Zig based JSON serializer/deserializer for Playdate

playdate_json_serializer.zig

/// Module that wraps up the zig json system for use in playdate

const std = @import("std");
const pdapi = @import("playdate_api_definitions.zig");

pub fn read_from_json_str(
    input: []const u8,
    comptime thing_to_read: type,
    allocator: std.mem.Allocator,
) !thing_to_read
{
    const read_it = try std.json.parseFromSlice(
        thing_to_read,
        allocator,
        input,
        .{}
    );
    defer read_it.deinit();

    return read_it.value;
}

pub fn read_from_json_file(
    filepath: [:0]const u8,
    comptime thing_to_read: type,
    allocator: std.mem.Allocator,
    playdate: *pdapi.PlaydateAPI,
) !thing_to_read
{
    var buf2:[2048:0]u8 = undefined;
    var fh = playdate.file.open(filepath, pdapi.FILE_READ_DATA);
    if (fh == null) {
        return error.JsonFileOpenError;
    }
    const bits_read = playdate.file.read(fh, &buf2, 1024);
    const read_buf = buf2[0..@intCast(bits_read)];

    return try read_from_json_str(
        read_buf,
        thing_to_read,
        allocator,
    );
}

pub fn write_to_json_str(
    thing_to_write: anytype,
    output: []u8,
    allocator: std.mem.Allocator,
) ![]u8
{
    var string = std.ArrayList(u8).init(allocator);
    defer string.deinit();
    try std.json.stringify(thing_to_write, .{}, string.writer());

    return try std.fmt.bufPrintZ(output, "{s}\n", .{string.items});
}

pub fn write_to_json_file(
    thing_to_write: anytype,
    filepath: [:0]const u8,
    allocator: std.mem.Allocator,
    playdate: *pdapi.PlaydateAPI,
) !void
{
    var buf2:[2048:0]u8 = undefined;

    const result = try write_to_json_str(thing_to_write, &buf2, allocator);
    var fh = playdate.file.open(filepath, pdapi.FILE_WRITE);
    _ = playdate.file.write(fh, result.ptr, @intCast(result.len));
    _ = playdate.file.close(fh);
    _ = playdate.file.flush(fh);
}