harfbuzz/src/hb-subset-plan.cc

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/*
* Copyright © 2018 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): Garret Rieger, Roderick Sheeter
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*/
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#include "hb-subset-private.hh"
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#include "hb-subset-plan.hh"
#include "hb-ot-cmap-table.hh"
static int
_hb_codepoint_t_cmp (const void *pa, const void *pb)
{
hb_codepoint_t a = * (hb_codepoint_t *) pa;
hb_codepoint_t b = * (hb_codepoint_t *) pb;
return a < b ? -1 : a > b ? +1 : 0;
}
hb_bool_t
hb_subset_plan_new_gid_for_codepoint (hb_subset_plan_t *plan,
hb_codepoint_t codepoint,
hb_codepoint_t *new_gid)
{
// TODO actual map, delete this garbage.
for (unsigned int i = 0; i < plan->codepoints.len; i++)
{
if (plan->codepoints[i] != codepoint) continue;
if (!hb_subset_plan_new_gid_for_old_id(plan, plan->gids_to_retain[i], new_gid))
{
return false;
}
return true;
}
return false;
}
hb_bool_t
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hb_subset_plan_new_gid_for_old_id (hb_subset_plan_t *plan,
hb_codepoint_t old_gid,
hb_codepoint_t *new_gid)
{
// the index in old_gids is the new gid; only up to codepoints.len are valid
for (unsigned int i = 0; i < plan->gids_to_retain.len; i++) {
if (plan->gids_to_retain[i] == old_gid) {
// +1: assign new gids from 1..N; 0 is special
*new_gid = i + 1;
return true;
}
}
return false;
}
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hb_bool_t
hb_subset_plan_add_table (hb_subset_plan_t *plan,
hb_tag_t tag,
hb_blob_t *contents)
{
return hb_subset_face_add_table(plan->dest, tag, contents);
}
static void
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_populate_codepoints (hb_set_t *input_codepoints,
hb_prealloced_array_t<hb_codepoint_t>& plan_codepoints)
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{
plan_codepoints.alloc (hb_set_get_population (input_codepoints));
hb_codepoint_t cp = -1;
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while (hb_set_next (input_codepoints, &cp)) {
hb_codepoint_t *wr = plan_codepoints.push();
*wr = cp;
}
plan_codepoints.qsort (_hb_codepoint_t_cmp);
}
static void
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_populate_gids_to_retain (hb_face_t *face,
hb_prealloced_array_t<hb_codepoint_t>& codepoints,
hb_prealloced_array_t<hb_codepoint_t>& old_gids,
hb_prealloced_array_t<hb_codepoint_t>& old_gids_sorted)
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{
OT::cmap::accelerator_t cmap;
cmap.init (face);
hb_auto_array_t<unsigned int> bad_indices;
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old_gids.alloc (codepoints.len);
bool has_zero = false;
for (unsigned int i = 0; i < codepoints.len; i++) {
hb_codepoint_t gid;
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if (!cmap.get_nominal_glyph (codepoints[i], &gid)) {
gid = -1;
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*(bad_indices.push ()) = i;
}
if (gid == 0) {
has_zero = true;
}
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*(old_gids.push ()) = gid;
}
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/* Generally there shouldn't be any */
while (bad_indices.len > 0) {
unsigned int i = bad_indices[bad_indices.len - 1];
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bad_indices.pop ();
DEBUG_MSG(SUBSET, nullptr, "Drop U+%04X; no gid", codepoints[i]);
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codepoints.remove (i);
old_gids.remove (i);
}
// Populate a second glyph id array that is sorted by glyph id
// and is gauranteed to contain 0.
old_gids_sorted.alloc (old_gids.len + (has_zero ? 0 : 1));
for (unsigned int i = 0; i < old_gids.len; i++) {
*(old_gids_sorted.push ()) = old_gids[i];
}
if (!has_zero)
*(old_gids_sorted.push ()) = 0;
old_gids_sorted.qsort (_hb_codepoint_t_cmp);
// TODO(Q1) expand with glyphs that make up complex glyphs
// TODO expand with glyphs reached by G*
//
cmap.fini ();
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}
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/**
* hb_subset_plan_create:
* Computes a plan for subsetting the supplied face according
* to a provide profile and input. The plan describes
* which tables and glyphs should be retained.
*
* Return value: New subset plan.
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*
* Since: 1.7.5
**/
hb_subset_plan_t *
hb_subset_plan_create (hb_face_t *face,
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hb_subset_profile_t *profile,
hb_subset_input_t *input)
{
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hb_subset_plan_t *plan = hb_object_create<hb_subset_plan_t> ();
plan->codepoints.init();
plan->gids_to_retain.init();
plan->gids_to_retain_sorted.init();
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plan->source = face;
plan->dest = hb_subset_face_create ();
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_populate_codepoints (input->unicodes, plan->codepoints);
_populate_gids_to_retain (face,
plan->codepoints,
plan->gids_to_retain,
plan->gids_to_retain_sorted);
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return plan;
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}
/**
* hb_subset_plan_destroy:
*
* Since: 1.7.5
**/
void
hb_subset_plan_destroy (hb_subset_plan_t *plan)
{
if (!hb_object_destroy (plan)) return;
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plan->codepoints.finish ();
plan->gids_to_retain.finish ();
plan->gids_to_retain_sorted.finish ();
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free (plan);
}