Export a C library

build.zig

@@ -30,6 +30,18 @@ pub fn build(b: *std.Build) void {
         },
     });
 
+    // Static Library
+    const lib = b.addStaticLibrary(.{
+        .name = "fastlanez",
+        .target = target,
+        .optimize = optimize,
+        .root_source_file = .{ .path = "src/lib.zig" },
+    });
+    b.installArtifact(lib);
+    // Ideally we would use dlib.getEmittedH(), but https://github.com/ziglang/zig/issues/18497
+    const lib_header = b.addInstallFile(.{ .path = "zig-cache/fastlanez.h" }, "include/fastlanez.h");
+    b.getInstallStep().dependOn(&lib_header.step);
+
     // Unit Tests
     const unit_tests = b.addTest(.{
         .root_source_file = .{ .path = "src/fastlanez.zig" },

src/lib.zig

@@ -0,0 +1,31 @@
+//! The C library for FastLanez.
+const fl = @import("./fastlanez.zig");
+const std = @import("std");
+
+// BitPacking
+comptime {
+    const BitPacking = @import("./bitpacking.zig").BitPacking;
+    for (.{u8}) |E| {
+        const FL = fl.FastLanez(E);
+
+        for (1..@bitSizeOf(E)) |W| {
+            // TODO(ngates): configure this in build.zig
+            const dbg = @import("builtin").mode == .Debug;
+            if (dbg and !std.math.isPowerOfTwo(W)) {
+                // Avoid too much code-gen in debug mode.
+                continue;
+            }
+
+            const Wrapper = struct {
+                fn encode(in: *const FL.Vector, out: *FL.PackedBytes(W)) callconv(.C) void {
+                    @call(.always_inline, BitPacking(FL).encode, .{ W, in, out });
+                }
+            };
+
+            @export(Wrapper.encode, .{
+                .name = "bitpack_" ++ @typeName(E) ++ "_" ++ @typeName(std.meta.Int(.unsigned, W)),
+                .linkage = .Strong,
+            });
+        }
+    }
+}