
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const hb_ot_complex_shaper_t _hb_ot_complex_shaper_thai =
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{
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"thai",
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NULL, /* collect_features */
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NULL, /* override_features */
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NULL, /* data_create */
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NULL, /* data_destroy */
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preprocess_text_thai,
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NULL, /* normalization_preference */
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NULL, /* decompose */
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NULL, /* compose */
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NULL, /* setup_masks */
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true, /* zero_width_attached_marks */
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false,/* fallback_position */
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};
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@ -0,0 +1,141 @@
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/*
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* Copyright © 2010,2012 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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#include "hb-ot-shape-complex-private.hh"
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/* Thai / Lao shaper */
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static void
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preprocess_text_thai (const hb_ot_shape_plan_t *plan HB_UNUSED,
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hb_buffer_t *buffer,
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hb_font_t *font HB_UNUSED)
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{
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/* The following is NOT specified in the MS OT Thai spec, however, it seems
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* to be what Uniscribe and other engines implement. According to Eric Muller:
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*
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* When you have a SARA AM, decompose it in NIKHAHIT + SARA AA, *and* move the
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* NIKHAHIT backwards over any tone mark (0E48-0E4B).
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*
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* <0E14, 0E4B, 0E33> -> <0E14, 0E4D, 0E4B, 0E32>
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*
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* This reordering is legit only when the NIKHAHIT comes from a SARA AM, not
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* when it's there to start with. The string <0E14, 0E4B, 0E4D> is probably
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* not what a user wanted, but the rendering is nevertheless nikhahit above
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* chattawa.
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*
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* Same for Lao.
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*
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* Note:
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*
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* Uniscribe also does some below-marks reordering. Namely, it positions U+0E3A
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* after U+0E38 and U+0E39. We do that by modifying the ccc for U+0E3A.
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* See unicode->modified_combining_class (). Lao does NOT have a U+0E3A
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* equivalent.
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*/
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/*
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* Here are the characters of significance:
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*
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* Thai Lao
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* SARA AM: U+0E33 U+0EB3
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* SARA AA: U+0E32 U+0EB2
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* Nikhahit: U+0E4D U+0ECD
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*
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* Testing shows that Uniscribe reorder the following marks:
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* Thai: <0E31,0E34..0E37,0E47..0E4E>
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* Lao: <0EB1,0EB4..0EB7,0EC7..0ECE>
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*
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* Note how the Lao versions are the same as Thai + 0x80.
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*/
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/* We only get one script at a time, so a script-agnostic implementation
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* is adequate here. */
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#define IS_SARA_AM(x) (((x) & ~0x0080) == 0x0E33)
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#define NIKHAHIT_FROM_SARA_AM(x) ((x) - 0xE33 + 0xE4D)
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#define SARA_AA_FROM_SARA_AM(x) ((x) - 1)
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#define IS_TONE_MARK(x) (hb_in_ranges<hb_codepoint_t> ((x) & ~0x0080, 0x0E34, 0x0E37, 0x0E47, 0x0E4E, 0x0E31, 0x0E31))
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buffer->clear_output ();
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unsigned int count = buffer->len;
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for (buffer->idx = 0; buffer->idx < count;)
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{
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hb_codepoint_t u = buffer->cur().codepoint;
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if (likely (!IS_SARA_AM (u))) {
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buffer->next_glyph ();
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continue;
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}
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/* Is SARA AM. Decompose and reorder. */
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hb_codepoint_t decomposed[2] = {hb_codepoint_t (NIKHAHIT_FROM_SARA_AM (u)),
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hb_codepoint_t (SARA_AA_FROM_SARA_AM (u))};
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buffer->replace_glyphs (1, 2, decomposed);
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if (unlikely (buffer->in_error))
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return;
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/* Ok, let's see... */
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unsigned int end = buffer->out_len;
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unsigned int start = end - 2;
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while (start > 0 && IS_TONE_MARK (buffer->out_info[start - 1].codepoint))
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start--;
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if (start + 2 < end)
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{
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/* Move Nikhahit (end-2) to the beginning */
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buffer->merge_out_clusters (start, end);
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hb_glyph_info_t t = buffer->out_info[end - 2];
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memmove (buffer->out_info + start + 1,
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buffer->out_info + start,
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sizeof (buffer->out_info[0]) * (end - start - 2));
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buffer->out_info[start] = t;
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}
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else
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{
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/* Since we decomposed, and NIKHAHIT is combining, merge clusters with the
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* previous cluster. */
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if (start)
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buffer->merge_out_clusters (start - 1, end);
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}
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}
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buffer->swap_buffers ();
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}
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const hb_ot_complex_shaper_t _hb_ot_complex_shaper_thai =
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{
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"thai",
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NULL, /* collect_features */
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NULL, /* override_features */
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NULL, /* data_create */
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NULL, /* data_destroy */
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preprocess_text_thai,
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NULL, /* normalization_preference */
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NULL, /* decompose */
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NULL, /* compose */
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NULL, /* setup_masks */
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true, /* zero_width_attached_marks */
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false,/* fallback_position */
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};
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