Software / code / prosody
Changeset
6898:d01254d5a825
net.websocket.frames: Pack and unpack 64bit ints without overflows (lua-bitop/bit32 are 32bit)
| author | Kim Alvefur <zash@zash.se> |
|---|---|
| date | Tue, 06 Oct 2015 18:03:04 +0200 |
| parents | 6897:8972b1a96526 |
| children | 6899:5f3da8b00b9b |
| files | net/websocket/frames.lua |
| diffstat | 1 files changed, 6 insertions(+), 4 deletions(-) [+] |
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line diff
--- a/net/websocket/frames.lua Tue Oct 06 16:49:01 2015 +0200 +++ b/net/websocket/frames.lua Tue Oct 06 18:03:04 2015 +0200 @@ -30,8 +30,9 @@ -- FIXME: this may lose precision local function read_uint64be(str, pos) local l1, l2, l3, l4, l5, l6, l7, l8 = s_byte(str, pos, pos+7); - return lshift(l1, 56) + lshift(l2, 48) + lshift(l3, 40) + lshift(l4, 32) - + lshift(l5, 24) + lshift(l6, 16) + lshift(l7, 8) + l8; + local h = lshift(l1, 24) + lshift(l2, 16) + lshift(l3, 8) + l4; + local l = lshift(l5, 24) + lshift(l6, 16) + lshift(l7, 8) + l8; + return h * 2^32 + l; end local function pack_uint16be(x) return s_char(rshift(x, 8), band(x, 0xFF)); @@ -40,8 +41,9 @@ return band(rshift(x, n), 0xFF); end local function pack_uint64be(x) - return s_char(rshift(x, 56), get_byte(x, 48), get_byte(x, 40), get_byte(x, 32), - get_byte(x, 24), get_byte(x, 16), get_byte(x, 8), band(x, 0xFF)); + local h = band(x / 2^32, 2^32-1); + return s_char(get_byte(h, 24), get_byte(h, 16), get_byte(h, 8), band(h, 0xFF)); + get_byte(x, 24), get_byte(x, 16), get_byte(x, 8), band(x, 0xFF); end local function parse_frame_header(frame)
