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authorAsbjørn Sloth Tønnesen <ast@2e8.dk>2019-07-28 21:28:21 +0000
committerAsbjørn Sloth Tønnesen <ast@2e8.dk>2019-07-28 21:28:21 +0000
commit9c31bbc8cfd2ea8cfe2740c47c045e1773725315 (patch)
treed6616b441ac1fdcb4785b1dc727bf1e3f105baf9 /lua/inet/bitops
parentde97a7a8473f68eff527c1ec6fb2482ba3d31523 (diff)
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add support for lua 5.4 alpha
Signed-off-by: Asbjørn Sloth Tønnesen <ast@2e8.dk>
Diffstat (limited to 'lua/inet/bitops')
-rw-r--r--lua/inet/bitops/init.lua6
-rw-r--r--lua/inet/bitops/native.lua105
2 files changed, 111 insertions, 0 deletions
diff --git a/lua/inet/bitops/init.lua b/lua/inet/bitops/init.lua
new file mode 100644
index 0000000..6af992b
--- /dev/null
+++ b/lua/inet/bitops/init.lua
@@ -0,0 +1,6 @@
+local versions = {
+ ['Lua 5.2'] = 'bit32',
+}
+
+local library = versions[_VERSION] or 'inet.bitops.native'
+return assert(require(library))
diff --git a/lua/inet/bitops/native.lua b/lua/inet/bitops/native.lua
new file mode 100644
index 0000000..48470f9
--- /dev/null
+++ b/lua/inet/bitops/native.lua
@@ -0,0 +1,105 @@
+-- Until Lua 5.2 support is dropped, we can't use the native operators directly
+-- https://pastebin.com/fepexfdU - assumed public domain license
+
+--[[ Backwards compat for Lua 5.3; only loaded in 5.3 because package.loaded is
+ prepopulated with the existing global bit32 in 5.2. ]]
+
+local bit32 = {}
+
+-------------------------------------------------------------------------------
+
+local function fold(init, op, ...)
+ local result = init
+ local args = table.pack(...)
+ for i = 1, args.n do
+ result = op(result, args[i])
+ end
+ return result
+end
+
+local function trim(n)
+ return n & 0xFFFFFFFF
+end
+
+local function mask(w)
+ return ~(0xFFFFFFFF << w)
+end
+
+function bit32.arshift(x, disp)
+ return x // (2 ^ disp)
+end
+
+function bit32.band(...)
+ return fold(0xFFFFFFFF, function(a, b) return a & b end, ...)
+end
+
+function bit32.bnot(x)
+ return ~x
+end
+
+function bit32.bor(...)
+ return fold(0, function(a, b) return a | b end, ...)
+end
+
+function bit32.btest(...)
+ return bit32.band(...) ~= 0
+end
+
+function bit32.bxor(...)
+ return fold(0, function(a, b) return a ~ b end, ...)
+end
+
+local function fieldargs(f, w)
+ w = w or 1
+ assert(f >= 0, "field cannot be negative")
+ assert(w > 0, "width must be positive")
+ assert(f + w <= 32, "trying to access non-existent bits")
+ return f, w
+end
+
+function bit32.extract(n, field, width)
+ local f, w = fieldargs(field, width)
+ return (n >> f) & mask(w)
+end
+
+function bit32.replace(n, v, field, width)
+ local f, w = fieldargs(field, width)
+ local m = mask(w)
+ return (n & ~(m << f)) | ((v & m) << f)
+end
+
+function bit32.lrotate(x, disp)
+ if disp == 0 then
+ return x
+ elseif disp < 0 then
+ return bit32.rrotate(x, -disp)
+ else
+ disp = disp & 31
+ x = trim(x)
+ return trim((x << disp) | (x >> (32 - disp)))
+ end
+end
+
+function bit32.lshift(x, disp)
+ return trim(x << disp)
+end
+
+function bit32.rrotate(x, disp)
+ if disp == 0 then
+ return x
+ elseif disp < 0 then
+ return bit32.lrotate(x, -disp)
+ else
+ disp = disp & 31
+ x = trim(x)
+ return trim((x >> disp) | (x << (32 - disp)))
+ end
+end
+
+function bit32.rshift(x, disp)
+ return trim(x >> disp)
+end
+
+-------------------------------------------------------------------------------
+
+return bit32