From 3d5794ed7cdf9fea8c8baaa8a6bb6cf377e5b7e7 Mon Sep 17 00:00:00 2001
From: fallenoak <git@fallenoak.me>
Date: Fri, 25 Sep 2020 16:50:56 -0500
Subject: [PATCH] feat(array): add growable array template

---
 storm/Array.hpp                 |   1 +
 storm/array/TSGrowableArray.hpp | 141 ++++++++++++++++++++++++++++++++
 test/Array.cpp                  |   7 ++
 3 files changed, 149 insertions(+)
 create mode 100644 storm/array/TSGrowableArray.hpp

diff --git a/storm/Array.hpp b/storm/Array.hpp
index 12b966c..535de1e 100644
--- a/storm/Array.hpp
+++ b/storm/Array.hpp
@@ -3,5 +3,6 @@
 
 #include "array/TSBaseArray.hpp"
 #include "array/TSFixedArray.hpp"
+#include "array/TSGrowableArray.hpp"
 
 #endif
diff --git a/storm/array/TSGrowableArray.hpp b/storm/array/TSGrowableArray.hpp
new file mode 100644
index 0000000..196fbcb
--- /dev/null
+++ b/storm/array/TSGrowableArray.hpp
@@ -0,0 +1,141 @@
+#ifndef STORM_ARRAY_TS_GROWABLE_ARRAY_HPP
+#define STORM_ARRAY_TS_GROWABLE_ARRAY_HPP
+
+#include "array/TSFixedArray.hpp"
+#include <algorithm>
+#include <cstdint>
+#include <cstring>
+#include <new>
+
+template<class T>
+class TSGrowableArray : public TSFixedArray<T> {
+    public:
+    uint32_t m_chunk = 0;
+
+    uint32_t Add(uint32_t count, const T* data);
+    uint32_t Add(uint32_t count, uint32_t incr, const T* data);
+    uint32_t CalcChunkSize(uint32_t count);
+    void GrowToFit(uint32_t index, int32_t zero);
+    T* New(void);
+    void Reserve(uint32_t count, int32_t round);
+    uint32_t RoundToChunk(uint32_t count, uint32_t chunk);
+    void SetCount(uint32_t count);
+};
+
+template<class T>
+uint32_t TSGrowableArray<T>::Add(uint32_t count, const T* data) {
+    this->Reserve(count, 1);
+
+    for (int32_t i = 0; i < count; i++) {
+        T* element = &this->m_data[this->m_count + i];
+        *element = data[i];
+    }
+
+    this->m_count += count;
+    return this->m_count - count;
+}
+
+template<class T>
+uint32_t TSGrowableArray<T>::Add(uint32_t count, uint32_t incr, const T* data) {
+    this->Reserve(count, 1);
+
+    const char* dataptr = reinterpret_cast<const char*>(data);
+
+    for (int32_t i = 0; i < count; i++) {
+        T* element = &this->m_data[this->m_count + i];
+        *element = *reinterpret_cast<const T*>(dataptr);
+        dataptr += incr;
+    }
+
+    this->m_count += count;
+    return this->m_count - count;
+}
+
+template<class T>
+uint32_t TSGrowableArray<T>::CalcChunkSize(uint32_t count) {
+    uint32_t maxChunk = std::max(static_cast<int32_t>(256 / sizeof(T)), 8);
+
+    if (count >= maxChunk) {
+        this->m_chunk = maxChunk;
+        return maxChunk;
+    }
+
+    uint32_t result = count;
+
+    for (uint32_t i = count & (count - 1); i; i &= i - 1) {
+        result = i;
+    }
+
+    if (result < 1) {
+        result = 1;
+    }
+
+    return result;
+}
+
+template<class T>
+void TSGrowableArray<T>::GrowToFit(uint32_t index, int32_t zero) {
+    uint32_t count = this->m_count;
+
+    if (index >= count) {
+        this->Reserve(index - count + 1, 1);
+
+        if (zero) {
+            memset(&this->m_data[count], 0, sizeof(T) * (index - count + 1));
+        }
+
+        this->m_count = index + 1;
+    }
+}
+
+template<class T>
+T* TSGrowableArray<T>::New() {
+    this->Reserve(1, 1);
+    void* element = &this->m_data[this->m_count++];
+    return new (element) T();
+}
+
+template<class T>
+void TSGrowableArray<T>::Reserve(uint32_t count, int32_t round) {
+    if (count + this->m_count > this->m_alloc) {
+        if (round) {
+            uint32_t chunk = this->m_chunk;
+
+            if (!chunk) {
+                chunk = this->CalcChunkSize(count + this->m_count);
+            }
+
+            count = this->RoundToChunk(count, chunk);
+        }
+
+        this->ReallocData(count + this->m_count);
+    }
+}
+
+template<class T>
+uint32_t TSGrowableArray<T>::RoundToChunk(uint32_t count, uint32_t chunk) {
+    if (count % chunk) {
+        return chunk - count % chunk + count;
+    } else {
+        return count;
+    }
+}
+
+template<class T>
+void TSGrowableArray<T>::SetCount(uint32_t count) {
+    if (count > this->m_count) {
+        // Expand size
+        this->Reserve(count - this->m_count, 1);
+
+        T* element;
+
+        for (int32_t i = this->m_count; i < count; ++i) {
+            element = &this->m_data[i];
+            new (element) T();
+        }
+    }
+
+    this->m_count = count;
+}
+
+#endif
diff --git a/test/Array.cpp b/test/Array.cpp
index 0a65a56..9d3e8f4 100644
--- a/test/Array.cpp
+++ b/test/Array.cpp
@@ -14,3 +14,10 @@ TEST_CASE("TSFixedArray", "[list]") {
         REQUIRE(array.Count() == 0);
     }
 }
+
+TEST_CASE("TSGrowableArray", "[list]") {
+    SECTION("constructs correctly") {
+        TSGrowableArray<uint32_t> array;
+        REQUIRE(array.Count() == 0);
+    }
+}