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100 lines
2.4 KiB
100 lines
2.4 KiB
/* Distributed under the OSI-approved BSD 3-Clause License. See accompanying
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file Copyright.txt or https://cmake.org/licensing for details. */
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#include "cmBase32.h"
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// -- Static functions
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static const unsigned char Base32EncodeTable[33] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
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inline unsigned char Base32EncodeChar(int schar)
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{
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return Base32EncodeTable[schar];
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}
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void Base32Encode5(const unsigned char src[5], char dst[8])
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{
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// [0]:5 bits
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dst[0] = Base32EncodeChar((src[0] >> 3) & 0x1F);
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// [0]:3 bits + [1]:2 bits
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dst[1] = Base32EncodeChar(((src[0] << 2) & 0x1C) + ((src[1] >> 6) & 0x03));
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// [1]:5 bits
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dst[2] = Base32EncodeChar((src[1] >> 1) & 0x1F);
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// [1]:1 bit + [2]:4 bits
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dst[3] = Base32EncodeChar(((src[1] << 4) & 0x10) + ((src[2] >> 4) & 0x0F));
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// [2]:4 bits + [3]:1 bit
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dst[4] = Base32EncodeChar(((src[2] << 1) & 0x1E) + ((src[3] >> 7) & 0x01));
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// [3]:5 bits
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dst[5] = Base32EncodeChar((src[3] >> 2) & 0x1F);
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// [3]:2 bits + [4]:3 bit
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dst[6] = Base32EncodeChar(((src[3] << 3) & 0x18) + ((src[4] >> 5) & 0x07));
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// [4]:5 bits
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dst[7] = Base32EncodeChar((src[4] << 0) & 0x1F);
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}
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// -- Class methods
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cmBase32Encoder::cmBase32Encoder()
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{
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}
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cmBase32Encoder::~cmBase32Encoder()
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{
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}
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std::string cmBase32Encoder::encodeString(const unsigned char* input,
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size_t len, bool padding)
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{
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std::string res;
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static const size_t blockSize = 5;
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static const size_t bufferSize = 8;
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char buffer[bufferSize];
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const unsigned char* end = input + len;
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while ((input + blockSize) <= end) {
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Base32Encode5(input, buffer);
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res.append(buffer, bufferSize);
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input += blockSize;
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}
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size_t remain(end - input);
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if (remain != 0) {
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// Temporary source buffer filled up with 0s
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unsigned char extended[blockSize];
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for (size_t ii = 0; ii != remain; ++ii) {
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extended[ii] = input[ii];
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}
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for (size_t ii = remain; ii != blockSize; ++ii) {
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extended[ii] = 0;
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}
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Base32Encode5(extended, buffer);
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size_t numPad(0);
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switch (remain) {
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case 1:
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numPad = 6;
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break;
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case 2:
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numPad = 4;
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break;
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case 3:
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numPad = 3;
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break;
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case 4:
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numPad = 1;
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break;
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default:
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break;
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}
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res.append(buffer, bufferSize - numPad);
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if (padding) {
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for (size_t ii = 0; ii != numPad; ++ii) {
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res.push_back(paddingChar);
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}
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}
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}
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return res;
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}
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