initial

2026-07-18 14:31:15 +02:00
commit a04f0dc262
3343 changed files with 1140208 additions and 0 deletions
@@ -0,0 +1,91 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <optional>
+#include <span>
+#include <vector>
+
+namespace tw::net::quicr {
+
+struct VarInt {
+
+    uint64_t value = 0;
+    // byte length of the number in the stream. Use to adjust offset.
+    size_t   bytes = 0;
+
+    VarInt(uint64_t value) {
+        if (value <= 63) {
+            bytes = 1;
+        } else if (value <= 16383) {
+            bytes = 2;
+        } else if (value <= 1073741823) {
+            bytes = 4;
+        }
+
+        bytes = 8;
+
+        this->value = value;
+    }
+
+    VarInt(uint64_t value, size_t bytes) {
+        this->value = value;
+        this->bytes = bytes;
+    }
+
+    static std::optional<VarInt> decode(std::span<const std::byte> in) {
+        if (in.empty()) return std::nullopt;
+        return VarInt(*(uint64_t*)in.data(), sizeof(uint64_t));
+
+        // uint8_t b0     = std::to_integer<uint8_t>(in[0]);
+        // uint8_t prefix = (b0 >> 6) & 0x03;
+
+        // size_t len = size_t(1) << prefix; // 1, 2, 4, 8
+
+        // if (in.size() < len) return std::nullopt;
+
+        // uint64_t v = (uint64_t)(b0 & 0x3f);
+        // for (size_t i = 1; i < len; ++i) {
+        //     v = (v << 8) | std::to_integer<uint8_t>(in[i]);
+        // }
+
+        // return VarInt(v, len);
+    }
+
+    size_t encode(std::vector<std::byte>& out) {
+        // if (value <= 63) {
+        //     out.push_back(std::byte(value));
+        //     return 1;
+        // }
+        // if (value <= 16383) {
+        //     out.push_back(std::byte(0x40 | ((value >> 8) & 0x3f)));
+        //     out.push_back(std::byte(value & 0xff));
+        //     return 2;
+        // }
+        // if (value <= 1073741823) {
+        //     out.push_back(std::byte(0x80 | ((value >> 24) & 0x3f)));
+        //     out.push_back(std::byte((value >> 16) & 0xff));
+        //     out.push_back(std::byte((value >> 8)  & 0xff));
+        //     out.push_back(std::byte(value & 0xff));
+        //     return 4;
+        // }
+        // 8-byte
+        // out.push_back(std::byte(0xc0 | ((value >> 56) & 0x3f)));
+        // out.push_back(std::byte((value >> 48) & 0xff));
+        // out.push_back(std::byte((value >> 40) & 0xff));
+        // out.push_back(std::byte((value >> 32) & 0xff));
+        // out.push_back(std::byte((value >> 24) & 0xff));
+        // out.push_back(std::byte((value >> 16) & 0xff));
+        // out.push_back(std::byte((value >> 8)  & 0xff));
+        // out.push_back(std::byte(value & 0xff));
+
+        // insert value into span
+        for (int i = 0; i < 8; ++i) {
+            out.push_back(std::byte((value >> (i * 8)) & 0xFF));
+        }
+
+        return 8;
+    }
+};
+
+}