prosody
638f627e707f
util/hex.lua

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util/hex.lua @ 13134:638f627e707f

util.datamanager: Add O(1) list indexing with on-disk index Index file contains offsets and lengths of each item() which allows seeking directly to each item and reading it without parsing the entire file. Also allows tricks like binary search, assuming items have some defined order. We take advantage of the 1-based indexing in tables to store a magic header in the 0 position, so that table index 1 ends up at file index 1.
author Kim Alvefur <zash@zash.se>
date Tue, 11 May 2021 02:09:56 +0200
parent 12355:a0ff5c438e9d
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:
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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;
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442019e955dc util.hex: Normalize hex to lowercase and discard non-hex input
Kim Alvefur <zash@zash.se>
parents: 6545
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4 local s_lower = string.lower;
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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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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
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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
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7 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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8
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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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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
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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
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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
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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
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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
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parents: 6384
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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
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15 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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16 end
76d8907d5301 util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
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17
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3f4809d01783 util.hex: Use locals!
Kim Alvefur <zash@zash.se>
parents: 6375
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18 local function to(s)
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parents: 6384
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19 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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20 end
76d8907d5301 util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
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21
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parents: 6375
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22 local function from(s)
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23 return (s_gsub(s_lower(s), "%X*(%x%x)%X*", 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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24 end
76d8907d5301 util.hex: Small util lib for converting to/from hex strings
Matthew Wild <mwild1@gmail.com>
parents:
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25
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a0ff5c438e9d util.hex: Deprecate to/from in favour of encode/decode, for consistency!
Matthew Wild <mwild1@gmail.com>
parents: 6802
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26 return {
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parents: 6802
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27 encode = to, decode = from;
a0ff5c438e9d util.hex: Deprecate to/from in favour of encode/decode, for consistency!
Matthew Wild <mwild1@gmail.com>
parents: 6802
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28 -- COMPAT w/pre-0.12:
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parents: 6802
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29 to = to, from = from;
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Matthew Wild <mwild1@gmail.com>
parents: 6802
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30 };