Use binary operators rather than "Python modulo" in decoding block positions

diff --git a/src/database.cpp b/src/database.cpp
index e3d92f91578495b2ea55d0146f565334f1431355..cf208be8dc0708212ca3444154ac6467368af43f 100644 (file)
--- a/src/database.cpp
+++ b/src/database.cpp
@@ -20,33 +20,29 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "database.h"
 #include "irrlichttypes.h"
 
-static s32 unsignedToSigned(s32 i, s32 max_positive)
+static inline s16 unsigned_to_signed(u16 i, u16 max_positive)
 {
-       if(i < max_positive)
+       if (i < max_positive) {
                return i;
-       else
-               return i - 2*max_positive;
+       } else {
+               return i - (max_positive * 2);
+       }
 }
 
-// modulo of a negative number does not work consistently in C
-static s64 pythonmodulo(s64 i, s64 mod)
-{
-       if(i >= 0)
-               return i % mod;
-       return mod - ((-i) % mod);
-}
 
-s64 Database::getBlockAsInteger(const v3s16 pos) {
-       return (u64) pos.Z * 16777216 +
-               (u64) pos.Y * 4096 +
+s64 Database::getBlockAsInteger(const v3s16 pos) const
+{
+       return (u64) pos.Z * 0x1000000 +
+               (u64) pos.Y * 0x1000 +
                (u64) pos.X;
 }
 
-v3s16 Database::getIntegerAsBlock(s64 i) {
-       s32 x = unsignedToSigned(pythonmodulo(i, 4096), 2048);
-       i = (i - x) / 4096;
-       s32 y = unsignedToSigned(pythonmodulo(i, 4096), 2048);
-       i = (i - y) / 4096;
-       s32 z = unsignedToSigned(pythonmodulo(i, 4096), 2048);
-       return v3s16(x,y,z);
+v3s16 Database::getIntegerAsBlock(const s64 i) const
+{
+        v3s16 pos;
+        pos.Z = unsigned_to_signed((i >> 24) & 0xFFF, 0x1000 / 2);
+        pos.Y = unsigned_to_signed((i >> 12) & 0xFFF, 0x1000 / 2);
+        pos.X = unsigned_to_signed((i      ) & 0xFFF, 0x1000 / 2);
+        return pos;
 }
+

diff --git a/src/database.h b/src/database.h
index 4ce80ed9315bdad82cb92a89e9cad5083e69ec66..a8686137949ba251a1a8075c55e9f6819305f93a 100644 (file)
--- a/src/database.h
+++ b/src/database.h
@@ -34,8 +34,8 @@ public:
 
        virtual void saveBlock(MapBlock *block)=0;
        virtual MapBlock* loadBlock(v3s16 blockpos)=0;
-       s64 getBlockAsInteger(const v3s16 pos);
-       v3s16 getIntegerAsBlock(s64 i);
+       s64 getBlockAsInteger(const v3s16 pos) const;
+       v3s16 getIntegerAsBlock(const s64 i) const;
        virtual void listAllLoadableBlocks(std::list<v3s16> &dst)=0;
        virtual int Initialized(void)=0;
        virtual ~Database() {};