Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1165 insertions, 0 deletions

diff --git a/gfx/harfbuzz/src/hb-subset-cff-common.hh b/gfx/harfbuzz/src/hb-subset-cff-common.hh
new file mode 100644
index 0000000000..ff50b0e518
--- /dev/null
+++ b/gfx/harfbuzz/src/hb-subset-cff-common.hh
@@ -0,0 +1,1165 @@
+/*
+ * Copyright © 2018 Adobe 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.
+ *
+ * Adobe Author(s): Michiharu Ariza
+ */
+
+#ifndef HB_SUBSET_CFF_COMMON_HH
+#define HB_SUBSET_CFF_COMMON_HH
+
+#include "hb.hh"
+
+#include "hb-subset-plan.hh"
+#include "hb-cff-interp-cs-common.hh"
+
+namespace CFF {
+
+/* Used for writing a temporary charstring */
+struct str_encoder_t
+{
+  str_encoder_t (str_buff_t &buff_)
+    : buff (buff_) {}
+
+  void reset () { buff.reset (); }
+
+  void encode_byte (unsigned char b)
+  {
+    if (likely ((signed) buff.length < buff.allocated))
+      buff.arrayZ[buff.length++] = b;
+    else
+      buff.push (b);
+  }
+
+  void encode_int (int v)
+  {
+    if ((-1131 <= v) && (v <= 1131))
+    {
+      if ((-107 <= v) && (v <= 107))
+	encode_byte (v + 139);
+      else if (v > 0)
+      {
+	v -= 108;
+	encode_byte ((v >> 8) + OpCode_TwoBytePosInt0);
+	encode_byte (v & 0xFF);
+      }
+      else
+      {
+	v = -v - 108;
+	encode_byte ((v >> 8) + OpCode_TwoByteNegInt0);
+	encode_byte (v & 0xFF);
+      }
+    }
+    else
+    {
+      if (unlikely (v < -32768))
+	v = -32768;
+      else if (unlikely (v > 32767))
+	v = 32767;
+      encode_byte (OpCode_shortint);
+      encode_byte ((v >> 8) & 0xFF);
+      encode_byte (v & 0xFF);
+    }
+  }
+
+  // Encode number for CharString
+  void encode_num_cs (const number_t& n)
+  {
+    if (n.in_int_range ())
+    {
+      encode_int (n.to_int ());
+    }
+    else
+    {
+      int32_t v = n.to_fixed ();
+      encode_byte (OpCode_fixedcs);
+      encode_byte ((v >> 24) & 0xFF);
+      encode_byte ((v >> 16) & 0xFF);
+      encode_byte ((v >> 8) & 0xFF);
+      encode_byte (v & 0xFF);
+    }
+  }
+
+  // Encode number for TopDict / Private
+  void encode_num_tp (const number_t& n)
+  {
+    if (n.in_int_range ())
+    {
+      // TODO longint
+      encode_int (n.to_int ());
+    }
+    else
+    {
+      // Sigh. BCD
+      // https://learn.microsoft.com/en-us/typography/opentype/spec/cff2#table-5-nibble-definitions
+      double v = n.to_real ();
+      encode_byte (OpCode_BCD);
+
+      // Based on:
+      // https://github.com/fonttools/fonttools/blob/97ed3a61cde03e17b8be36f866192fbd56f1d1a7/Lib/fontTools/misc/psCharStrings.py#L265-L294
+
+      char buf[16];
+      /* FontTools has the following comment:
+       *
+       * # Note: 14 decimal digits seems to be the limitation for CFF real numbers
+       * # in macOS. However, we use 8 here to match the implementation of AFDKO.
+       *
+       * We use 8 here to match FontTools X-).
+       */
+
+      hb_locale_t clocale HB_UNUSED;
+      hb_locale_t oldlocale HB_UNUSED;
+      oldlocale = hb_uselocale (clocale = newlocale (LC_ALL_MASK, "C", NULL));
+      snprintf (buf, sizeof (buf), "%.8G", v);
+      (void) hb_uselocale (((void) freelocale (clocale), oldlocale));
+
+      char *s = buf;
+      if (s[0] == '0' && s[1] == '.')
+	s++;
+      else if (s[0] == '-' && s[1] == '0' && s[2] == '.')
+      {
+	s[1] = '-';
+	s++;
+      }
+      hb_vector_t<char> nibbles;
+      while (*s)
+      {
+	char c = s[0];
+	s++;
+
+	switch (c)
+	{
+	  case 'E':
+	  {
+	    char c2 = *s;
+	    if (c2 == '-')
+	    {
+	      s++;
+	      nibbles.push (0x0C); // E-
+	      continue;
+	    }
+	    if (c2 == '+')
+	      s++;
+	    nibbles.push (0x0B); // E
+	    continue;
+	  }
+
+	  case '.': case ',': // Comma for some European locales in case no uselocale available.
+	    nibbles.push (0x0A); // .
+	    continue;
+
+	  case '-':
+	    nibbles.push (0x0E); // .
+	    continue;
+	}
+
+	nibbles.push (c - '0');
+      }
+      nibbles.push (0x0F);
+      if (nibbles.length % 2)
+	nibbles.push (0x0F);
+
+      unsigned count = nibbles.length;
+      for (unsigned i = 0; i < count; i += 2)
+        encode_byte ((nibbles[i] << 4) | nibbles[i+1]);
+    }
+  }
+
+  void encode_op (op_code_t op)
+  {
+    if (Is_OpCode_ESC (op))
+    {
+      encode_byte (OpCode_escape);
+      encode_byte (Unmake_OpCode_ESC (op));
+    }
+    else
+      encode_byte (op);
+  }
+
+  void copy_str (const unsigned char *str, unsigned length)
+  {
+    assert ((signed) (buff.length + length) <= buff.allocated);
+    hb_memcpy (buff.arrayZ + buff.length, str, length);
+    buff.length += length;
+  }
+
+  bool in_error () const { return buff.in_error (); }
+
+  protected:
+
+  str_buff_t &buff;
+};
+
+struct cff_sub_table_info_t {
+  cff_sub_table_info_t ()
+    : fd_array_link (0),
+      char_strings_link (0)
+  {
+    fd_select.init ();
+  }
+
+  table_info_t     fd_select;
+  objidx_t     	   fd_array_link;
+  objidx_t     	   char_strings_link;
+};
+
+template <typename OPSTR=op_str_t>
+struct cff_top_dict_op_serializer_t : op_serializer_t
+{
+  bool serialize (hb_serialize_context_t *c,
+		  const OPSTR &opstr,
+		  const cff_sub_table_info_t &info) const
+  {
+    TRACE_SERIALIZE (this);
+
+    switch (opstr.op)
+    {
+      case OpCode_CharStrings:
+	return_trace (FontDict::serialize_link4_op(c, opstr.op, info.char_strings_link, whence_t::Absolute));
+
+      case OpCode_FDArray:
+	return_trace (FontDict::serialize_link4_op(c, opstr.op, info.fd_array_link, whence_t::Absolute));
+
+      case OpCode_FDSelect:
+	return_trace (FontDict::serialize_link4_op(c, opstr.op, info.fd_select.link, whence_t::Absolute));
+
+      default:
+	return_trace (copy_opstr (c, opstr));
+    }
+    return_trace (true);
+  }
+};
+
+struct cff_font_dict_op_serializer_t : op_serializer_t
+{
+  bool serialize (hb_serialize_context_t *c,
+		  const op_str_t &opstr,
+		  const table_info_t &privateDictInfo) const
+  {
+    TRACE_SERIALIZE (this);
+
+    if (opstr.op == OpCode_Private)
+    {
+      /* serialize the private dict size & offset as 2-byte & 4-byte integers */
+      return_trace (UnsizedByteStr::serialize_int2 (c, privateDictInfo.size) &&
+		    Dict::serialize_link4_op (c, opstr.op, privateDictInfo.link, whence_t::Absolute));
+    }
+    else
+    {
+      unsigned char *d = c->allocate_size<unsigned char> (opstr.length);
+      if (unlikely (!d)) return_trace (false);
+      /* Faster than hb_memcpy for small strings. */
+      for (unsigned i = 0; i < opstr.length; i++)
+	d[i] = opstr.ptr[i];
+      //hb_memcpy (d, opstr.ptr, opstr.length);
+    }
+    return_trace (true);
+  }
+};
+
+struct flatten_param_t
+{
+  str_buff_t     &flatStr;
+  bool	drop_hints;
+  const hb_subset_plan_t *plan;
+};
+
+template <typename ACC, typename ENV, typename OPSET, op_code_t endchar_op=OpCode_Invalid>
+struct subr_flattener_t
+{
+  subr_flattener_t (const ACC &acc_,
+		    const hb_subset_plan_t *plan_)
+		   : acc (acc_), plan (plan_) {}
+
+  bool flatten (str_buff_vec_t &flat_charstrings)
+  {
+    unsigned count = plan->num_output_glyphs ();
+    if (!flat_charstrings.resize_exact (count))
+      return false;
+    for (unsigned int i = 0; i < count; i++)
+    {
+      hb_codepoint_t  glyph;
+      if (!plan->old_gid_for_new_gid (i, &glyph))
+      {
+	/* add an endchar only charstring for a missing glyph if CFF1 */
+	if (endchar_op != OpCode_Invalid) flat_charstrings[i].push (endchar_op);
+	continue;
+      }
+      const hb_ubytes_t str = (*acc.charStrings)[glyph];
+      unsigned int fd = acc.fdSelect->get_fd (glyph);
+      if (unlikely (fd >= acc.fdCount))
+	return false;
+
+
+      ENV env (str, acc, fd,
+	       plan->normalized_coords.arrayZ, plan->normalized_coords.length);
+      cs_interpreter_t<ENV, OPSET, flatten_param_t> interp (env);
+      flatten_param_t  param = {
+        flat_charstrings.arrayZ[i],
+        (bool) (plan->flags & HB_SUBSET_FLAGS_NO_HINTING),
+	plan
+      };
+      if (unlikely (!interp.interpret (param)))
+	return false;
+    }
+    return true;
+  }
+
+  const ACC &acc;
+  const hb_subset_plan_t *plan;
+};
+
+struct subr_closures_t
+{
+  subr_closures_t (unsigned int fd_count) : global_closure (), local_closures ()
+  {
+    local_closures.resize_exact (fd_count);
+  }
+
+  void reset ()
+  {
+    global_closure.clear();
+    for (unsigned int i = 0; i < local_closures.length; i++)
+      local_closures[i].clear();
+  }
+
+  bool in_error () const { return local_closures.in_error (); }
+  hb_set_t  global_closure;
+  hb_vector_t<hb_set_t> local_closures;
+};
+
+struct parsed_cs_op_t : op_str_t
+{
+  parsed_cs_op_t (unsigned int subr_num_ = 0) :
+    subr_num (subr_num_) {}
+
+  bool is_hinting () const { return hinting_flag; }
+  void set_hinting ()       { hinting_flag = true; }
+
+  /* The layout of this struct is designed to fit within the
+   * padding of op_str_t! */
+
+  protected:
+  bool	  hinting_flag = false;
+
+  public:
+  uint16_t subr_num;
+};
+
+struct parsed_cs_str_t : parsed_values_t<parsed_cs_op_t>
+{
+  parsed_cs_str_t () :
+    parsed (false),
+    hint_dropped (false),
+    has_prefix_ (false),
+    has_calls_ (false)
+  {
+    SUPER::init ();
+  }
+
+  void add_op (op_code_t op, const byte_str_ref_t& str_ref)
+  {
+    if (!is_parsed ())
+      SUPER::add_op (op, str_ref);
+  }
+
+  void add_call_op (op_code_t op, const byte_str_ref_t& str_ref, unsigned int subr_num)
+  {
+    if (!is_parsed ())
+    {
+      has_calls_ = true;
+
+      /* Pop the subroutine number. */
+      values.pop ();
+
+      SUPER::add_op (op, str_ref, {subr_num});
+    }
+  }
+
+  void set_prefix (const number_t &num, op_code_t op = OpCode_Invalid)
+  {
+    has_prefix_ = true;
+    prefix_op_ = op;
+    prefix_num_ = num;
+  }
+
+  bool at_end (unsigned int pos) const
+  {
+    return ((pos + 1 >= values.length) /* CFF2 */
+	|| (values[pos + 1].op == OpCode_return));
+  }
+
+  bool is_parsed () const { return parsed; }
+  void set_parsed ()      { parsed = true; }
+
+  bool is_hint_dropped () const { return hint_dropped; }
+  void set_hint_dropped ()      { hint_dropped = true; }
+
+  bool is_vsindex_dropped () const { return vsindex_dropped; }
+  void set_vsindex_dropped ()      { vsindex_dropped = true; }
+
+  bool has_prefix () const          { return has_prefix_; }
+  op_code_t prefix_op () const         { return prefix_op_; }
+  const number_t &prefix_num () const { return prefix_num_; }
+
+  bool has_calls () const          { return has_calls_; }
+
+  void compact ()
+  {
+    unsigned count = values.length;
+    if (!count) return;
+    auto &opstr = values.arrayZ;
+    unsigned j = 0;
+    for (unsigned i = 1; i < count; i++)
+    {
+      /* See if we can combine op j and op i. */
+      bool combine =
+        (opstr[j].op != OpCode_callsubr && opstr[j].op != OpCode_callgsubr) &&
+        (opstr[i].op != OpCode_callsubr && opstr[i].op != OpCode_callgsubr) &&
+        (opstr[j].is_hinting () == opstr[i].is_hinting ()) &&
+        (opstr[j].ptr + opstr[j].length == opstr[i].ptr) &&
+        (opstr[j].length + opstr[i].length <= 255);
+
+      if (combine)
+      {
+	opstr[j].length += opstr[i].length;
+	opstr[j].op = OpCode_Invalid;
+      }
+      else
+      {
+	opstr[++j] = opstr[i];
+      }
+    }
+    values.shrink (j + 1);
+  }
+
+  protected:
+  bool    parsed : 1;
+  bool    hint_dropped : 1;
+  bool    vsindex_dropped : 1;
+  bool    has_prefix_ : 1;
+  bool    has_calls_ : 1;
+  op_code_t	prefix_op_;
+  number_t	prefix_num_;
+
+  private:
+  typedef parsed_values_t<parsed_cs_op_t> SUPER;
+};
+
+struct parsed_cs_str_vec_t : hb_vector_t<parsed_cs_str_t>
+{
+  private:
+  typedef hb_vector_t<parsed_cs_str_t> SUPER;
+};
+
+struct cff_subset_accelerator_t
+{
+  static cff_subset_accelerator_t* create (
+      hb_blob_t* original_blob,
+      const parsed_cs_str_vec_t& parsed_charstrings,
+      const parsed_cs_str_vec_t& parsed_global_subrs,
+      const hb_vector_t<parsed_cs_str_vec_t>& parsed_local_subrs) {
+    cff_subset_accelerator_t* accel =
+        (cff_subset_accelerator_t*) hb_malloc (sizeof(cff_subset_accelerator_t));
+    new (accel) cff_subset_accelerator_t (original_blob,
+                                          parsed_charstrings,
+                                          parsed_global_subrs,
+                                          parsed_local_subrs);
+    return accel;
+  }
+
+  static void destroy (void* value) {
+    if (!value) return;
+
+    cff_subset_accelerator_t* accel = (cff_subset_accelerator_t*) value;
+    accel->~cff_subset_accelerator_t ();
+    hb_free (accel);
+  }
+
+  cff_subset_accelerator_t(
+      hb_blob_t* original_blob_,
+      const parsed_cs_str_vec_t& parsed_charstrings_,
+      const parsed_cs_str_vec_t& parsed_global_subrs_,
+      const hb_vector_t<parsed_cs_str_vec_t>& parsed_local_subrs_)
+  {
+    parsed_charstrings = parsed_charstrings_;
+    parsed_global_subrs = parsed_global_subrs_;
+    parsed_local_subrs = parsed_local_subrs_;
+
+    // the parsed charstrings point to memory in the original CFF table so we must hold a reference
+    // to it to keep the memory valid.
+    original_blob = hb_blob_reference (original_blob_);
+  }
+
+  ~cff_subset_accelerator_t() {
+    hb_blob_destroy (original_blob);
+    hb_map_destroy (glyph_to_sid_map.get_relaxed ());
+  }
+
+  parsed_cs_str_vec_t parsed_charstrings;
+  parsed_cs_str_vec_t parsed_global_subrs;
+  hb_vector_t<parsed_cs_str_vec_t> parsed_local_subrs;
+  mutable hb_atomic_ptr_t<hb_map_t> glyph_to_sid_map = nullptr;
+
+ private:
+  hb_blob_t* original_blob;
+};
+
+struct subr_subset_param_t
+{
+  subr_subset_param_t (parsed_cs_str_t *parsed_charstring_,
+		       parsed_cs_str_vec_t *parsed_global_subrs_,
+		       parsed_cs_str_vec_t *parsed_local_subrs_,
+		       hb_set_t *global_closure_,
+		       hb_set_t *local_closure_,
+		       bool drop_hints_) :
+      current_parsed_str (parsed_charstring_),
+      parsed_charstring (parsed_charstring_),
+      parsed_global_subrs (parsed_global_subrs_),
+      parsed_local_subrs (parsed_local_subrs_),
+      global_closure (global_closure_),
+      local_closure (local_closure_),
+      drop_hints (drop_hints_) {}
+
+  parsed_cs_str_t *get_parsed_str_for_context (call_context_t &context)
+  {
+    switch (context.type)
+    {
+      case CSType_CharString:
+	return parsed_charstring;
+
+      case CSType_LocalSubr:
+	if (likely (context.subr_num < parsed_local_subrs->length))
+	  return &(*parsed_local_subrs)[context.subr_num];
+	break;
+
+      case CSType_GlobalSubr:
+	if (likely (context.subr_num < parsed_global_subrs->length))
+	  return &(*parsed_global_subrs)[context.subr_num];
+	break;
+    }
+    return nullptr;
+  }
+
+  template <typename ENV>
+  void set_current_str (ENV &env, bool calling)
+  {
+    parsed_cs_str_t *parsed_str = get_parsed_str_for_context (env.context);
+    if (unlikely (!parsed_str))
+    {
+      env.set_error ();
+      return;
+    }
+    /* If the called subroutine is parsed partially but not completely yet,
+     * it must be because we are calling it recursively.
+     * Handle it as an error. */
+    if (unlikely (calling && !parsed_str->is_parsed () && (parsed_str->values.length > 0)))
+      env.set_error ();
+    else
+    {
+      if (!parsed_str->is_parsed ())
+        parsed_str->alloc (env.str_ref.total_size ());
+      current_parsed_str = parsed_str;
+    }
+  }
+
+  parsed_cs_str_t	*current_parsed_str;
+
+  parsed_cs_str_t	*parsed_charstring;
+  parsed_cs_str_vec_t	*parsed_global_subrs;
+  parsed_cs_str_vec_t	*parsed_local_subrs;
+  hb_set_t      *global_closure;
+  hb_set_t      *local_closure;
+  bool	  drop_hints;
+};
+
+struct subr_remap_t : hb_inc_bimap_t
+{
+  void create (const hb_set_t *closure)
+  {
+    /* create a remapping of subroutine numbers from old to new.
+     * no optimization based on usage counts. fonttools doesn't appear doing that either.
+     */
+
+    resize (closure->get_population ());
+    hb_codepoint_t old_num = HB_SET_VALUE_INVALID;
+    while (hb_set_next (closure, &old_num))
+      add (old_num);
+
+    if (get_population () < 1240)
+      bias = 107;
+    else if (get_population () < 33900)
+      bias = 1131;
+    else
+      bias = 32768;
+  }
+
+  int biased_num (unsigned int old_num) const
+  {
+    hb_codepoint_t new_num = get (old_num);
+    return (int)new_num - bias;
+  }
+
+  protected:
+  int bias;
+};
+
+struct subr_remaps_t
+{
+  subr_remaps_t (unsigned int fdCount)
+  {
+    local_remaps.resize (fdCount);
+  }
+
+  bool in_error()
+  {
+    return local_remaps.in_error ();
+  }
+
+  void create (subr_closures_t& closures)
+  {
+    global_remap.create (&closures.global_closure);
+    for (unsigned int i = 0; i < local_remaps.length; i++)
+      local_remaps.arrayZ[i].create (&closures.local_closures[i]);
+  }
+
+  subr_remap_t	       global_remap;
+  hb_vector_t<subr_remap_t>  local_remaps;
+};
+
+template <typename SUBSETTER, typename SUBRS, typename ACC, typename ENV, typename OPSET, op_code_t endchar_op=OpCode_Invalid>
+struct subr_subsetter_t
+{
+  subr_subsetter_t (ACC &acc_, const hb_subset_plan_t *plan_)
+      : acc (acc_), plan (plan_), closures(acc_.fdCount),
+        remaps(acc_.fdCount)
+  {}
+
+  /* Subroutine subsetting with --no-desubroutinize runs in phases:
+   *
+   * 1. execute charstrings/subroutines to determine subroutine closures
+   * 2. parse out all operators and numbers
+   * 3. mark hint operators and operands for removal if --no-hinting
+   * 4. re-encode all charstrings and subroutines with new subroutine numbers
+   *
+   * Phases #1 and #2 are done at the same time in collect_subrs ().
+   * Phase #3 walks charstrings/subroutines forward then backward (hence parsing required),
+   * because we can't tell if a number belongs to a hint op until we see the first moveto.
+   *
+   * Assumption: a callsubr/callgsubr operator must immediately follow a (biased) subroutine number
+   * within the same charstring/subroutine, e.g., not split across a charstring and a subroutine.
+   */
+  bool subset (void)
+  {
+    unsigned fd_count = acc.fdCount;
+    const cff_subset_accelerator_t* cff_accelerator = nullptr;
+    if (plan->accelerator && plan->accelerator->cff_accelerator) {
+      cff_accelerator = plan->accelerator->cff_accelerator;
+      fd_count = cff_accelerator->parsed_local_subrs.length;
+    }
+
+    if (cff_accelerator) {
+      // If we are not dropping hinting then charstrings are not modified so we can
+      // just use a reference to the cached copies.
+      cached_charstrings.resize_exact (plan->num_output_glyphs ());
+      parsed_global_subrs = &cff_accelerator->parsed_global_subrs;
+      parsed_local_subrs = &cff_accelerator->parsed_local_subrs;
+    } else {
+      parsed_charstrings.resize_exact (plan->num_output_glyphs ());
+      parsed_global_subrs_storage.resize_exact (acc.globalSubrs->count);
+
+      if (unlikely (!parsed_local_subrs_storage.resize (fd_count))) return false;
+
+      for (unsigned int i = 0; i < acc.fdCount; i++)
+      {
+        unsigned count = acc.privateDicts[i].localSubrs->count;
+        parsed_local_subrs_storage[i].resize (count);
+        if (unlikely (parsed_local_subrs_storage[i].in_error ())) return false;
+      }
+
+      parsed_global_subrs = &parsed_global_subrs_storage;
+      parsed_local_subrs = &parsed_local_subrs_storage;
+    }
+
+    if (unlikely (remaps.in_error()
+                  || cached_charstrings.in_error ()
+                  || parsed_charstrings.in_error ()
+                  || parsed_global_subrs->in_error ()
+                  || closures.in_error ())) {
+      return false;
+    }
+
+    /* phase 1 & 2 */
+    for (unsigned int i = 0; i < plan->num_output_glyphs (); i++)
+    {
+      hb_codepoint_t  glyph;
+      if (!plan->old_gid_for_new_gid (i, &glyph))
+        continue;
+
+      const hb_ubytes_t str = (*acc.charStrings)[glyph];
+      unsigned int fd = acc.fdSelect->get_fd (glyph);
+      if (unlikely (fd >= acc.fdCount))
+        return false;
+
+      if (cff_accelerator)
+      {
+        // parsed string already exists in accelerator, copy it and move
+        // on.
+        if (cached_charstrings)
+          cached_charstrings[i] = &cff_accelerator->parsed_charstrings[glyph];
+        else
+          parsed_charstrings[i] = cff_accelerator->parsed_charstrings[glyph];
+
+        continue;
+      }
+
+      ENV env (str, acc, fd);
+      cs_interpreter_t<ENV, OPSET, subr_subset_param_t> interp (env);
+
+      parsed_charstrings[i].alloc (str.length);
+      subr_subset_param_t  param (&parsed_charstrings[i],
+                                  &parsed_global_subrs_storage,
+                                  &parsed_local_subrs_storage[fd],
+                                  &closures.global_closure,
+                                  &closures.local_closures[fd],
+                                  plan->flags & HB_SUBSET_FLAGS_NO_HINTING);
+
+      if (unlikely (!interp.interpret (param)))
+        return false;
+
+      /* complete parsed string esp. copy CFF1 width or CFF2 vsindex to the parsed charstring for encoding */
+      SUBSETTER::complete_parsed_str (interp.env, param, parsed_charstrings[i]);
+
+      /* mark hint ops and arguments for drop */
+      if ((plan->flags & HB_SUBSET_FLAGS_NO_HINTING) || plan->inprogress_accelerator)
+      {
+	subr_subset_param_t  param (&parsed_charstrings[i],
+				    &parsed_global_subrs_storage,
+				    &parsed_local_subrs_storage[fd],
+				    &closures.global_closure,
+				    &closures.local_closures[fd],
+				    plan->flags & HB_SUBSET_FLAGS_NO_HINTING);
+
+	drop_hints_param_t  drop;
+	if (drop_hints_in_str (parsed_charstrings[i], param, drop))
+	{
+	  parsed_charstrings[i].set_hint_dropped ();
+	  if (drop.vsindex_dropped)
+	    parsed_charstrings[i].set_vsindex_dropped ();
+	}
+      }
+
+      /* Doing this here one by one instead of compacting all at the en
+       * has massive peak-memory saving.
+       *
+       * The compacting both saves memory and makes further operations
+       * faster.
+       */
+      parsed_charstrings[i].compact ();
+    }
+
+    /* Since parsed strings were loaded from accelerator, we still need
+     * to compute the subroutine closures which would have normally happened during
+     * parsing.
+     *
+     * Or if we are dropping hinting, redo closure to get actually used subrs.
+     */
+    if ((cff_accelerator ||
+	(!cff_accelerator && plan->flags & HB_SUBSET_FLAGS_NO_HINTING)) &&
+        !closure_subroutines(*parsed_global_subrs,
+                             *parsed_local_subrs))
+      return false;
+
+    remaps.create (closures);
+
+    populate_subset_accelerator ();
+    return true;
+  }
+
+  bool encode_charstrings (str_buff_vec_t &buffArray, bool encode_prefix = true) const
+  {
+    if (unlikely (!buffArray.resize_exact (plan->num_output_glyphs ())))
+      return false;
+    for (unsigned int i = 0; i < plan->num_output_glyphs (); i++)
+    {
+      hb_codepoint_t  glyph;
+      if (!plan->old_gid_for_new_gid (i, &glyph))
+      {
+	/* add an endchar only charstring for a missing glyph if CFF1 */
+	if (endchar_op != OpCode_Invalid) buffArray.arrayZ[i].push (endchar_op);
+	continue;
+      }
+      unsigned int  fd = acc.fdSelect->get_fd (glyph);
+      if (unlikely (fd >= acc.fdCount))
+	return false;
+      if (unlikely (!encode_str (get_parsed_charstring (i), fd, buffArray.arrayZ[i], encode_prefix)))
+	return false;
+    }
+    return true;
+  }
+
+  bool encode_subrs (const parsed_cs_str_vec_t &subrs, const subr_remap_t& remap, unsigned int fd, str_buff_vec_t &buffArray) const
+  {
+    unsigned int  count = remap.get_population ();
+
+    if (unlikely (!buffArray.resize_exact (count)))
+      return false;
+    for (unsigned int new_num = 0; new_num < count; new_num++)
+    {
+      hb_codepoint_t old_num = remap.backward (new_num);
+      assert (old_num != CFF_UNDEF_CODE);
+
+      if (unlikely (!encode_str (subrs[old_num], fd, buffArray[new_num])))
+	return false;
+    }
+    return true;
+  }
+
+  bool encode_globalsubrs (str_buff_vec_t &buffArray)
+  {
+    return encode_subrs (*parsed_global_subrs, remaps.global_remap, 0, buffArray);
+  }
+
+  bool encode_localsubrs (unsigned int fd, str_buff_vec_t &buffArray) const
+  {
+    return encode_subrs ((*parsed_local_subrs)[fd], remaps.local_remaps[fd], fd, buffArray);
+  }
+
+  protected:
+  struct drop_hints_param_t
+  {
+    drop_hints_param_t ()
+      : seen_moveto (false),
+	ends_in_hint (false),
+	all_dropped (false),
+	vsindex_dropped (false) {}
+
+    bool  seen_moveto;
+    bool  ends_in_hint;
+    bool  all_dropped;
+    bool  vsindex_dropped;
+  };
+
+  bool drop_hints_in_subr (parsed_cs_str_t &str, unsigned int pos,
+			   parsed_cs_str_vec_t &subrs, unsigned int subr_num,
+			   const subr_subset_param_t &param, drop_hints_param_t &drop)
+  {
+    drop.ends_in_hint = false;
+    bool has_hint = drop_hints_in_str (subrs[subr_num], param, drop);
+
+    /* if this subr ends with a stem hint (i.e., not a number; potential argument for moveto),
+     * then this entire subroutine must be a hint. drop its call. */
+    if (drop.ends_in_hint)
+    {
+      str.values[pos].set_hinting ();
+      /* if this subr call is at the end of the parent subr, propagate the flag
+       * otherwise reset the flag */
+      if (!str.at_end (pos))
+	drop.ends_in_hint = false;
+    }
+    else if (drop.all_dropped)
+    {
+      str.values[pos].set_hinting ();
+    }
+
+    return has_hint;
+  }
+
+  /* returns true if it sees a hint op before the first moveto */
+  bool drop_hints_in_str (parsed_cs_str_t &str, const subr_subset_param_t &param, drop_hints_param_t &drop)
+  {
+    bool  seen_hint = false;
+
+    unsigned count = str.values.length;
+    auto *values = str.values.arrayZ;
+    for (unsigned int pos = 0; pos < count; pos++)
+    {
+      bool  has_hint = false;
+      switch (values[pos].op)
+      {
+	case OpCode_callsubr:
+	  has_hint = drop_hints_in_subr (str, pos,
+					*param.parsed_local_subrs, values[pos].subr_num,
+					param, drop);
+	  break;
+
+	case OpCode_callgsubr:
+	  has_hint = drop_hints_in_subr (str, pos,
+					*param.parsed_global_subrs, values[pos].subr_num,
+					param, drop);
+	  break;
+
+	case OpCode_rmoveto:
+	case OpCode_hmoveto:
+	case OpCode_vmoveto:
+	  drop.seen_moveto = true;
+	  break;
+
+	case OpCode_hintmask:
+	case OpCode_cntrmask:
+	  if (drop.seen_moveto)
+	  {
+	    values[pos].set_hinting ();
+	    break;
+	  }
+	  HB_FALLTHROUGH;
+
+	case OpCode_hstemhm:
+	case OpCode_vstemhm:
+	case OpCode_hstem:
+	case OpCode_vstem:
+	  has_hint = true;
+	  values[pos].set_hinting ();
+	  if (str.at_end (pos))
+	    drop.ends_in_hint = true;
+	  break;
+
+	case OpCode_dotsection:
+	  values[pos].set_hinting ();
+	  break;
+
+	default:
+	  /* NONE */
+	  break;
+      }
+      if (has_hint)
+      {
+	for (int i = pos - 1; i >= 0; i--)
+	{
+	  parsed_cs_op_t  &csop = values[(unsigned)i];
+	  if (csop.is_hinting ())
+	    break;
+	  csop.set_hinting ();
+	  if (csop.op == OpCode_vsindexcs)
+	    drop.vsindex_dropped = true;
+	}
+	seen_hint |= has_hint;
+      }
+    }
+
+    /* Raise all_dropped flag if all operators except return are dropped from a subr.
+     * It may happen even after seeing the first moveto if a subr contains
+     * only (usually one) hintmask operator, then calls to this subr can be dropped.
+     */
+    drop.all_dropped = true;
+    for (unsigned int pos = 0; pos < count; pos++)
+    {
+      parsed_cs_op_t  &csop = values[pos];
+      if (csop.op == OpCode_return)
+	break;
+      if (!csop.is_hinting ())
+      {
+	drop.all_dropped = false;
+	break;
+      }
+    }
+
+    return seen_hint;
+  }
+
+  bool closure_subroutines (const parsed_cs_str_vec_t& global_subrs,
+                            const hb_vector_t<parsed_cs_str_vec_t>& local_subrs)
+  {
+    closures.reset ();
+    for (unsigned int i = 0; i < plan->num_output_glyphs (); i++)
+    {
+      hb_codepoint_t  glyph;
+      if (!plan->old_gid_for_new_gid (i, &glyph))
+        continue;
+      unsigned int fd = acc.fdSelect->get_fd (glyph);
+      if (unlikely (fd >= acc.fdCount))
+        return false;
+
+      // Note: const cast is safe here because the collect_subr_refs_in_str only performs a
+      //       closure and does not modify any of the charstrings.
+      subr_subset_param_t  param (const_cast<parsed_cs_str_t*> (&get_parsed_charstring (i)),
+                                  const_cast<parsed_cs_str_vec_t*> (&global_subrs),
+                                  const_cast<parsed_cs_str_vec_t*> (&local_subrs[fd]),
+                                  &closures.global_closure,
+                                  &closures.local_closures[fd],
+                                  plan->flags & HB_SUBSET_FLAGS_NO_HINTING);
+      collect_subr_refs_in_str (get_parsed_charstring (i), param);
+    }
+
+    return true;
+  }
+
+  void collect_subr_refs_in_subr (unsigned int subr_num, parsed_cs_str_vec_t &subrs,
+				  hb_set_t *closure,
+				  const subr_subset_param_t &param)
+  {
+    if (closure->has (subr_num))
+      return;
+    closure->add (subr_num);
+    collect_subr_refs_in_str (subrs[subr_num], param);
+  }
+
+  void collect_subr_refs_in_str (const parsed_cs_str_t &str,
+                                 const subr_subset_param_t &param)
+  {
+    if (!str.has_calls ())
+      return;
+
+    for (auto &opstr : str.values)
+    {
+      if (!param.drop_hints || !opstr.is_hinting ())
+      {
+	switch (opstr.op)
+	{
+	  case OpCode_callsubr:
+	    collect_subr_refs_in_subr (opstr.subr_num, *param.parsed_local_subrs,
+				       param.local_closure, param);
+	    break;
+
+	  case OpCode_callgsubr:
+	    collect_subr_refs_in_subr (opstr.subr_num, *param.parsed_global_subrs,
+				       param.global_closure, param);
+	    break;
+
+	  default: break;
+	}
+      }
+    }
+  }
+
+  bool encode_str (const parsed_cs_str_t &str, const unsigned int fd, str_buff_t &buff, bool encode_prefix = true) const
+  {
+    str_encoder_t  encoder (buff);
+    encoder.reset ();
+    bool hinting = !(plan->flags & HB_SUBSET_FLAGS_NO_HINTING);
+    /* if a prefix (CFF1 width or CFF2 vsindex) has been removed along with hints,
+     * re-insert it at the beginning of charstreing */
+    if (encode_prefix && str.has_prefix () && !hinting && str.is_hint_dropped ())
+    {
+      encoder.encode_num_cs (str.prefix_num ());
+      if (str.prefix_op () != OpCode_Invalid)
+	encoder.encode_op (str.prefix_op ());
+    }
+
+    unsigned size = 0;
+    for (auto &opstr : str.values)
+    {
+      size += opstr.length;
+      if (opstr.op == OpCode_callsubr || opstr.op == OpCode_callgsubr)
+        size += 3;
+    }
+    if (!buff.alloc (buff.length + size, true))
+      return false;
+
+    for (auto &opstr : str.values)
+    {
+      if (hinting || !opstr.is_hinting ())
+      {
+	switch (opstr.op)
+	{
+	  case OpCode_callsubr:
+	    encoder.encode_int (remaps.local_remaps[fd].biased_num (opstr.subr_num));
+	    encoder.copy_str (opstr.ptr, opstr.length);
+	    break;
+
+	  case OpCode_callgsubr:
+	    encoder.encode_int (remaps.global_remap.biased_num (opstr.subr_num));
+	    encoder.copy_str (opstr.ptr, opstr.length);
+	    break;
+
+	  default:
+	    encoder.copy_str (opstr.ptr, opstr.length);
+	    break;
+	}
+      }
+    }
+    return !encoder.in_error ();
+  }
+
+  void compact_parsed_subrs () const
+  {
+    for (auto &cs : parsed_global_subrs_storage)
+      cs.compact ();
+    for (auto &vec : parsed_local_subrs_storage)
+      for (auto &cs : vec)
+	cs.compact ();
+  }
+
+  void populate_subset_accelerator () const
+  {
+    if (!plan->inprogress_accelerator) return;
+
+    compact_parsed_subrs ();
+
+    plan->inprogress_accelerator->cff_accelerator =
+        cff_subset_accelerator_t::create(acc.blob,
+                                         parsed_charstrings,
+                                         parsed_global_subrs_storage,
+                                         parsed_local_subrs_storage);
+    plan->inprogress_accelerator->destroy_cff_accelerator =
+        cff_subset_accelerator_t::destroy;
+
+  }
+
+  const parsed_cs_str_t& get_parsed_charstring (unsigned i) const
+  {
+    if (cached_charstrings) return *(cached_charstrings[i]);
+    return parsed_charstrings[i];
+  }
+
+  protected:
+  const ACC			&acc;
+  const hb_subset_plan_t	*plan;
+
+  subr_closures_t		closures;
+
+  hb_vector_t<const parsed_cs_str_t*>     cached_charstrings;
+  const parsed_cs_str_vec_t*              parsed_global_subrs;
+  const hb_vector_t<parsed_cs_str_vec_t>* parsed_local_subrs;
+
+  subr_remaps_t			remaps;
+
+  private:
+
+  parsed_cs_str_vec_t		parsed_charstrings;
+  parsed_cs_str_vec_t		parsed_global_subrs_storage;
+  hb_vector_t<parsed_cs_str_vec_t>  parsed_local_subrs_storage;
+  typedef typename SUBRS::count_type subr_count_type;
+};
+
+} /* namespace CFF */
+
+HB_INTERNAL bool
+hb_plan_subset_cff_fdselect (const hb_subset_plan_t *plan,
+			    unsigned int fdCount,
+			    const CFF::FDSelect &src, /* IN */
+			    unsigned int &subset_fd_count /* OUT */,
+			    unsigned int &subset_fdselect_size /* OUT */,
+			    unsigned int &subset_fdselect_format /* OUT */,
+			    hb_vector_t<CFF::code_pair_t> &fdselect_ranges /* OUT */,
+			    hb_inc_bimap_t &fdmap /* OUT */);
+
+HB_INTERNAL bool
+hb_serialize_cff_fdselect (hb_serialize_context_t *c,
+			  unsigned int num_glyphs,
+			  const CFF::FDSelect &src,
+			  unsigned int fd_count,
+			  unsigned int fdselect_format,
+			  unsigned int size,
+			  const hb_vector_t<CFF::code_pair_t> &fdselect_ranges);
+
+#endif /* HB_SUBSET_CFF_COMMON_HH */