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ec566d7cd518
util/hex.lua

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util/hex.lua @ 6545:ec566d7cd518

util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster
author Kim Alvefur <zash@zash.se>
date Mon, 12 Jan 2015 15:10:37 +0100
parent 6384:3f4809d01783
child 6802:442019e955dc
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
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;
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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
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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
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3 local s_gsub = string.gsub;
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
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4
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
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5 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
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6 local hex_to_char = {};
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76d8907d5301 util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
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7
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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
8 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
9 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
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10 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
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11 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
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12 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
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13 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
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14 end
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76d8907d5301 util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
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15 end
76d8907d5301 util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
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16
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3f4809d01783 util.hex: Use locals!
Kim Alvefur <zash@zash.se>
parents: 6375
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17 local function to(s)
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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
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18 return (s_gsub(s, ".", char_to_hex));
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76d8907d5301 util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
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19 end
76d8907d5301 util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
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20
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3f4809d01783 util.hex: Use locals!
Kim Alvefur <zash@zash.se>
parents: 6375
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21 local function from(s)
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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
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22 return (s_gsub(s, "..", hex_to_char));
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Matthew Wild <mwild1@gmail.com>
parents:
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23 end
76d8907d5301 util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
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24
76d8907d5301 util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
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25 return { to = to, from = from }