From 889595a742dd5b36cd2d2aaba75bf741f1db83c2 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 00:18:09 +0200
Subject: [PATCH] pkstrings: convert HEXTOSTR to const fn
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Maxime “pep” Buquet <pep@bouah.net>
---
 pkstrings/src/lib.rs | 185 +++++++++++++++++++++----------------------
 1 file changed, 90 insertions(+), 95 deletions(-)

diff --git a/pkstrings/src/lib.rs b/pkstrings/src/lib.rs
index cc59b8b..4cc196f 100644
--- a/pkstrings/src/lib.rs
+++ b/pkstrings/src/lib.rs
@@ -108,100 +108,96 @@ lazy_static! {
             ('@', 0x50),
         ].iter().copied().collect()
     };
-    static ref HEXTOSTR: Vec<Option<char>> = {
-        let tmp = [
-            (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'),
-            (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'),
-            (0xe0, '\''),
-            (0xe3, '-'),
-            (0xe6, '?'),
-            (0xe7, '!'),
-            (0xe8, '.'),
-            (0xec, '▷'),
-            (0xed, '▶'),
-            (0xee, '▼'),
-            (0xef, '♂'),
-            (0xf1, '×'),
-            (0xf2, '.'),
-            (0xf3, '/'),
-            (0xf4, ','),
-            (0xf5, '♀'),
-            (0xf6, '0'),
-            (0xf7, '1'),
-            (0xf8, '2'),
-            (0xf9, '3'),
-            (0xfa, '4'),
-            (0xfb, '5'),
-            (0xfc, '6'),
-            (0xfd, '7'),
-            (0xfe, '8'),
-            (0xff, '9'),
-            (0x7f, ' '),
-            (0x50, '@'),
-        ];
+}
 
-        let mut vec: Vec<Option<char>> = [None; 256].to_vec();
-        for (k, v) in tmp.iter() {
-            vec[*k] = Some(*v);
-        }
-        vec
-    };
+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',
+        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',
+        0xe0 => '\'',
+        0xe3 => '-',
+        0xe6 => '?',
+        0xe7 => '!',
+        0xe8 => '.',
+        0xec => '▷',
+        0xed => '▶',
+        0xee => '▼',
+        0xef => '♂',
+        0xf1 => '×',
+        0xf2 => '.',
+        0xf3 => '/',
+        0xf4 => ',',
+        0xf5 => '♀',
+        0xf6 => '0',
+        0xf7 => '1',
+        0xf8 => '2',
+        0xf9 => '3',
+        0xfa => '4',
+        0xfb => '5',
+        0xfc => '6',
+        0xfd => '7',
+        0xfe => '8',
+        0xff => '9',
+        0x7f => ' ',
+        0x50 => '@',
+        _ => return None,
+    })
 }
 
 #[derive(Debug, Eq, PartialEq)]
@@ -234,8 +230,7 @@ impl TryFrom<&[u8]> for PKString {
         let placeholder = '_';
 
         for ord in data {
-            let ord = *ord as usize;
-            if let Some(chr) = HEXTOSTR[ord] {
+            if let Some(chr) = hextostr(*ord) {
                 buf.push(chr.clone());
             } else {
                 buf.push(placeholder);