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@RyuaNerin RyuaNerin/Base64Write.cs

Last active Apr 9, 2016
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From Stream -> Base64 -> To Stream
private static byte[] Base64Table = {
0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x53, 0x54,
0x55, 0x56, 0x57, 0x58, 0x59, 0x5a,
0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a,
0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74,
0x75, 0x76, 0x77, 0x78, 0x79, 0x7a,
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
0x2b, 0x2f, 0x3d }; // ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=
// 0x2d, 0x5f, 0x3d }; // ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_=
private static void WriteByBase64(Stream from, Stream to)
{
var buff = new byte[4096];
int read = 0;
int i = 0;
int b;
long pos = to.Position;
WriteByBase64_Read(buff, from, ref i, ref read);
while (true)
{
if (i >= read) WriteByBase64_Read(buff, from, ref i, ref read);
if (i >= read) break;
b = (buff[i] & 0xFC) >> 2;
to.WriteByte(Base64Table[b]);
b = (buff[i] & 0x03) << 4;
if (i + 1 >= read) WriteByBase64_Read(buff, from, ref i, ref read);
if (i + 1 < read)
{
b |= (buff[i + 1] & 0xF0) >> 4;
to.WriteByte(Base64Table[b]);
b = (buff[i + 1] & 0x0F) << 2;
if (i + 2 >= read) WriteByBase64_Read(buff, from, ref i, ref read);
if (i + 2 < read)
{
b |= (buff[i + 2] & 0xC0) >> 6;
to.WriteByte(Base64Table[b]);
b = buff[i + 2] & 0x3F;
to.WriteByte(Base64Table[b]);
}
else
{
to.WriteByte(Base64Table[b]);
to.WriteByte(Base64Table[64]);
}
}
else
{
to.WriteByte(Base64Table[b]);
to.WriteByte(Base64Table[64]);
to.WriteByte(Base64Table[64]);
}
i += 3;
}
pos = to.Position - pos;
while (pos++ % 4 != 0)
to.WriteByte(Base64Table[64]);
}
private static void WriteByBase64_Read(byte[] buff, Stream from, ref int i, ref int read)
{
int index = 0;
int k;
for (k = i; k < read; ++k) buff[index++] = buff[k];
var nr = from.Read(buff, index, buff.Length - index);
if (nr > 0)
{
read = nr + index;
i = 0;
}
}
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