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PR #18845.

src/base/utils/bytearray.cpp

@@ -1,5 +1,6 @@
 /*
  * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2023  Vladimir Golovnev <glassez@yandex.ru>
  * Copyright (C) 2018  Mike Tzou (Chocobo1)
  *
  * This program is free software; you can redistribute it and/or
@@ -68,3 +69,45 @@ const QByteArray Utils::ByteArray::midView(const QByteArray &in, const int pos,
             : len;
     return QByteArray::fromRawData(in.constData() + pos, validLen);
 }
+
+QByteArray Utils::ByteArray::toBase32(const QByteArray &in)
+{
+    const char alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
+    const char padchar = '=';
+
+    const qsizetype inSize = in.size();
+
+    auto tmp = QByteArray((inSize + 4) / 5 * 8, Qt::Uninitialized);
+    qsizetype inIndex = 0;
+    char *out = tmp.data();
+    while (inIndex < inSize)
+    {
+        // encode 5 bytes at a time
+        qsizetype inPadLen = 5;
+        int64_t chunk = 0;
+        while (inPadLen > 0)
+        {
+            chunk |= static_cast<int64_t>(static_cast<uchar>(in.data()[inIndex++])) << (--inPadLen * 8);
+            if (inIndex == inSize)
+                break;
+        }
+
+        const int outCharCounts[] = {8, 7, 5, 4, 2};
+        for (int i = 7; i >= 0; --i)
+        {
+            if (i >= (8 - outCharCounts[inPadLen]))
+            {
+                const int shift = (i * 5);
+                const int64_t mask = static_cast<int64_t>(0x1f) << shift;
+                const int charIndex = (chunk & mask) >> shift;
+                *out++ = alphabet[charIndex];
+            }
+            else
+            {
+                *out++ = padchar;
+            }
+        }
+    }
+
+    return tmp;
+}

src/base/utils/bytearray.h

@@ -1,5 +1,6 @@
 /*
  * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2023  Vladimir Golovnev <glassez@yandex.ru>
  * Copyright (C) 2018  Mike Tzou (Chocobo1)
  *
  * This program is free software; you can redistribute it and/or
@@ -41,4 +42,6 @@ namespace Utils::ByteArray
     // Mimic QByteArray::mid(pos, len) but instead of returning a full-copy,
     // we only return a partial view
     const QByteArray midView(const QByteArray &in, int pos, int len = -1);
+
+    QByteArray toBase32(const QByteArray &in);
 }