From d4a7938369ccf39639c3fac8f6efa9df42af8168 Mon Sep 17 00:00:00 2001
From: Dnomd343 <i@343.re>
Date: Sat, 7 Jan 2023 17:32:49 +0800
Subject: [PATCH] feat: common code from string

---
 klotski/common_code.cc | 23 ++++++++++++++++++++++-
 klotski/common_code.h  |  2 +-
 klotski/main.cc        |  7 +++++--
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/klotski/common_code.cc b/klotski/common_code.cc
index 83374ae..52a50aa 100644
--- a/klotski/common_code.cc
+++ b/klotski/common_code.cc
@@ -11,7 +11,7 @@ std::string CommonCode::code_to_string(uint64_t common_code, bool shorten) {
     if (!CommonCode::check(common_code)) {
         throw std::invalid_argument("invalid common code");
     }
-    char result[10];
+    char result[10]; // max length 9-bits
     sprintf(result, "%09lX", common_code);
     if (shorten) { // remove `0` after common code
         if (common_code == 0x000000000) {
@@ -22,6 +22,27 @@ std::string CommonCode::code_to_string(uint64_t common_code, bool shorten) {
     return result;
 }
 
+uint64_t CommonCode::code_from_string(const std::string &common_code) {
+    if (common_code.length() > 9 || common_code.length() == 0) {
+        throw std::invalid_argument("common code format error");
+    }
+    uint64_t result = 0;
+    for (auto const &bit : common_code) {
+        result <<= 4;
+        if (bit >= '0' && bit <= '9') { // 0 ~ 9
+            result |= (bit - 48);
+        } else if (bit >= 'A' && bit <= 'Z') { // A ~ Z
+            result |= (bit - 55);
+        } else if (bit >= 'a' && bit <= 'z') { // a ~ z
+            result |= (bit - 87);
+        } else {
+            throw std::invalid_argument("common code format error");
+        }
+    }
+    // TODO: should we ensure that common code is valid?
+    return result << (9 - common_code.length()) * 4; // low-bits fill with zero
+}
+
 bool CommonCode::check(uint64_t common_code) {
     uint32_t head = common_code >> 32;
     if (head >= 16 || (head & 0b11) == 0b11) { // check 2x2 block address
diff --git a/klotski/common_code.h b/klotski/common_code.h
index 833adc8..430dcea 100644
--- a/klotski/common_code.h
+++ b/klotski/common_code.h
@@ -6,6 +6,6 @@
 class CommonCode {
 public:
     static bool check(uint64_t common_code);
-//    static uint64_t code_from_string(const std::string &common_code);
+    static uint64_t code_from_string(const std::string &common_code);
     static std::string code_to_string(uint64_t common_code, bool shorten = false);
 };
diff --git a/klotski/main.cc b/klotski/main.cc
index b73f139..15d4ad3 100644
--- a/klotski/main.cc
+++ b/klotski/main.cc
@@ -32,8 +32,11 @@ int main() {
 //    std::cout << ShortCode::code_from_string("EP4HZ") << std::endl;
 
 
-    std::cout << CommonCode::code_to_string(0x4FEA13400, true) << std::endl;
-    std::cout << CommonCode::code_to_string(0x4FEA13400) << std::endl;
+//    std::cout << CommonCode::code_to_string(0x4FEA13400, true) << std::endl;
+//    std::cout << CommonCode::code_to_string(0x4FEA13400) << std::endl;
+
+    printf("%09lX\n", CommonCode::code_from_string("4FEa134"));
+    printf("%09lX\n", CommonCode::code_from_string("1A9bf0C0"));
 
     return 0;
 }