replace padding functions with ones from std.mem

src/DB.zig

@@ -12,7 +12,6 @@ const BoundedArray = std.BoundedArray;
 
 const ErrCtx = @import("ErrCtx.zig");
 const Corpus = @import("Corpus.zig");
-const pad = @import("padding.zig");
 const compress = @import("compress.zig");
 const Group = @import("Group.zig");
 const CGroup = Group.CGroup;
@@ -195,7 +194,7 @@ pub fn iov(self: *align(8) const DB) BoundedArray(os.iovec_const, DB_fields.len
             .iov_base = bytes.ptr,
             .iov_len = bytes.len,
         });
-        const padding = pad.until(usize, section_length_bits, bytes.len);
+        const padding = mem.alignForward(bytes.len, section_length) - bytes.len;
         if (padding != 0)
             result.appendAssumeCapacity(.{
                 .iov_base = zeroes,
@@ -592,7 +591,7 @@ fn usersSection(
             gids.idx2offset[i],
             shells.shell2idx,
         );
-        try pad.arrayList(&blob, PackedUser.alignment_bits);
+        try blob.appendNTimes(0, mem.alignForward(blob.items.len, 8) - blob.items.len);
     }
     return UsersSection{
         .len = @intCast(u32, corpus.users.len),
@@ -680,7 +679,7 @@ fn groupsSection(
             .members_offset = members_offset[i],
         };
         try PackedGroup.packTo(&blob, group_stored);
-        try pad.arrayList(&blob, PackedGroup.alignment_bits);
+        try blob.appendNTimes(0, mem.alignForward(blob.items.len, 8) - blob.items.len);
     }
 
     return GroupsSection{
@@ -727,7 +726,7 @@ pub fn nblocks_n(comptime T: type, nbytes: usize) T {
         u64 => u70,
         else => @compileError("got " ++ @typeName(T) ++ ", only u8, u32 and u64 are supported"),
     };
-    const upper = pad.roundUp(B, section_length_bits, @intCast(B, nbytes));
+    const upper = @intCast(B, mem.alignForward(nbytes, section_length));
     assert(upper & (section_length - 1) == 0);
     return @truncate(T, upper >> section_length_bits);
 }

src/PackedGroup.zig

@@ -6,7 +6,6 @@ const Allocator = mem.Allocator;
 const ArrayListAligned = std.ArrayListAligned;
 const BufSet = std.BufSet;
 
-const pad = @import("padding.zig");
 const validate = @import("validate.zig");
 const compress = @import("compress.zig");
 const InvalidRecord = validate.InvalidRecord;
@@ -55,7 +54,7 @@ pub fn fromBytes(bytes: []align(8) const u8) Entry {
             .groupdata = bytes[start_blob..end_strings],
             .members_offset = members_offset.value,
         },
-        .end = pad.roundUp(usize, alignment_bits, end_blob),
+        .end = mem.alignForward(end_blob, 8),
     };
 }
 
@@ -145,7 +144,7 @@ test "PackedGroup construct" {
 
     for (groups) |group| {
         try PackedGroup.packTo(&buf, group);
-        try pad.arrayList(&buf, PackedGroup.alignment_bits);
+        try buf.appendNTimes(0, mem.alignForward(buf.items.len, 8) - buf.items.len);
     }
 
     var i: u29 = 0;

src/PackedUser.zig

@@ -7,7 +7,6 @@ const ArrayListAligned = std.ArrayListAligned;
 const StringHashMap = std.StringHashMap;
 const fieldInfo = std.meta.fieldInfo;
 
-const pad = @import("padding.zig");
 const validate = @import("validate.zig");
 const compress = @import("compress.zig");
 const ShellReader = @import("shell.zig").ShellReader;
@@ -99,7 +98,7 @@ pub fn fromBytes(blob: []align(8) const u8) Entry {
             .var_payload = blob[start_var_payload..end_payload],
             .additional_gids_offset = gids_offset.value,
         },
-        .end = pad.roundUp(usize, alignment_bits, end_payload),
+        .end = mem.alignForward(end_payload, 8),
     };
 }
 
@@ -292,7 +291,7 @@ test "PackedUser construct section" {
     defer shellIndex.deinit();
     for (users) |user| {
         try PackedUser.packTo(&buf, user, additional_gids, shellIndex);
-        try pad.arrayList(&buf, PackedUser.alignment_bits);
+        try buf.appendNTimes(0, mem.alignForward(buf.items.len, 8) - buf.items.len);
     }
 
     var i: u29 = 0;

src/padding.zig

@@ -1,53 +0,0 @@
-const std = @import("std");
-const assert = std.debug.assert;
-const Allocator = std.mem.Allocator;
-const ArrayListAligned = std.ArrayListAligned;
-
-// rounds up an int to the nearest factor of nbits.
-pub fn roundUp(comptime T: type, comptime nbits: u8, n: T) T {
-    comptime assert(nbits < @bitSizeOf(T));
-    const factor = comptime (1 << nbits) - 1;
-    return ((n + factor) & ~@as(T, factor));
-}
-
-// rounds up an integer to the nearest factor of nbits and returns the
-// difference (padding)
-pub fn until(comptime T: type, comptime nbits: u8, n: T) T {
-    return roundUp(T, nbits, n) - n;
-}
-
-// arrayList adds padding to an ArrayListAligned(u8, 8) for a given number of nbits
-pub fn arrayList(arr: *ArrayListAligned(u8, 8), comptime nbits: u8) Allocator.Error!void {
-    const padding = until(u64, nbits, arr.items.len);
-    try arr.*.appendNTimes(0, padding);
-}
-
-const testing = std.testing;
-
-test "padding" {
-    try testing.expectEqual(until(u12, 2, 0), 0);
-    try testing.expectEqual(until(u12, 2, 1), 3);
-    try testing.expectEqual(until(u12, 2, 2), 2);
-    try testing.expectEqual(until(u12, 2, 3), 1);
-    try testing.expectEqual(until(u12, 2, 4), 0);
-    try testing.expectEqual(until(u12, 2, 40), 0);
-    try testing.expectEqual(until(u12, 2, 41), 3);
-    try testing.expectEqual(until(u12, 2, 42), 2);
-    try testing.expectEqual(until(u12, 2, 43), 1);
-    try testing.expectEqual(until(u12, 2, 44), 0);
-    try testing.expectEqual(until(u12, 2, 4091), 1);
-    try testing.expectEqual(until(u12, 2, 4092), 0);
-}
-
-test "padding arrayList" {
-    var buf = try ArrayListAligned(u8, 8).initCapacity(testing.allocator, 16);
-    defer buf.deinit();
-
-    buf.appendAssumeCapacity(1);
-    try arrayList(&buf, 3);
-    try testing.expectEqual(buf.items.len, 8);
-
-    buf.appendAssumeCapacity(2);
-    try arrayList(&buf, 10);
-    try testing.expectEqual(buf.items.len, 1024);
-}

src/test_all.zig

@@ -10,7 +10,6 @@ test "turbonss test suite" {
     _ = @import("libnss.zig");
     _ = @import("PackedGroup.zig");
     _ = @import("PackedUser.zig");
-    _ = @import("padding.zig");
     _ = @import("shell.zig");
     _ = @import("User.zig");
     _ = @import("validate.zig");