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cmph may return a larger hash than there are items.

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Motiejus Jakštys 2022-04-20 06:04:34 +03:00 committed by Motiejus Jakštys
parent 2205d6c4b2
commit 1a01175c46
2 changed files with 14 additions and 33 deletions
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5
lib/DB.zig
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@ -275,6 +275,7 @@ fn getGroup(self: *const DB, group: PackedGroup, buf: *[]u8) error{OutOfMemory}!
// get a CGroup entry by name.
fn getgrnam(self: *const DB, name: []const u8, buf: *[]u8) error{OutOfMemory}!?CGroup {
const idx = bdz.search(self.bdz_groupname, name);
if (idx >= self.header.num_groups) return null;
const offset = self.idx_groupname2group[idx];
const nbits = PackedGroup.alignment_bits;
const group = PackedGroup.fromBytes(self.groups[offset << nbits ..]).group;
@ -285,6 +286,7 @@ fn getgrnam(self: *const DB, name: []const u8, buf: *[]u8) error{OutOfMemory}!?C
// get a CGroup entry by it's gid.
fn getgrgid(self: *const DB, gid: u32, buf: *[]u8) error{OutOfMemory}!?CGroup {
const idx = bdz.search_u32(self.bdz_gid, gid);
if (idx >= self.header.num_groups) return null;
const offset = self.idx_gid2group[idx];
const nbits = PackedGroup.alignment_bits;
const group = PackedGroup.fromBytes(self.groups[offset << nbits ..]).group;
@ -336,6 +338,8 @@ fn getUser(self: *const DB, user: PackedUser, buf: *[]u8) error{OutOfMemory}!CUs
// get a CUser entry by name.
fn getpwnam(self: *const DB, name: []const u8, buf: *[]u8) error{OutOfMemory}!?CUser {
const idx = bdz.search(self.bdz_username, name);
// bdz may return a hash that's bigger than the number of users
if (idx >= self.header.num_users) return null;
const offset = self.idx_name2user[idx];
const nbits = PackedUser.alignment_bits;
const user = PackedUser.fromBytes(self.users[offset << nbits ..]).user;
@ -346,6 +350,7 @@ fn getpwnam(self: *const DB, name: []const u8, buf: *[]u8) error{OutOfMemory}!?C
// get a CUser entry by uid.
fn getpwuid(self: *const DB, uid: u32, buf: *[]u8) error{OutOfMemory}!?CUser {
const idx = bdz.search_u32(self.bdz_uid, uid);
if (idx >= self.header.num_users) return null;
const offset = self.idx_uid2user[idx];
const nbits = PackedUser.alignment_bits;
const user = PackedUser.fromBytes(self.users[offset << nbits ..]).user;

42
lib/cmph.zig
View File

@ -6,19 +6,9 @@ const assert = std.debug.assert;
const bdz = @import("bdz.zig");
// must be kept in sync with the definition in cmph_types.h
const CMPH_ALGO = enum(c_int) {
CMPH_BMZ,
CMPH_BMZ8,
CMPH_CHM,
CMPH_BRZ,
CMPH_FCH,
CMPH_BDZ,
CMPH_BDZ_PH,
CMPH_CHD_PH,
CMPH_CHD,
CMPH_COUNT,
};
const CMPH_BDZ = @cImport({
@cInclude("cmph_types.h");
}).CMPH_BDZ;
extern fn cmph_io_vector_adapter(vector: [*]const [*:0]const u8, len: c_uint) [*]u8;
extern fn cmph_io_vector_adapter_destroy(key_source: [*]u8) void;
@ -29,18 +19,17 @@ extern fn cmph_new(config: [*]const u8) ?[*]u8;
extern fn cmph_config_destroy(mph: [*]u8) void;
extern fn cmph_packed_size(mphf: [*]const u8) u32;
extern fn cmph_pack(mphf: [*]const u8, packed_mphf: [*]u8) void;
extern fn cmph_destroy(mphf: [*]const u8) void;
extern fn cmph_destroy(mphf: [*]u8) void;
// pack packs cmph hashes for the given input and returns a slice ("cmph pack
// minus first 4 bytes") for further storage. The slice must be freed by the
// caller.
pub fn pack(allocator: Allocator, input: [][*:0]const u8) error{OutOfMemory}![]const u8 {
assert(input.len <= math.maxInt(c_uint));
const input_len = @intCast(c_uint, input.len);
var source = cmph_io_vector_adapter(input.ptr, input_len);
defer cmph_io_vector_adapter_destroy(source);
var config = cmph_config_new(source) orelse return error.OutOfMemory;
cmph_config_set_algo(config, @enumToInt(CMPH_ALGO.CMPH_BDZ));
cmph_config_set_algo(config, CMPH_BDZ);
cmph_config_set_b(config, 7);
var mph = cmph_new(config) orelse return error.OutOfMemory;
cmph_config_destroy(config);
@ -104,24 +93,20 @@ 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 = bdz.search(buf, elem);
used[hashed] = true;
}
for (used) |item| {
try testing.expect(item);
}
for (used) |item| try testing.expect(item);
}
// encodes a u32 to 6 bytes so no bytes except the last one is a '\0'.
// This is useful for cmph-packing, where it accepts 0-terminated char*s.
pub fn unzeroZ(x: u32) [6]u8 {
var buf: [6]u8 = undefined;
std.mem.copy(u8, buf[0..], bdz.unzero(x)[0..]);
std.mem.copy(u8, &buf, &bdz.unzero(x));
buf[5] = 0;
return buf;
}
@ -141,9 +126,8 @@ test "pack u32" {
const packed_mphf = try packU32(testing.allocator, keys);
defer testing.allocator.free(packed_mphf);
var hashes: [keys.len]u32 = undefined;
for (keys) |key, i| {
for (keys) |key, i|
hashes[i] = bdz.search_u32(packed_mphf, key);
}
sort.sort(u32, hashes[0..], {}, comptime sort.asc(u32));
for (hashes) |hash, i|
try testing.expectEqual(i, hash);
@ -154,17 +138,9 @@ test "pack str" {
const packed_mphf = try packStr(testing.allocator, keys[0..]);
defer testing.allocator.free(packed_mphf);
var hashes: [keys.len]u32 = undefined;
for (keys) |key, i| {
for (keys) |key, i|
hashes[i] = bdz.search(packed_mphf, key);
}
sort.sort(u32, hashes[0..], {}, comptime sort.asc(u32));
for (hashes) |hash, i|
try testing.expectEqual(i, hash);
}
test "CMPH_ALGO.CMPH_BDZ is in sync with our definition" {
const c = @cImport({
@cInclude("cmph_types.h");
});
try testing.expectEqual(c.CMPH_BDZ, @enumToInt(CMPH_ALGO.CMPH_BDZ));
}