Stuff

2026-07-01 18:28:25 +00:00 · 2022-09-06 13:25:14 -04:00
parent 77542ebad7
commit 7b932060d4
16 changed files with 562 additions and 55 deletions
@@ -0,0 +1,92 @@
+package dev.brighten.ac.utils;
+
+public final class Base64 {
+    private static final int BYTES_PER_UNENCODED_BLOCK = 3;
+    private static final int BYTES_PER_ENCODED_BLOCK = 4;
+    private static final int SIX_BIT_MASK = 63;
+    private static final byte PAD = 61;
+    private static final byte[] ENCODE_TABLE = new byte[]{65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 43, 47};
+    private static final int[] DECODE_TABLE = new int[128];
+
+    public static byte[] decode(String s) {
+        int delta = s.endsWith("==") ? 2 : (s.endsWith("=") ? 1 : 0);
+        byte[] buffer = new byte[s.length() * 3 / 4 - delta];
+        int mask = 255;
+        int pos = 0;
+
+        for(int i = 0; i < s.length(); i += 4) {
+            int c0 = DECODE_TABLE[s.charAt(i)];
+            int c1 = DECODE_TABLE[s.charAt(i + 1)];
+            buffer[pos++] = (byte)((c0 << 2 | c1 >> 4) & mask);
+            if (pos >= buffer.length) {
+                return buffer;
+            }
+
+            int c2 = DECODE_TABLE[s.charAt(i + 2)];
+            buffer[pos++] = (byte)((c1 << 4 | c2 >> 2) & mask);
+            if (pos >= buffer.length) {
+                return buffer;
+            }
+
+            int c3 = DECODE_TABLE[s.charAt(i + 3)];
+            buffer[pos++] = (byte)((c2 << 6 | c3) & mask);
+        }
+
+        return buffer;
+    }
+
+    public static String encode(byte[] in) {
+        int modulus = 0;
+        int bitWorkArea = 0;
+        int numEncodedBytes = in.length / 3 * 4 + (in.length % 3 == 0 ? 0 : 4);
+        byte[] buffer = new byte[numEncodedBytes];
+        int pos = 0;
+        byte[] var6 = in;
+        int var7 = in.length;
+
+        for(int var8 = 0; var8 < var7; ++var8) {
+            int b = var6[var8];
+            modulus = (modulus + 1) % 3;
+            if (b < 0) {
+                b += 256;
+            }
+
+            bitWorkArea = (bitWorkArea << 8) + b;
+            if (0 == modulus) {
+                buffer[pos++] = ENCODE_TABLE[bitWorkArea >> 18 & 63];
+                buffer[pos++] = ENCODE_TABLE[bitWorkArea >> 12 & 63];
+                buffer[pos++] = ENCODE_TABLE[bitWorkArea >> 6 & 63];
+                buffer[pos++] = ENCODE_TABLE[bitWorkArea & 63];
+            }
+        }
+
+        switch (modulus) {
+            case 1:
+                buffer[pos++] = ENCODE_TABLE[bitWorkArea >> 2 & 63];
+                buffer[pos++] = ENCODE_TABLE[bitWorkArea << 4 & 63];
+                buffer[pos++] = 61;
+                buffer[pos] = 61;
+                break;
+            case 2:
+                buffer[pos++] = ENCODE_TABLE[bitWorkArea >> 10 & 63];
+                buffer[pos++] = ENCODE_TABLE[bitWorkArea >> 4 & 63];
+                buffer[pos++] = ENCODE_TABLE[bitWorkArea << 2 & 63];
+                buffer[pos] = 61;
+        }
+
+        return byteArrayToString(buffer);
+    }
+
+    private static String byteArrayToString(byte[] buffer) {
+        return new String(buffer, 0, 0, buffer.length);
+    }
+
+    private Base64() {
+    }
+
+    static {
+        for(int i = 0; i < ENCODE_TABLE.length; DECODE_TABLE[ENCODE_TABLE[i]] = i++) {
+        }
+
+    }
+}