From e0e571971a5fc2bda90053377ee4b6ce9a672c47 Mon Sep 17 00:00:00 2001
From: Aaron Griffith <aargri@gmail.com>
Date: Sun, 27 Mar 2011 06:07:43 -0400
Subject: [PATCH] added endianness helper functions, and reading biome data
 directly

---
 setup.py                |  2 +-
 src/endian.c            | 39 +++++++++++++++++++++++++++++++++++++++
 src/main.c              |  2 ++
 src/overviewer.h        |  5 +++++
 src/rendermode-normal.c |  9 ++-------
 5 files changed, 49 insertions(+), 8 deletions(-)
 create mode 100644 src/endian.c

diff --git a/setup.py b/setup.py
index 9d2f7aa..85ade1e 100644
--- a/setup.py
+++ b/setup.py
@@ -46,7 +46,7 @@ except AttributeError:
     numpy_include = numpy.get_numpy_include()
 
 
-c_overviewer_files = ['src/main.c', 'src/composite.c', 'src/iterate.c']
+c_overviewer_files = ['src/main.c', 'src/composite.c', 'src/iterate.c', 'src/endian.c']
 c_overviewer_files += ['src/rendermodes.c', 'src/rendermode-normal.c', 'src/rendermode-lighting.c', 'src/rendermode-night.c', 'src/rendermode-spawn.c']
 setup_kwargs['ext_modules'].append(Extension('c_overviewer', c_overviewer_files, include_dirs=['.', numpy_include], extra_link_args=[]))
 # tell build_ext to build the extension in-place
diff --git a/src/endian.c b/src/endian.c
new file mode 100644
index 0000000..5b0a105
--- /dev/null
+++ b/src/endian.c
@@ -0,0 +1,39 @@
+/* 
+ * This file is part of the Minecraft Overviewer.
+ *
+ * Minecraft Overviewer is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Minecraft Overviewer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with the Overviewer.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* simple routines for dealing with endian conversion */
+
+#define UNKNOWN_ENDIAN 0
+#define BIG_ENDIAN 1
+#define LITTLE_ENDIAN 2
+
+static int endianness = UNKNOWN_ENDIAN;
+
+void init_endian() {
+    /* figure out what our endianness is! */
+    short word = 0x0001;
+    char* byte = (char*)(&word);
+    endianness = byte[0] ? LITTLE_ENDIAN : BIG_ENDIAN;
+}
+
+unsigned short big_endian_ushort(unsigned short in) {
+    return (endianness == LITTLE_ENDIAN) ? ((in >> 8) | (in << 8)) : in;
+}
+
+unsigned int big_endian_uint(unsigned int in) {
+    return (endianness == LITTLE_ENDIAN) ? (((in & 0x000000FF) << 24) + ((in & 0x0000FF00) << 8) + ((in & 0x00FF0000) >> 8) + ((in & 0xFF000000) >> 24)) : in;
+}
diff --git a/src/main.c b/src/main.c
index 32ca491..a8c6075 100644
--- a/src/main.c
+++ b/src/main.c
@@ -37,4 +37,6 @@ initc_overviewer(void)
         fprintf(stderr, "failed to init_chunk_render\n");
         exit(1); // TODO better way to indicate error?
     }
+    
+    init_endian();
 }
diff --git a/src/overviewer.h b/src/overviewer.h
index ebf83ce..3475fdf 100644
--- a/src/overviewer.h
+++ b/src/overviewer.h
@@ -78,4 +78,9 @@ PyObject *chunk_render(PyObject *self, PyObject *args);
 /* pull in the rendermode info */
 #include "rendermodes.h"
 
+/* in endian.c */
+void init_endian();
+unsigned short big_endian_ushort(unsigned short in);
+unsigned int big_endian_uint(unsigned int in);
+
 #endif /* __OVERVIEWER_H_INCLUDED__ */
diff --git a/src/rendermode-normal.c b/src/rendermode-normal.c
index 85e55ed..d7a1367 100644
--- a/src/rendermode-normal.c
+++ b/src/rendermode-normal.c
@@ -128,16 +128,11 @@ rendermode_normal_draw(void *data, RenderState *state, PyObject *src, PyObject *
     if (self->biome_data) {
         /* do the biome stuff! */
         unsigned int index;
-        PyObject *index_py, *color = NULL, *facemask = NULL;
+        PyObject *color = NULL, *facemask = NULL;
         unsigned char r, g, b;
         
         index = ((self->chunk_y * 16) + state->y) * 16 * 32 + (self->chunk_x * 16) + state->x;
-        /* TODO for some reason, this one doesn't work:
-         * index = getArrayShort1D(self->biome_data, index);
-         */
-        index_py = PySequence_GetItem(self->biome_data, index);
-        index = PyInt_AsLong(index_py);
-        Py_DECREF(index_py);
+        index = big_endian_ushort(getArrayShort1D(self->biome_data, index));
         
         switch (state->block) {
         case 2: