math: Add SimpleStack ...

1 files changed, 115 insertions, 0 deletions

diff --git a/include/jau/math/util/sstack.hpp b/include/jau/math/util/sstack.hpp
new file mode 100644
index 0000000..a36df49
--- /dev/null
+++ b/include/jau/math/util/sstack.hpp
@@ -0,0 +1,115 @@
+/*
+ * Author: Sven Gothel <[email protected]>
+ * Copyright (c) 2014-2024 Gothel Software e.K.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef JAU_SSTACK_HPP_
+#define JAU_SSTACK_HPP_
+
+#include <cmath>
+#include <cstdarg>
+#include <cstdint>
+#include <cassert>
+#include <limits>
+#include <vector>
+#include <type_traits>
+#include <algorithm>
+
+#include <jau/cpp_lang_util.hpp>
+
+namespace jau::math::util {
+
+    /** \addtogroup Math
+     *
+     *  @{
+     */
+
+    /**
+     * A simple stack of compounds, each consisting of `element_size` * `T`
+     * @tparam T type of one element used in each compound
+     * @tparam element_size number of T elements making up one compound
+     */
+    template<typename Value_type, size_t Element_size,
+             std::enable_if_t<std::is_floating_point_v<Value_type> ||
+                              std::is_integral_v<Value_type>,
+                              bool> = true>
+    class SimpleStack {
+        public:
+            typedef Value_type  value_type;
+            constexpr static const size_t element_size = Element_size;
+
+        private:
+            int growSize;
+            std::vector<Value_type> buffer;
+
+        public:
+            /**
+             * Start w/ zero size and growSize is 16, half GL-min size (32)
+             */
+            constexpr_cxx20 SimpleStack() noexcept
+            : growSize(16*element_size), buffer(0) {}
+
+            /**
+             * @param initialSize initial size
+             * @param growSize grow size if {@link #position()} is reached, maybe <code>0</code>
+             */
+            constexpr_cxx20 SimpleStack(int initialSize, int growSize_) noexcept
+            : growSize(growSize_), buffer(initialSize) {}
+
+            constexpr_cxx20 size_t growIfNecessary(int length) noexcept {
+                const size_t p = buffer.size();
+                const size_t nsz = buffer.size() + length;
+                if( nsz > buffer.capacity() ) {
+                    buffer.reserve(buffer.size() + std::max(length, growSize));
+                }
+                buffer.resize(nsz);
+                return p;
+            }
+
+            constexpr_cxx20 void push(const Value_type* src) noexcept {
+                size_t p = growIfNecessary(element_size);
+                for(size_t i=0; i<element_size; ++i) {
+                    buffer[p+i] = src[i];
+                }
+            }
+
+            constexpr_cxx20 void pop(Value_type* dest) noexcept {
+                const size_t sz = buffer.size();
+                assert( sz >= element_size );
+                const size_t p = sz - element_size;
+                for(size_t i=0; i<element_size; ++i) {
+                    dest[i] = buffer[p+i];
+                }
+                buffer.resize(p);
+            }
+    };
+
+    /**
+     * 4x4 float matrix stack
+     */
+    typedef SimpleStack<float, 16 /* Element_size */> Stack16f;
+
+
+    /**@}*/
+
+} // namespace jau::math
+
+#endif // JAU_SSTACK_HPP_