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