initial commit

build/config.zig

@@ -0,0 +1,83 @@
+const std = @import("std");
+const builtin = @import("builtin");
+
+pub const Config = std.StringHashMap([]const u8);
+
+pub const Platform = struct {
+    arch: std.Target.Cpu.Arch,
+    os: std.Target.Os.Tag,
+};
+
+pub fn parseConfig(b: *std.Build) !Config {
+    const file = try std.Io.Dir.cwd().readFileAlloc(b.graph.io, ".config", b.allocator, std.Io.Limit.unlimited);
+
+    var lines = std.mem.splitScalar(u8, file, '\n');
+
+    var map = std.StringHashMap([]const u8).init(b.allocator);
+
+    while (lines.next()) |line| {
+        const trimmed = std.mem.trim(u8, line, " \r\t");
+        if (trimmed.len == 0 or std.mem.startsWith(u8, trimmed, "#")) {
+            continue;
+        }
+
+        var kv = std.mem.splitScalar(u8, trimmed, '=');
+        const key = kv.first();
+        const value = kv.rest();
+
+        try map.put(key, value);
+    }
+
+    return map;
+}
+
+pub fn configStep(b: *std.Build) *std.Build.Step {
+    return &b.addSystemCommand(&.{ "bash", "build/menuconfig" }).step;
+}
+
+fn isInteger(str: []const u8) bool {
+    _ = std.fmt.parseInt(i64, str, 10) catch return false;
+    return true;
+}
+
+pub fn generateConfig(b: *std.Build, config: Config) !*std.Build.Step.WriteFile {
+    var out = std.Io.Writer.Allocating.init(b.allocator);
+
+    var it = config.iterator();
+    while (it.next()) |entry| {
+        const key = entry.key_ptr.*;
+        const value = entry.value_ptr.*;
+
+        if (std.mem.eql(u8, value, "y")) {
+            try out.writer.print("pub const {s}: bool = true;\n", .{key});
+        } else if (isInteger(value)) {
+            try out.writer.print("pub const {s}: i64 = {s};\n", .{ key, value });
+        } else {
+            try out.writer.print("pub const {s} = \"{s}\";\n", .{ key, value });
+        }
+    }
+
+    const wf = b.addWriteFiles();
+
+    _ = wf.add("config.gen.zig", out.written());
+    _ = wf.addCopyFile(b.path(".config"), ".config");
+
+    return wf;
+}
+
+pub fn getPlatform(config: Config) !Platform {
+    const keys = .{
+        .{ "CONFIG_ARCH_AMD64", Platform{ .arch = .x86_64, .os = .freestanding } },
+        .{ "CONFIG_ARCH_AARCH64", Platform{ .arch = .aarch64, .os = .freestanding } },
+        .{ "CONFIG_ARCH_RISCV64", Platform{ .arch = .riscv64, .os = .freestanding } },
+        .{ "CONFIG_ARCH_UM", Platform{ .arch = builtin.cpu.arch, .os = .linux } },
+    };
+
+    inline for (keys) |entry| {
+        if (config.get(entry[0])) |val| {
+            if (std.mem.eql(u8, val, "y")) return entry[1];
+        }
+    }
+
+    return error.NoArchConfigured;
+}