add memory module

src/main.zig

@@ -8,6 +8,7 @@ const calendar = @import("modules/calendar.zig");
 const display = @import("modules/display.zig");
 const uptime = @import("modules/uptime.zig");
 const volume = @import("modules/volume.zig");
+const memory = @import("modules/memory.zig");
 const Module = @import("module.zig");
 
 pub fn main() !void {
@@ -23,6 +24,7 @@ pub fn main() !void {
 
     var modules = [_]Module{
         uptime.init(arena.allocator()).module,
+        memory.init(arena.allocator()).module,
         volume.init(arena.allocator()).module,
         display.init(arena.allocator()).module,
         battery.init(arena.allocator()).module,

src/modules/memory.zig

@@ -0,0 +1,40 @@
+const std = @import("std");
+const Module = @import("../module.zig");
+const Self = @This();
+
+module: Module,
+
+pub fn init(allocator: std.mem.Allocator) Self {
+    return .{
+        .module = .{
+            .allocator = allocator,
+            .getJsonFn = getJson,
+        },
+    };
+}
+
+pub fn getJson(module: *const Module) !Module.JSON {
+    const self = @fieldParentPtr(Self, "module", module);
+
+    var meminfo_file = try std.fs.openFileAbsolute("/proc/meminfo", .{});
+    defer meminfo_file.close();
+
+    const meminfo_string = try meminfo_file.reader().readAllAlloc(self.module.allocator, 4096);
+    const mem_total_idx = std.mem.indexOf(u8, meminfo_string, "MemTotal:");
+    const mem_available_idx = std.mem.indexOf(u8, meminfo_string, "MemAvailable:");
+    const mem_total_newline = std.mem.indexOfScalarPos(u8, meminfo_string, mem_total_idx.?, '\n');
+    const mem_available_newline = std.mem.indexOfScalarPos(u8, meminfo_string, mem_available_idx.?, '\n');
+    var mem_total_split = std.mem.splitBackwardsScalar(u8, meminfo_string[mem_total_idx.?..mem_total_newline.?], ' ');
+    var mem_available_split = std.mem.splitBackwardsScalar(u8, meminfo_string[mem_available_idx.?..mem_available_newline.?], ' ');
+    _ = mem_total_split.next();
+    _ = mem_available_split.next();
+
+    const mem_total = try std.fmt.parseInt(usize, mem_total_split.next().?, 10);
+    const mem_available = try std.fmt.parseInt(usize, mem_available_split.next().?, 10);
+
+    const mem = @as(f32, @floatFromInt(mem_total)) - @as(f32, @floatFromInt(mem_available));
+
+    return .{
+        .full_text = try std.fmt.allocPrint(self.module.allocator, "{d:.3} GB", .{mem / 1000 / 1000}),
+    };
+}