std.compress.xz: flatten namespaces

This commit is contained in:
Andrew Kelley 2025-08-22 14:14:26 -07:00
parent ea0ce7afb5
commit 6464e0d4fc
2 changed files with 207 additions and 212 deletions

View file

@ -1,7 +1,10 @@
const std = @import("std");
const block = @import("xz/block.zig");
const Allocator = std.mem.Allocator;
const ArrayList = std.ArrayList;
const Crc32 = std.hash.Crc32;
const Crc64 = std.hash.crc.Crc64Xz;
const Sha256 = std.crypto.hash.sha2.Sha256;
const lzma2 = std.compress.lzma2;
pub const Check = enum(u4) {
none = 0x00,
@ -27,11 +30,11 @@ pub fn Decompress(comptime ReaderType: type) type {
return struct {
const Self = @This();
pub const Error = ReaderType.Error || block.Decoder(ReaderType).Error;
pub const Error = ReaderType.Error || Decoder(ReaderType).Error;
pub const Reader = std.io.GenericReader(*Self, Error, read);
allocator: Allocator,
block_decoder: block.Decoder(ReaderType),
block_decoder: Decoder(ReaderType),
in_reader: ReaderType,
fn init(allocator: Allocator, source: ReaderType) !Self {
@ -52,7 +55,7 @@ pub fn Decompress(comptime ReaderType: type) type {
return Self{
.allocator = allocator,
.block_decoder = try block.decoder(allocator, source, check),
.block_decoder = try decoder(allocator, source, check),
.in_reader = source,
};
}
@ -161,6 +164,206 @@ pub fn hashedReader(
return .{ .child_reader = reader, .hasher = hasher };
}
const DecodeError = error{
CorruptInput,
EndOfStream,
EndOfStreamWithNoError,
WrongChecksum,
Unsupported,
Overflow,
};
pub fn decoder(allocator: Allocator, reader: anytype, check: Check) !Decoder(@TypeOf(reader)) {
return Decoder(@TypeOf(reader)).init(allocator, reader, check);
}
pub fn Decoder(comptime ReaderType: type) type {
return struct {
const Self = @This();
pub const Error =
ReaderType.Error ||
DecodeError ||
Allocator.Error;
pub const Reader = std.io.GenericReader(*Self, Error, read);
allocator: Allocator,
inner_reader: ReaderType,
check: Check,
err: ?Error,
to_read: ArrayList(u8),
read_pos: usize,
block_count: usize,
fn init(allocator: Allocator, in_reader: ReaderType, check: Check) !Self {
return Self{
.allocator = allocator,
.inner_reader = in_reader,
.check = check,
.err = null,
.to_read = .{},
.read_pos = 0,
.block_count = 0,
};
}
pub fn deinit(self: *Self) void {
self.to_read.deinit(self.allocator);
}
pub fn reader(self: *Self) Reader {
return .{ .context = self };
}
pub fn read(self: *Self, output: []u8) Error!usize {
while (true) {
const unread_len = self.to_read.items.len - self.read_pos;
if (unread_len > 0) {
const n = @min(unread_len, output.len);
@memcpy(output[0..n], self.to_read.items[self.read_pos..][0..n]);
self.read_pos += n;
return n;
}
if (self.err) |e| {
if (e == DecodeError.EndOfStreamWithNoError) {
return 0;
}
return e;
}
if (self.read_pos > 0) {
self.to_read.shrinkRetainingCapacity(0);
self.read_pos = 0;
}
self.readBlock() catch |e| {
self.err = e;
};
}
}
fn readBlock(self: *Self) Error!void {
var block_counter = std.io.countingReader(self.inner_reader);
const block_reader = block_counter.reader();
var packed_size: ?u64 = null;
var unpacked_size: ?u64 = null;
// Block Header
{
var header_hasher = hashedReader(block_reader, Crc32.init());
const header_reader = header_hasher.reader();
const header_size = @as(u64, try header_reader.readByte()) * 4;
if (header_size == 0)
return error.EndOfStreamWithNoError;
const Flags = packed struct(u8) {
last_filter_index: u2,
reserved: u4,
has_packed_size: bool,
has_unpacked_size: bool,
};
const flags = @as(Flags, @bitCast(try header_reader.readByte()));
const filter_count = @as(u3, flags.last_filter_index) + 1;
if (filter_count > 1)
return error.Unsupported;
if (flags.has_packed_size)
packed_size = try std.leb.readUleb128(u64, header_reader);
if (flags.has_unpacked_size)
unpacked_size = try std.leb.readUleb128(u64, header_reader);
const FilterId = enum(u64) {
lzma2 = 0x21,
_,
};
const filter_id = @as(
FilterId,
@enumFromInt(try std.leb.readUleb128(u64, header_reader)),
);
if (@intFromEnum(filter_id) >= 0x4000_0000_0000_0000)
return error.CorruptInput;
if (filter_id != .lzma2)
return error.Unsupported;
const properties_size = try std.leb.readUleb128(u64, header_reader);
if (properties_size != 1)
return error.CorruptInput;
// TODO: use filter properties
_ = try header_reader.readByte();
while (block_counter.bytes_read != header_size) {
if (try header_reader.readByte() != 0)
return error.CorruptInput;
}
const hash_a = header_hasher.hasher.final();
const hash_b = try header_reader.readInt(u32, .little);
if (hash_a != hash_b)
return error.WrongChecksum;
}
// Compressed Data
var packed_counter = std.io.countingReader(block_reader);
try lzma2.decompress(
self.allocator,
packed_counter.reader(),
self.to_read.writer(self.allocator),
);
if (packed_size) |s| {
if (s != packed_counter.bytes_read)
return error.CorruptInput;
}
const unpacked_bytes = self.to_read.items;
if (unpacked_size) |s| {
if (s != unpacked_bytes.len)
return error.CorruptInput;
}
// Block Padding
while (block_counter.bytes_read % 4 != 0) {
if (try block_reader.readByte() != 0)
return error.CorruptInput;
}
switch (self.check) {
.none => {},
.crc32 => {
const hash_a = Crc32.hash(unpacked_bytes);
const hash_b = try self.inner_reader.readInt(u32, .little);
if (hash_a != hash_b)
return error.WrongChecksum;
},
.crc64 => {
const hash_a = Crc64.hash(unpacked_bytes);
const hash_b = try self.inner_reader.readInt(u64, .little);
if (hash_a != hash_b)
return error.WrongChecksum;
},
.sha256 => {
var hash_a: [Sha256.digest_length]u8 = undefined;
Sha256.hash(unpacked_bytes, &hash_a, .{});
var hash_b: [Sha256.digest_length]u8 = undefined;
try self.inner_reader.readNoEof(&hash_b);
if (!std.mem.eql(u8, &hash_a, &hash_b))
return error.WrongChecksum;
},
else => return error.Unsupported,
}
self.block_count += 1;
}
};
}
test {
_ = @import("xz/test.zig");
}

View file

@ -1,208 +0,0 @@
const std = @import("../../std.zig");
const lzma2 = std.compress.lzma2;
const Allocator = std.mem.Allocator;
const ArrayListUnmanaged = std.ArrayListUnmanaged;
const Crc32 = std.hash.Crc32;
const Crc64 = std.hash.crc.Crc64Xz;
const Sha256 = std.crypto.hash.sha2.Sha256;
const xz = std.compress.xz;
const DecodeError = error{
CorruptInput,
EndOfStream,
EndOfStreamWithNoError,
WrongChecksum,
Unsupported,
Overflow,
};
pub fn decoder(allocator: Allocator, reader: anytype, check: xz.Check) !Decoder(@TypeOf(reader)) {
return Decoder(@TypeOf(reader)).init(allocator, reader, check);
}
pub fn Decoder(comptime ReaderType: type) type {
return struct {
const Self = @This();
pub const Error =
ReaderType.Error ||
DecodeError ||
Allocator.Error;
pub const Reader = std.io.GenericReader(*Self, Error, read);
allocator: Allocator,
inner_reader: ReaderType,
check: xz.Check,
err: ?Error,
to_read: ArrayListUnmanaged(u8),
read_pos: usize,
block_count: usize,
fn init(allocator: Allocator, in_reader: ReaderType, check: xz.Check) !Self {
return Self{
.allocator = allocator,
.inner_reader = in_reader,
.check = check,
.err = null,
.to_read = .{},
.read_pos = 0,
.block_count = 0,
};
}
pub fn deinit(self: *Self) void {
self.to_read.deinit(self.allocator);
}
pub fn reader(self: *Self) Reader {
return .{ .context = self };
}
pub fn read(self: *Self, output: []u8) Error!usize {
while (true) {
const unread_len = self.to_read.items.len - self.read_pos;
if (unread_len > 0) {
const n = @min(unread_len, output.len);
@memcpy(output[0..n], self.to_read.items[self.read_pos..][0..n]);
self.read_pos += n;
return n;
}
if (self.err) |e| {
if (e == DecodeError.EndOfStreamWithNoError) {
return 0;
}
return e;
}
if (self.read_pos > 0) {
self.to_read.shrinkRetainingCapacity(0);
self.read_pos = 0;
}
self.readBlock() catch |e| {
self.err = e;
};
}
}
fn readBlock(self: *Self) Error!void {
var block_counter = std.io.countingReader(self.inner_reader);
const block_reader = block_counter.reader();
var packed_size: ?u64 = null;
var unpacked_size: ?u64 = null;
// Block Header
{
var header_hasher = xz.hashedReader(block_reader, Crc32.init());
const header_reader = header_hasher.reader();
const header_size = @as(u64, try header_reader.readByte()) * 4;
if (header_size == 0)
return error.EndOfStreamWithNoError;
const Flags = packed struct(u8) {
last_filter_index: u2,
reserved: u4,
has_packed_size: bool,
has_unpacked_size: bool,
};
const flags = @as(Flags, @bitCast(try header_reader.readByte()));
const filter_count = @as(u3, flags.last_filter_index) + 1;
if (filter_count > 1)
return error.Unsupported;
if (flags.has_packed_size)
packed_size = try std.leb.readUleb128(u64, header_reader);
if (flags.has_unpacked_size)
unpacked_size = try std.leb.readUleb128(u64, header_reader);
const FilterId = enum(u64) {
lzma2 = 0x21,
_,
};
const filter_id = @as(
FilterId,
@enumFromInt(try std.leb.readUleb128(u64, header_reader)),
);
if (@intFromEnum(filter_id) >= 0x4000_0000_0000_0000)
return error.CorruptInput;
if (filter_id != .lzma2)
return error.Unsupported;
const properties_size = try std.leb.readUleb128(u64, header_reader);
if (properties_size != 1)
return error.CorruptInput;
// TODO: use filter properties
_ = try header_reader.readByte();
while (block_counter.bytes_read != header_size) {
if (try header_reader.readByte() != 0)
return error.CorruptInput;
}
const hash_a = header_hasher.hasher.final();
const hash_b = try header_reader.readInt(u32, .little);
if (hash_a != hash_b)
return error.WrongChecksum;
}
// Compressed Data
var packed_counter = std.io.countingReader(block_reader);
try lzma2.decompress(
self.allocator,
packed_counter.reader(),
self.to_read.writer(self.allocator),
);
if (packed_size) |s| {
if (s != packed_counter.bytes_read)
return error.CorruptInput;
}
const unpacked_bytes = self.to_read.items;
if (unpacked_size) |s| {
if (s != unpacked_bytes.len)
return error.CorruptInput;
}
// Block Padding
while (block_counter.bytes_read % 4 != 0) {
if (try block_reader.readByte() != 0)
return error.CorruptInput;
}
switch (self.check) {
.none => {},
.crc32 => {
const hash_a = Crc32.hash(unpacked_bytes);
const hash_b = try self.inner_reader.readInt(u32, .little);
if (hash_a != hash_b)
return error.WrongChecksum;
},
.crc64 => {
const hash_a = Crc64.hash(unpacked_bytes);
const hash_b = try self.inner_reader.readInt(u64, .little);
if (hash_a != hash_b)
return error.WrongChecksum;
},
.sha256 => {
var hash_a: [Sha256.digest_length]u8 = undefined;
Sha256.hash(unpacked_bytes, &hash_a, .{});
var hash_b: [Sha256.digest_length]u8 = undefined;
try self.inner_reader.readNoEof(&hash_b);
if (!std.mem.eql(u8, &hash_a, &hash_b))
return error.WrongChecksum;
},
else => return error.Unsupported,
}
self.block_count += 1;
}
};
}