hb-ot-shape-normalize.cc revision 34c22f816808d061a980cffca12de03beb437fa0
1655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod/* 2655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * Copyright © 2011 Google, Inc. 3655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * 4655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * This is part of HarfBuzz, a text shaping library. 5655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * 6655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * Permission is hereby granted, without written agreement and without 7655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * license or royalty fees, to use, copy, modify, and distribute this 8655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * software and its documentation for any purpose, provided that the 9655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * above copyright notice and the following two paragraphs appear in 10655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * all copies of this software. 11655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * 12655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR 13655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES 14655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN 15655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH 16655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * DAMAGE. 17655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * 18655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, 19655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 20655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS 21655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO 22655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. 23655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * 24655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod * Google Author(s): Behdad Esfahbod 25655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod */ 26655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod 27655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod#include "hb-ot-shape-private.hh" 285d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod#include "hb-ot-shape-complex-private.hh" 29655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod 30655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad EsfahbodHB_BEGIN_DECLS 31655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod 325d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod/* 335d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * HIGHLEVEL DESIGN: 345d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * 355d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * This file exports one main function: _hb_ot_shape_normalize(). 365d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * 375d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * This function closely reflects the Unicode Normalization Algorithm, 385d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * yet it's different. The shaper an either prefer decomposed (NFD) or 395d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * composed (NFC). 405d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * 415d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * In general what happens is that: each grapheme is decomposed in a chain 425d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * of 1:2 decompositions, marks reordered, and then recomposed if desires, 435d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * so far it's like Unicode Normalization. However, the decomposition and 445d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * recomposition only happens if the font supports the resulting characters. 455d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * 465d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * The goals are: 475d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * 485d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * - Try to render all canonically equivalent strings similarly. To really 495d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * achieve this we have to always do the full decomposition and then 505d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * selectively recompose from there. It's kinda too expensive though, so 515d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * we skip some cases. For example, if composed is desired, we simply 525d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * don't touch 1-character clusters that are supported by the font, even 535d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * though their NFC may be different. 545d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * 555d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * - When a font has a precomposed character for a sequence but the 'ccmp' 565d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * feature in the font is not adequate, form use the precomposed character 575d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * which typically has better mark positioning. 585d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * 595d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * - When a font does not support a character but supports its decomposition, 605d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * well, use the decomposition. 615d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * 625d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * - The Indic shaper requests decomposed output. This will handle splitting 635d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod * matra for the Indic shaper. 645d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod */ 655d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod 6645412523dc295cb5ee12e096bfacb282cc925843Behdad Esfahbod 675c6f5982d78e2d7fadc2fbb8b4f3a4be9420c59aBehdad Esfahbodstatic bool 6845412523dc295cb5ee12e096bfacb282cc925843Behdad Esfahboddecompose (hb_ot_shape_context_t *c, 694ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod bool shortest, 7045412523dc295cb5ee12e096bfacb282cc925843Behdad Esfahbod hb_codepoint_t ab) 71655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod{ 7245412523dc295cb5ee12e096bfacb282cc925843Behdad Esfahbod hb_codepoint_t a, b, glyph; 7345412523dc295cb5ee12e096bfacb282cc925843Behdad Esfahbod 744ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod if (!hb_unicode_decompose (c->buffer->unicode, ab, &a, &b) || 754ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod !hb_font_get_glyph (c->font, b, 0, &glyph)) 764ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod return FALSE; 7745412523dc295cb5ee12e096bfacb282cc925843Behdad Esfahbod 784ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod /* XXX handle singleton decompositions */ 794ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod bool has_a = hb_font_get_glyph (c->font, a, 0, &glyph); 804ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod if (shortest && has_a) { 814ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod /* Output a and b */ 824ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod c->buffer->output_glyph (a); 834ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod c->buffer->output_glyph (b); 844ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod return TRUE; 854ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod } 86655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod 874ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod if (decompose (c, shortest, a)) { 884ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod c->buffer->output_glyph (b); 894ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod return TRUE; 904ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod } 9145412523dc295cb5ee12e096bfacb282cc925843Behdad Esfahbod 924ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod if (has_a) { 934ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod c->buffer->output_glyph (a); 944ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod c->buffer->output_glyph (b); 9545412523dc295cb5ee12e096bfacb282cc925843Behdad Esfahbod return TRUE; 9645412523dc295cb5ee12e096bfacb282cc925843Behdad Esfahbod } 9745412523dc295cb5ee12e096bfacb282cc925843Behdad Esfahbod 984ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod return FALSE; 995c6f5982d78e2d7fadc2fbb8b4f3a4be9420c59aBehdad Esfahbod} 1005c6f5982d78e2d7fadc2fbb8b4f3a4be9420c59aBehdad Esfahbod 10134c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbodstatic bool 1024ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahboddecompose_current_glyph (hb_ot_shape_context_t *c, 1034ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod bool shortest) 104d6b9c6d20041b4f4fa11befc179aee757c41904dBehdad Esfahbod{ 10534c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod if (decompose (c, shortest, c->buffer->info[c->buffer->idx].codepoint)) { 1064ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod c->buffer->skip_glyph (); 10734c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod return TRUE; 10834c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod } else { 1094ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod c->buffer->next_glyph (); 11034c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod return FALSE; 11134c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod } 112d6b9c6d20041b4f4fa11befc179aee757c41904dBehdad Esfahbod} 113d6b9c6d20041b4f4fa11befc179aee757c41904dBehdad Esfahbod 11434c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbodstatic bool 1154ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahboddecompose_single_char_cluster (hb_ot_shape_context_t *c, 1164ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod bool will_recompose) 1175c6f5982d78e2d7fadc2fbb8b4f3a4be9420c59aBehdad Esfahbod{ 1184ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod hb_codepoint_t glyph; 1194ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod 1204ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod /* If recomposing and font supports this, we're good to go */ 1214ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod if (will_recompose && hb_font_get_glyph (c->font, c->buffer->info[c->buffer->idx].codepoint, 0, &glyph)) { 1224ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod c->buffer->next_glyph (); 12334c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod return FALSE; 1244ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod } 1254ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod 12634c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod return decompose_current_glyph (c, will_recompose); 127655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod} 128655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod 12934c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbodstatic bool 1304ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahboddecompose_multi_char_cluster (hb_ot_shape_context_t *c, 1314ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod unsigned int end) 132655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod{ 13334c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod bool changed = FALSE; 13434c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 1355d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod /* TODO Currently if there's a variation-selector we give-up, it's just too hard. */ 1364ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod for (unsigned int i = c->buffer->idx; i < end; i++) 137d6b9c6d20041b4f4fa11befc179aee757c41904dBehdad Esfahbod if (unlikely (is_variation_selector (c->buffer->info[i].codepoint))) 13834c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod return changed; 139d6b9c6d20041b4f4fa11befc179aee757c41904dBehdad Esfahbod 1404ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod while (c->buffer->idx < end) 14134c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod changed |= decompose_current_glyph (c, FALSE); 14234c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 14334c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod return changed; 144655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod} 145655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod 14645412523dc295cb5ee12e096bfacb282cc925843Behdad Esfahbodvoid 1475d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod_hb_ot_shape_normalize (hb_ot_shape_context_t *c) 148655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod{ 1495d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod hb_buffer_t *buffer = c->buffer; 1505d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod bool recompose = !hb_ot_shape_complex_prefer_decomposed (c->plan->shaper); 15134c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod bool changed = FALSE; 1524ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod bool has_multichar_clusters = FALSE; 15334c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod unsigned int count; 1545d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod 1555d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod buffer->clear_output (); 1565d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod 15734c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 1584ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod /* First round, decompose */ 1594ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod 16034c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod count = buffer->len; 161468e9cb25c9bc14781b7013e447d763f93bf76a3Behdad Esfahbod for (buffer->idx = 0; buffer->idx < count;) 1625d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod { 163655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod unsigned int end; 164468e9cb25c9bc14781b7013e447d763f93bf76a3Behdad Esfahbod for (end = buffer->idx + 1; end < count; end++) 165468e9cb25c9bc14781b7013e447d763f93bf76a3Behdad Esfahbod if (buffer->info[buffer->idx].cluster != buffer->info[end].cluster) 166655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod break; 1675d90a342e319068716429bf7af76c3896b61a0e5Behdad Esfahbod 168468e9cb25c9bc14781b7013e447d763f93bf76a3Behdad Esfahbod if (buffer->idx + 1 == end) 16934c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod changed |= decompose_single_char_cluster (c, recompose); 1704ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod else { 17134c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod changed |= decompose_multi_char_cluster (c, end); 1724ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod has_multichar_clusters = TRUE; 1734ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod } 174655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod } 175468e9cb25c9bc14781b7013e447d763f93bf76a3Behdad Esfahbod buffer->swap_buffers (); 1764ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod 17734c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 1784ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod /* Technically speaking, two characters with ccc=0 may combine. But all 1794ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod * those cases are in languages that the indic module handles (which expects 1804ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod * decomposed), or in Hangul jamo, which again, we want decomposed anyway. 1814ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod * So we don't bother combining across cluster boundaries. */ 1824ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod 1834ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod if (!has_multichar_clusters) 1844ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod return; /* Done! */ 1854ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod 18634c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod if (changed) 18734c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod _hb_set_unicode_props (c->buffer); /* BUFFER: Set general_category and combining_class in var1 */ 18834c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 18934c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 1904ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod /* Second round, reorder (inplace) */ 1914ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod 19234c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod count = buffer->len; 19334c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod for (unsigned int i = 0; i < count; i++) 19434c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod { 19534c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod if (buffer->info[i].combining_class() == 0) 19634c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod continue; 19734c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 19834c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod unsigned int end; 19934c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod for (end = i + 1; end < count; end++) 20034c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod if (buffer->info[end].combining_class() == 0) 20134c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod break; 20234c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 20334c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod /* We are going to do a bubble-sort. Only do this if the 20434c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod * sequence is short. Doing it on long sequences can result 20534c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod * in an O(n^2) DoS. */ 20634c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod if (end - i > 10) { 20734c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod i = end; 20834c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod continue; 20934c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod } 21034c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 21134c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod unsigned int k = end - i - 1; 21234c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod do { 21334c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod hb_glyph_info_t *pinfo = buffer->info + i; 21434c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod unsigned int new_k = 0; 21534c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 21634c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod for (unsigned int j = 0; j < k; j++) 21734c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod if (pinfo[j].combining_class() > pinfo[j+1].combining_class()) { 21834c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod hb_glyph_info_t t; 21934c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod t = pinfo[j]; 22034c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod pinfo[j] = pinfo[j + 1]; 22134c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod pinfo[j + 1] = t; 22234c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 22334c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod new_k = j; 22434c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod } 22534c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod k = new_k; 22634c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod } while (k); 22734c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 22834c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod i = end; 22934c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod } 23034c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 2314ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod 2324ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod /* Third round, recompose */ 23334c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 2344ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod if (recompose) { 2354ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod 2364ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod 2374ff0d2d9dfc4f7e4880a4e964ca9872624508ea0Behdad Esfahbod } 23834c22f816808d061a980cffca12de03beb437fa0Behdad Esfahbod 239655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod} 240655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad Esfahbod 241655586fe5e1fadf2a2ef7826e61ee9a445ffa37aBehdad EsfahbodHB_END_DECLS 242