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/* Copyright (c) 2010 Wildfire Games
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* base32 conversion
*/
#include "precompiled.h"
// big endian!
void base32(const size_t in_len, const u8* in, u8* out)
{
u32 pool = 0; // of bits from buffer
ssize_t pool_bits = 0; // # bits currently in buffer
static const u8 tbl[33] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
size_t in_bytes_left = in_len; // to avoid overrunning input buffer
const size_t out_chars = (in_len*8 + 4) / 5; // = ceil(# 5-bit blocks)
for(size_t i = 0; i < out_chars; i++)
{
if(pool_bits < 5 && in_bytes_left)
{
pool <<= 8;
pool |= *in++;
pool_bits += 8;
in_bytes_left--;
}
pool_bits -= 5;
size_t c;
if (pool_bits < 0)
c = (pool << -pool_bits) & 31;
else
c = (pool >> pool_bits) & 31;
*out++ = tbl[c];
}
*out++ = '\0';
}
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