Browse code
Add base32 encoder prototype
Ed Langley authored on 02/06/2017 18:00:49Showing 1 changed files
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new file mode 100644 |
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+#include <iostream> |
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+#include <iomanip> |
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+#include <vector> |
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+ |
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+std::string encodeBase32(const std::vector<uint8_t> data) {
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+ std::vector<char> alphabet = {
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+ 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', |
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+ 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', |
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+ 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', |
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+ 'Y', 'Z', '2', '3', '4', '5', '6', '7' |
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+ }; |
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+ |
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+ uint8_t tmp = 0; |
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+ auto data_size = data.size(); |
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+ |
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+ std::string result; |
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+ auto begin = data.begin(); |
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+ auto end = data.end(); |
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+ |
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+ auto extra_bytes = (data_size % 5); |
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+ auto padding_chars = 0; |
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+ switch (extra_bytes) {
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+ case 1: |
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+ padding_chars = 6; |
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+ break; |
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+ case 2: |
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+ padding_chars = 4; |
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+ break; |
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+ case 3: |
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+ padding_chars = 3; |
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+ break; |
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+ case 4: |
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+ padding_chars = 1; |
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+ break; |
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+ } |
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+ |
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+ auto leftover = (5 - extra_bytes) % 5; |
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+ for (auto cur = begin; cur+5 < (end + leftover + 1); cur+=5) {
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+ std::vector<uint8_t> batch; |
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+ if (cur+5 < end) {
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+ batch = std::vector<uint8_t> (cur, cur+5); |
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+ } else {
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+ batch = std::vector<uint8_t> (cur, end); |
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+ for (int x = 0; x < leftover; x++) {
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+ batch.push_back(0); |
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+ } |
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+ } |
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+ |
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+ std::bitset<40> everything; |
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+ everything |= (static_cast<uint64_t>(batch[0]) << 32); |
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+ everything |= (static_cast<uint64_t>(batch[1]) << 24); |
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+ everything |= (static_cast<uint64_t>(batch[2]) << 16); |
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+ everything |= (static_cast<uint64_t>(batch[3]) << 8); |
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+ everything |= batch[4]; |
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+ |
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+ uint64_t mask = 31; |
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+ uint64_t offset = 35; |
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+ mask <<= offset; |
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+ |
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+ int counter = 0; |
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+ while (offset <= 35) {
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+ auto idx = everything; |
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+ idx &= mask; |
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+ idx >>= offset; |
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+ |
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+ mask >>= 5; |
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+ offset -= 5; |
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+ |
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+ result.push_back(alphabet[idx.to_ullong()]); |
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+ } |
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+ } |
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+ |
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+ if (padding_chars > 0) {
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+ auto replace_end = result.end(); |
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+ auto replace_start = replace_end - padding_chars; |
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+ auto replace_count = replace_end - replace_start; |
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+ |
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+ result.replace(replace_start, replace_end, replace_count, '='); |
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+ } |
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+ |
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+ return result; |
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+} |
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+ |
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+int main(int argc, char** argv) {
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+ std::string data; |
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+ while (std::getline(std::cin,data)) {
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+ std::vector<unsigned char> v(data.begin(), data.end()); |
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+ |
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+ std::string res = encodeBase32(v); |
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+ std::cout << "{\"ORIGINAL\": \"" << data << "\", \"BASE32\": \"" << res << "\"}" << std::endl;
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+ } |
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+} |