Add base64 tool

.gitignore

@@ -12,9 +12,9 @@ CTestTestfile.cmake
 _deps
 CMakeUserPresets.json
 
-build/*
-.cache/*
-out/*
+build
+.cache
+out
 
 # ---> VisualStudioCode
 .vscode/*

.vscode/launch.json

@@ -0,0 +1,19 @@
+{
+    // 使用 IntelliSense 了解相关属性。 
+    // 悬停以查看现有属性的描述。
+    // 欲了解更多信息，请访问: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Launch",
+            "type": "lldb",
+            "request": "launch",
+            // "program": "${command:cmake.launchTargetPath}",
+            "program": "${workspaceFolder}/out/hello-world",
+            "args": [],
+            "cwd": "${workspaceRoot}",
+            "console": "internalConsole",
+            "preLaunchTask": "Build",
+        },
+    ]
+}

.vscode/tasks.json

@@ -0,0 +1,20 @@
+{
+    // See https://go.microsoft.com/fwlink/?LinkId=733558
+    // for the documentation about the tasks.json format
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "Build",
+            "type": "process",
+            "command": "/data/data/com.termux/files/usr/bin/g++",
+            "echoCommand": true,
+            "isBuildCommand": true,
+            "args": [
+                "-g",
+                "-o",
+                "${workspaceFolder}/out/hello-world",
+                "${workspaceFolder}/hello.cpp"
+            ],
+        },
+    ]
+}

CMakeLists.txt

@@ -31,7 +31,3 @@ add_executable(
     ./calender.cpp
 )
 
-add_executable(
-    hello-world
-    ./hello.cpp
-)

base64/CMakeLists.txt

@@ -0,0 +1,9 @@
+add_executable(
+    encoder
+    ./encode.cpp
+)
+
+add_executable(
+    decoder
+    ./decode.cpp
+)

base64/binary.cpp

@@ -0,0 +1,46 @@
+#include <cstdio>
+#include <cstdlib>
+
+#include <ctime>
+#include <climits>
+
+int main(int argc, char **argv) {
+    const char *filename = "a.bin";
+    int bytes_count = 256;
+
+    if (argc > 1)
+        filename = argv[1];
+    
+    if (argc > 2)
+        bytes_count = atoi(argv[2]);
+
+    auto hex_file = fopen(filename, "wb");
+
+    if (hex_file == NULL) {
+        return -1;
+    }
+
+    srand(time(NULL));
+
+    constexpr int chunk_size = 0x400;
+    unsigned char buffer[chunk_size];
+    for (int total_bytes = bytes_count; chunk_size < total_bytes; total_bytes -= chunk_size) {
+        memset(buffer, 0, chunk_size);
+
+        for (int i = 0; i < chunk_size; ++ i) {
+            buffer[i] = rand() % UCHAR_MAX;
+        }
+
+        fwrite(buffer, chunk_size, 1, hex_file);
+    }
+
+    memset(buffer, 0, chunk_size);
+    for (int i = 0; i < bytes_count % chunk_size; ++ i) {
+        buffer[i] = rand() % UCHAR_MAX;
+    }
+    fwrite(buffer, bytes_count % chunk_size, 1, hex_file);
+
+    fclose(hex_file);
+
+    return 0;
+}

base64/encode.cpp

@@ -0,0 +1,73 @@
+#include <array>
+#include <fstream>
+#include <iterator>
+#include <string>
+
+constexpr char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+int main(int argc, char *argv[]) {
+    std::string
+        filename("a.bin"),
+        textfile("a.txt");
+
+    if (argc > 1) {
+        filename.assign(argv[1]);
+    }
+
+    if (argc > 2) {
+        textfile.assign(argv[2]);
+    }
+
+    std::fstream
+        file(filename, std::ios::binary | std::ios::in),
+        text(textfile, std::ios::out);
+
+    std::istreambuf_iterator<char>
+        iter_cur(file),
+        iter_end;
+
+    std::array<unsigned char, 0x1000> raw;
+    std::array<unsigned char, 0x2000> b64;
+    while (iter_cur != iter_end) {
+        raw.fill(0);
+        b64.fill(0);
+
+        auto beg = raw.begin();
+        auto cur = beg;
+        auto end = raw.end();
+
+        while (cur != end && iter_cur != iter_end) {
+            *cur++ = *iter_cur++;
+        }
+
+        auto delta = cur - beg;
+        auto repeat = delta / 3 + (delta % 3 != 0);
+        auto bin_ptr = beg;
+        auto b64_ptr = b64.begin();
+
+        for (auto a = 0; a < repeat; ++ a, bin_ptr += 3, b64_ptr += 4) {
+            int hex[4] = {
+                (bin_ptr[0] & 0b11111100) >> 2,
+                ((bin_ptr[0] & 0b00000011) << 4) +
+                    ((bin_ptr[1] & 0b11110000) >> 4),
+                ((bin_ptr[1] & 0b00001111) << 2) +
+                    ((bin_ptr[2] & 0b11000000) >> 6),
+                (bin_ptr[2] & 0b00111111),
+            };
+
+            for (int i = 0; i < 4; ++ i) {
+                b64_ptr[i] = base64[hex[i]];
+            }
+        }
+
+        for (int i = 1; i < delta % 3; ++ i) {
+            b64_ptr[-i] = '=';
+        }
+
+        text << b64.data();
+    }
+
+    text.flush();
+
+    return 0;
+}

hello.cpp

@@ -1,8 +0,0 @@
-#include <cstdio>
-#include <cstdlib>
-
-int main(int argc, char *argv[]) {
-    printf("Hello, world!\n");
-
-    return 0;
-}