diff mupdf-source/thirdparty/harfbuzz/src/hb-uniscribe.cc @ 3:2c135c81b16c

MERGE: upstream PyMuPDF 1.26.4 with MuPDF 1.26.7
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:44:09 +0200
parents b50eed0cc0ef
children
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/harfbuzz/src/hb-uniscribe.cc	Mon Sep 15 11:44:09 2025 +0200
@@ -0,0 +1,889 @@
+/*
+ * Copyright © 2011,2012,2013  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): Behdad Esfahbod
+ */
+
+#include "hb.hh"
+
+#ifdef HAVE_UNISCRIBE
+
+#ifdef HB_NO_OT_TAG
+#error "Cannot compile 'uniscribe' shaper with HB_NO_OT_TAG."
+#endif
+
+#include "hb-shaper-impl.hh"
+
+#include <windows.h>
+#include <usp10.h>
+#include <rpc.h>
+
+#ifndef E_NOT_SUFFICIENT_BUFFER
+#define E_NOT_SUFFICIENT_BUFFER HRESULT_FROM_WIN32 (ERROR_INSUFFICIENT_BUFFER)
+#endif
+
+#include "hb-uniscribe.h"
+
+#include "hb-ms-feature-ranges.hh"
+#include "hb-open-file.hh"
+#include "hb-ot-name-table.hh"
+#include "hb-ot-layout.h"
+
+
+/**
+ * SECTION:hb-uniscribe
+ * @title: hb-uniscribe
+ * @short_description: Windows integration
+ * @include: hb-uniscribe.h
+ *
+ * Functions for using HarfBuzz with Windows fonts.
+ **/
+
+typedef HRESULT (WINAPI *SIOT) /*ScriptItemizeOpenType*/(
+  const WCHAR *pwcInChars,
+  int cInChars,
+  int cMaxItems,
+  const SCRIPT_CONTROL *psControl,
+  const SCRIPT_STATE *psState,
+  SCRIPT_ITEM *pItems,
+  OPENTYPE_TAG *pScriptTags,
+  int *pcItems
+);
+
+typedef HRESULT (WINAPI *SSOT) /*ScriptShapeOpenType*/(
+  HDC hdc,
+  SCRIPT_CACHE *psc,
+  SCRIPT_ANALYSIS *psa,
+  OPENTYPE_TAG tagScript,
+  OPENTYPE_TAG tagLangSys,
+  int *rcRangeChars,
+  TEXTRANGE_PROPERTIES **rpRangeProperties,
+  int cRanges,
+  const WCHAR *pwcChars,
+  int cChars,
+  int cMaxGlyphs,
+  WORD *pwLogClust,
+  SCRIPT_CHARPROP *pCharProps,
+  WORD *pwOutGlyphs,
+  SCRIPT_GLYPHPROP *pOutGlyphProps,
+  int *pcGlyphs
+);
+
+typedef HRESULT (WINAPI *SPOT) /*ScriptPlaceOpenType*/(
+  HDC hdc,
+  SCRIPT_CACHE *psc,
+  SCRIPT_ANALYSIS *psa,
+  OPENTYPE_TAG tagScript,
+  OPENTYPE_TAG tagLangSys,
+  int *rcRangeChars,
+  TEXTRANGE_PROPERTIES **rpRangeProperties,
+  int cRanges,
+  const WCHAR *pwcChars,
+  WORD *pwLogClust,
+  SCRIPT_CHARPROP *pCharProps,
+  int cChars,
+  const WORD *pwGlyphs,
+  const SCRIPT_GLYPHPROP *pGlyphProps,
+  int cGlyphs,
+  int *piAdvance,
+  GOFFSET *pGoffset,
+  ABC *pABC
+);
+
+
+/* Fallback implementations. */
+
+static HRESULT WINAPI
+hb_ScriptItemizeOpenType(
+  const WCHAR *pwcInChars,
+  int cInChars,
+  int cMaxItems,
+  const SCRIPT_CONTROL *psControl,
+  const SCRIPT_STATE *psState,
+  SCRIPT_ITEM *pItems,
+  OPENTYPE_TAG *pScriptTags,
+  int *pcItems
+)
+{
+{
+  return ScriptItemize (pwcInChars,
+			cInChars,
+			cMaxItems,
+			psControl,
+			psState,
+			pItems,
+			pcItems);
+}
+}
+
+static HRESULT WINAPI
+hb_ScriptShapeOpenType(
+  HDC hdc,
+  SCRIPT_CACHE *psc,
+  SCRIPT_ANALYSIS *psa,
+  OPENTYPE_TAG tagScript,
+  OPENTYPE_TAG tagLangSys,
+  int *rcRangeChars,
+  TEXTRANGE_PROPERTIES **rpRangeProperties,
+  int cRanges,
+  const WCHAR *pwcChars,
+  int cChars,
+  int cMaxGlyphs,
+  WORD *pwLogClust,
+  SCRIPT_CHARPROP *pCharProps,
+  WORD *pwOutGlyphs,
+  SCRIPT_GLYPHPROP *pOutGlyphProps,
+  int *pcGlyphs
+)
+{
+  SCRIPT_VISATTR *psva = (SCRIPT_VISATTR *) pOutGlyphProps;
+  return ScriptShape (hdc,
+		      psc,
+		      pwcChars,
+		      cChars,
+		      cMaxGlyphs,
+		      psa,
+		      pwOutGlyphs,
+		      pwLogClust,
+		      psva,
+		      pcGlyphs);
+}
+
+static HRESULT WINAPI
+hb_ScriptPlaceOpenType(
+  HDC hdc,
+  SCRIPT_CACHE *psc,
+  SCRIPT_ANALYSIS *psa,
+  OPENTYPE_TAG tagScript,
+  OPENTYPE_TAG tagLangSys,
+  int *rcRangeChars,
+  TEXTRANGE_PROPERTIES **rpRangeProperties,
+  int cRanges,
+  const WCHAR *pwcChars,
+  WORD *pwLogClust,
+  SCRIPT_CHARPROP *pCharProps,
+  int cChars,
+  const WORD *pwGlyphs,
+  const SCRIPT_GLYPHPROP *pGlyphProps,
+  int cGlyphs,
+  int *piAdvance,
+  GOFFSET *pGoffset,
+  ABC *pABC
+)
+{
+  SCRIPT_VISATTR *psva = (SCRIPT_VISATTR *) pGlyphProps;
+  return ScriptPlace (hdc,
+		      psc,
+		      pwGlyphs,
+		      cGlyphs,
+		      psva,
+		      psa,
+		      piAdvance,
+		      pGoffset,
+		      pABC);
+}
+
+
+struct hb_uniscribe_shaper_funcs_t
+{
+  SIOT ScriptItemizeOpenType;
+  SSOT ScriptShapeOpenType;
+  SPOT ScriptPlaceOpenType;
+
+  void init ()
+  {
+    HMODULE hinstLib;
+    this->ScriptItemizeOpenType = nullptr;
+    this->ScriptShapeOpenType   = nullptr;
+    this->ScriptPlaceOpenType   = nullptr;
+
+    hinstLib = GetModuleHandle (TEXT ("usp10.dll"));
+    if (hinstLib)
+    {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-function-type"
+      this->ScriptItemizeOpenType = (SIOT) GetProcAddress (hinstLib, "ScriptItemizeOpenType");
+      this->ScriptShapeOpenType   = (SSOT) GetProcAddress (hinstLib, "ScriptShapeOpenType");
+      this->ScriptPlaceOpenType   = (SPOT) GetProcAddress (hinstLib, "ScriptPlaceOpenType");
+#pragma GCC diagnostic pop
+    }
+    if (!this->ScriptItemizeOpenType ||
+	!this->ScriptShapeOpenType   ||
+	!this->ScriptPlaceOpenType)
+    {
+      DEBUG_MSG (UNISCRIBE, nullptr, "OpenType versions of functions not found; falling back.");
+      this->ScriptItemizeOpenType = hb_ScriptItemizeOpenType;
+      this->ScriptShapeOpenType   = hb_ScriptShapeOpenType;
+      this->ScriptPlaceOpenType   = hb_ScriptPlaceOpenType;
+    }
+  }
+};
+
+static inline void free_static_uniscribe_shaper_funcs ();
+
+static struct hb_uniscribe_shaper_funcs_lazy_loader_t : hb_lazy_loader_t<hb_uniscribe_shaper_funcs_t,
+									 hb_uniscribe_shaper_funcs_lazy_loader_t>
+{
+  static hb_uniscribe_shaper_funcs_t *create ()
+  {
+    hb_uniscribe_shaper_funcs_t *funcs = (hb_uniscribe_shaper_funcs_t *) hb_calloc (1, sizeof (hb_uniscribe_shaper_funcs_t));
+    if (unlikely (!funcs))
+      return nullptr;
+
+    funcs->init ();
+
+    hb_atexit (free_static_uniscribe_shaper_funcs);
+
+    return funcs;
+  }
+  static void destroy (hb_uniscribe_shaper_funcs_t *p)
+  {
+    hb_free ((void *) p);
+  }
+  static hb_uniscribe_shaper_funcs_t *get_null ()
+  {
+    return nullptr;
+  }
+} static_uniscribe_shaper_funcs;
+
+static inline
+void free_static_uniscribe_shaper_funcs ()
+{
+  static_uniscribe_shaper_funcs.free_instance ();
+}
+
+static hb_uniscribe_shaper_funcs_t *
+hb_uniscribe_shaper_get_funcs ()
+{
+  return static_uniscribe_shaper_funcs.get_unconst ();
+}
+
+
+/*
+ * shaper face data
+ */
+
+struct hb_uniscribe_face_data_t {
+  HANDLE fh;
+  hb_uniscribe_shaper_funcs_t *funcs;
+  wchar_t face_name[LF_FACESIZE];
+};
+
+/* face_name should point to a wchar_t[LF_FACESIZE] object. */
+static void
+_hb_generate_unique_face_name (wchar_t *face_name, unsigned int *plen)
+{
+  /* We'll create a private name for the font from a UUID using a simple,
+   * somewhat base64-like encoding scheme */
+  const char *enc = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+-";
+  UUID id;
+  UuidCreate ((UUID*) &id);
+  static_assert ((2 + 3 * (16/2) < LF_FACESIZE), "");
+  unsigned int name_str_len = 0;
+  face_name[name_str_len++] = 'F';
+  face_name[name_str_len++] = '_';
+  unsigned char *p = (unsigned char *) &id;
+  for (unsigned int i = 0; i < 16; i += 2)
+  {
+    /* Spread the 16 bits from two bytes of the UUID across three chars of face_name,
+     * using the bits in groups of 5,5,6 to select chars from enc.
+     * This will generate 24 characters; with the 'F_' prefix we already provided,
+     * the name will be 26 chars (plus the NUL terminator), so will always fit within
+     * face_name (LF_FACESIZE = 32). */
+    face_name[name_str_len++] = enc[p[i] >> 3];
+    face_name[name_str_len++] = enc[((p[i] << 2) | (p[i + 1] >> 6)) & 0x1f];
+    face_name[name_str_len++] = enc[p[i + 1] & 0x3f];
+  }
+  face_name[name_str_len] = 0;
+  if (plen)
+    *plen = name_str_len;
+}
+
+/* Destroys blob. */
+static hb_blob_t *
+_hb_rename_font (hb_blob_t *blob, wchar_t *new_name)
+{
+  /* Create a copy of the font data, with the 'name' table replaced by a
+   * table that names the font with our private F_* name created above.
+   * For simplicity, we just append a new 'name' table and update the
+   * sfnt directory; the original table is left in place, but unused.
+   *
+   * The new table will contain just 5 name IDs: family, style, unique,
+   * full, PS. All of them point to the same name data with our unique name.
+   */
+
+  blob = hb_sanitize_context_t ().sanitize_blob<OT::OpenTypeFontFile> (blob);
+
+  unsigned int length, new_length, name_str_len;
+  const char *orig_sfnt_data = hb_blob_get_data (blob, &length);
+
+  _hb_generate_unique_face_name (new_name, &name_str_len);
+
+  static const uint16_t name_IDs[] = { 1, 2, 3, 4, 6 };
+
+  unsigned int name_table_length = OT::name::min_size +
+				   ARRAY_LENGTH (name_IDs) * OT::NameRecord::static_size +
+				   name_str_len * 2; /* for name data in UTF16BE form */
+  unsigned int padded_name_table_length = ((name_table_length + 3) & ~3);
+  unsigned int name_table_offset = (length + 3) & ~3;
+
+  new_length = name_table_offset + padded_name_table_length;
+  void *new_sfnt_data = hb_calloc (1, new_length);
+  if (!new_sfnt_data)
+  {
+    hb_blob_destroy (blob);
+    return nullptr;
+  }
+
+  hb_memcpy(new_sfnt_data, orig_sfnt_data, length);
+
+  OT::name &name = StructAtOffset<OT::name> (new_sfnt_data, name_table_offset);
+  name.format = 0;
+  name.count = ARRAY_LENGTH (name_IDs);
+  name.stringOffset = name.get_size ();
+  for (unsigned int i = 0; i < ARRAY_LENGTH (name_IDs); i++)
+  {
+    OT::NameRecord &record = name.nameRecordZ[i];
+    record.platformID = 3;
+    record.encodingID = 1;
+    record.languageID = 0x0409u; /* English */
+    record.nameID = name_IDs[i];
+    record.length = name_str_len * 2;
+    record.offset = 0;
+  }
+
+  /* Copy string data from new_name, converting wchar_t to UTF16BE. */
+  unsigned char *p = &StructAfter<unsigned char> (name);
+  for (unsigned int i = 0; i < name_str_len; i++)
+  {
+    *p++ = new_name[i] >> 8;
+    *p++ = new_name[i] & 0xff;
+  }
+
+  /* Adjust name table entry to point to new name table */
+  const OT::OpenTypeFontFile &file = * (OT::OpenTypeFontFile *) (new_sfnt_data);
+  unsigned int face_count = file.get_face_count ();
+  for (unsigned int face_index = 0; face_index < face_count; face_index++)
+  {
+    /* Note: doing multiple edits (ie. TTC) can be unsafe.  There may be
+     * toe-stepping.  But we don't really care. */
+    const OT::OpenTypeFontFace &face = file.get_face (face_index);
+    unsigned int index;
+    if (face.find_table_index (HB_OT_TAG_name, &index))
+    {
+      OT::TableRecord &record = const_cast<OT::TableRecord &> (face.get_table (index));
+      record.checkSum.set_for_data (&name, padded_name_table_length);
+      record.offset = name_table_offset;
+      record.length = name_table_length;
+    }
+    else if (face_index == 0) /* Fail if first face doesn't have 'name' table. */
+    {
+      hb_free (new_sfnt_data);
+      hb_blob_destroy (blob);
+      return nullptr;
+    }
+  }
+
+  /* The checkSumAdjustment field in the 'head' table is now wrong,
+   * but that doesn't actually seem to cause any problems so we don't
+   * bother. */
+
+  hb_blob_destroy (blob);
+  return hb_blob_create ((const char *) new_sfnt_data, new_length,
+			 HB_MEMORY_MODE_WRITABLE, new_sfnt_data, hb_free);
+}
+
+hb_uniscribe_face_data_t *
+_hb_uniscribe_shaper_face_data_create (hb_face_t *face)
+{
+  hb_uniscribe_face_data_t *data = (hb_uniscribe_face_data_t *) hb_calloc (1, sizeof (hb_uniscribe_face_data_t));
+  if (unlikely (!data))
+    return nullptr;
+
+  data->funcs = hb_uniscribe_shaper_get_funcs ();
+  if (unlikely (!data->funcs))
+  {
+    hb_free (data);
+    return nullptr;
+  }
+
+  hb_blob_t *blob = hb_face_reference_blob (face);
+  if (unlikely (!hb_blob_get_length (blob)))
+    DEBUG_MSG (UNISCRIBE, face, "Face has empty blob");
+
+  blob = _hb_rename_font (blob, data->face_name);
+  if (unlikely (!blob))
+  {
+    hb_free (data);
+    return nullptr;
+  }
+
+  DWORD num_fonts_installed;
+  data->fh = AddFontMemResourceEx ((void *) hb_blob_get_data (blob, nullptr),
+				   hb_blob_get_length (blob),
+				   0, &num_fonts_installed);
+  if (unlikely (!data->fh))
+  {
+    DEBUG_MSG (UNISCRIBE, face, "Face AddFontMemResourceEx() failed");
+    hb_free (data);
+    return nullptr;
+  }
+
+  return data;
+}
+
+void
+_hb_uniscribe_shaper_face_data_destroy (hb_uniscribe_face_data_t *data)
+{
+  RemoveFontMemResourceEx (data->fh);
+  hb_free (data);
+}
+
+
+/*
+ * shaper font data
+ */
+
+struct hb_uniscribe_font_data_t
+{
+  HDC hdc;
+  mutable LOGFONTW log_font;
+  HFONT hfont;
+  mutable SCRIPT_CACHE script_cache;
+  double x_mult, y_mult; /* From LOGFONT space to HB space. */
+};
+
+static bool
+populate_log_font (LOGFONTW  *lf,
+		   hb_font_t *font,
+		   unsigned int font_size)
+{
+  hb_memset (lf, 0, sizeof (*lf));
+  lf->lfHeight = - (int) font_size;
+  lf->lfCharSet = DEFAULT_CHARSET;
+
+  hb_memcpy (lf->lfFaceName, font->face->data.uniscribe->face_name, sizeof (lf->lfFaceName));
+
+  return true;
+}
+
+hb_uniscribe_font_data_t *
+_hb_uniscribe_shaper_font_data_create (hb_font_t *font)
+{
+  hb_uniscribe_font_data_t *data = (hb_uniscribe_font_data_t *) hb_calloc (1, sizeof (hb_uniscribe_font_data_t));
+  if (unlikely (!data))
+    return nullptr;
+
+  int font_size = font->face->get_upem (); /* Default... */
+  /* No idea if the following is even a good idea. */
+  if (font->y_ppem)
+    font_size = font->y_ppem;
+
+  if (font_size < 0)
+    font_size = -font_size;
+  data->x_mult = (double) font->x_scale / font_size;
+  data->y_mult = (double) font->y_scale / font_size;
+
+  data->hdc = GetDC (nullptr);
+
+  if (unlikely (!populate_log_font (&data->log_font, font, font_size))) {
+    DEBUG_MSG (UNISCRIBE, font, "Font populate_log_font() failed");
+    _hb_uniscribe_shaper_font_data_destroy (data);
+    return nullptr;
+  }
+
+  data->hfont = CreateFontIndirectW (&data->log_font);
+  if (unlikely (!data->hfont)) {
+    DEBUG_MSG (UNISCRIBE, font, "Font CreateFontIndirectW() failed");
+    _hb_uniscribe_shaper_font_data_destroy (data);
+     return nullptr;
+  }
+
+  if (!SelectObject (data->hdc, data->hfont)) {
+    DEBUG_MSG (UNISCRIBE, font, "Font SelectObject() failed");
+    _hb_uniscribe_shaper_font_data_destroy (data);
+     return nullptr;
+  }
+
+  return data;
+}
+
+void
+_hb_uniscribe_shaper_font_data_destroy (hb_uniscribe_font_data_t *data)
+{
+  if (data->hdc)
+    ReleaseDC (nullptr, data->hdc);
+  if (data->hfont)
+    DeleteObject (data->hfont);
+  if (data->script_cache)
+    ScriptFreeCache (&data->script_cache);
+  hb_free (data);
+}
+
+/**
+ * hb_uniscribe_font_get_logfontw:
+ * @font: The #hb_font_t to work upon
+ *
+ * Fetches the LOGFONTW structure that corresponds to the
+ * specified #hb_font_t font.
+ *
+ * Return value: a pointer to the LOGFONTW retrieved
+ *
+ **/
+LOGFONTW *
+hb_uniscribe_font_get_logfontw (hb_font_t *font)
+{
+  const hb_uniscribe_font_data_t *data =  font->data.uniscribe;
+  return data ? &data->log_font : nullptr;
+}
+
+/**
+ * hb_uniscribe_font_get_hfont:
+ * @font: The #hb_font_t to work upon
+ *
+ * Fetches the HFONT handle that corresponds to the
+ * specified #hb_font_t font.
+ *
+ * Return value: the HFONT retreieved
+ *
+ **/
+HFONT
+hb_uniscribe_font_get_hfont (hb_font_t *font)
+{
+  const hb_uniscribe_font_data_t *data =  font->data.uniscribe;
+  return data ? data->hfont : nullptr;
+}
+
+
+/*
+ * shaper
+ */
+
+
+hb_bool_t
+_hb_uniscribe_shape (hb_shape_plan_t    *shape_plan,
+		     hb_font_t          *font,
+		     hb_buffer_t        *buffer,
+		     const hb_feature_t *features,
+		     unsigned int        num_features)
+{
+  hb_face_t *face = font->face;
+  const hb_uniscribe_face_data_t *face_data = face->data.uniscribe;
+  const hb_uniscribe_font_data_t *font_data = font->data.uniscribe;
+  hb_uniscribe_shaper_funcs_t *funcs = face_data->funcs;
+
+#define FAIL(...) \
+  HB_STMT_START { \
+    DEBUG_MSG (UNISCRIBE, nullptr, __VA_ARGS__); \
+    return false; \
+  } HB_STMT_END
+
+  HRESULT hr;
+
+retry:
+
+  unsigned int scratch_size;
+  hb_buffer_t::scratch_buffer_t *scratch = buffer->get_scratch_buffer (&scratch_size);
+
+#define ALLOCATE_ARRAY(Type, name, len) \
+  Type *name = (Type *) scratch; \
+  do { \
+    unsigned int _consumed = DIV_CEIL ((len) * sizeof (Type), sizeof (*scratch)); \
+    assert (_consumed <= scratch_size); \
+    scratch += _consumed; \
+    scratch_size -= _consumed; \
+  } while (0)
+
+#define utf16_index() var1.u32
+
+  ALLOCATE_ARRAY (WCHAR, pchars, buffer->len * 2);
+
+  unsigned int chars_len = 0;
+  for (unsigned int i = 0; i < buffer->len; i++)
+  {
+    hb_codepoint_t c = buffer->info[i].codepoint;
+    buffer->info[i].utf16_index() = chars_len;
+    if (likely (c <= 0xFFFFu))
+      pchars[chars_len++] = c;
+    else if (unlikely (c > 0x10FFFFu))
+      pchars[chars_len++] = 0xFFFDu;
+    else {
+      pchars[chars_len++] = 0xD800u + ((c - 0x10000u) >> 10);
+      pchars[chars_len++] = 0xDC00u + ((c - 0x10000u) & ((1u << 10) - 1));
+    }
+  }
+
+  ALLOCATE_ARRAY (WORD, log_clusters, chars_len);
+  ALLOCATE_ARRAY (SCRIPT_CHARPROP, char_props, chars_len);
+
+  if (num_features)
+  {
+    /* Need log_clusters to assign features. */
+    chars_len = 0;
+    for (unsigned int i = 0; i < buffer->len; i++)
+    {
+      hb_codepoint_t c = buffer->info[i].codepoint;
+      unsigned int cluster = buffer->info[i].cluster;
+      log_clusters[chars_len++] = cluster;
+      if (hb_in_range (c, 0x10000u, 0x10FFFFu))
+	log_clusters[chars_len++] = cluster; /* Surrogates. */
+    }
+  }
+
+  /* The -2 in the following is to compensate for possible
+   * alignment needed after the WORD array.  sizeof(WORD) == 2. */
+  unsigned int glyphs_size = (scratch_size * sizeof (int) - 2)
+			   / (sizeof (WORD) +
+			      sizeof (SCRIPT_GLYPHPROP) +
+			      sizeof (int) +
+			      sizeof (GOFFSET) +
+			      sizeof (uint32_t));
+
+  ALLOCATE_ARRAY (WORD, glyphs, glyphs_size);
+  ALLOCATE_ARRAY (SCRIPT_GLYPHPROP, glyph_props, glyphs_size);
+  ALLOCATE_ARRAY (int, advances, glyphs_size);
+  ALLOCATE_ARRAY (GOFFSET, offsets, glyphs_size);
+  ALLOCATE_ARRAY (uint32_t, vis_clusters, glyphs_size);
+
+  /* Note:
+   * We can't touch the contents of glyph_props.  Our fallback
+   * implementations of Shape and Place functions use that buffer
+   * by casting it to a different type.  It works because they
+   * both agree about it, but if we want to access it here we
+   * need address that issue first.
+   */
+
+#undef ALLOCATE_ARRAY
+
+#define MAX_ITEMS 256
+
+  SCRIPT_ITEM items[MAX_ITEMS + 1];
+  SCRIPT_CONTROL bidi_control = {0};
+  SCRIPT_STATE bidi_state = {0};
+  ULONG script_tags[MAX_ITEMS];
+  int item_count;
+
+  /* MinGW32 doesn't define fMergeNeutralItems, so we bruteforce */
+  //bidi_control.fMergeNeutralItems = true;
+  *(uint32_t*)&bidi_control |= 1u<<24;
+
+  bidi_state.uBidiLevel = HB_DIRECTION_IS_FORWARD (buffer->props.direction) ? 0 : 1;
+  bidi_state.fOverrideDirection = 1;
+
+  hr = funcs->ScriptItemizeOpenType (pchars,
+				     chars_len,
+				     MAX_ITEMS,
+				     &bidi_control,
+				     &bidi_state,
+				     items,
+				     script_tags,
+				     &item_count);
+  if (unlikely (FAILED (hr)))
+    FAIL ("ScriptItemizeOpenType() failed: 0x%08lx", hr);
+
+#undef MAX_ITEMS
+
+  hb_tag_t lang_tag;
+  unsigned int lang_count = 1;
+  hb_ot_tags_from_script_and_language (buffer->props.script,
+				       buffer->props.language,
+				       nullptr, nullptr,
+				       &lang_count, &lang_tag);
+  OPENTYPE_TAG language_tag = hb_uint32_swap (lang_count ? lang_tag : HB_TAG_NONE);
+
+  /*
+   * Set up features.
+   */
+  static_assert ((sizeof (TEXTRANGE_PROPERTIES) == sizeof (hb_ms_features_t)), "");
+  static_assert ((sizeof (OPENTYPE_FEATURE_RECORD) == sizeof (hb_ms_feature_t)), "");
+  hb_vector_t<hb_ms_feature_t> feature_records;
+  hb_vector_t<hb_ms_range_record_t> range_records;
+  bool has_features = false;
+  if (num_features)
+    has_features = hb_ms_setup_features (features,
+					 num_features,
+					 feature_records,
+					 range_records);
+
+  hb_vector_t<hb_ms_features_t*> range_properties;
+  hb_vector_t<uint32_t> range_char_counts;
+
+  unsigned int glyphs_offset = 0;
+  unsigned int glyphs_len;
+  bool backward = HB_DIRECTION_IS_BACKWARD (buffer->props.direction);
+  for (int i = 0; i < item_count; i++)
+  {
+    unsigned int chars_offset = items[i].iCharPos;
+    unsigned int item_chars_len = items[i + 1].iCharPos - chars_offset;
+
+    if (has_features)
+      hb_ms_make_feature_ranges (feature_records,
+				 range_records,
+				 item_chars_len,
+				 chars_offset,
+				 log_clusters,
+				 range_properties,
+				 range_char_counts);
+
+    /* Asking for glyphs in logical order circumvents at least
+     * one bug in Uniscribe. */
+    items[i].a.fLogicalOrder = true;
+
+  retry_shape:
+    hr = funcs->ScriptShapeOpenType (font_data->hdc,
+				     &font_data->script_cache,
+				     &items[i].a,
+				     script_tags[i],
+				     language_tag,
+				     (int *) range_char_counts.arrayZ,
+				     (TEXTRANGE_PROPERTIES**) range_properties.arrayZ,
+				     range_properties.length,
+				     pchars + chars_offset,
+				     item_chars_len,
+				     glyphs_size - glyphs_offset,
+				     /* out */
+				     log_clusters + chars_offset,
+				     char_props + chars_offset,
+				     glyphs + glyphs_offset,
+				     glyph_props + glyphs_offset,
+				     (int *) &glyphs_len);
+
+    if (unlikely (items[i].a.fNoGlyphIndex))
+      FAIL ("ScriptShapeOpenType() set fNoGlyphIndex");
+    if (unlikely (hr == E_OUTOFMEMORY || hr == E_NOT_SUFFICIENT_BUFFER))
+    {
+      if (unlikely (!buffer->ensure (buffer->allocated * 2)))
+	FAIL ("Buffer resize failed");
+      goto retry;
+    }
+    if (unlikely (hr == USP_E_SCRIPT_NOT_IN_FONT))
+    {
+      if (items[i].a.eScript == SCRIPT_UNDEFINED)
+	FAIL ("ScriptShapeOpenType() failed: Font doesn't support script");
+      items[i].a.eScript = SCRIPT_UNDEFINED;
+      goto retry_shape;
+    }
+    if (unlikely (FAILED (hr)))
+    {
+      FAIL ("ScriptShapeOpenType() failed: 0x%08lx", hr);
+    }
+
+    for (unsigned int j = chars_offset; j < chars_offset + item_chars_len; j++)
+      log_clusters[j] += glyphs_offset;
+
+    hr = funcs->ScriptPlaceOpenType (font_data->hdc,
+				     &font_data->script_cache,
+				     &items[i].a,
+				     script_tags[i],
+				     language_tag,
+				     (int *) range_char_counts.arrayZ,
+				     (TEXTRANGE_PROPERTIES**) range_properties.arrayZ,
+				     range_properties.length,
+				     pchars + chars_offset,
+				     log_clusters + chars_offset,
+				     char_props + chars_offset,
+				     item_chars_len,
+				     glyphs + glyphs_offset,
+				     glyph_props + glyphs_offset,
+				     glyphs_len,
+				     /* out */
+				     advances + glyphs_offset,
+				     offsets + glyphs_offset,
+				     nullptr);
+    if (unlikely (FAILED (hr)))
+      FAIL ("ScriptPlaceOpenType() failed: 0x%08lx", hr);
+
+    if (DEBUG_ENABLED (UNISCRIBE))
+      fprintf (stderr, "Item %d RTL %d LayoutRTL %d LogicalOrder %d ScriptTag %c%c%c%c\n",
+	       i,
+	       items[i].a.fRTL,
+	       items[i].a.fLayoutRTL,
+	       items[i].a.fLogicalOrder,
+	       HB_UNTAG (hb_uint32_swap (script_tags[i])));
+
+    glyphs_offset += glyphs_len;
+  }
+  glyphs_len = glyphs_offset;
+
+  /* Ok, we've got everything we need, now compose output buffer,
+   * very, *very*, carefully! */
+
+  /* Calculate visual-clusters.  That's what we ship. */
+  for (unsigned int i = 0; i < glyphs_len; i++)
+    vis_clusters[i] = (uint32_t) -1;
+  for (unsigned int i = 0; i < buffer->len; i++) {
+    uint32_t *p = &vis_clusters[log_clusters[buffer->info[i].utf16_index()]];
+    *p = hb_min (*p, buffer->info[i].cluster);
+  }
+  for (unsigned int i = 1; i < glyphs_len; i++)
+    if (vis_clusters[i] == (uint32_t) -1)
+      vis_clusters[i] = vis_clusters[i - 1];
+
+#undef utf16_index
+
+  if (unlikely (!buffer->ensure (glyphs_len)))
+    FAIL ("Buffer in error");
+
+#undef FAIL
+
+  /* Set glyph infos */
+  buffer->len = 0;
+  for (unsigned int i = 0; i < glyphs_len; i++)
+  {
+    hb_glyph_info_t *info = &buffer->info[buffer->len++];
+
+    info->codepoint = glyphs[i];
+    info->cluster = vis_clusters[i];
+
+    /* The rest is crap.  Let's store position info there for now. */
+    info->mask = advances[i];
+    info->var1.i32 = offsets[i].du;
+    info->var2.i32 = offsets[i].dv;
+  }
+
+  /* Set glyph positions */
+  buffer->clear_positions ();
+  double x_mult = font_data->x_mult, y_mult = font_data->y_mult;
+  for (unsigned int i = 0; i < glyphs_len; i++)
+  {
+    hb_glyph_info_t *info = &buffer->info[i];
+    hb_glyph_position_t *pos = &buffer->pos[i];
+
+    /* TODO vertical */
+    pos->x_advance = x_mult * (int32_t) info->mask;
+    pos->x_offset = x_mult * (backward ? -info->var1.i32 : info->var1.i32);
+    pos->y_offset = y_mult * info->var2.i32;
+  }
+
+  if (backward)
+    hb_buffer_reverse (buffer);
+
+  buffer->clear_glyph_flags ();
+  buffer->unsafe_to_break ();
+
+  /* Wow, done! */
+  return true;
+}
+
+
+#endif