Support Byte Arrays in Glaze

[kaladron]

Add byte_array wrapper for explicit fixed-size character array serialization. This introduces glz::byte_array.

Currently:
char arr[4] = {0, 0, 1, 0};
std::string json;
glz::write_json(arr, json);
// Previously: json == """" (empty string - WRONG) // Expected: json == ""\u0000\u0000\u0001\u0000"" (desired behavior)

This happens because there's no way to distinguish between a regular character array and a byte array in C/C++.

This introduces:

char arr[4] = {0, 0, 1, 0};

// Traditional behavior (unchanged)
glz::write_json(arr, json); // → ""

// NEW: Explicit byte array behavior
glz::write_json(glz::byte_array{arr}, json); // → "\u0000\u0000\u0001\u0000"

Tested:
Null-only arrays: glz::byte_array{char[3]{0,0,0}} → "\u0000\u0000\u0000" Mixed content: glz::byte_array{char[4]{'a',0,'b','\n'}} → "a\u0000b\n" Normal strings: glz::byte_array{char[5]{'h','e','l','l','o'}} → "hello" Round-trip: Full serialization and deserialization support

[kaladron]

This was built in collaboration with GitHub Copilot. My apologies if I got something wrong. I'm also happy to take a different approach if you'd rather.

[stephenberry]

@kaladron, this approach works. But, what you're wanting is already supported by wrapping your char array in a std::string_view and then using the option: escape_control_characters

char raw[4] = {0, 0, 1, 0};
std::string_view view{raw, sizeof(raw)};

std::string buffer{};
expect(not glz::write<opts_escape_control_characters{}>(view, buffer));

expect(buffer == R"("\u0000\u0000\u0001\u0000")");

I do think an explicitly named wrapper type would make sense. But, I'm not sure what to name it. I think glz::byte_array is a little too generic, and doesn't sound like a slow, auto escaping wrapper. Maybe something like glz::escape_bytes_json. What do you think?

[kaladron]

I got a bit swamped this week - I'll get to this shortly. Thank you!