From 621350ab8318cbe7eccecb78daa852fb62ecc3a4 Mon Sep 17 00:00:00 2001
From: Dnomd343 <i@343.re>
Date: Fri, 6 Jan 2023 19:40:56 +0800
Subject: [PATCH] perf: short code string convert

---
 klotski/main.cc       |  4 ++++
 klotski/short_code.cc | 20 +++++++-------------
 klotski/short_code.h  | 36 ++++++++++++++++++++----------------
 3 files changed, 31 insertions(+), 29 deletions(-)

diff --git a/klotski/main.cc b/klotski/main.cc
index b0fe356..71133d3 100644
--- a/klotski/main.cc
+++ b/klotski/main.cc
@@ -65,5 +65,9 @@ int main() {
     std::cout << ShortCode::code_to_string(14323231) << std::endl;
     std::cout << ShortCode::code_from_string("EP4HZ") << std::endl;
 
+//    for (int i = 0; i < 32; ++i) {
+//        std::cout << int(SHORT_CODE_TABLE[i] - 49) << ": " << i << std::endl;
+//    }
+
     return 0;
 }
diff --git a/klotski/short_code.cc b/klotski/short_code.cc
index a97ba91..f2b2fd2 100644
--- a/klotski/short_code.cc
+++ b/klotski/short_code.cc
@@ -33,22 +33,16 @@ uint32_t ShortCode::code_from_string(const std::string &short_code) { // 5-bits
     uint32_t result = 0;
     for (auto bit : short_code) {
         result *= 32;
-        if (bit >= '1' && bit <= '9') { // 1 ~ 9
-            result += bit - 49;
-            continue;
+        if (bit >= 'a' && bit <= 'z') {
+            bit -= 32; // convert to uppercase
         }
-        if (bit >= 'a' && bit <= 'z') { // a ~ z
-            bit -= ('a' - 'A'); // convert to A ~ Z
-        }
-        if (bit >= 'A' && bit <= 'Z') { // A ~ Z
-            bit = SHORT_CODE_TABLE_REV[bit - 65]; // table convert
-            if (bit == 0) {
-                throw std::runtime_error("invalid short code");
+        if (bit >= '1' && bit <= 'Z') {
+            result += (bit = SHORT_CODE_TABLE_REV[bit - 49]); // table convert
+            if (bit != -1) {
+                continue; // pass check
             }
-            result += bit;
-        } else {
-            throw std::runtime_error("invalid short code");
         }
+        throw std::runtime_error("invalid short code");
     }
     if (!ShortCode::check(result)) {
         throw std::range_error("short code out of range");
diff --git a/klotski/short_code.h b/klotski/short_code.h
index 1cd6ca9..44d11c2 100644
--- a/klotski/short_code.h
+++ b/klotski/short_code.h
@@ -11,28 +11,32 @@ const char SHORT_CODE_TABLE[32] = {
     'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
 };
 
-const char SHORT_CODE_TABLE_REV[26] = {
-//  00  01  02  03  04  05  06  07  08  09
-     9, 10, 11, 12, 13, 14, 15, 16,  0, 17,
-//  10  11  12  13  14  15  16  17  18  19
-    18,  0, 19, 20,  0, 21, 22, 23, 24, 25,
-//  20  21  22  23  24  25
+const char SHORT_CODE_TABLE_REV[42] = {
+//  00  01  02  03  04  05  06  07  08
+     0,  1,  2,  3,  4,  5,  6,  7,  8,
+//  09  10  11  12  13  14  15
+    -1, -1, -1, -1, -1, -1, -1,
+//  16  17  18  19  20  21  22  23  24  25
+     9, 10, 11, 12, 13, 14, 15, 16, -1, 17,
+//  26  27  28  29  30  31  32  33  34  35
+    18, -1, 19, 20, -1, 21, 22, 23, 24, 25,
+//  36  37  38  39  40  41
     26, 27, 28, 29, 30, 31,
 };
 
-// 00: 1 -> 48
+// 00: 1 -> 49 (00)
 // ...
-// 08: 9 -> 57
-// 09: A -> 65 (00)
+// 08: 9 -> 57 (08)
+// 09: A -> 65 (16)
 // ...
-// 16: H -> 72 (07)
-// 17: J -> 74 (09)
-// 18: K -> 75 (10)
-// 19: M -> 77 (12)
-// 20: N -> 78 (13)
-// 21: P -> 80 (15)
+// 16: H -> 72 (23)
+// 17: J -> 74 (25)
+// 18: K -> 75 (26)
+// 19: M -> 77 (28)
+// 20: N -> 78 (29)
+// 21: P -> 80 (31)
 // ...
-// 31: Z -> 90 (25)
+// 31: Z -> 90 (41)
 
 class ShortCode {
 public: