From eaec2bf0a1ef54d1b20a79bd8772a162b155529a Mon Sep 17 00:00:00 2001
From: Luigi Scarso <luigi.scarso@gmail.com>
Date: Sat, 15 Mar 2025 22:24:19 +0100
Subject: [PATCH] Added missed files.
---
.../harfbuzz/harfbuzz-src/src/hb-decycler.hh | 164 ++++++++++++++++++
.../harfbuzz-src/src/test-decycler.cc | 116 +++++++++++++
.../libpng-src/contrib/conftest/fixed.dfa | 15 ++
.../contrib/conftest/float-fixed.dfa | 14 ++
.../contrib/conftest/nocompile-limits.dfa | 21 +++
.../libpng-src/contrib/conftest/nolimits.dfa | 19 ++
6 files changed, 349 insertions(+)
create mode 100644 source/libs/harfbuzz/harfbuzz-src/src/hb-decycler.hh
create mode 100644 source/libs/harfbuzz/harfbuzz-src/src/test-decycler.cc
create mode 100644 source/libs/libpng/libpng-src/contrib/conftest/fixed.dfa
create mode 100644 source/libs/libpng/libpng-src/contrib/conftest/float-fixed.dfa
create mode 100644 source/libs/libpng/libpng-src/contrib/conftest/nocompile-limits.dfa
create mode 100644 source/libs/libpng/libpng-src/contrib/conftest/nolimits.dfa
diff --git a/source/libs/harfbuzz/harfbuzz-src/src/hb-decycler.hh b/source/libs/harfbuzz/harfbuzz-src/src/hb-decycler.hh
new file mode 100644
index 000000000..95b961027
--- /dev/null
+++ b/source/libs/harfbuzz/harfbuzz-src/src/hb-decycler.hh
@@ -0,0 +1,164 @@
+/*
+ * Copyright © 2025 Behdad Esfahbod
+ *
+ * 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): Behdad Esfahbod
+ */
+
+#ifndef HB_DECYCLER_HH
+#define HB_DECYCLER_HH
+
+#include "hb.hh"
+
+/*
+ * hb_decycler_t is an efficient cycle detector for graph traversal.
+ * It's a simple tortoise-and-hare algorithm with a twist: it's
+ * designed to detect cycles while traversing a graph in a DFS manner,
+ * instead of just a linked list.
+ *
+ * For Floyd's tortoise and hare algorithm, see:
+ * https://en.wikipedia.org/wiki/Cycle_detection#Floyd's_tortoise_and_hare
+ *
+ * hb_decycler_t is O(n) in the number of nodes in the DFS traversal
+ * if there are no cycles. Unlike Floyd's algorithm, hb_decycler_t
+ * can be used in a DFS traversal, where the graph is not a simple
+ * linked list, but a tree with possible cycles. Like Floyd's algorithm,
+ * it is constant-memory (~three pointers).
+ *
+ * The decycler works by creating an implicit linked-list on the stack,
+ * of the path from the root to the current node, and apply Floyd's
+ * algorithm on that list as it goes.
+ *
+ * The decycler is malloc-free, and as such, much faster to use than a
+ * hb_set_t or hb_map_t equivalent.
+ *
+ * The decycler detects cycles in the graph *eventually*, not *immediately*.
+ * That is, it may not detect a cycle until the cycle is fully traversed,
+ * even multiple times. See Floyd's algorithm analysis for details.
+ *
+ * The implementation saves a pointer storage on the stack by combining
+ * this->u.decycler and this->u.next into a union. This is possible because
+ * at any point we only need one of those values. The invariant is that
+ * after construction, and before destruction, of a node, the u.decycler
+ * field is always valid. The u.next field is only valid when the node is
+ * in the traversal path, parent to another node.
+ *
+ * There are three method's:
+ *
+ * - hb_decycler_node_t() constructor: Creates a new node in the traversal.
+ * The constructor takes a reference to the decycler object and inserts
+ * itself as the latest node in the traversal path, by advancing the hare
+ * pointer, and for every other descent, advancing the tortoise pointer.
+ *
+ * - ~hb_decycler_node_t() destructor: Restores the decycler object to its
+ * previous state by removing the node from the traversal path.
+ *
+ * - bool visit(uintptr_t value): Called on every node in the graph. Returns
+ * true if the node is not part of a cycle, and false if it is. The value
+ * parameter is used to detect cycles. It's the caller's responsibility
+ * to ensure that the value is unique for each node in the graph.
+ * The cycle detection is as simple as comparing the value to the value
+ * held by the tortoise pointer, which is the Floyd's algorithm.
+ *
+ * For usage examples see test-decycler.cc.
+ */
+
+struct hb_decycler_node_t;
+
+struct hb_decycler_t
+{
+ friend struct hb_decycler_node_t;
+
+ private:
+ bool tortoise_awake = false;
+ hb_decycler_node_t *tortoise = nullptr;
+ hb_decycler_node_t *hare = nullptr;
+};
+
+struct hb_decycler_node_t
+{
+ hb_decycler_node_t (hb_decycler_t &decycler)
+ {
+ u.decycler = &decycler;
+
+ decycler.tortoise_awake = !decycler.tortoise_awake;
+
+ if (!decycler.tortoise)
+ {
+ // First node.
+ assert (decycler.tortoise_awake);
+ assert (!decycler.hare);
+ decycler.tortoise = decycler.hare = this;
+ return;
+ }
+
+ if (decycler.tortoise_awake)
+ decycler.tortoise = decycler.tortoise->u.next; // Time to move.
+
+ this->prev = decycler.hare;
+ decycler.hare->u.next = this;
+ decycler.hare = this;
+ }
+
+ ~hb_decycler_node_t ()
+ {
+ hb_decycler_t &decycler = *u.decycler;
+
+ // Inverse of the constructor.
+
+ assert (decycler.hare == this);
+ decycler.hare = prev;
+ if (prev)
+ prev->u.decycler = &decycler;
+
+ assert (decycler.tortoise);
+ if (decycler.tortoise_awake)
+ decycler.tortoise = decycler.tortoise->prev;
+
+ decycler.tortoise_awake = !decycler.tortoise_awake;
+ }
+
+ bool visit (uintptr_t value_)
+ {
+ value = value_;
+
+ hb_decycler_t &decycler = *u.decycler;
+
+ if (decycler.tortoise == this)
+ return true; // First node; not a cycle.
+
+ if (decycler.tortoise->value == value)
+ return false; // Cycle detected.
+
+ return true;
+ }
+
+ private:
+ union {
+ hb_decycler_t *decycler;
+ hb_decycler_node_t *next;
+ } u = {nullptr};
+ hb_decycler_node_t *prev = nullptr;
+ uintptr_t value = 0;
+};
+
+#endif /* HB_DECYCLER_HH */
diff --git a/source/libs/harfbuzz/harfbuzz-src/src/test-decycler.cc b/source/libs/harfbuzz/harfbuzz-src/src/test-decycler.cc
new file mode 100644
index 000000000..dbe0f24f2
--- /dev/null
+++ b/source/libs/harfbuzz/harfbuzz-src/src/test-decycler.cc
@@ -0,0 +1,116 @@
+/*
+ * Copyright © 2025 Behdad Esfahbod
+ *
+ * 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): Behdad Esfahbod
+ */
+
+#include "hb.hh"
+#include "hb-decycler.hh"
+
+static void
+tree_recurse_binary (unsigned value,
+ unsigned max_value,
+ hb_decycler_t &decycler)
+{
+ if (value >= max_value)
+ return;
+
+ hb_decycler_node_t node (decycler);
+
+ bool ret = node.visit (value);
+ assert (ret);
+
+ tree_recurse_binary (value * 2 + 1, max_value, decycler);
+ tree_recurse_binary (value * 2 + 2, max_value, decycler);
+}
+
+static void
+tree_recurse_tertiary (unsigned value,
+ unsigned max_value,
+ hb_decycler_t &decycler)
+{
+ /* This function implements an alternative way to use the
+ * decycler. It checks for each node before visiting it.
+ * It demonstrates reusing a node for multiple visits. */
+
+ if (value >= max_value)
+ return;
+
+ hb_decycler_node_t node (decycler);
+
+ value *= 3;
+
+ for (unsigned i = 1; i <= 3; i++)
+ {
+ bool ret = node.visit (value + i);
+ assert (ret);
+
+ tree_recurse_tertiary (value + i, max_value, decycler);
+ }
+}
+
+static void
+test_tree ()
+{
+ hb_decycler_t decycler;
+ tree_recurse_binary (0, 64, decycler);
+ tree_recurse_tertiary (0, 1000, decycler);
+}
+
+static void
+cycle_recurse (signed value,
+ signed cycle_length,
+ hb_decycler_t &decycler)
+{
+ assert (cycle_length > 0);
+
+ hb_decycler_node_t node (decycler);
+
+ if (!node.visit (value))
+ return;
+
+ if (value >= cycle_length)
+ value = value % cycle_length;
+
+ cycle_recurse (value + 1, cycle_length, decycler);
+}
+
+static void
+test_cycle ()
+{
+ hb_decycler_t decycler;
+ cycle_recurse (0, 1, decycler);
+ cycle_recurse (0, 2, decycler);
+ cycle_recurse (2, 3, decycler);
+ cycle_recurse (-20, 8, decycler);
+}
+
+int
+main (int argc, char **argv)
+{
+ test_tree ();
+ test_cycle ();
+
+ return 0;
+}
+
diff --git a/source/libs/libpng/libpng-src/contrib/conftest/fixed.dfa b/source/libs/libpng/libpng-src/contrib/conftest/fixed.dfa
new file mode 100644
index 000000000..cb45f0136
--- /dev/null
+++ b/source/libs/libpng/libpng-src/contrib/conftest/fixed.dfa
@@ -0,0 +1,15 @@
+# fixed.dfa
+# Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2025
+# Usage rights:
+# To the extent possible under law, the author has waived all copyright and
+# related or neighboring rights to this work. This work is published from:
+# United States.
+#
+# Test the standard libpng configuration without floating point (the internal
+# fixed point implementations are used instead).
+#
+option FLOATING_ARITHMETIC off
+option FLOATING_POINT off
diff --git a/source/libs/libpng/libpng-src/contrib/conftest/float-fixed.dfa b/source/libs/libpng/libpng-src/contrib/conftest/float-fixed.dfa
new file mode 100644
index 000000000..c13da3198
--- /dev/null
+++ b/source/libs/libpng/libpng-src/contrib/conftest/float-fixed.dfa
@@ -0,0 +1,14 @@
+# fixed-float.dfa
+# Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2025
+# Usage rights:
+# To the extent possible under law, the author has waived all copyright and
+# related or neighboring rights to this work. This work is published from:
+# United States.
+#
+# Test the standard libpng configuration with the fixed point internal
+# implementation in place of the default floating point
+#
+option FLOATING_ARITHMETIC off
diff --git a/source/libs/libpng/libpng-src/contrib/conftest/nocompile-limits.dfa b/source/libs/libpng/libpng-src/contrib/conftest/nocompile-limits.dfa
new file mode 100644
index 000000000..24e1e2e08
--- /dev/null
+++ b/source/libs/libpng/libpng-src/contrib/conftest/nocompile-limits.dfa
@@ -0,0 +1,21 @@
+# nolimits.dfa
+# Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2025
+#
+# Usage rights:
+# To the extent possible under law, the author has waived all copyright and
+# related or neighboring rights to this work. This work is published from:
+# United States.
+#
+# Build libpng without any limits and without run-time settable limits. Turning
+# USER_LIMITS off reduces libpng code size by allowing compile-time elimination
+# of some checking code.
+#
+option USER_LIMITS off
+
+@# define PNG_USER_WIDTH_MAX PNG_UINT_31_MAX
+@# define PNG_USER_HEIGHT_MAX PNG_UINT_31_MAX
+@# define PNG_USER_CHUNK_CACHE_MAX 0
+@# define PNG_USER_CHUNK_MALLOC_MAX 0
diff --git a/source/libs/libpng/libpng-src/contrib/conftest/nolimits.dfa b/source/libs/libpng/libpng-src/contrib/conftest/nolimits.dfa
new file mode 100644
index 000000000..5b37fcf72
--- /dev/null
+++ b/source/libs/libpng/libpng-src/contrib/conftest/nolimits.dfa
@@ -0,0 +1,19 @@
+# nolimits.dfa
+# Build time configuration of libpng
+#
+# Author: John Bowler
+# Copyright: (c) John Bowler, 2025
+#
+# Usage rights:
+# To the extent possible under law, the author has waived all copyright and
+# related or neighboring rights to this work. This work is published from:
+# United States.
+#
+# Build libpng without any limits. With these settigs run-time limits are still
+# possible.
+#
+@# define PNG_USER_WIDTH_MAX PNG_UINT_31_MAX
+@# define PNG_USER_HEIGHT_MAX PNG_UINT_31_MAX
+@# define PNG_USER_CHUNK_CACHE_MAX 0
+@# define PNG_USER_CHUNK_MALLOC_MAX 0
+
--
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