start on editor

.ignore

@@ -1,3 +1,4 @@
 .git
 src/VulkanRenderer/vma
 src/DLibs/external
+build

dub.json

@@ -15,7 +15,7 @@
 			"libs-windows": [],
 			"preGenerateCommands-linux": ["./build.sh"],
 			"preGenerateCommands-windows": [],
-			"dflags": ["-Xcc=-mno-sse", "-P-I/usr/include/freetype2", "-vgc"],
+			"dflags": ["-Xcc=-mno-sse", "-P-I/usr/include/freetype2"],
 			"dflags-dmd": ["-P=-DSTBI_NO_SIMD"]
 		},
 	]

src/editor/buffer.d

@@ -0,0 +1,211 @@
+import aliases;
+import math;
+import alloc;
+import util;
+
+struct GapBuffer
+{
+	u8[] data;
+	u64  length;
+	u64  gap_start;
+	u64  gap_end;
+	u64  gap_size;
+}
+
+GapBuffer
+CreateGapBuffer(u8[] data)
+{
+	// Match 4k page sizes
+	u64 capacity = RoundUp(cast(u64)data.length, KB(4));
+	if (data.length % KB(4) == 0)
+	{
+		capacity += KB(4);
+	}
+
+	u8[] buf = MAllocArray!(u8)(capacity);
+
+	buf[0 .. data.length] = data[0 .. $];
+
+	GapBuffer buffer = {
+		data: buf,
+		length: data.length,
+		gap_start: data.length,
+		gap_end: data.length + (capacity - data.length),
+		gap_size: capacity - cast(u64)(data.length),
+	};
+
+	return buffer;
+}
+
+void
+GrowBuffer(GapBuffer* buffer)
+{
+	u8[] temp_buf = buffer.data[0 .. buffer.length];
+	GapBuffer temp_gap = CreateGapBuffer(temp_buf);
+	MFreeArray(buffer.data);
+	*buffer = temp_gap;
+}
+
+void
+Insert(GapBuffer* buffer, u8[] insert, u64 length, i64 pos)
+{
+	assert(length <= insert.length, "Insert Error: length is greater than insert buffer length");
+
+	if (buffer.length + length > buffer.data.length)
+	{
+		if (buffer.length < buffer.data.length)
+		{
+			Shift(buffer, buffer.data.length);
+		}
+		GrowBuffer(buffer);
+	}
+
+	Shift(buffer, pos);
+
+	buffer.data[buffer.gap_start .. buffer.gap_start+length] = insert[0 .. length];
+	buffer.length += length;
+	buffer.gap_start += length;
+	buffer.gap_size -= length;
+}
+
+void
+Shift(GapBuffer* buffer, i64 pos)
+{
+	if (pos < 0)
+	{
+		pos = 0;
+	}
+	else if (pos > buffer.length)
+	{
+		pos = buffer.length;
+	}
+
+	u64 old_pos = buffer.gap_start;
+	u64 new_pos = cast(u64)pos;
+
+	u64 diff;
+	if (old_pos < new_pos)
+	{
+		diff = new_pos - old_pos;
+		buffer.data[buffer.gap_start .. buffer.gap_start+diff] = buffer.data[buffer.gap_end .. buffer.gap_end+diff];
+		buffer.gap_start += diff;
+		buffer.gap_end += diff;
+	}
+	else if (old_pos > new_pos)
+	{
+		diff = old_pos - new_pos;
+		buffer.data[buffer.gap_end-diff .. buffer.gap_end] = buffer.data[buffer.gap_start-diff .. buffer.gap_start];
+		buffer.gap_start -= diff;
+		buffer.gap_end -= diff;
+	}
+}
+
+void
+GetLines(GapBuffer* buffer, u8[][] lines, u64 start_line)
+{
+	Shift(buffer, buffer.data.length);
+
+	u64 count;
+	u64 start;
+	foreach(i, ch; buffer.data)
+	{
+		if (count == lines.length)
+		{
+			break;
+		}
+
+		if (ch == '\n')
+		{
+			scope(exit) count += 1;
+
+			if (count < start_line)
+			{
+				continue;
+			}
+
+			lines[count][start .. i-start] = buffer.data[start .. i];
+			lines[count][i-start] = '\0';
+			start = i + 1;
+		}
+	}
+}
+
+void
+MoveCursorL(GapBuffer* buffer, u64 length)
+{
+	assert(length, "MoveCursorL Error: 0 length provided");
+
+	u64 new_pos = length >= buffer.length ? buffer.length - length : 0;
+}
+
+unittest
+{
+	// Inserts
+	{
+		string test_str = "This is a test string for testing the GapBuffer struct.";
+		string test_str_2 = "This is an additional string. ";
+		u8[] data = (cast(u8*)test_str.ptr)[0 .. test_str.length];
+		GapBuffer buf = CreateGapBuffer(data);
+
+		u8[] insert = (cast(u8*)test_str_2.ptr)[0 .. test_str_2.length];
+		Insert(&buf, insert, insert.length, 0);
+
+		u8[][] line_buf =  new u8[][](1, 1024);
+		GetLines(&buf, line_buf, 0);
+
+		u64 count = 0;
+		foreach(i, ch; test_str_2)
+		{
+			assert(buf.data[count] == ch, "Buffer doesn't match test_str_2");
+			count += 1;
+		}
+
+		foreach(i, ch; test_str)
+		{
+			assert(buf.data[count] == ch, "Buffer doesn't match test_str");
+			count += 1;
+		}
+
+		string test_str_3 = "not ";
+		insert = (cast(u8*)test_str_3.ptr)[0 .. test_str_3.length];
+		Insert(&buf, insert, insert.length, 8);
+		GetLines(&buf, line_buf, 0);
+
+		string result = "This is not an additional string. This is a test string for testing the GapBuffer struct.";
+		foreach(i, ch; result)
+		{
+			assert(buf.data[i] == ch, "Buffer doesn't match result");
+		}
+	}
+
+	// Grow Buffer
+	{
+		u8[] data;
+		GapBuffer buf = CreateGapBuffer(data);
+
+		foreach(i; 0 .. buf.data.length)
+		{
+			Insert(&buf, ['a'], 1, 0);
+		}
+
+		foreach(i; 0 .. 1024)
+		{
+			Insert(&buf, ['b'], 1, 0);
+		}
+
+		u8[][] line_buf = new u8[][](1, 8096);
+		GetLines(&buf, line_buf, 0);
+
+		foreach(i; 0 .. 5120)
+		{
+			if (i < 1024)
+			{
+				assert(line_buf[0][i] == 'b');
+			}
+			else
+			{
+				assert(line_buf[0][i] == 'a');
+			}
+		}
+	}
+}

src/editor/main.d

@@ -1,6 +1,76 @@
+import aliases;
 import std.stdio;
+import buffer;
+import util;
 
 void main(string[] argv)
 {
-	writeln("Hello, World!");
+	// Inserts
+	{
+		string test_str = "This is a test string for testing the GapBuffer struct.";
+		string test_str_2 = "This is an additional string. ";
+		u8[] data = (cast(u8*)test_str.ptr)[0 .. test_str.length];
+		GapBuffer buf = CreateGapBuffer(data);
+
+		u8[] insert = (cast(u8*)test_str_2.ptr)[0 .. test_str_2.length];
+		Insert(&buf, insert, insert.length, 0);
+
+		u8[][] line_buf =  new u8[][](1, 1024);
+		GetLines(&buf, line_buf, 0);
+
+		u64 count = 0;
+		foreach(i, ch; test_str_2)
+		{
+			assert(buf.data[count] == ch, "Buffer doesn't match test_str_2");
+			count += 1;
+		}
+
+		foreach(i, ch; test_str)
+		{
+			assert(buf.data[count] == ch, "Buffer doesn't match test_str");
+			count += 1;
+		}
+
+		string test_str_3 = "not ";
+		insert = (cast(u8*)test_str_3.ptr)[0 .. test_str_3.length];
+		Insert(&buf, insert, insert.length, 8);
+		GetLines(&buf, line_buf, 0);
+
+		string result = "This is not an additional string. This is a test string for testing the GapBuffer struct.";
+		foreach(i, ch; result)
+		{
+			assert(buf.data[i] == ch, "Buffer doesn't match result");
+		}
+	}
+
+	// Grow Buffer
+	{
+		u8[] data;
+		GapBuffer buf = CreateGapBuffer(data);
+
+		foreach(i; 0 .. buf.data.length)
+		{
+			Insert(&buf, ['a'], 1, 0);
+		}
+
+		foreach(i; 0 .. 1024)
+		{
+			Insert(&buf, ['b'], 1, 0);
+		}
+
+		u8[][] line_buf = new u8[][](1, 8096);
+		GetLines(&buf, line_buf, 0);
+
+		foreach(i; 0 .. 5120)
+		{
+			if (i < 1024)
+			{
+				assert(line_buf[0][i] == 'b');
+			}
+			else
+			{
+				assert(line_buf[0][i] == 'a');
+			}
+		}
+	}
 }