group_members

src/sections.zig

@@ -102,17 +102,14 @@ const Corpus = struct {
                     members.len += 1;
                     members[members.len - 1] = user_idx;
                     try user2groups[user_idx].append(allocator, @intCast(u32, i));
-                } else {
-                    return error.NotFound;
-                }
+                } else return error.NotFound;
             }
 
             group2users[i] = members;
         }
 
-        for (group2users) |*groupusers| {
+        for (group2users) |*groupusers|
             sort.sort(u32, groupusers.*, {}, comptime sort.asc(u32));
-        }
 
         var user2groups_final = try allocator.alloc([]const u32, users.len);
         user2groups_final.len = users.len;
@@ -270,6 +267,7 @@ pub fn usersSection(
 pub const GroupMembers = struct {
     // group index to it's offset in blob
     idx2offset: []const u64,
+    // members are delta-varint encoded byte-offsets to the user struct
     blob: []const u8,
 
     pub fn deinit(self: *GroupMembers, allocator: Allocator) void {
@@ -291,8 +289,8 @@ pub fn groupMembers(
     // zero'th entry is empty, so empty groups can refer to it
     try compress.appendUvarint(&blob, 0);
 
-    var scratch = try allocator.alloc(u32, 256);
-    defer allocator.free(scratch);
+    var scratch = try ArrayList(u32).initCapacity(allocator, 1024);
+    defer scratch.deinit();
 
     for (corpus.group2users) |members, group_idx| {
         if (members.len == 0) {
@@ -300,16 +298,18 @@ pub fn groupMembers(
             continue;
         }
 
-        scratch = try allocator.realloc(scratch, members.len);
-        scratch.len = members.len;
-        mem.copy(u32, scratch, members);
+        idx2offset[group_idx] = blob.items.len;
+        try scratch.ensureTotalCapacity(members.len);
+        scratch.items.len = members.len;
+        for (members) |user_idx, i|
+            scratch.items[i] = user2offset[user_idx];
 
-        compress.deltaCompress(u32, scratch) catch |err| switch (err) {
+        compress.deltaCompress(u32, scratch.items) catch |err| switch (err) {
             error.NotSorted => unreachable,
         };
         try compress.appendUvarint(&blob, members.len);
-        for (scratch) |user_idx|
-            try compress.appendUvarint(&blob, user2offset[user_idx]);
+        for (scratch.items) |elem|
+            try compress.appendUvarint(&blob, elem);
     }
     return GroupMembers{
         .idx2offset = idx2offset,
@@ -325,9 +325,7 @@ fn cmpUser(_: void, a: User, b: User) bool {
         if (utf8_b.nextCodepoint()) |codepoint_b| {
             if (codepoint_a == codepoint_b) {
                 continue;
-            } else {
-                return codepoint_a < codepoint_b;
-            }
+            } else return codepoint_a < codepoint_b;
         }
 
         // a is a prefix of b. It is thus shorter.
@@ -373,11 +371,11 @@ pub const AllSections = struct {
             &user_gids,
             &shell_sections,
         );
-        //const group_members = try groupMembers(
-        //    allocator,
-        //    corpus,
-        //    users.idx2offset,
-        //);
+        const group_members = try groupMembers(
+            allocator,
+            corpus,
+            users.idx2offset,
+        );
         return AllSections{
             .allocator = allocator,
             .bdz_gid = bdz_gid,
@@ -389,8 +387,7 @@ pub const AllSections = struct {
             .shell_blob = mem.sliceAsBytes(shell_blob.constSlice()),
             .user_gids = user_gids,
             .users = users,
-            //.group_members = group_members,
-            .group_members = undefined,
+            .group_members = group_members,
         };
     }
 
@@ -402,6 +399,7 @@ pub const AllSections = struct {
         self.shell_sections.deinit();
         self.user_gids.deinit(self.allocator);
         self.users.deinit(self.allocator);
+        self.group_members.deinit(self.allocator);
         self.* = undefined;
     }
 };
@@ -512,13 +510,26 @@ test "test corpus" {
     try testing.expectEqual(groupsOfVidmantas[2], g_all);
 }
 
-test "test sections" {
+test "test group members" {
     const allocator = testing.allocator;
     var corpus = try testCorpus(allocator);
     defer corpus.deinit();
 
-    var all = try AllSections.init(allocator, &corpus);
-    defer all.deinit();
+    var sections = try AllSections.init(allocator, &corpus);
+    defer sections.deinit();
+
+    const blob = sections.group_members.blob;
+    var group_idx: usize = 0;
+    while (group_idx < corpus.groups.len) : (group_idx += 1) {
+        const offset = sections.group_members.idx2offset[group_idx];
+        var vit = try compress.VarintSliceIterator(blob[offset..]);
+        var it = compress.DeltaDecompressionIterator(&vit);
+        for (corpus.group2users[group_idx]) |user_idx| {
+            const got_user_offset = (try it.next()).?;
+            const want_user_offset = sections.users.idx2offset[user_idx];
+            try testing.expectEqual(got_user_offset, want_user_offset);
+        }
+    }
 }
 
 test "userGids" {
@@ -529,9 +540,10 @@ test "userGids" {
     var user_gids = try userGids(allocator, &corpus);
     defer user_gids.deinit(allocator);
 
-    for (corpus.users) |_, userIdx| {
-        const groups = corpus.user2groups[userIdx];
-        const offset = user_gids.idx2offset[userIdx];
+    var user_idx: usize = 0;
+    while (user_idx < corpus.users.len) : (user_idx += 1) {
+        const groups = corpus.user2groups[user_idx];
+        const offset = user_gids.idx2offset[user_idx];
         if (groups.len == 0) {
             try testing.expect(offset == 0);
             continue;

src/user.zig

@@ -105,9 +105,7 @@ fn packedUser(comptime ShellIndexType: type) type {
                 const name_len = self.nameLen();
                 if (self.name_is_a_suffix) {
                     return self.homeLen() - name_len;
-                } else {
-                    return self.homeLen();
-                }
+                } else return self.homeLen();
             }
 
             fn nameLen(self: *const Inner) usize {
@@ -117,9 +115,7 @@ fn packedUser(comptime ShellIndexType: type) type {
             fn gecosStart(self: *const Inner) usize {
                 if (self.name_is_a_suffix) {
                     return self.homeLen();
-                } else {
-                    return self.homeLen() + self.nameLen();
-                }
+                } else return self.homeLen() + self.nameLen();
             }
 
             fn gecosLen(self: *const Inner) usize {