Merge bfa7c6020f into b6106883da

- Fixed range-based `opSlice(...)`

View (unittests)

- Added unittest

source/niknaks/config.d

@@ -345,7 +345,6 @@ public struct ConfigEntry
         {
             return numeric();
         }
-        
         else static if(__traits(isSame, T, string[]))
         {
             return array();

source/niknaks/containers.d

@@ -597,4 +597,354 @@ unittest
 
     // Destroy the map (such that it ends the sweeper
     destroy(map);
+}
+
+private struct Sector(T)
+{
+    private T[] data;
+
+    this(T[] data)
+    {
+        this.data = data;
+    }
+
+    public T opIndex(size_t idx)
+    {
+        return this.data[idx];
+    }
+
+    public void opIndexAssign(T value, size_t index)
+    {
+        this.data[index] = value;
+    }
+
+    // Contract: Obtaining the length must be present
+    public size_t opDollar()
+    {
+        return this.data.length;
+    }
+
+    // Contract: Obtaining the length must be present
+    @property
+    public size_t length()
+    {
+        return opDollar();
+    }
+
+    public T[] opSlice(size_t start, size_t end)
+    {
+        return this.data[start..end];
+    }
+
+    public T[] opSlice()
+    {
+        return opSlice(0, opDollar);
+    }
+
+    // Contract: Rezising must be implemented
+    // TODO: This would then be the very reason for
+    // using ref actually, as resizing may only
+    // change a local copy when extding on
+    // the tail-end "extent" (SectorType)
+
+    // Actually should resizing even be done here?
+
+}
+
+// TODO: Make a bit better
+private bool isSector(S)()
+{
+    return __traits(hasMember, S, "opIndex");
+}
+
+import core.exception : ArrayIndexError;
+import core.exception : RangeError;
+
+public struct View(T, SectorType = Sector!(T))
+if(isSector!(SectorType)())
+{
+    private SectorType[] sectors;
+    // private 
+
+    // Maybe current size should be here as we
+    // are a view, we should allow modofication
+    // but not make any NEW arrays
+    private size_t curSize;
+
+    private size_t computeTotalLen()
+    {
+        size_t l;
+        foreach(SectorType sector; this.sectors)
+        {
+            l += sector.opDollar();
+        }
+        return l;
+    }
+
+    public size_t opDollar()
+    {
+        return this.length;
+    }
+
+    public T opIndex(size_t idx)
+    {
+        // Within range of "fake" size
+        if(!(idx < this.length))
+        {
+            throw new ArrayIndexError(idx, this.length);
+        }
+
+        size_t thunk;
+        foreach(SectorType sector; this.sectors)
+        {
+            if(idx-thunk < sector.opDollar())
+            {
+                return sector[idx-thunk];
+            }
+            else
+            {
+                thunk += sector.opDollar();
+            }
+        }
+
+        throw new ArrayIndexError(idx, this.length);
+    }
+
+    public void opIndexAssign(T value, size_t idx)
+    {
+        // Within range of "fake" size
+        if(!(idx < this.length))
+        {
+            throw new ArrayIndexError(idx, this.length);
+        }
+
+        size_t thunk;
+        // TODO: Should be ref, else it is just a local struct copy
+        // could cheat if sector is never replaced, hence why it works
+        foreach(SectorType sector; this.sectors)
+        {
+            writeln(sector);
+            writeln("idx: ", idx);
+            writeln("thunk: ", thunk);
+            if(idx-thunk < sector.opDollar())
+            {
+                sector[idx-thunk] = value;
+                return;
+            }
+            else
+            {
+                thunk += sector.opDollar();
+            }
+        }
+
+        throw new ArrayIndexError(idx, this.length);
+    }
+
+    public T[] opSlice()
+    {
+        T[] buff;
+        foreach(SectorType sector; this.sectors)
+        {
+            buff ~= sector[];
+        }
+
+        // Trim to "fake" size
+        buff.length = this.curSize;
+
+        return buff;
+    }
+
+    public T[] opSlice(size_t start, size_t end)
+    {
+        // FIXME: This is lazy, do a check for up to where
+        // and actually make THIS the real implementation
+        return this.opSlice()[start..end];
+    }
+
+    private static bool isArrayAppend(P)()
+    {
+        return __traits(isSame, P, T[]);
+    }
+
+    private static bool isElementAppend(P)()
+    {
+        return __traits(isSame, P, T);
+    }
+
+    // Append
+    public void opOpAssign(string op, E)(E value)
+    if(op == "~" && (isArrayAppend!(E) || isElementAppend!(E)))
+    {
+        static if(isArrayAppend!(E))
+        {
+            add(value);
+        }
+        else
+        {
+            add([value]);
+        }
+    }
+
+    // Takes the data, constructs a kind-of SectorType
+    // and adds it
+    private void add(T[] data)
+    {
+        // Create a new sector
+        SectorType sec = SectorType(data);
+
+        // Update the tracking size
+        this.curSize += sec.length;
+
+        // Concatenate it to the view
+        this.sectors ~= SectorType(data);
+    }
+
+    @property
+    public size_t length()
+    {
+        return this.curSize;
+    }
+
+    @property
+    public void length(size_t size)
+    {
+        // TODO: Add support for sizing down
+        // TODO: Add support for sizing up
+
+        // TODO: Need we continuously compute this?
+        // ... we should have a tracking field for
+        // ... this
+        size_t actualSize = computeTotalLen();
+
+        // On successful exit, update the "fake" size
+        scope(success)
+        {
+            this.curSize = size;
+        }
+
+
+        // Don't allow sizing up (doesn't make sense for a view)
+        if(size > actualSize)
+        {
+            auto r = new RangeError();
+            r.msg = "Cannot extend the size of a view past its total size (of all attached sectors)";
+            throw r;
+        }
+        // If nothing changes
+        else if(size == actualSize)
+        {
+            // Nothing
+        }
+        // If shrinking to zero
+        else if(size == 0)
+        {
+            // Just drop everything
+            this.sectors.length = 0;
+        }
+        // If shrinking (arbitrary)
+        else
+        {
+            // Sectors from left-to-right to keep
+            size_t sectorCnt;
+
+            // Accumulator
+            size_t accumulator;
+
+            foreach(SectorType sector; this.sectors)
+            {
+                accumulator += sector.length;
+                sectorCnt++;
+                if(size <= accumulator)
+                {
+                    break;
+                }
+            }
+
+            this.sectors.length = sectorCnt;
+        }
+        
+    }
+}
+
+unittest
+{
+    View!(int) view;
+    assert(view.opDollar() == 0);
+
+    try
+    {
+        view[1];
+        assert(false);
+    }
+    catch(ArrayIndexError e)
+    {
+        assert(e.index == 1);
+        assert(e.length == 0);
+    }
+
+    view ~= [1,3,45];
+    assert(view.opDollar() == 3);
+    assert(view.length == 3);
+
+    view ~= 2;
+    assert(view.opDollar() == 4);
+    assert(view.length == 4);
+
+    assert(view[0] == 1);
+    assert(view[1] == 3);
+    assert(view[2] == 45);
+    assert(view[3] == 2);
+    assert(view[0..2] == [1,3]);
+
+    // Update elements
+    view[0] = 71;
+    view[3] = 50;
+
+    // Set size to same size
+    view.length = view.length;
+
+    // Check that update is present
+    // and size unchanged
+    int[] all = view[];
+    assert(all == [71,3,45,50]);
+
+    // Truncate by 1 element
+    view.length = view.length-1;
+    all = view[];
+    assert(all == [71,3,45]);
+
+    // This should fail
+    try
+    {
+        view[3] = 3;
+        assert(false);
+    }
+    catch(RangeError e)
+    {
+    }
+
+    // This should fail
+    try
+    {
+        int j = view[3];
+        assert(false);
+    }
+    catch(RangeError e)
+    {
+    }
+
+    // Up-sizing past real size should not be allowed
+    try
+    {
+        view.length =  view.length+1;
+        assert(false);
+    }
+    catch(RangeError e)
+    {
+    }
+
+    // Size to zero
+    view.length = 0;
+    assert(view.length == 0);
+    assert(view[] == []);
 }