src/java.desktop/share/native/libfontmanager/harfbuzz/hb-subset.cc
changeset 54232 7c11a7cc7c1d
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.desktop/share/native/libfontmanager/harfbuzz/hb-subset.cc	Fri Mar 01 16:59:19 2019 -0800
@@ -0,0 +1,293 @@
+/*
+ * 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, Rod Sheeter, Behdad Esfahbod
+ */
+
+#include "hb.hh"
+#include "hb-open-type.hh"
+
+#include "hb-subset.hh"
+#include "hb-subset-glyf.hh"
+
+#include "hb-open-file.hh"
+#include "hb-ot-cmap-table.hh"
+#include "hb-ot-glyf-table.hh"
+#include "hb-ot-hdmx-table.hh"
+#include "hb-ot-head-table.hh"
+#include "hb-ot-hhea-table.hh"
+#include "hb-ot-hmtx-table.hh"
+#include "hb-ot-maxp-table.hh"
+#include "hb-ot-os2-table.hh"
+#include "hb-ot-post-table.hh"
+#include "hb-ot-cff1-table.hh"
+#include "hb-ot-cff2-table.hh"
+#include "hb-ot-vorg-table.hh"
+#include "hb-ot-layout-gsub-table.hh"
+#include "hb-ot-layout-gpos-table.hh"
+
+
+static unsigned int
+_plan_estimate_subset_table_size (hb_subset_plan_t *plan,
+                                  unsigned int table_len)
+{
+  unsigned int src_glyphs = plan->source->get_num_glyphs ();
+  unsigned int dst_glyphs = plan->glyphset->get_population ();
+
+  if (unlikely (!src_glyphs))
+    return 512 + table_len;
+
+  return 512 + (unsigned int) (table_len * sqrt ((double) dst_glyphs / src_glyphs));
+}
+
+template<typename TableType>
+static bool
+_subset2 (hb_subset_plan_t *plan)
+{
+  hb_blob_t *source_blob = hb_sanitize_context_t ().reference_table<TableType> (plan->source);
+  const TableType *table = source_blob->as<TableType> ();
+
+  hb_tag_t tag = TableType::tableTag;
+  hb_bool_t result = false;
+  if (source_blob->data)
+  {
+    hb_vector_t<char> buf;
+    unsigned int buf_size = _plan_estimate_subset_table_size (plan, source_blob->length);
+    DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c initial estimated table size: %u bytes.", HB_UNTAG (tag), buf_size);
+    if (unlikely (!buf.alloc (buf_size)))
+    {
+      DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c failed to allocate %u bytes.", HB_UNTAG (tag), buf_size);
+      return false;
+    }
+  retry:
+    hb_serialize_context_t serializer ((void *) buf, buf_size);
+    hb_subset_context_t c (plan, &serializer);
+    result = table->subset (&c);
+    if (serializer.in_error ())
+    {
+      buf_size += (buf_size >> 1) + 32;
+      DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c ran out of room; reallocating to %u bytes.", HB_UNTAG (tag), buf_size);
+      if (unlikely (!buf.alloc (buf_size)))
+      {
+        DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c failed to reallocate %u bytes.", HB_UNTAG (tag), buf_size);
+        return false;
+      }
+      goto retry;
+    }
+    if (result)
+    {
+      hb_blob_t *dest_blob = serializer.copy_blob ();
+      DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c final subset table size: %u bytes.", HB_UNTAG (tag), dest_blob->length);
+      result = c.plan->add_table (tag, dest_blob);
+      hb_blob_destroy (dest_blob);
+    }
+    else
+    {
+      DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c::subset table subsetted to empty.", HB_UNTAG (tag));
+      result = true;
+    }
+  }
+  else
+    DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c::subset sanitize failed on source table.", HB_UNTAG (tag));
+
+  hb_blob_destroy (source_blob);
+  DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c::subset %s", HB_UNTAG (tag), result ? "success" : "FAILED!");
+  return result;
+}
+
+template<typename TableType>
+static bool
+_subset (hb_subset_plan_t *plan)
+{
+  hb_blob_t *source_blob = hb_sanitize_context_t ().reference_table<TableType> (plan->source);
+  const TableType *table = source_blob->as<TableType> ();
+
+  hb_tag_t tag = TableType::tableTag;
+  hb_bool_t result = false;
+  if (source_blob->data)
+    result = table->subset (plan);
+  else
+    DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c::subset sanitize failed on source table.", HB_UNTAG (tag));
+
+  hb_blob_destroy (source_blob);
+  DEBUG_MSG(SUBSET, nullptr, "OT::%c%c%c%c::subset %s", HB_UNTAG (tag), result ? "success" : "FAILED!");
+  return result;
+}
+
+
+static bool
+_subset_table (hb_subset_plan_t *plan,
+               hb_tag_t          tag)
+{
+  DEBUG_MSG(SUBSET, nullptr, "begin subset %c%c%c%c", HB_UNTAG (tag));
+  bool result = true;
+  switch (tag) {
+    case HB_OT_TAG_glyf:
+      result = _subset<const OT::glyf> (plan);
+      break;
+    case HB_OT_TAG_hdmx:
+      result = _subset<const OT::hdmx> (plan);
+      break;
+    case HB_OT_TAG_head:
+      // TODO that won't work well if there is no glyf
+      DEBUG_MSG(SUBSET, nullptr, "skip head, handled by glyf");
+      result = true;
+      break;
+    case HB_OT_TAG_hhea:
+      DEBUG_MSG(SUBSET, nullptr, "skip hhea handled by hmtx");
+      return true;
+    case HB_OT_TAG_hmtx:
+      result = _subset<const OT::hmtx> (plan);
+      break;
+    case HB_OT_TAG_vhea:
+      DEBUG_MSG(SUBSET, nullptr, "skip vhea handled by vmtx");
+      return true;
+    case HB_OT_TAG_vmtx:
+      result = _subset<const OT::vmtx> (plan);
+      break;
+    case HB_OT_TAG_maxp:
+      result = _subset<const OT::maxp> (plan);
+      break;
+    case HB_OT_TAG_loca:
+      DEBUG_MSG(SUBSET, nullptr, "skip loca handled by glyf");
+      return true;
+    case HB_OT_TAG_cmap:
+      result = _subset<const OT::cmap> (plan);
+      break;
+    case HB_OT_TAG_OS2:
+      result = _subset<const OT::OS2> (plan);
+      break;
+    case HB_OT_TAG_post:
+      result = _subset<const OT::post> (plan);
+      break;
+    case HB_OT_TAG_cff1:
+      result = _subset<const OT::cff1> (plan);
+      break;
+    case HB_OT_TAG_cff2:
+      result = _subset<const OT::cff2> (plan);
+      break;
+    case HB_OT_TAG_VORG:
+      result = _subset<const OT::VORG> (plan);
+      break;
+    case HB_OT_TAG_GDEF:
+      result = _subset2<const OT::GDEF> (plan);
+      break;
+    case HB_OT_TAG_GSUB:
+      result = _subset2<const OT::GSUB> (plan);
+      break;
+    case HB_OT_TAG_GPOS:
+      result = _subset2<const OT::GPOS> (plan);
+      break;
+
+    default:
+      hb_blob_t *source_table = hb_face_reference_table (plan->source, tag);
+      if (likely (source_table))
+        result = plan->add_table (tag, source_table);
+      else
+        result = false;
+      hb_blob_destroy (source_table);
+      break;
+  }
+  DEBUG_MSG(SUBSET, nullptr, "subset %c%c%c%c %s", HB_UNTAG (tag), result ? "ok" : "FAILED");
+  return result;
+}
+
+static bool
+_should_drop_table (hb_subset_plan_t *plan, hb_tag_t tag)
+{
+  switch (tag) {
+    case HB_TAG ('c', 'v', 'a', 'r'): /* hint table, fallthrough */
+    case HB_TAG ('c', 'v', 't', ' '): /* hint table, fallthrough */
+    case HB_TAG ('f', 'p', 'g', 'm'): /* hint table, fallthrough */
+    case HB_TAG ('p', 'r', 'e', 'p'): /* hint table, fallthrough */
+    case HB_TAG ('h', 'd', 'm', 'x'): /* hint table, fallthrough */
+    case HB_TAG ('V', 'D', 'M', 'X'): /* hint table, fallthrough */
+      return plan->drop_hints;
+    // Drop Layout Tables if requested.
+    case HB_OT_TAG_GDEF:
+    case HB_OT_TAG_GPOS:
+    case HB_OT_TAG_GSUB:
+      return plan->drop_layout;
+    // Drop these tables below by default, list pulled
+    // from fontTools:
+    case HB_TAG ('B', 'A', 'S', 'E'):
+    case HB_TAG ('J', 'S', 'T', 'F'):
+    case HB_TAG ('D', 'S', 'I', 'G'):
+    case HB_TAG ('E', 'B', 'D', 'T'):
+    case HB_TAG ('E', 'B', 'L', 'C'):
+    case HB_TAG ('E', 'B', 'S', 'C'):
+    case HB_TAG ('S', 'V', 'G', ' '):
+    case HB_TAG ('P', 'C', 'L', 'T'):
+    case HB_TAG ('L', 'T', 'S', 'H'):
+    // Graphite tables:
+    case HB_TAG ('F', 'e', 'a', 't'):
+    case HB_TAG ('G', 'l', 'a', 't'):
+    case HB_TAG ('G', 'l', 'o', 'c'):
+    case HB_TAG ('S', 'i', 'l', 'f'):
+    case HB_TAG ('S', 'i', 'l', 'l'):
+    // Colour
+    case HB_TAG ('s', 'b', 'i', 'x'):
+      return true;
+    default:
+      return false;
+  }
+}
+
+/**
+ * hb_subset:
+ * @source: font face data to be subset.
+ * @input: input to use for the subsetting.
+ *
+ * Subsets a font according to provided input.
+ **/
+hb_face_t *
+hb_subset (hb_face_t *source,
+           hb_subset_input_t *input)
+{
+  if (unlikely (!input || !source)) return hb_face_get_empty ();
+
+  hb_subset_plan_t *plan = hb_subset_plan_create (source, input);
+
+  hb_tag_t table_tags[32];
+  unsigned int offset = 0, count;
+  bool success = true;
+  do {
+    count = ARRAY_LENGTH (table_tags);
+    hb_face_get_table_tags (source, offset, &count, table_tags);
+    for (unsigned int i = 0; i < count; i++)
+    {
+      hb_tag_t tag = table_tags[i];
+      if (_should_drop_table (plan, tag))
+      {
+        DEBUG_MSG(SUBSET, nullptr, "drop %c%c%c%c", HB_UNTAG (tag));
+        continue;
+      }
+      success = success && _subset_table (plan, tag);
+    }
+    offset += count;
+  } while (success && count == ARRAY_LENGTH (table_tags));
+
+  hb_face_t *result = success ? hb_face_reference (plan->dest) : hb_face_get_empty ();
+  hb_subset_plan_destroy (plan);
+  return result;
+}