Added some foreachSubRange

src/libs/services/database/include/services/database/Types.hpp

@@ -41,6 +41,23 @@ namespace Database
         operator bool() const { return size != 0; }
     };
 
+    // Func must return true to continue iterating
+    template <typename Func>
+    void foreachSubRange(Range range, std::size_t subRangeSize, Func&& func)
+    {
+        assert(subRangeSize > 0);
+
+        Range subRange{ range.offset, std::min(range.size, subRangeSize) };
+        while (subRange.size > 0)
+        {
+            if (!func(subRange))
+                break;
+
+            subRange.offset += subRange.size;
+            subRange.size = std::min(subRangeSize, range.size - (subRange.offset - range.offset));
+        }
+    }
+
     template <typename T>
     struct RangeResults
     {

src/libs/services/database/test/Common.cpp

@@ -124,6 +124,44 @@ TEST_F(DatabaseFixture, Common_subRangeEmpty)
     }
 }
 
+TEST_F(DatabaseFixture, Common_subRangeForeach)
+{
+    using namespace Database;
+
+    struct TestCase
+    {
+        Range range;
+        std::size_t subRangeSize;
+        std::vector<Range> expectedSubRanges;
+    };
+
+    TestCase testCases[]
+    {
+        {Range{0, 0},     1,   {}},
+        {Range{1, 0},     1,   {}},
+        {Range{1, 1},     1,   { Range{ 1,1 } }},
+        {Range{1, 3},     1,   { Range{ 1,1 }, Range {2,1}, Range{3,1} }},
+        {Range{0, 100},   100, { Range{0,100} }},
+        {Range{0, 50},    100, { Range{0,50} }},
+        {Range{100, 200}, 100, { Range{100,100}, Range{200,100} }},
+        {Range{100, 101}, 100, { Range{100,100}, Range{200,1}}},
+        {Range{1000, 10}, 100, { Range{1000,10} }},
+        {Range{1, 100}, 50, { Range{1,50}, Range{51, 50} }},
+    };
+
+    for (const TestCase& test : testCases)
+    {
+        std::vector<Range> subRanges;
+        foreachSubRange(test.range, test.subRangeSize, [&](Range subRange)
+        {
+            subRanges.push_back(subRange);
+            return true;
+        });
+
+        EXPECT_EQ(subRanges, test.expectedSubRanges) << ", test index = " << std::distance(std::cbegin(testCases), &test);
+    }
+}
+
 TEST_F(DatabaseFixture, Common_IdType)
 {
     using namespace Database;