1 files changed, 47 insertions, 0 deletions
diff --git a/api/src/util/Base64.ts b/api/src/util/Base64.ts
new file mode 100644
index 00000000..46cff77a
--- /dev/null
+++ b/api/src/util/Base64.ts
@@ -0,0 +1,47 @@
+const alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+";
+
+// binary to string lookup table
+const b2s = alphabet.split("");
+
+// string to binary lookup table
+// 123 == 'z'.charCodeAt(0) + 1
+const s2b = new Array(123);
+for (let i = 0; i < alphabet.length; i++) {
+ s2b[alphabet.charCodeAt(i)] = i;
+}
+
+// number to base64
+export const ntob = (n: number): string => {
+ if (n < 0) return `-${ntob(-n)}`;
+
+ let lo = n >>> 0;
+ let hi = (n / 4294967296) >>> 0;
+
+ let right = "";
+ while (hi > 0) {
+ right = b2s[0x3f & lo] + right;
+ lo >>>= 6;
+ lo |= (0x3f & hi) << 26;
+ hi >>>= 6;
+ }
+
+ let left = "";
+ do {
+ left = b2s[0x3f & lo] + left;
+ lo >>>= 6;
+ } while (lo > 0);
+
+ return left + right;
+};
+
+// base64 to number
+export const bton = (base64: string) => {
+ let number = 0;
+ const sign = base64.charAt(0) === "-" ? 1 : 0;
+
+ for (let i = sign; i < base64.length; i++) {
+ number = number * 64 + s2b[base64.charCodeAt(i)];
+ }
+
+ return sign ? -number : number;
+};
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