Commit 6eac56caf715bdc2dbd63b628ca48c0e32d5a70c | zig

author	Andrew Kelley <andrew@ziglang.org> 2025-07-31 17:31:54-07:00
committer	Andrew Kelley <andrew@ziglang.org> 2025-07-31 22:10:11-07:00
log	6eac56caf715bdc2dbd63b628ca48c0e32d5a70c
tree	2fdf465c77963be579faef35461b9366fcddf8f6
parent	2024abda6ae7c02c7fc1667d221e98da23ebcd2a

std.compress.flate.Decompress: allow users to swap out Writer

1 files changed, 26 insertions(+), 7 deletions(-)

lib
- std
  - compress
    flate
    Decompress.zig

lib/std/compress/flate/Decompress.zig+26-7

...	...	@@ -58,7 +58,7 @@ pub fn init(input: *Reader, container: Container, buffer: []u8) Decompress {
58	58	.reader = .{
59	59	.vtable = &.{
60	60	.stream = stream,
61		.rebase = rebase,
	61	.rebase = rebaseFallible,
62	62	.discard = discard,
63	63	.readVec = readVec,
64	64	},
...	...	@@ -78,12 +78,19 @@ pub fn init(input: *Reader, container: Container, buffer: []u8) Decompress {
78	78	};
79	79	}
80	80
81		fn rebase(r: *Reader, capacity: usize) Reader.RebaseError!void {
	81	fn rebaseFallible(r: *Reader, capacity: usize) Reader.RebaseError!void {
	82	const d: *Decompress = @alignCast(@fieldParentPtr("reader", r));
	83	rebase(d, capacity);
	84	}
	85
	86	fn rebase(d: *Decompress, capacity: usize) void {
	87	const r = &d.reader;
82	88	assert(capacity <= r.buffer.len - flate.history_len);
83	89	assert(r.end + capacity > r.buffer.len);
84	90	const discard_n = r.end - flate.history_len;
85	91	const keep = r.buffer[discard_n..r.end];
86	92	@memmove(r.buffer[0..keep.len], keep);
	93	assert(keep.len != 0);
87	94	r.end = keep.len;
88	95	r.seek -= discard_n;
89	96	}
...	...	@@ -101,6 +108,7 @@ fn discard(r: *Reader, limit: std.Io.Limit) Reader.Error!usize {
101	108	.end = r.end,
102	109	};
103	110	defer {
	111	assert(writer.end != 0);
104	112	r.end = writer.end;
105	113	r.seek = r.end;
106	114	}
...	...	@@ -115,14 +123,20 @@ fn discard(r: *Reader, limit: std.Io.Limit) Reader.Error!usize {
115	123
116	124	fn readVec(r: *Reader, data: [][]u8) Reader.Error!usize {
117	125	_ = data;
118		assert(r.seek == r.end);
119		r.rebase(flate.history_len) catch unreachable;
	126	const d: *Decompress = @alignCast(@fieldParentPtr("reader", r));
	127	return streamIndirect(d);
	128	}
	129
	130	fn streamIndirect(d: *Decompress) Reader.Error!usize {
	131	const r = &d.reader;
	132	if (r.end + flate.history_len > r.buffer.len) rebase(d, flate.history_len);
120	133	var writer: Writer = .{
121	134	.buffer = r.buffer,
122	135	.end = r.end,
123	136	.vtable = &.{ .drain = Writer.fixedDrain },
124	137	};
125		r.end += r.vtable.stream(r, &writer, .limited(writer.buffer.len - writer.end)) catch \|err\| switch (err) {
	138	defer r.end = writer.end;
	139	_ = streamFallible(d, &writer, .limited(writer.buffer.len - writer.end)) catch \|err\| switch (err) {
126	140	error.WriteFailed => unreachable,
127	141	else => \|e\| return e,
128	142	};
...	...	@@ -188,7 +202,12 @@ fn decodeSymbol(self: *Decompress, decoder: anytype) !Symbol {
188	202
189	203	pub fn stream(r: Reader, w: Writer, limit: std.Io.Limit) Reader.StreamError!usize {
190	204	const d: *Decompress = @alignCast(@fieldParentPtr("reader", r));
191		return readInner(d, w, limit) catch \|err\| switch (err) {
	205	if (w.end >= r.end) return streamFallible(d, w, limit);
	206	return streamIndirect(d);
	207	}
	208
	209	fn streamFallible(d: Decompress, w: Writer, limit: std.Io.Limit) Reader.StreamError!usize {
	210	return streamInner(d, w, limit) catch \|err\| switch (err) {
192	211	error.EndOfStream => {
193	212	if (d.state == .end) {
194	213	return error.EndOfStream;
...	...	@@ -207,7 +226,7 @@ pub fn stream(r: Reader, w: Writer, limit: std.Io.Limit) Reader.StreamError!us
207	226	};
208	227	}
209	228
210		fn readInner(d: Decompress, w: Writer, limit: std.Io.Limit) (Error \|\| Reader.StreamError)!usize {
	229	fn streamInner(d: Decompress, w: Writer, limit: std.Io.Limit) (Error \|\| Reader.StreamError)!usize {
211	230	var remaining = @intFromEnum(limit);
212	231	const in = d.input;
213	232	sw: switch (d.state) {