diff options
| -rw-r--r-- | lobject.c | 31 |
1 files changed, 11 insertions, 20 deletions
@@ -1,5 +1,5 @@ /* -** $Id: lobject.c,v 1.96 2003/02/18 16:02:56 roberto Exp roberto $ +** $Id: lobject.c,v 1.97 2003/04/03 13:35:34 roberto Exp roberto $ ** Some generic functions over Lua objects ** See Copyright Notice in lua.h */ @@ -45,29 +45,20 @@ int luaO_int2fb (unsigned int x) { int luaO_log2 (unsigned int x) { - static const lu_byte log_8[255] = { - 0, - 1,1, - 2,2,2,2, - 3,3,3,3,3,3,3,3, - 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4, - 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, + static const lu_byte log_2[256] = { + 0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, - 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, - 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, - 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7 + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8 }; - if (x >= 0x00010000) { - if (x >= 0x01000000) return log_8[((x>>24) & 0xff) - 1]+24; - else return log_8[((x>>16) & 0xff) - 1]+16; - } - else { - if (x >= 0x00000100) return log_8[((x>>8) & 0xff) - 1]+8; - else if (x) return log_8[(x & 0xff) - 1]; - return -1; /* special `log' for 0 */ - } + int l = -1; + while (x >= 256) { l += 8; x >>= 8; } + return l + log_2[x]; + } |