provide callbacks used by libvorbis for ogg reading

engine/renderers/OggBufferCallback.h

@@ -0,0 +1,126 @@
+/*
+Copyright (c) 2013 Daniele Bartolini, Michele Rossi
+Copyright (c) 2012 Daniele Bartolini, Simone Boscaratto
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+#pragma once
+
+#include <cstring>
+
+#include "Assert.h"
+
+namespace crown
+{
+
+//-----------------------------------------------------------------------------
+struct OggBuffer
+{
+	char*	cur_ptr;
+	char*	buffer_ptr;
+	size_t	length;
+
+	OggBuffer(char* data, size_t len) : cur_ptr(data), buffer_ptr(data), length(len) {}
+};
+
+//-----------------------------------------------------------------------------
+size_t ogg_buffer_read(void* dst, size_t size, size_t num, void* src)
+{
+    OggBuffer* ob = reinterpret_cast<OggBuffer*>(src);
+
+    size_t len = size * num;
+
+    if ((ob->cur_ptr + len) > (ob->buffer_ptr + ob->length))
+    {
+    	len = ob->buffer_ptr + ob->length - ob->cur_ptr;
+    }
+
+    memcpy(dst, ob->cur_ptr, len);
+
+    ob->cur_ptr += len;
+
+    return len;
+}
+
+//-----------------------------------------------------------------------------
+int32_t	ogg_buffer_seek(void * src, ogg_int64_t offset, int32_t whence)
+{
+    OggBuffer* ob = reinterpret_cast<OggBuffer*>(src);
+
+    switch(whence)
+    {
+    	case SEEK_CUR:
+    	{
+    		ob->cur_ptr += offset;
+    		break;
+    	}
+    	case SEEK_END:
+    	{
+    		ob->cur_ptr = ob->buffer_ptr + ob->length - offset;
+    		break;
+    	}
+    	case SEEK_SET:
+    	{
+    		ob->cur_ptr = ob->buffer_ptr + offset;
+    		break;
+    	}
+    	default:
+    	{
+    		return -1;
+    	}
+    }
+
+    // Checks inferior limit
+    if (ob->cur_ptr < ob->buffer_ptr)
+    {
+    	ob->cur_ptr = ob->buffer_ptr;
+    	return -1;
+    }
+
+    // Checks superior limit
+    if (ob->cur_ptr > ob->buffer_ptr + ob->length)
+    {
+    	ob->cur_ptr = ob->buffer_ptr + ob->length;
+    	return -1;
+    }
+
+    // Success
+    return 0;
+}
+
+//-----------------------------------------------------------------------------
+int32_t ogg_buffer_close(void* src)
+{
+	(void)src;
+	return 0;
+}
+
+//-----------------------------------------------------------------------------
+long int ogg_buffer_tell(void* src)
+{
+    OggBuffer* ob = reinterpret_cast<OggBuffer*>(src);
+
+    return ob->cur_ptr - ob->buffer_ptr;
+}
+
+} // namespace crown