From cb93e2fae0500067dd5d49cb7927dfc95cb2518b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maxime=20=E2=80=9Cpep=E2=80=9D=20Buquet?= <pep@bouah.net>
Date: Mon, 6 Jul 2020 01:20:47 +0200
Subject: [PATCH] pkstrings: Use ranges to reduce match pattern sizes
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Thanks ekleog!

Signed-off-by: Maxime “pep” Buquet <pep@bouah.net>
---
 pkstrings/src/lib.rs | 130 ++-----------------------------------------
 1 file changed, 6 insertions(+), 124 deletions(-)

diff --git a/pkstrings/src/lib.rs b/pkstrings/src/lib.rs
index 2cec5d3..eb1baef 100644
--- a/pkstrings/src/lib.rs
+++ b/pkstrings/src/lib.rs
@@ -19,64 +19,14 @@ use std::ops::Deref;
 
 const fn strtohex(chr: &char) -> Option<u8> {
     Some(match chr {
-        'A' => 0x80,
-        'B' => 0x81,
-        'C' => 0x82,
-        'D' => 0x83,
-        'E' => 0x84,
-        'F' => 0x85,
-        'G' => 0x86,
-        'H' => 0x87,
-        'I' => 0x88,
-        'J' => 0x89,
-        'K' => 0x8a,
-        'L' => 0x8b,
-        'M' => 0x8c,
-        'N' => 0x8d,
-        'O' => 0x8e,
-        'P' => 0x8f,
-        'Q' => 0x90,
-        'R' => 0x91,
-        'S' => 0x92,
-        'T' => 0x93,
-        'U' => 0x94,
-        'V' => 0x95,
-        'W' => 0x96,
-        'X' => 0x97,
-        'Y' => 0x98,
-        'Z' => 0x99,
+        cap @ 'A'..='Z' => 0x80 - ('A' as u8) + (*cap as u8),
         '(' => 0x9a,
         ')' => 0x9b,
         ':' => 0x9c,
         ';' => 0x9d,
         '[' => 0x9e,
         ']' => 0x9f,
-        'a' => 0xa0,
-        'b' => 0xa1,
-        'c' => 0xa2,
-        'd' => 0xa3,
-        'e' => 0xa4,
-        'f' => 0xa5,
-        'g' => 0xa6,
-        'h' => 0xa7,
-        'i' => 0xa8,
-        'j' => 0xa9,
-        'k' => 0xaa,
-        'l' => 0xab,
-        'm' => 0xac,
-        'n' => 0xad,
-        'o' => 0xae,
-        'p' => 0xaf,
-        'q' => 0xb0,
-        'r' => 0xb1,
-        's' => 0xb2,
-        't' => 0xb3,
-        'u' => 0xb4,
-        'v' => 0xb5,
-        'w' => 0xb6,
-        'x' => 0xb7,
-        'y' => 0xb8,
-        'z' => 0xb9,
+        low @ 'a'..='z' => 0xa0 - ('a' as u8) + (*low as u8),
         '\'' => 0xe0,
         '-' => 0xe3,
         '?' => 0xe6,
@@ -98,16 +48,7 @@ const fn strtohex(chr: &char) -> Option<u8> {
         '/' => 0xf3,
         ',' => 0xf4,
         '♀' => 0xf5,
-        '0' => 0xf6,
-        '1' => 0xf7,
-        '2' => 0xf8,
-        '3' => 0xf9,
-        '4' => 0xfa,
-        '5' => 0xfb,
-        '6' => 0xfc,
-        '7' => 0xfd,
-        '8' => 0xfe,
-        '9' => 0xff,
+        num @ '0'..='9' => 0xf6 - ('0' as u8) + (*num as u8),
         ' ' => 0x7f,
         '@' => 0x50,
         _ => return None,
@@ -116,64 +57,14 @@ const fn strtohex(chr: &char) -> Option<u8> {
 
 const fn hextostr(hex: u8) -> Option<char> {
     Some(match hex {
-        0x80 => 'A',
-        0x81 => 'B',
-        0x82 => 'C',
-        0x83 => 'D',
-        0x84 => 'E',
-        0x85 => 'F',
-        0x86 => 'G',
-        0x87 => 'H',
-        0x88 => 'I',
-        0x89 => 'J',
-        0x8a => 'K',
-        0x8b => 'L',
-        0x8c => 'M',
-        0x8d => 'N',
-        0x8e => 'O',
-        0x8f => 'P',
-        0x90 => 'Q',
-        0x91 => 'R',
-        0x92 => 'S',
-        0x93 => 'T',
-        0x94 => 'U',
-        0x95 => 'V',
-        0x96 => 'W',
-        0x97 => 'X',
-        0x98 => 'Y',
-        0x99 => 'Z',
+        cap @ 0x80..=0x99 => (('A' as u8) + cap - 0x80) as char,
         0x9a => '(',
         0x9b => ')',
         0x9c => ':',
         0x9d => ';',
         0x9e => '[',
         0x9f => ']',
-        0xa0 => 'a',
-        0xa1 => 'b',
-        0xa2 => 'c',
-        0xa3 => 'd',
-        0xa4 => 'e',
-        0xa5 => 'f',
-        0xa6 => 'g',
-        0xa7 => 'h',
-        0xa8 => 'i',
-        0xa9 => 'j',
-        0xaa => 'k',
-        0xab => 'l',
-        0xac => 'm',
-        0xad => 'n',
-        0xae => 'o',
-        0xaf => 'p',
-        0xb0 => 'q',
-        0xb1 => 'r',
-        0xb2 => 's',
-        0xb3 => 't',
-        0xb4 => 'u',
-        0xb5 => 'v',
-        0xb6 => 'w',
-        0xb7 => 'x',
-        0xb8 => 'y',
-        0xb9 => 'z',
+        low @ 0xa0..=0xb9 => (('a' as u8) + low - 0xa0) as char,
         0xe0 => '\'',
         0xe3 => '-',
         0xe6 => '?',
@@ -188,16 +79,7 @@ const fn hextostr(hex: u8) -> Option<char> {
         0xf3 => '/',
         0xf4 => ',',
         0xf5 => '♀',
-        0xf6 => '0',
-        0xf7 => '1',
-        0xf8 => '2',
-        0xf9 => '3',
-        0xfa => '4',
-        0xfb => '5',
-        0xfc => '6',
-        0xfd => '7',
-        0xfe => '8',
-        0xff => '9',
+        num @ 0xf6..=0xff => (('0' as u8) + num - 0xf6) as char,
         0x7f => ' ',
         0x50 => '@',
         _ => return None,