create sha1_info

src/ft_sha1_info.hpp

@@ -0,0 +1,64 @@
+#pragma once
+
+#include <cstdint>
+#include <array>
+#include <vector>
+#include <cassert>
+#include <string>
+
+struct SHA1Digest {
+	std::array<uint8_t, 20> data;
+
+	SHA1Digest(const std::vector<uint8_t>& v) {
+		assert(v.size() == data.size());
+		for (size_t i = 0; i < data.size(); i++) {
+			data[i] = v[i];
+		}
+	}
+};
+
+struct FTInfoSHA1 {
+	std::string file_name;
+	uint64_t file_size {0};
+	static constexpr size_t chunk_size {4*1024}; // 4KiB for now
+	std::vector<SHA1Digest> chunks;
+
+	std::vector<uint8_t> toBuffer(void) const {
+		std::vector<uint8_t> buffer;
+
+		assert(!file_name.empty());
+		// TODO: optimize
+		for (size_t i = 0; i < 256; i++) {
+			if (i < file_name.size()) {
+				buffer.push_back(file_name.at(i));
+			} else {
+				buffer.push_back(0);
+			}
+		}
+		assert(buffer.size() == 256);
+
+		{ // HACK: endianess
+			buffer.push_back((file_size>>(0*8)) & 0xff);
+			buffer.push_back((file_size>>(1*8)) & 0xff);
+			buffer.push_back((file_size>>(2*8)) & 0xff);
+			buffer.push_back((file_size>>(3*8)) & 0xff);
+			buffer.push_back((file_size>>(4*8)) & 0xff);
+			buffer.push_back((file_size>>(5*8)) & 0xff);
+			buffer.push_back((file_size>>(6*8)) & 0xff);
+			buffer.push_back((file_size>>(7*8)) & 0xff);
+		}
+		assert(buffer.size() == 256+8);
+
+		// chunk size?
+
+		for (const auto& chunk : chunks) {
+			for (size_t i = 0; i < chunk.data.size(); i++) {
+				buffer.push_back(chunk.data[i]);
+			}
+		}
+		assert(buffer.size() == 256+8+20*chunks.size());
+
+		return buffer;
+	}
+};
+