start with cmph.zig and bdz.zig

README.md

@@ -139,8 +139,8 @@ OFFSET     TYPE     NAME                          DESCRIPTION
    8        u32     num_users                     number of passwd entries
   12        u32     num_groups                    number of group entries
   16        u32     offset_bdz_uid2user
-  20        u32     offset_bdz_groupname2group
   24        u32     offset_bdz_name2user
+  20        u32     offset_bdz_groupname2group
   28        u32     offset_idx                    offset to the first idx_ section
   32        u32     offset_groups
   36        u32     offset_users
@@ -180,7 +180,7 @@ referred by their byte offset in the `Users` and `Groups` section relative to
 the beginning of the section.
 
 ```
-const Group = struct {
+const PackedGroup = struct {
     gid: u32,
     // index to a separate structure with a list of members. The memberlist is
     // always 2^5-byte aligned (32b), this is an index there.
@@ -345,10 +345,10 @@ Each section is padded to 64 bytes.
 ```
 STATUS  SECTION               SIZE             DESCRIPTION
 ✅      Header                48               see "Turbonss header" section
-        bdz_gid2group         ?                gid->group bdz
-        bdz_uid2user          ?                uid->user bdz
-        bdz_groupname2group   ?                groupname->group bdz
-        bdz_name2user         ?                username->user bdz
+        bdz_gid               ?                bdz(gid)
+        bdz_groupname         ?                bdz(groupname)
+        bdz_uid               ?                bdz(uid)
+        bdz_name              ?                bdz(username)
         idx_gid2group         len(group)*29/8  bdz->offset Groups
         idx_groupname2group   len(group)*29/8  bdz->offset Groups
         idx_uid2user          len(user)*29/8   bdz->offset Users

src/bdz.zig

@@ -0,0 +1,12 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+const c = @cImport({
+    @cInclude("bdz.h");
+});
+
+pub fn search_packed(packed_mphf: []const u8, key: []const u8) error{Overflow}!u32 {
+    const bdz_start = @intToPtr(?*anyopaque, @ptrToInt(&packed_mphf[4]));
+    const len = try std.math.cast(c_uint, key.len);
+    return @as(u32, c.bdz_search_packed(bdz_start, key.ptr, len));
+}

src/cmph.zig

@@ -0,0 +1,68 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const bdz = @import("bdz.zig");
+
+const c = @cImport({
+    @cInclude("cmph.h");
+});
+
+// pack packs cmph hashes for the given input and returns a slice ("cmph
+// userdata") for further storage. The slice must be freed by the caller.
+const packErr = Allocator.Error || error{Overflow};
+pub fn pack(allocator: Allocator, input: [][*:0]const u8) packErr![]const u8 {
+    var cvector = @ptrCast([*c][*c]u8, input.ptr);
+    const len = try std.math.cast(c_uint, input.len);
+    var source = c.cmph_io_vector_adapter(cvector, len);
+    defer c.cmph_io_vector_adapter_destroy(source);
+    var config: *c.cmph_config_t = c.cmph_config_new(source) orelse return error.OutOfMemory;
+    c.cmph_config_set_algo(config, c.CMPH_BDZ);
+    c.cmph_config_set_b(config, 7);
+    var hash: *c.cmph_t = c.cmph_new(config) orelse return error.OutOfMemory;
+    c.cmph_config_destroy(config);
+
+    const size = c.cmph_packed_size(hash);
+    var buf = try allocator.alloc(u8, size);
+    c.cmph_pack(hash, &buf[0]);
+    c.cmph_destroy(hash);
+    return buf;
+}
+
+const testing = std.testing;
+
+const items = .{
+    "aaaaaaaaaa",
+    "bbbbbbbbbb",
+    "cccccccccc",
+    "dddddddddd",
+    "eeeeeeeeee",
+    "ffffffffff",
+    "gggggggggg",
+    "hhhhhhhhhh",
+    "iiiiiiiiii",
+    "jjjjjjjjjj",
+};
+const items_len = items.len;
+
+fn samplePack(allocator: Allocator) ![]const u8 {
+    var vector = std.ArrayList([*:0]const u8).init(allocator);
+    defer vector.deinit();
+    try vector.appendSlice(&items);
+    return pack(allocator, vector.items);
+}
+
+test "basic pack/unpack" {
+    const buf = try samplePack(testing.allocator);
+    defer testing.allocator.free(buf);
+    try testing.expect(buf.len < 100);
+
+    var used: [items_len]bool = undefined;
+
+    inline for (items) |elem| {
+        const hashed = try bdz.search_packed(buf, elem);
+        used[hashed] = true;
+    }
+
+    for (used) |item| {
+        try testing.expect(item);
+    }
+}

src/main.zig

@@ -1,65 +1,3 @@
 const std = @import("std");
 
-const c = @cImport({
-    @cDefine("DEBUG", "1");
-    @cInclude("stdio.h");
-    @cInclude("string.h");
-    @cInclude("cmph.h");
-});
-
-const tempMph = "temp.mph";
-
 pub fn main() !void {}
-
-test "simple cmph usage" {
-    var arena_instance = std.heap.ArenaAllocator.init(std.heap.page_allocator);
-    const arena = arena_instance.allocator();
-    const stdout = std.io.getStdOut().writer();
-
-    var vector = std.ArrayList([*:0]const u8).init(arena);
-    try vector.appendSlice(&.{
-        "aaaaaaaaaa",
-        "bbbbbbbbbb",
-        "cccccccccc",
-        "dddddddddd",
-        "eeeeeeeeee",
-        "ffffffffff",
-        "gggggggggg",
-        "hhhhhhhhhh",
-        "iiiiiiiiii",
-        "jjjjjjjjjj",
-    });
-    var nkeys = @truncate(c_uint, vector.items.len);
-
-    var mphf_fd = c.fopen(tempMph, "w");
-    var cvector = @ptrCast([*c][*c]u8, vector.items.ptr);
-    var source = c.cmph_io_vector_adapter(cvector, nkeys);
-    defer c.cmph_io_vector_adapter_destroy(source);
-    var config: *c.cmph_config_t = c.cmph_config_new(source) orelse return error.OutOfMemory;
-    c.cmph_config_set_algo(config, c.CMPH_BRZ);
-    c.cmph_config_set_mphf_fd(config, mphf_fd);
-    var hash: *c.cmph_t = c.cmph_new(config) orelse return error.OutOfMemory;
-    c.cmph_config_destroy(config);
-    _ = c.cmph_dump(hash, mphf_fd);
-    c.cmph_destroy(hash);
-    try closeCFile(mphf_fd);
-
-    mphf_fd = c.fopen(tempMph, "r");
-    defer _ = c.fclose(mphf_fd);
-
-    hash = c.cmph_load(mphf_fd) orelse unreachable;
-    defer c.cmph_destroy(hash);
-
-    try stdout.print("\n", .{});
-    for (vector.items) |key| {
-        var id = c.cmph_search(hash, key, @truncate(c_uint, c.strlen(key)));
-        try stdout.print("key: {s}, id: {d}\n", .{ key, id });
-    }
-}
-
-fn closeCFile(f: *c.FILE) !void {
-    var close_code = c.fclose(f);
-    if (close_code != 0) {
-        return std.os.unexpectedErrno(std.os.errno(close_code));
-    }
-}

src/test_main.zig

@@ -6,4 +6,5 @@ test "turbonss test suite" {
     _ = @import("group.zig");
     _ = @import("padding.zig");
     _ = @import("varint.zig");
+    _ = @import("cmph.zig");
 }