Improve TContiguouseData interface

improve TContiguousData interface

3 files changed, 44 insertions, 12 deletions

diff --git a/library/cpp/actors/util/contiguous_data.h b/library/cpp/actors/util/contiguous_data.h
index 382b19f82c..d7123ca457 100644
--- a/library/cpp/actors/util/contiguous_data.h
+++ b/library/cpp/actors/util/contiguous_data.h
@@ -882,6 +882,16 @@ public:
         }
     }
 
+    static TContiguousData Copy(TContiguousSpan data, size_t headroom = 0, size_t tailroom = 0) {
+        TContiguousData res = Uninitialized(data.size(), headroom, tailroom);
+        std::memcpy(res.UnsafeGetDataMut(), data.GetData(), data.GetSize());
+        return res;
+    }
+
+    static TContiguousData Copy(const char* data, size_t size, size_t headroom = 0, size_t tailroom = 0) {
+        return Copy({data, size}, headroom, tailroom);
+    }
+
     static NActors::TSharedData UninitializedSharedData(size_t size) {
         return NActors::TSharedData::AttachUnsafe(TBackend::TSharedDataControllingOwner::Allocate(size), size);
     }
@@ -1062,10 +1072,18 @@ public:
         }
     }
 
-    void Trim(size_t size, size_t frontOffset = 0) {
-        Y_VERIFY(size <= End - Begin - frontOffset);
-        Begin = Begin + frontOffset;
-        End = Begin + size;
+    void TrimBack(size_t size) {
+        Y_VERIFY(size <= GetSize());
+        End = End - (GetSize() - size);
+    }
+
+    void TrimFront(size_t size) {
+        Y_VERIFY(size <= GetSize());
+        Begin = Begin + (GetSize() - size);
+    }
+
+    char* Detach() {
+        return GetDataMut();
     }
 
     size_t UnsafeHeadroom() const {
diff --git a/library/cpp/actors/util/contiguous_data_ut.cpp b/library/cpp/actors/util/contiguous_data_ut.cpp
index b7b9029f85..6452e748b8 100644
--- a/library/cpp/actors/util/contiguous_data_ut.cpp
+++ b/library/cpp/actors/util/contiguous_data_ut.cpp
@@ -50,6 +50,16 @@ Y_UNIT_TEST_SUITE(TContiguousData) {
             constSharedData);
     }
 
+    Y_UNIT_TEST(Detach) {
+        TContiguousData data = TContiguousData::Copy(TString("test"));
+        TContiguousData data2 = data;
+        char* res = data2.Detach();
+        UNIT_ASSERT_UNEQUAL(data.GetData(), data2.GetData());
+        UNIT_ASSERT_EQUAL(res, data2.GetData());
+        UNIT_ASSERT_EQUAL(::memcmp(res, "test", 4), 0);
+        UNIT_ASSERT_EQUAL(::memcmp(data.GetData(), "test", 4), 0);
+    }
+
     Y_UNIT_TEST(Resize) {
         TContiguousData data = TContiguousData::Uninitialized(10, 20, 30);
         UNIT_ASSERT_EQUAL(data.size(), 10);
@@ -108,7 +118,8 @@ Y_UNIT_TEST_SUITE(TContiguousData) {
         UNIT_ASSERT_EQUAL(otherData.Headroom(), 15);
         UNIT_ASSERT_EQUAL(otherData.Tailroom(), 30);
         UNIT_ASSERT_EQUAL(otherData.GetOccupiedMemorySize(), 60);
-        data.Trim(10, 5);
+        data.TrimBack(15);
+        data.TrimFront(10);
         UNIT_ASSERT_EQUAL(data.size(), 10);
         UNIT_ASSERT_EQUAL(data.Headroom(), 20);
         UNIT_ASSERT_EQUAL(data.Tailroom(), 30);
@@ -118,16 +129,18 @@ Y_UNIT_TEST_SUITE(TContiguousData) {
     Y_UNIT_TEST(Trim) {
         TContiguousData data = TContiguousData::Uninitialized(10, 20, 30);
         TContiguousData otherData(data);
-        otherData.Trim(5);
+        otherData.TrimBack(5);
         UNIT_ASSERT_EQUAL(data.data(), otherData.data());
         UNIT_ASSERT_EQUAL(otherData.Headroom(), 20);
         UNIT_ASSERT_EQUAL(otherData.Tailroom(), 0);
         TContiguousData otherData2(data);
-        otherData2.Trim(1, 1);
+        otherData2.TrimBack(2);
+        otherData2.TrimFront(1);
         UNIT_ASSERT_EQUAL(data.data() + 1, otherData2.data());
         UNIT_ASSERT_EQUAL(otherData2.Headroom(), 0);
         UNIT_ASSERT_EQUAL(otherData2.Tailroom(), 0);
-        otherData.Trim(1, 1);
+        otherData.TrimBack(2);
+        otherData.TrimFront(1);
         UNIT_ASSERT_EQUAL(otherData.data(), otherData2.data());
         data.GrowFront(5);
         data.GrowBack(5);
@@ -139,7 +152,7 @@ Y_UNIT_TEST_SUITE(TContiguousData) {
         UNIT_ASSERT_UNEQUAL(data.data() + 6, otherData2.data());
         data = TContiguousData::Uninitialized(10);
         otherData = data;
-        data.Trim(5);
+        data.TrimBack(5);
         UNIT_ASSERT_EQUAL(data.data(), otherData.data());
         UNIT_ASSERT_EQUAL(data.size(), 5);
     }
diff --git a/ydb/core/erasure/erasure.cpp b/ydb/core/erasure/erasure.cpp
index a97e264cd0..e0174a7e1e 100644
--- a/ydb/core/erasure/erasure.cpp
+++ b/ydb/core/erasure/erasure.cpp
@@ -2562,7 +2562,7 @@ void MirrorRestore(TErasureType::ECrcMode crcMode, const TErasureType &type, TDa
                             TContiguousData newOutBuffer(outBuffer);
                             Y_VERIFY(outBuffer.size() >= partSet.FullDataSize, "Unexpected outBuffer.size# %" PRIu64
                                     " fullDataSize# %" PRIu64, (ui64)outBuffer.size(), (ui64)partSet.FullDataSize);
-                            newOutBuffer.Trim(partSet.FullDataSize); // To pad with zeroes!
+                            newOutBuffer.TrimBack(partSet.FullDataSize); // To pad with zeroes!
                             outBuffer = TRope(newOutBuffer);
                         }
                         partSet.FullDataFragment.ReferenceTo(outBuffer);
@@ -2688,7 +2688,8 @@ void EoBlockSplitDiff(TErasureType::ECrcMode crcMode, const TErasureType &type,
                 Y_VERIFY_S(diffShift + bufferSize <= diff.Buffer.size(), "diffShift# " << diffShift
                         << " bufferSize# " << bufferSize << " diff.GetDiffLength()# " << diff.GetDiffLength());
                 TContiguousData newBuffer(diff.Buffer);
-                newBuffer.Trim(bufferSize, diffShift);
+                newBuffer.TrimBack(bufferSize + diffShift);
+                newBuffer.TrimFront(bufferSize);
                 part.Diffs.emplace_back(newBuffer, 0, false, true);
 
                 if (diffEnd <= nextOffset) {
@@ -2714,7 +2715,7 @@ void EoBlockSplitDiff(TErasureType::ECrcMode crcMode, const TErasureType &type,
                 ui32 bufferSize = nextOffset - diff.Offset + lineOffset;
                 TContiguousData newBuffer = diff.Buffer;
                 newBuffer.GrowFront(lineOffset); // FIXME(innokentii) should the [0..lineOffset) be zeroed?
-                newBuffer.Trim(bufferSize);
+                newBuffer.TrimBack(bufferSize);
                 Y_VERIFY(bufferSize);
                 part.Diffs.emplace_back(newBuffer, diff.Offset - partOffset, false, true);
                 break;