From 73e259d6e7270ac3f0cff1197a711268113b3cfa Mon Sep 17 00:00:00 2001
From: WerWolv <werwolv98@gmail.com>
Date: Mon, 11 Jan 2021 00:27:00 +0100
Subject: [PATCH] Added engineering display mode to calculator

---
 plugins/libimhex/include/helpers/utils.hpp | 18 ++++++++++++++++++
 source/views/view_tools.cpp                | 12 +++++++++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/plugins/libimhex/include/helpers/utils.hpp b/plugins/libimhex/include/helpers/utils.hpp
index 9259ec107..ae6b8b944 100644
--- a/plugins/libimhex/include/helpers/utils.hpp
+++ b/plugins/libimhex/include/helpers/utils.hpp
@@ -158,6 +158,24 @@ namespace hex {
         return T(1) << bit_width(T(x - 1));
     }
 
+    std::string toEngineeringString(double value) {
+        constexpr std::array prefixes = { "a", "f", "p", "n", "u", "m", "", "k", "M", "G", "T", "P", "E" };
+
+        int8_t prefixIndex = 6;
+
+        while (prefixIndex != 0 && prefixIndex != 12 && (value >= 1000 || value < 1) && value != 0) {
+            if (value >= 1000) {
+                value /= 1000;
+                prefixIndex++;
+            } else if (value < 1) {
+                value *= 1000;
+                prefixIndex--;
+            }
+        }
+
+        return std::to_string(value).substr(0, 5) + prefixes[prefixIndex];
+    }
+
     std::vector<u8> readFile(std::string_view path);
 
     #define SCOPE_EXIT(func) ScopeExit TOKEN_CONCAT(scopeGuard, __COUNTER__)([&] { func })
diff --git a/source/views/view_tools.cpp b/source/views/view_tools.cpp
index 2c1d52a8b..cf2c0e298 100644
--- a/source/views/view_tools.cpp
+++ b/source/views/view_tools.cpp
@@ -195,7 +195,7 @@ namespace hex {
             else
                 ImGui::NewLine();
 
-            enum class MathDisplayType { Standard, Scientific, Programmer } mathDisplayType;
+            enum class MathDisplayType { Standard, Scientific, Engineering, Programmer } mathDisplayType;
             if (ImGui::BeginTabBar("##mathFormatTabBar")) {
                 if (ImGui::BeginTabItem("Standard")) {
                     mathDisplayType = MathDisplayType::Standard;
@@ -205,6 +205,10 @@ namespace hex {
                     mathDisplayType = MathDisplayType::Scientific;
                     ImGui::EndTabItem();
                 }
+                if (ImGui::BeginTabItem("Engineering")) {
+                    mathDisplayType = MathDisplayType::Engineering;
+                    ImGui::EndTabItem();
+                }
                 if (ImGui::BeginTabItem("Programmer")) {
                     mathDisplayType = MathDisplayType::Programmer;
                     ImGui::EndTabItem();
@@ -242,6 +246,9 @@ namespace hex {
                                 case MathDisplayType::Scientific:
                                     ImGui::Text("%.6Le", this->m_mathHistory[(this->m_mathHistory.size() - 1) - i]);
                                     break;
+                                case MathDisplayType::Engineering:
+                                    ImGui::Text("%s", hex::toEngineeringString(this->m_mathHistory[(this->m_mathHistory.size() - 1) - i]).c_str());
+                                    break;
                                 case MathDisplayType::Programmer:
                                     ImGui::Text("0x%llX (%llu)",
                                                 u64(this->m_mathHistory[(this->m_mathHistory.size() - 1) - i]),
@@ -279,6 +286,9 @@ namespace hex {
                             case MathDisplayType::Scientific:
                                 ImGui::Text("%.6Le", value);
                                 break;
+                            case MathDisplayType::Engineering:
+                                ImGui::Text("%s", hex::toEngineeringString(value).c_str());
+                                break;
                             case MathDisplayType::Programmer:
                                 ImGui::Text("0x%llX (%llu)", u64(value),  u64(value));
                                 break;