41 lines
985 B
C++
41 lines
985 B
C++
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/**
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* =========================================================================
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* File : base32.cpp
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* Project : 0 A.D.
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* Description : base32 conversion
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* =========================================================================
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*/
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// license: GPL; see lib/license.txt
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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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uint 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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const uint 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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