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Unified Diff: third_party/lua/src/lbitlib.c

Issue 14907017: add SkLuaCanvas (Closed) Base URL: https://skia.googlecode.com/svn/trunk
Patch Set: Created 7 years, 7 months ago
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Index: third_party/lua/src/lbitlib.c
diff --git a/third_party/lua/src/lbitlib.c b/third_party/lua/src/lbitlib.c
new file mode 100644
index 0000000000000000000000000000000000000000..9637532e3d858de0b7961f50690ca7c9efaaec1b
--- /dev/null
+++ b/third_party/lua/src/lbitlib.c
@@ -0,0 +1,211 @@
+/*
+** $Id: lbitlib.c,v 1.18 2013/03/19 13:19:12 roberto Exp $
+** Standard library for bitwise operations
+** See Copyright Notice in lua.h
+*/
+
+#define lbitlib_c
+#define LUA_LIB
+
+#include "lua.h"
+
+#include "lauxlib.h"
+#include "lualib.h"
+
+
+/* number of bits to consider in a number */
+#if !defined(LUA_NBITS)
+#define LUA_NBITS 32
+#endif
+
+
+#define ALLONES (~(((~(lua_Unsigned)0) << (LUA_NBITS - 1)) << 1))
+
+/* macro to trim extra bits */
+#define trim(x) ((x) & ALLONES)
+
+
+/* builds a number with 'n' ones (1 <= n <= LUA_NBITS) */
+#define mask(n) (~((ALLONES << 1) << ((n) - 1)))
+
+
+typedef lua_Unsigned b_uint;
+
+
+
+static b_uint andaux (lua_State *L) {
+ int i, n = lua_gettop(L);
+ b_uint r = ~(b_uint)0;
+ for (i = 1; i <= n; i++)
+ r &= luaL_checkunsigned(L, i);
+ return trim(r);
+}
+
+
+static int b_and (lua_State *L) {
+ b_uint r = andaux(L);
+ lua_pushunsigned(L, r);
+ return 1;
+}
+
+
+static int b_test (lua_State *L) {
+ b_uint r = andaux(L);
+ lua_pushboolean(L, r != 0);
+ return 1;
+}
+
+
+static int b_or (lua_State *L) {
+ int i, n = lua_gettop(L);
+ b_uint r = 0;
+ for (i = 1; i <= n; i++)
+ r |= luaL_checkunsigned(L, i);
+ lua_pushunsigned(L, trim(r));
+ return 1;
+}
+
+
+static int b_xor (lua_State *L) {
+ int i, n = lua_gettop(L);
+ b_uint r = 0;
+ for (i = 1; i <= n; i++)
+ r ^= luaL_checkunsigned(L, i);
+ lua_pushunsigned(L, trim(r));
+ return 1;
+}
+
+
+static int b_not (lua_State *L) {
+ b_uint r = ~luaL_checkunsigned(L, 1);
+ lua_pushunsigned(L, trim(r));
+ return 1;
+}
+
+
+static int b_shift (lua_State *L, b_uint r, int i) {
+ if (i < 0) { /* shift right? */
+ i = -i;
+ r = trim(r);
+ if (i >= LUA_NBITS) r = 0;
+ else r >>= i;
+ }
+ else { /* shift left */
+ if (i >= LUA_NBITS) r = 0;
+ else r <<= i;
+ r = trim(r);
+ }
+ lua_pushunsigned(L, r);
+ return 1;
+}
+
+
+static int b_lshift (lua_State *L) {
+ return b_shift(L, luaL_checkunsigned(L, 1), luaL_checkint(L, 2));
+}
+
+
+static int b_rshift (lua_State *L) {
+ return b_shift(L, luaL_checkunsigned(L, 1), -luaL_checkint(L, 2));
+}
+
+
+static int b_arshift (lua_State *L) {
+ b_uint r = luaL_checkunsigned(L, 1);
+ int i = luaL_checkint(L, 2);
+ if (i < 0 || !(r & ((b_uint)1 << (LUA_NBITS - 1))))
+ return b_shift(L, r, -i);
+ else { /* arithmetic shift for 'negative' number */
+ if (i >= LUA_NBITS) r = ALLONES;
+ else
+ r = trim((r >> i) | ~(~(b_uint)0 >> i)); /* add signal bit */
+ lua_pushunsigned(L, r);
+ return 1;
+ }
+}
+
+
+static int b_rot (lua_State *L, int i) {
+ b_uint r = luaL_checkunsigned(L, 1);
+ i &= (LUA_NBITS - 1); /* i = i % NBITS */
+ r = trim(r);
+ r = (r << i) | (r >> (LUA_NBITS - i));
+ lua_pushunsigned(L, trim(r));
+ return 1;
+}
+
+
+static int b_lrot (lua_State *L) {
+ return b_rot(L, luaL_checkint(L, 2));
+}
+
+
+static int b_rrot (lua_State *L) {
+ return b_rot(L, -luaL_checkint(L, 2));
+}
+
+
+/*
+** get field and width arguments for field-manipulation functions,
+** checking whether they are valid.
+** ('luaL_error' called without 'return' to avoid later warnings about
+** 'width' being used uninitialized.)
+*/
+static int fieldargs (lua_State *L, int farg, int *width) {
+ int f = luaL_checkint(L, farg);
+ int w = luaL_optint(L, farg + 1, 1);
+ luaL_argcheck(L, 0 <= f, farg, "field cannot be negative");
+ luaL_argcheck(L, 0 < w, farg + 1, "width must be positive");
+ if (f + w > LUA_NBITS)
+ luaL_error(L, "trying to access non-existent bits");
+ *width = w;
+ return f;
+}
+
+
+static int b_extract (lua_State *L) {
+ int w;
+ b_uint r = luaL_checkunsigned(L, 1);
+ int f = fieldargs(L, 2, &w);
+ r = (r >> f) & mask(w);
+ lua_pushunsigned(L, r);
+ return 1;
+}
+
+
+static int b_replace (lua_State *L) {
+ int w;
+ b_uint r = luaL_checkunsigned(L, 1);
+ b_uint v = luaL_checkunsigned(L, 2);
+ int f = fieldargs(L, 3, &w);
+ int m = mask(w);
+ v &= m; /* erase bits outside given width */
+ r = (r & ~(m << f)) | (v << f);
+ lua_pushunsigned(L, r);
+ return 1;
+}
+
+
+static const luaL_Reg bitlib[] = {
+ {"arshift", b_arshift},
+ {"band", b_and},
+ {"bnot", b_not},
+ {"bor", b_or},
+ {"bxor", b_xor},
+ {"btest", b_test},
+ {"extract", b_extract},
+ {"lrotate", b_lrot},
+ {"lshift", b_lshift},
+ {"replace", b_replace},
+ {"rrotate", b_rrot},
+ {"rshift", b_rshift},
+ {NULL, NULL}
+};
+
+
+
+LUAMOD_API int luaopen_bit32 (lua_State *L) {
+ luaL_newlib(L, bitlib);
+ return 1;
+}
+
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