/// <summary> /// Write out contents of byte array b as a JSON string with base-64 encoded /// data /// </summary> private async Task WriteJsonBase64Async(byte[] bytes, CancellationToken cancellationToken) { await Context.WriteAsync(cancellationToken); await Trans.WriteAsync(TJSONProtocolConstants.Quote, cancellationToken); var len = bytes.Length; var off = 0; while (len >= 3) { // Encode 3 bytes at a time TBase64Helper.Encode(bytes, off, 3, _tempBuffer, 0); await Trans.WriteAsync(_tempBuffer, 0, 4, cancellationToken); off += 3; len -= 3; } if (len > 0) { // Encode remainder TBase64Helper.Encode(bytes, off, len, _tempBuffer, 0); await Trans.WriteAsync(_tempBuffer, 0, len + 1, cancellationToken); } await Trans.WriteAsync(TJSONProtocolConstants.Quote, cancellationToken); }
/// <summary> /// Read in a JSON string containing base-64 encoded data and decode it. /// </summary> private async Task <byte[]> ReadJsonBase64Async(CancellationToken cancellationToken) { var b = await ReadJsonStringAsync(false, cancellationToken); var len = b.Length; var off = 0; var size = 0; // reduce len to ignore fill bytes while ((len > 0) && (b[len - 1] == '=')) { --len; } // read & decode full byte triplets = 4 source bytes while (len > 4) { // Decode 4 bytes at a time TBase64Helper.Decode(b, off, 4, b, size); // NB: decoded in place off += 4; len -= 4; size += 3; } // Don't decode if we hit the end or got a single leftover byte (invalid // base64 but legal for skip of regular string exType) if (len > 1) { // Decode remainder TBase64Helper.Decode(b, off, len, b, size); // NB: decoded in place size += len - 1; } // Sadly we must copy the byte[] (any way around this?) var result = new byte[size]; Array.Copy(b, 0, result, 0, size); return(result); }