Add VectorWriter

src/athena/VectorWriter.cpp

@@ -0,0 +1,98 @@
+#include "athena/VectorWriter.hpp"
+
+#include <cstdio>
+#include <cstring>
+#include <vector>
+#include <iostream>
+
+namespace athena::io
+{
+
+void VectorWriter::seek(atInt64 position, SeekOrigin origin)
+{
+    switch (origin)
+    {
+    case SeekOrigin::Begin:
+        if (position < 0)
+        {
+            atError("Position outside stream bounds");
+            setError();
+            return;
+        }
+
+        if ((atUint64)position > m_data.size())
+        {
+            atError("data exceeds vector size");
+            setError();
+            return;
+        }
+
+        m_position = position;
+        break;
+
+    case SeekOrigin::Current:
+        if ((((atInt64)m_position + position) < 0))
+        {
+            atError("Position outside stream bounds");
+            setError();
+            return;
+        }
+
+        if (m_position + position > m_data.size())
+        {
+            atError("data exceeds vector size");
+            setError();
+            return;
+        }
+
+        m_position += position;
+        break;
+
+    case SeekOrigin::End:
+        if (((atInt64)m_data.size() - position) < 0)
+        {
+            atError("Position outside stream bounds");
+            setError();
+            return;
+        }
+
+        if ((atUint64)position > m_data.size())
+        {
+            atError("data exceeds vector size");
+            setError();
+            return;
+        }
+
+        m_position = m_data.size() - position;
+        break;
+    }
+}
+
+void VectorWriter::writeUBytes(const atUint8* data, atUint64 length)
+{
+    if (!data)
+    {
+        atError("data cannnot be NULL");
+        setError();
+        return;
+    }
+
+    if (m_position < m_data.size())
+    {
+        size_t delta = std::min(m_data.size() - m_position, length);
+        memmove(reinterpret_cast<atInt8*>(&m_data[m_position]), data, delta);
+        data += delta;
+        length -= delta;
+        m_position += delta;
+    }
+
+    if (length != 0)
+    {
+        size_t insertPos = m_data.size();
+        m_data.resize(insertPos + length);
+        memmove(reinterpret_cast<atInt8*>(&m_data[insertPos]), data, length);
+        m_position += length;
+    }
+}
+
+} // Athena