test/api/test-glyph-names.c - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2023 Red Hat, 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.
  *
  * Author(s): Matthias Clasen
  */

 #include "hb-test.h"

 static void
 test_glyph_names_post (void)
 {
   hb_face_t *face;
   hb_font_t *font;
   hb_bool_t ret;
   char name [64];

   face = hb_test_open_font_file ("fonts/adwaita.ttf");
   font = hb_font_create (face);

   ret = hb_font_get_glyph_name (font, 0, name, 64);
   g_assert_true (ret);
   g_assert_cmpstr (name, ==, ".notdef");

   ret = hb_font_get_glyph_name (font, 1, name, 64);
   g_assert_true (ret);
   g_assert_cmpstr (name, ==, ".space");

   ret = hb_font_get_glyph_name (font, 2, name, 64);
   g_assert_true (ret);
   g_assert_cmpstr (name, ==, "icon0");

   ret = hb_font_get_glyph_name (font, 3, name, 64);
   g_assert_true (ret);
   g_assert_cmpstr (name, ==, "icon0.0");

   ret = hb_font_get_glyph_name (font, 4, name, 64);
   g_assert_true (ret);
   g_assert_cmpstr (name, ==, "icon0.1");

   ret = hb_font_get_glyph_name (font, 5, name, 64);
   g_assert_true (ret);
   g_assert_cmpstr (name, ==, "icon0.2");

   /* beyond last glyph */
   ret = hb_font_get_glyph_name (font, 100, name, 64);
   g_assert_false (ret);

   hb_font_destroy (font);
   hb_face_destroy (face);
 }

 static void
 test_glyph_names_cff (void)
 {
   hb_face_t *face;
   hb_font_t *font;
   hb_bool_t ret;
   char name [64];

   face = hb_test_open_font_file ("fonts/SourceSansPro-Regular.otf");
   font = hb_font_create (face);

   ret = hb_font_get_glyph_name (font, 0, name, 64);
   g_assert_true (ret);
   g_assert_cmpstr (name, ==, ".notdef");

   ret = hb_font_get_glyph_name (font, 1, name, 64);
   g_assert_true (ret);
   g_assert_cmpstr (name, ==, "space");

   ret = hb_font_get_glyph_name (font, 2, name, 64);
   g_assert_true (ret);
   g_assert_cmpstr (name, ==, "A");

   /* beyond last glyph */
   ret = hb_font_get_glyph_name (font, 2000, name, 64);
   g_assert_false (ret);

   hb_font_destroy (font);
   hb_face_destroy (face);
 }

 /* Regression tests for issue #5946: hb_font_get_glyph_name (..., size=0)
  * must not underflow and write past a zero-capacity buffer, while preserving
  * the long-standing "return value only" probe behavior. */

 static void
 test_glyph_names_zero_size (void)
 {
   hb_face_t *face;
   hb_font_t *font;
   char guard[4] = { 0x7f, 0x7f, 0x7f, 0x7f };

   face = hb_test_open_font_file ("fonts/adwaita.ttf");
   font = hb_font_create (face);

   /* size == 0 must not write to the buffer. */
   g_assert_true (hb_font_get_glyph_name (font, 1, guard, 0));
   g_assert_cmpint (guard[0], ==, 0x7f);
   g_assert_cmpint (guard[1], ==, 0x7f);
   g_assert_cmpint (guard[2], ==, 0x7f);
   g_assert_cmpint (guard[3], ==, 0x7f);

   hb_font_destroy (font);
   hb_face_destroy (face);
 }

 static void
 test_glyph_names_zero_size_post (void)
 {
   hb_face_t *face;
   hb_font_t *font;
   hb_bool_t ret;
   char guard[8] = { 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f };
   unsigned int i;

   face = hb_test_open_font_file ("fonts/adwaita.ttf");
   font = hb_font_create (face);

   /* Named glyph, size == 0: keep the old return-value-only probe behavior
    * and leave the buffer untouched. */
   ret = hb_font_get_glyph_name (font, 1, guard, 0);
   g_assert_true (ret);
   for (i = 0; i < 8; i++)
     g_assert_cmpint (guard[i], ==, 0x7f);

   /* .notdef, size == 0: same invariant. Confirms it is not glyph-specific. */
   ret = hb_font_get_glyph_name (font, 0, guard, 0);
   g_assert_true (ret);
   for (i = 0; i < 8; i++)
     g_assert_cmpint (guard[i], ==, 0x7f);

   /* Perform a successful sized lookup first, then retry with size == 0.
    * Confirms no residual state corrupts the zero-size path. */
   {
     char name[64];
     ret = hb_font_get_glyph_name (font, 2, name, 64);
     g_assert_true (ret);
     g_assert_cmpstr (name, ==, "icon0");
   }
   ret = hb_font_get_glyph_name (font, 2, guard, 0);
   g_assert_true (ret);
   for (i = 0; i < 8; i++)
     g_assert_cmpint (guard[i], ==, 0x7f);

   hb_font_destroy (font);
   hb_face_destroy (face);
 }

 static void
 test_glyph_names_zero_size_cff (void)
 {
   hb_face_t *face;
   hb_font_t *font;
   hb_bool_t ret;
   char guard[8] = { 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f };
   unsigned int i;

   face = hb_test_open_font_file ("fonts/SourceSansPro-Regular.otf");
   font = hb_font_create (face);

   /* CFF-backed named glyph, size == 0: preserve the return-value-only probe
    * behavior without writing into the buffer. */
   ret = hb_font_get_glyph_name (font, 2, guard, 0);
   g_assert_true (ret);
   for (i = 0; i < 8; i++)
     g_assert_cmpint (guard[i], ==, 0x7f);

   /* .notdef on CFF. */
   ret = hb_font_get_glyph_name (font, 0, guard, 0);
   g_assert_true (ret);
   for (i = 0; i < 8; i++)
     g_assert_cmpint (guard[i], ==, 0x7f);

   hb_font_destroy (font);
   hb_face_destroy (face);
 }

 static void
 test_glyph_names_zero_size_unnamed_glyph (void)
 {
   /* size == 0 on a glyph beyond the font's range must also return false
    * and must not write. */
   hb_face_t *face;
   hb_font_t *font;
   hb_bool_t ret;
   char guard[4] = { 0x7f, 0x7f, 0x7f, 0x7f };
   unsigned int i;

   face = hb_test_open_font_file ("fonts/adwaita.ttf");
   font = hb_font_create (face);

   ret = hb_font_get_glyph_name (font, 100, guard, 0);
   g_assert_false (ret);
   for (i = 0; i < 4; i++)
     g_assert_cmpint (guard[i], ==, 0x7f);

   hb_font_destroy (font);
   hb_face_destroy (face);
 }

 static void
 test_glyph_names_zero_size_null_buffer (void)
 {
   /* name == NULL with size == 0 is a valid return-value-only probe. */
   hb_face_t *face;
   hb_font_t *font;
   hb_bool_t ret;

   face = hb_test_open_font_file ("fonts/adwaita.ttf");
   font = hb_font_create (face);

   /* Glyph with a name. */
   ret = hb_font_get_glyph_name (font, 1, NULL, 0);
   g_assert_true (ret);

   /* Glyph beyond the font's range. */
   ret = hb_font_get_glyph_name (font, 100, NULL, 0);
   g_assert_false (ret);

   hb_font_destroy (font);
   hb_face_destroy (face);
 }

 static void
 test_glyph_names_size_one (void)
 {
   /* Boundary: size == 1. The backend must produce exactly a trailing NUL
    * at name[0] (len = min(|name|, size-1) = 0 bytes of name copied) and
    * must not touch any byte past name[0]. */
   hb_face_t *face;
   hb_font_t *font;
   hb_bool_t ret;
   char buf[4] = { 0x7f, 0x7f, 0x7f, 0x7f };

   face = hb_test_open_font_file ("fonts/adwaita.ttf");
   font = hb_font_create (face);

   ret = hb_font_get_glyph_name (font, 1, buf, 1);
   g_assert_true (ret);
   g_assert_cmpint (buf[0], ==, 0);
   /* Bytes beyond the caller-declared capacity must remain intact. */
   g_assert_cmpint (buf[1], ==, 0x7f);
   g_assert_cmpint (buf[2], ==, 0x7f);
   g_assert_cmpint (buf[3], ==, 0x7f);

   hb_font_destroy (font);
   hb_face_destroy (face);
 }

 static void
 test_glyph_names_small_buffer_truncation (void)
 {
   /* Non-regression sanity: a small-but-nonzero buffer must truncate to
    * size-1 bytes of the name plus a trailing NUL. */
   hb_face_t *face;
   hb_font_t *font;
   hb_bool_t ret;
   char buf[4] = { 0x7f, 0x7f, 0x7f, 0x7f };

   face = hb_test_open_font_file ("fonts/adwaita.ttf");
   font = hb_font_create (face);

   /* ".notdef" truncated to capacity 4 -> ".no\0". */
   ret = hb_font_get_glyph_name (font, 0, buf, 4);
   g_assert_true (ret);
   g_assert_cmpint (buf[0], ==, '.');
   g_assert_cmpint (buf[1], ==, 'n');
   g_assert_cmpint (buf[2], ==, 'o');
   g_assert_cmpint (buf[3], ==, 0);

   hb_font_destroy (font);
   hb_face_destroy (face);
 }

 static void
 test_glyph_names_exact_fit_buffer (void)
 {
   /* Non-regression sanity: a buffer exactly sized to fit the full name
    * (including the trailing NUL) must hold the full name. For ".notdef"
    * that is 8 bytes. */
   hb_face_t *face;
   hb_font_t *font;
   hb_bool_t ret;
   char buf[8] = { 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f };

   face = hb_test_open_font_file ("fonts/adwaita.ttf");
   font = hb_font_create (face);

   ret = hb_font_get_glyph_name (font, 0, buf, 8);
   g_assert_true (ret);
   g_assert_cmpstr (buf, ==, ".notdef");
   g_assert_cmpint (buf[7], ==, 0);

   hb_font_destroy (font);
   hb_face_destroy (face);
 }

 static void
 test_glyph_names_nonzero_sizes_unchanged (void)
 {
   /* Non-regression sanity: the existing behaviour at typical sizes must
    * be preserved by the fix. */
   hb_face_t *face;
   hb_font_t *font;
   hb_bool_t ret;
   char name[64];

   face = hb_test_open_font_file ("fonts/adwaita.ttf");
   font = hb_font_create (face);

   ret = hb_font_get_glyph_name (font, 0, name, 64);
   g_assert_true (ret);
   g_assert_cmpstr (name, ==, ".notdef");

   ret = hb_font_get_glyph_name (font, 1, name, 64);
   g_assert_true (ret);
   g_assert_cmpstr (name, ==, ".space");

   /* Beyond last glyph still returns false. */
   ret = hb_font_get_glyph_name (font, 100, name, 64);
   g_assert_false (ret);

   hb_font_destroy (font);
   hb_face_destroy (face);
 }

 static void
 test_glyph_names_zero_size_sub_font (void)
 {
   /* Sub-fonts delegate to the parent's glyph-name funcs. Preserve the
    * return-value-only probe behavior through the parent chain as well. */
   hb_face_t *face;
   hb_font_t *parent;
   hb_font_t *font;
   hb_bool_t ret;
   char guard[4] = { 0x7f, 0x7f, 0x7f, 0x7f };
   unsigned int i;

   face = hb_test_open_font_file ("fonts/adwaita.ttf");
   parent = hb_font_create (face);
   font = hb_font_create_sub_font (parent);

   ret = hb_font_get_glyph_name (font, 1, guard, 0);
   g_assert_true (ret);
   for (i = 0; i < 4; i++)
     g_assert_cmpint (guard[i], ==, 0x7f);

   hb_font_destroy (font);
   hb_font_destroy (parent);
   hb_face_destroy (face);
 }

 int
 main (int argc, char **argv)
 {
   hb_test_init (&argc, &argv);

   hb_test_add (test_glyph_names_post);
   hb_test_add (test_glyph_names_cff);
   hb_test_add (test_glyph_names_zero_size);
   hb_test_add (test_glyph_names_zero_size_post);
   hb_test_add (test_glyph_names_zero_size_cff);
   hb_test_add (test_glyph_names_zero_size_unnamed_glyph);
   hb_test_add (test_glyph_names_zero_size_null_buffer);
   hb_test_add (test_glyph_names_size_one);
   hb_test_add (test_glyph_names_small_buffer_truncation);
   hb_test_add (test_glyph_names_exact_fit_buffer);
   hb_test_add (test_glyph_names_nonzero_sizes_unchanged);
   hb_test_add (test_glyph_names_zero_size_sub_font);

   return hb_test_run();
 }
	/*
	* Copyright © 2023 Red Hat, 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.
	*
	* Author(s): Matthias Clasen
	*/

	#include "hb-test.h"

	static void
	test_glyph_names_post (void)
	{
	hb_face_t *face;
	hb_font_t *font;
	hb_bool_t ret;
	char name [64];

	face = hb_test_open_font_file ("fonts/adwaita.ttf");
	font = hb_font_create (face);

	ret = hb_font_get_glyph_name (font, 0, name, 64);
	g_assert_true (ret);
	g_assert_cmpstr (name, ==, ".notdef");

	ret = hb_font_get_glyph_name (font, 1, name, 64);
	g_assert_true (ret);
	g_assert_cmpstr (name, ==, ".space");

	ret = hb_font_get_glyph_name (font, 2, name, 64);
	g_assert_true (ret);
	g_assert_cmpstr (name, ==, "icon0");

	ret = hb_font_get_glyph_name (font, 3, name, 64);
	g_assert_true (ret);
	g_assert_cmpstr (name, ==, "icon0.0");

	ret = hb_font_get_glyph_name (font, 4, name, 64);
	g_assert_true (ret);
	g_assert_cmpstr (name, ==, "icon0.1");

	ret = hb_font_get_glyph_name (font, 5, name, 64);
	g_assert_true (ret);
	g_assert_cmpstr (name, ==, "icon0.2");

	/* beyond last glyph */
	ret = hb_font_get_glyph_name (font, 100, name, 64);
	g_assert_false (ret);

	hb_font_destroy (font);
	hb_face_destroy (face);
	}

	static void
	test_glyph_names_cff (void)
	{
	hb_face_t *face;
	hb_font_t *font;
	hb_bool_t ret;
	char name [64];

	face = hb_test_open_font_file ("fonts/SourceSansPro-Regular.otf");
	font = hb_font_create (face);

	ret = hb_font_get_glyph_name (font, 0, name, 64);
	g_assert_true (ret);
	g_assert_cmpstr (name, ==, ".notdef");

	ret = hb_font_get_glyph_name (font, 1, name, 64);
	g_assert_true (ret);
	g_assert_cmpstr (name, ==, "space");

	ret = hb_font_get_glyph_name (font, 2, name, 64);
	g_assert_true (ret);
	g_assert_cmpstr (name, ==, "A");

	/* beyond last glyph */
	ret = hb_font_get_glyph_name (font, 2000, name, 64);
	g_assert_false (ret);

	hb_font_destroy (font);
	hb_face_destroy (face);
	}

	/* Regression tests for issue #5946: hb_font_get_glyph_name (..., size=0)
	* must not underflow and write past a zero-capacity buffer, while preserving
	* the long-standing "return value only" probe behavior. */

	static void
	test_glyph_names_zero_size (void)
	{
	hb_face_t *face;
	hb_font_t *font;
	char guard[4] = { 0x7f, 0x7f, 0x7f, 0x7f };

	face = hb_test_open_font_file ("fonts/adwaita.ttf");
	font = hb_font_create (face);

	/* size == 0 must not write to the buffer. */
	g_assert_true (hb_font_get_glyph_name (font, 1, guard, 0));
	g_assert_cmpint (guard[0], ==, 0x7f);
	g_assert_cmpint (guard[1], ==, 0x7f);
	g_assert_cmpint (guard[2], ==, 0x7f);
	g_assert_cmpint (guard[3], ==, 0x7f);

	hb_font_destroy (font);
	hb_face_destroy (face);
	}

	static void
	test_glyph_names_zero_size_post (void)
	{
	hb_face_t *face;
	hb_font_t *font;
	hb_bool_t ret;
	char guard[8] = { 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f };
	unsigned int i;

	face = hb_test_open_font_file ("fonts/adwaita.ttf");
	font = hb_font_create (face);

	/* Named glyph, size == 0: keep the old return-value-only probe behavior
	* and leave the buffer untouched. */
	ret = hb_font_get_glyph_name (font, 1, guard, 0);
	g_assert_true (ret);
	for (i = 0; i < 8; i++)
	g_assert_cmpint (guard[i], ==, 0x7f);

	/* .notdef, size == 0: same invariant. Confirms it is not glyph-specific. */
	ret = hb_font_get_glyph_name (font, 0, guard, 0);
	g_assert_true (ret);
	for (i = 0; i < 8; i++)
	g_assert_cmpint (guard[i], ==, 0x7f);

	/* Perform a successful sized lookup first, then retry with size == 0.
	* Confirms no residual state corrupts the zero-size path. */
	{
	char name[64];
	ret = hb_font_get_glyph_name (font, 2, name, 64);
	g_assert_true (ret);
	g_assert_cmpstr (name, ==, "icon0");
	}
	ret = hb_font_get_glyph_name (font, 2, guard, 0);
	g_assert_true (ret);
	for (i = 0; i < 8; i++)
	g_assert_cmpint (guard[i], ==, 0x7f);

	hb_font_destroy (font);
	hb_face_destroy (face);
	}

	static void
	test_glyph_names_zero_size_cff (void)
	{
	hb_face_t *face;
	hb_font_t *font;
	hb_bool_t ret;
	char guard[8] = { 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f };
	unsigned int i;

	face = hb_test_open_font_file ("fonts/SourceSansPro-Regular.otf");
	font = hb_font_create (face);

	/* CFF-backed named glyph, size == 0: preserve the return-value-only probe
	* behavior without writing into the buffer. */
	ret = hb_font_get_glyph_name (font, 2, guard, 0);
	g_assert_true (ret);
	for (i = 0; i < 8; i++)
	g_assert_cmpint (guard[i], ==, 0x7f);

	/* .notdef on CFF. */
	ret = hb_font_get_glyph_name (font, 0, guard, 0);
	g_assert_true (ret);
	for (i = 0; i < 8; i++)
	g_assert_cmpint (guard[i], ==, 0x7f);

	hb_font_destroy (font);
	hb_face_destroy (face);
	}

	static void
	test_glyph_names_zero_size_unnamed_glyph (void)
	{
	/* size == 0 on a glyph beyond the font's range must also return false
	* and must not write. */
	hb_face_t *face;
	hb_font_t *font;
	hb_bool_t ret;
	char guard[4] = { 0x7f, 0x7f, 0x7f, 0x7f };
	unsigned int i;

	face = hb_test_open_font_file ("fonts/adwaita.ttf");
	font = hb_font_create (face);

	ret = hb_font_get_glyph_name (font, 100, guard, 0);
	g_assert_false (ret);
	for (i = 0; i < 4; i++)
	g_assert_cmpint (guard[i], ==, 0x7f);

	hb_font_destroy (font);
	hb_face_destroy (face);
	}

	static void
	test_glyph_names_zero_size_null_buffer (void)
	{
	/* name == NULL with size == 0 is a valid return-value-only probe. */
	hb_face_t *face;
	hb_font_t *font;
	hb_bool_t ret;

	face = hb_test_open_font_file ("fonts/adwaita.ttf");
	font = hb_font_create (face);

	/* Glyph with a name. */
	ret = hb_font_get_glyph_name (font, 1, NULL, 0);
	g_assert_true (ret);

	/* Glyph beyond the font's range. */
	ret = hb_font_get_glyph_name (font, 100, NULL, 0);
	g_assert_false (ret);

	hb_font_destroy (font);
	hb_face_destroy (face);
	}

	static void
	test_glyph_names_size_one (void)
	{
	/* Boundary: size == 1. The backend must produce exactly a trailing NUL
	* at name[0] (len = min(\|name\|, size-1) = 0 bytes of name copied) and
	* must not touch any byte past name[0]. */
	hb_face_t *face;
	hb_font_t *font;
	hb_bool_t ret;
	char buf[4] = { 0x7f, 0x7f, 0x7f, 0x7f };

	face = hb_test_open_font_file ("fonts/adwaita.ttf");
	font = hb_font_create (face);

	ret = hb_font_get_glyph_name (font, 1, buf, 1);
	g_assert_true (ret);
	g_assert_cmpint (buf[0], ==, 0);
	/* Bytes beyond the caller-declared capacity must remain intact. */
	g_assert_cmpint (buf[1], ==, 0x7f);
	g_assert_cmpint (buf[2], ==, 0x7f);
	g_assert_cmpint (buf[3], ==, 0x7f);

	hb_font_destroy (font);
	hb_face_destroy (face);
	}

	static void
	test_glyph_names_small_buffer_truncation (void)
	{
	/* Non-regression sanity: a small-but-nonzero buffer must truncate to
	* size-1 bytes of the name plus a trailing NUL. */
	hb_face_t *face;
	hb_font_t *font;
	hb_bool_t ret;
	char buf[4] = { 0x7f, 0x7f, 0x7f, 0x7f };

	face = hb_test_open_font_file ("fonts/adwaita.ttf");
	font = hb_font_create (face);

	/* ".notdef" truncated to capacity 4 -> ".no\0". */
	ret = hb_font_get_glyph_name (font, 0, buf, 4);
	g_assert_true (ret);
	g_assert_cmpint (buf[0], ==, '.');
	g_assert_cmpint (buf[1], ==, 'n');
	g_assert_cmpint (buf[2], ==, 'o');
	g_assert_cmpint (buf[3], ==, 0);

	hb_font_destroy (font);
	hb_face_destroy (face);
	}

	static void
	test_glyph_names_exact_fit_buffer (void)
	{
	/* Non-regression sanity: a buffer exactly sized to fit the full name
	* (including the trailing NUL) must hold the full name. For ".notdef"
	* that is 8 bytes. */
	hb_face_t *face;
	hb_font_t *font;
	hb_bool_t ret;
	char buf[8] = { 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f, 0x7f };

	face = hb_test_open_font_file ("fonts/adwaita.ttf");
	font = hb_font_create (face);

	ret = hb_font_get_glyph_name (font, 0, buf, 8);
	g_assert_true (ret);
	g_assert_cmpstr (buf, ==, ".notdef");
	g_assert_cmpint (buf[7], ==, 0);

	hb_font_destroy (font);
	hb_face_destroy (face);
	}

	static void
	test_glyph_names_nonzero_sizes_unchanged (void)
	{
	/* Non-regression sanity: the existing behaviour at typical sizes must
	* be preserved by the fix. */
	hb_face_t *face;
	hb_font_t *font;
	hb_bool_t ret;
	char name[64];

	face = hb_test_open_font_file ("fonts/adwaita.ttf");
	font = hb_font_create (face);

	ret = hb_font_get_glyph_name (font, 0, name, 64);
	g_assert_true (ret);
	g_assert_cmpstr (name, ==, ".notdef");

	ret = hb_font_get_glyph_name (font, 1, name, 64);
	g_assert_true (ret);
	g_assert_cmpstr (name, ==, ".space");

	/* Beyond last glyph still returns false. */
	ret = hb_font_get_glyph_name (font, 100, name, 64);
	g_assert_false (ret);

	hb_font_destroy (font);
	hb_face_destroy (face);
	}

	static void
	test_glyph_names_zero_size_sub_font (void)
	{
	/* Sub-fonts delegate to the parent's glyph-name funcs. Preserve the
	* return-value-only probe behavior through the parent chain as well. */
	hb_face_t *face;
	hb_font_t *parent;
	hb_font_t *font;
	hb_bool_t ret;
	char guard[4] = { 0x7f, 0x7f, 0x7f, 0x7f };
	unsigned int i;

	face = hb_test_open_font_file ("fonts/adwaita.ttf");
	parent = hb_font_create (face);
	font = hb_font_create_sub_font (parent);

	ret = hb_font_get_glyph_name (font, 1, guard, 0);
	g_assert_true (ret);
	for (i = 0; i < 4; i++)
	g_assert_cmpint (guard[i], ==, 0x7f);

	hb_font_destroy (font);
	hb_font_destroy (parent);
	hb_face_destroy (face);
	}

	int
	main (int argc, char **argv)
	{
	hb_test_init (&argc, &argv);

	hb_test_add (test_glyph_names_post);
	hb_test_add (test_glyph_names_cff);
	hb_test_add (test_glyph_names_zero_size);
	hb_test_add (test_glyph_names_zero_size_post);
	hb_test_add (test_glyph_names_zero_size_cff);
	hb_test_add (test_glyph_names_zero_size_unnamed_glyph);
	hb_test_add (test_glyph_names_zero_size_null_buffer);
	hb_test_add (test_glyph_names_size_one);
	hb_test_add (test_glyph_names_small_buffer_truncation);
	hb_test_add (test_glyph_names_exact_fit_buffer);
	hb_test_add (test_glyph_names_nonzero_sizes_unchanged);
	hb_test_add (test_glyph_names_zero_size_sub_font);

	return hb_test_run();
	}