author | Kim Alvefur <zash@zash.se> |
Sat, 09 Nov 2019 00:26:56 +0100 | |
changeset 10409 | e7f5735f19e1 |
parent 6805 | 442019e955dc |
child 12359 | a0ff5c438e9d |
permissions | -rw-r--r-- |
6375
76d8907d5301
util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
diff
changeset
|
1 |
local s_char = string.char; |
6548
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
2 |
local s_format = string.format; |
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
3 |
local s_gsub = string.gsub; |
6805
442019e955dc
util.hex: Normalize hex to lowercase and discard non-hex input
Kim Alvefur <zash@zash.se>
parents:
6548
diff
changeset
|
4 |
local s_lower = string.lower; |
6548
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
5 |
|
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
6 |
local char_to_hex = {}; |
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
7 |
local hex_to_char = {}; |
6375
76d8907d5301
util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
diff
changeset
|
8 |
|
6548
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
9 |
do |
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
10 |
local char, hex; |
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
11 |
for i = 0,255 do |
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
12 |
char, hex = s_char(i), s_format("%02x", i); |
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
13 |
char_to_hex[char] = hex; |
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
14 |
hex_to_char[hex] = char; |
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
15 |
end |
6375
76d8907d5301
util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
diff
changeset
|
16 |
end |
76d8907d5301
util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
diff
changeset
|
17 |
|
6384 | 18 |
local function to(s) |
6548
ec566d7cd518
util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
Kim Alvefur <zash@zash.se>
parents:
6384
diff
changeset
|
19 |
return (s_gsub(s, ".", char_to_hex)); |
6375
76d8907d5301
util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
diff
changeset
|
20 |
end |
76d8907d5301
util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
diff
changeset
|
21 |
|
6384 | 22 |
local function from(s) |
6805
442019e955dc
util.hex: Normalize hex to lowercase and discard non-hex input
Kim Alvefur <zash@zash.se>
parents:
6548
diff
changeset
|
23 |
return (s_gsub(s_lower(s), "%X*(%x%x)%X*", hex_to_char)); |
6375
76d8907d5301
util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
diff
changeset
|
24 |
end |
76d8907d5301
util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
diff
changeset
|
25 |
|
76d8907d5301
util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
diff
changeset
|
26 |
return { to = to, from = from } |