More work on extraction, especially for regular files

src/file.zig

@@ -8,7 +8,9 @@ const DirEntry = @import("directory.zig");
 const ExtractionOptions = @import("options.zig");
 const Inode = @import("inode.zig");
 const DataExtractor = @import("util/data_extractor.zig");
+const Decompressor = @import("util/decompressor.zig");
 const MetadataReader = @import("util/metadata.zig");
+const SharedCache = @import("util/shared_cache.zig");
 
 const File = @This();
 
@@ -83,16 +85,36 @@ pub fn open(self: File, alloc: std.mem.Allocator, io: Io, filepath: []const u8)
 }
 
 pub fn extract(self: File, alloc: std.mem.Allocator, io: Io, filepath: []const u8, options: ExtractionOptions) !void {
+    var cache: SharedCache = try .init(alloc, 10); // TODO: calculate a good initial cache size.
+    defer cache.deinit();
+    var decomp = switch (self.archive.super.compression) {
+        .gzip => {},
+        .lzma => {},
+        .xz => {},
+        .zstd => {},
+        else => unreachable,
+    };
+    return self.extractReal(alloc, io, &cache, &decomp.interface, filepath, options);
+}
+fn extractReal(self: File, alloc: std.mem.Allocator, io: Io, cache: *SharedCache, decomp: *const Decompressor, filepath: []const u8, options: ExtractionOptions) !void {
+    _ = options;
     switch (self.inode.hdr.inode_type) {
         .file, .ext_file => {
+            var ext = try self.inode.dataExtractor(
+                self.archive.file,
+                cache,
+                decomp,
+                self.archive.super.block_size,
+            );
+
             var atomic_file = try Io.Dir.cwd().createFileAtomic(io, filepath, .{});
             defer atomic_file.deinit(io);
+
+            try ext.extract(alloc, io, atomic_file.file);
+            try atomic_file.link(io);
         },
         else => return error.TODO,
     }
-    _ = alloc;
-    _ = options;
-    return error.TODO;
 }
 
 // Types

src/inode.zig

@@ -8,9 +8,12 @@ const DirEntry = @import("directory.zig");
 const dir = @import("inode_data/dir.zig");
 const file = @import("inode_data/file.zig");
 const misc = @import("inode_data/misc.zig");
+const DataExtractor = @import("util/data_extractor.zig");
+const DataReader = @import("util/data_reader.zig");
 const Decompressor = @import("util/decompressor.zig");
 const MetadataReader = @import("util/metadata.zig");
 const OffsetFile = @import("util/offset_file.zig");
+const SharedCache = @import("util/shared_cache.zig");
 
 const Inode = @This();
 
@@ -52,6 +55,7 @@ pub fn deinit(self: Inode, alloc: std.mem.Allocator) void {
 
 // Utility Functions
 
+/// Read the directory entries
 pub fn readDirectory(self: Inode, alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, dir_offset: u64) ![]DirEntry {
     return switch (self.data) {
         .dir => |d| readDirFromData(alloc, io, fil, decomp, dir_offset, d),
@@ -66,6 +70,38 @@ fn readDirFromData(alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *c
 
     return DirEntry.readDirectory(alloc, &meta.interface, d.size);
 }
+/// Get a reader for a regular file's data.
+pub fn dataReader(self: Inode, alloc: std.mem.Allocator, io: Io, fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32) !DataReader {
+    return switch (self.data) {
+        .file => |f| getReaderFromData(alloc, io, fil, cache, decomp, block_size, f),
+        .ext_file => |f| getReaderFromData(alloc, io, fil, cache, decomp, block_size, f),
+        else => Error.NotRegularFile,
+    };
+}
+fn getReaderFromData(alloc: std.mem.Allocator, io: Io, fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32, d: anytype) !DataReader {
+    const ext: DataReader = .init(alloc, io, fil, cache, decomp, block_size, d.size, d.block_start, d.blocks);
+    if (d.frag_block_offset == 0xFFFFFFFF) {
+        // TODO:
+        return error.TODO;
+    }
+    return ext;
+}
+/// Get an extractor for a regular file's data.
+pub fn dataExtractor(self: Inode, fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32) !DataExtractor {
+    return switch (self.data) {
+        .file => |f| getExtractorFromData(fil, cache, decomp, block_size, f),
+        .ext_file => |f| getExtractorFromData(fil, cache, decomp, block_size, f),
+        else => Error.NotRegularFile,
+    };
+}
+fn getExtractorFromData(fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32, d: anytype) !DataExtractor {
+    const ext: DataExtractor = .init(fil, cache, decomp, block_size, d.size, d.block_start, d.blocks);
+    if (d.frag_block_offset == 0xFFFFFFFF) {
+        // TODO:
+        return error.TODO;
+    }
+    return ext;
+}
 
 // Types
 

src/util/data_extractor.zig

@@ -3,16 +3,113 @@
 const std = @import("std");
 const Io = std.Io;
 
+const FragEntry = @import("../frag.zig").FragEntry;
 const BlockSize = @import("../inode_data/file.zig").BlockSize;
 const Decompressor = @import("decompressor.zig");
 const OffsetFile = @import("offset_file.zig");
+const SharedCache = @import("shared_cache.zig");
 
 const DataExtractor = @This();
 
 fil: OffsetFile,
+cache: *SharedCache,
 decomp: *const Decompressor,
 block_size: u32,
 
 file_size: u64,
 start: u64,
 blocks: []BlockSize,
+
+frag_offset: u32 = 0,
+frag_entry: ?FragEntry = null,
+
+pub fn init(fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32, file_size: u64, data_start: u64, blocks: []BlockSize) DataExtractor {
+    return .{
+        .fil = fil,
+        .cache = cache,
+        .decomp = decomp,
+        .block_size = block_size,
+
+        .file_size = file_size,
+        .start = data_start,
+        .blocks = blocks,
+    };
+}
+pub fn addFrag(self: *DataExtractor, frag_offset: u32, entry: FragEntry) void {
+    self.frag_offset = frag_offset;
+    self.frag_entry = entry;
+}
+
+fn numBlocks(self: DataExtractor) usize {
+    var num = self.blocks.len;
+    if (self.frag_entry != null) num += 1;
+    return num;
+}
+
+pub fn extract(self: DataExtractor, alloc: std.mem.Allocator, io: Io, fil: Io.File) !void {
+    _ = self;
+    _ = alloc;
+    _ = io;
+    _ = fil;
+}
+
+fn blockThread(self: DataExtractor, alloc: std.mem.Allocator, io: Io, fil: Io.File, read_offset: u64, offset: u64, idx: u32) !void {
+    const block = self.blocks[idx];
+
+    const cur_block_size = if (idx == self.numBlocks() - 1)
+        self.file_size % self.block_size
+    else
+        self.block_size;
+
+    var wrt = fil.writer(io, &[0]u8{});
+    try wrt.seekTo(offset);
+    defer wrt.flush() catch {};
+
+    if (block.size == 0) {
+        try wrt.interface.splatByteAll(0, cur_block_size);
+        return;
+    }
+
+    var rdr = try self.fil.readerAt(io, read_offset, &[0]u8{});
+    if (block.uncompressed) {
+        try rdr.interface.streamExact(&wrt, cur_block_size);
+        return;
+    } else {
+        @branchHint(.likely);
+        var cache = try self.cache.getCache(io);
+        defer self.cache.returnCache(cache);
+
+        var tmp = try self.cache.getCache(io);
+        defer self.cache.returnCache(tmp);
+
+        try rdr.interface.readSliceAll(cache.cache[0..block.size]);
+        _ = try self.decomp.Decompress(alloc, cache.cache[0..block.size], tmp.cache[0..cur_block_size]);
+        try wrt.interface.writeAll(tmp.cache[0..cur_block_size]);
+    }
+}
+fn fragThread(self: DataExtractor, alloc: std.mem.Allocator, io: Io, fil: Io.File, offset: u64) !void {
+    const frag = self.frag_entry.?;
+    const cur_block_size = self.file_size % self.block_size;
+
+    var wrt = fil.writer(io, &[0]u8{});
+    try wrt.seekTo(offset);
+    defer wrt.flush() catch {};
+
+    var rdr = try self.fil.readerAt(io, frag.start, &[0]u8{});
+    if (frag.size.uncompressed) {
+        try rdr.interface.discardAll(self.frag_offset);
+        try rdr.interface.streamExact(&wrt, cur_block_size);
+        return;
+    } else {
+        @branchHint(.likely);
+        var cache = try self.cache.getCache(io);
+        defer self.cache.returnCache(cache);
+
+        var tmp = try self.cache.getCache(io);
+        defer self.cache.returnCache(tmp);
+
+        try rdr.interface.readSliceAll(cache.cache[0..frag.size.size]);
+        _ = try self.decomp.Decompress(alloc, cache.cache[0..frag.size.size], tmp.cache[0..self.block_size]);
+        try wrt.interface.writeAll(tmp.cache[0..cur_block_size]);
+    }
+}

src/util/data_reader.zig

@@ -2,14 +2,23 @@
 
 const std = @import("std");
 const Io = std.Io;
+const Reader = Io.Reader;
+const Writer = Io.Writer;
+const Limit = Io.Limit;
 
+const FragEntry = @import("../frag.zig").FragEntry;
 const BlockSize = @import("../inode_data/file.zig").BlockSize;
 const Decompressor = @import("decompressor.zig");
 const OffsetFile = @import("offset_file.zig");
+const SharedCache = @import("shared_cache.zig");
 
-const DataExtractor = @This();
+const DataReader = @This();
+
+alloc: std.mem.Allocator,
 
 fil: OffsetFile,
+io: Io,
+cache: *SharedCache,
 decomp: *const Decompressor,
 block_size: u32,
 
@@ -17,4 +26,184 @@ file_size: u64,
 cur_offset: u64,
 blocks: []BlockSize,
 
+frag_offset: u32 = 0,
+frag_entry: ?FragEntry = null,
+
+block_idx: usize = 0,
+sparse_block: bool = false,
+
 interface: Io.Reader,
+
+pub fn init(alloc: std.mem.Allocator, io: Io, fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32, file_size: u64, data_start: u64, blocks: []BlockSize) !DataReader {
+    return .{
+        .alloc = alloc,
+
+        .fil = fil,
+        .io = io,
+        .decomp = decomp,
+        .block_size = block_size,
+
+        .file_size = file_size,
+        .cur_offset = data_start,
+        .blocks = blocks,
+
+        .interface = .{
+            .buffer = try cache.getCache(io),
+            .seek = 0,
+            .end = 0,
+            .vtable = &.{
+                .stream = stream,
+                .discard = discard,
+                .readVec = readVec,
+            },
+        },
+    };
+}
+pub fn deinit(self: *DataReader) void {
+    if (self.interface.buffer.len > 0) {
+        const buf_nod: *SharedCache.BufferNode = @fieldParentPtr("cache", self.interface.buffer);
+        self.cache.returnCache(buf_nod);
+    }
+}
+pub fn addFrag(self: *DataReader, frag_offset: u32, entry: FragEntry) void {
+    self.frag_offset = frag_offset;
+    self.frag_entry = entry;
+}
+
+fn numBlocks(self: DataReader) usize {
+    var num = self.blocks.len;
+    if (self.frag_entry != null) num += 1;
+    return num;
+}
+fn advanceBuffer(self: *DataReader) !void {
+    if (self.block_idx >= self.numBlocks()) {
+        return Reader.Error.EndOfStream;
+    }
+    defer self.block_idx += 1;
+
+    self.interface.end = if (self.block_idx == self.numBlocks() - 1)
+        self.size % self.block_size
+    else
+        self.block_size;
+
+    // Fragment
+    if (self.block_idx == self.blocks.len) {
+        const entry = self.frag_entry.?;
+        if (entry.size.uncompressed) {
+            var rdr = try self.fil.readerAt(self.io, entry.start + self.frag_offset, &[0]u8{});
+            try rdr.interface.readSliceAll(self.interface.buffer[0..self.interface.end]);
+        } else {
+            @branchHint(.likely);
+            const tmp = try self.cache.getCache(self.io);
+            defer self.cache.returnCache(tmp);
+
+            var rdr = try self.fil.readerAt(self.io, entry.start, &[0]u8{});
+            try rdr.interface.readSliceAll(tmp.cache[0..entry.size.size]);
+            _ = try self.decomp.Decompress(self.alloc, tmp.cache[0..entry.size.size], self.interface.buffer[0..self.block_size]);
+            @memmove(self.interface.buffer[0..self.interface.end], self.interface.buffer[self.frag_offset .. self.frag_offset + self.interface.end]);
+        }
+        self.interface.seek = 0;
+        return;
+    }
+
+    // Normal Block
+    const block = self.blocks[self.block_idx];
+    if (block.size == 0) {
+        self.interface.seek = 0;
+        self.sparse_block = true;
+        return;
+    } else {
+        self.sparse_block = false;
+    }
+    if (block.uncompressed) {
+        try self.fil.readAt(self.io, self.cur_offset, self.interface.buffer[0..self.interface.end]);
+        self.cur_offset += self.interface.end;
+    } else {
+        @branchHint(.likely);
+        const tmp = try self.cache.getCache(self.io);
+        defer self.cache.returnCache(tmp);
+
+        var rdr = try self.fil.readerAt(self.io, self.cur_offset, &[0]u8{});
+        try rdr.interface.readSliceAll(tmp.cache[0..block.size]);
+        self.cur_offset += block.size;
+        _ = try self.decomp.Decompress(self.alloc, tmp.cache[0..block.size], self.interface.buffer[0..self.interface.end]);
+    }
+    self.interface.seek = 0;
+}
+
+fn stream(rdr: *Reader, wrt: *Writer, limit: Limit) Reader.StreamError!usize {
+    var data: *DataReader = @fieldParentPtr("interface", rdr);
+    if (rdr.seek == rdr.end)
+        data.advanceBuffer() catch |err| return switch (err) {
+            error.ReadFailed => error.ReadFailed,
+            error.EndOfStream => error.EndOfStream,
+            else => error.ReadFailed,
+        };
+
+    switch (limit) {
+        .nothing => return 0,
+        .unlimited => {
+            const wrote = if (data.sparse_block)
+                try wrt.splatByte(0, rdr.end - rdr.seek)
+            else
+                try wrt.write(rdr.buffer[rdr.seek..rdr.end]);
+            rdr.seek += wrote;
+            return wrote;
+        },
+        else => {
+            const to_read = @min(rdr.end - rdr.seek, @intFromEnum(limit));
+            const wrote = if (data.sparse_block)
+                try wrt.splatByte(0, to_read)
+            else
+                try wrt.write(rdr.buffer[rdr.seek .. rdr.seek + to_read]);
+            rdr.seek += wrote;
+            return wrote;
+        },
+    }
+}
+fn discard(rdr: *Reader, limit: Limit) Reader.Error!usize {
+    var data: *DataReader = @fieldParentPtr("interface", rdr);
+    if (rdr.seek == rdr.end)
+        data.advanceBuffer() catch |err| return switch (err) {
+            error.ReadFailed => error.ReadFailed,
+            error.EndOfStream => error.EndOfStream,
+            else => error.ReadFailed,
+        };
+
+    switch (limit) {
+        .nothing => return 0,
+        .unlimited => {
+            const adv = rdr.end - rdr.seek;
+            rdr.seek = rdr.end;
+            return adv;
+        },
+        else => {
+            const adv = @min(rdr.end - rdr.seek, @intFromEnum(limit));
+            rdr.seek += adv;
+            return adv;
+        },
+    }
+}
+fn readVec(rdr: *Reader, vec: [][]u8) Reader.Error!usize {
+    var data: *DataReader = @fieldParentPtr("interface", rdr);
+    if (rdr.seek == rdr.end)
+        data.advanceBuffer() catch |err| return switch (err) {
+            error.ReadFailed => error.ReadFailed,
+            error.EndOfStream => error.EndOfStream,
+            else => error.ReadFailed,
+        };
+
+    var wrote: usize = 0;
+    for (vec) |buf| {
+        if (rdr.seek == rdr.end) break;
+
+        const to_copy = @min(rdr.end - rdr.seek, buf.len);
+        if (data.sparse_block)
+            @memset(buf[0..to_copy], 0)
+        else
+            @memcpy(buf[0..to_copy], rdr.buffer[rdr.seek .. rdr.seek + to_copy]);
+        rdr.seek += to_copy;
+        wrote += to_copy;
+    }
+    return wrote;
+}

src/util/decompressor.zig

@@ -13,7 +13,3 @@ decomp_fn: *const fn (?*const Decompressor, std.mem.Allocator, in: []u8, out: []
 pub fn Decompress(self: *const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
     return self.decomp_fn(self, alloc, in, out);
 }
-
-pub fn StatelessDecompression(self: Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
-    return self.decomp_fn(null, alloc, in, out);
-}

src/util/metadata.zig

@@ -49,11 +49,13 @@ fn advance(self: *This) !void {
         self.interface.end = hdr.size;
         self.interface.buffer = self.buf[0..hdr.size];
         return;
-    }
+    } else {
+        @branchHint(.likely);
         var tmp_buf: [8192]u8 = undefined;
         try self.rdr.readSliceAll(tmp_buf[0..hdr.size]);
         self.interface.end = try self.decomp.Decompress(self.alloc, tmp_buf[0..hdr.size], &self.buf);
         self.interface.buffer = self.buf[0..self.interface.end];
+    }
 }
 
 fn stream(rdr: *Reader, wrt: *Writer, limit: Limit) StreamError!usize {

src/util/offset_file.zig

@@ -1,7 +1,8 @@
 //! A File where it's meaningful (to us) content starts at a given offset.
 
 const std = @import("std");
-const File = std.Io.File;
+const Io = std.Io;
+const File = Io.File;
 const Reader = File.Reader;
 
 const OffsetFile = @This();
@@ -13,8 +14,16 @@ pub fn init(fil: File, init_offset: u64) OffsetFile {
     return .{ .fil = fil, .offset = init_offset };
 }
 
-pub fn readerAt(self: OffsetFile, io: std.Io, offset: u64, buffer: []u8) !Reader {
+pub fn readerAt(self: OffsetFile, io: Io, offset: u64, buffer: []u8) !Reader {
     var rdr = self.fil.reader(io, buffer);
     try rdr.seekTo(self.offset + offset);
     return rdr;
 }
+pub fn readAt(self: OffsetFile, io: Io, offset: u64, buf: []u8) !void {
+    _ = try self.fil.readPositionalAll(io, buf, self.offset + offset);
+}
+pub fn readValueAt(self: OffsetFile, comptime T: anytype, io: Io, offset: u64) !void {
+    //TODO: check for endianess and decode accordingly.
+    var new: T = undefined;
+    _ = try self.fil.readPositionalAll(io, @ptrCast(&new), self.offset + offset);
+}

src/util/shared_cache.zig

@@ -0,0 +1,52 @@
+const std = @import("std");
+const Io = std.Io;
+const Node = std.SinglyLinkedList.Node;
+
+const SharedCache = @This();
+
+pub const CACHE_SIZE = 1024 * 1024;
+
+pub const BufferNode = struct {
+    node: Node,
+    cache: [CACHE_SIZE]u8,
+};
+
+alloc: std.mem.Allocator,
+
+caches: std.ArrayList(BufferNode),
+cache_queue: std.SinglyLinkedList,
+queue_mut: Io.Mutex,
+
+pub fn init(alloc: std.mem.Allocator, init_cache_size: u32) !SharedCache {
+    const caches: std.ArrayList(BufferNode) = try .initCapacity(alloc, init_cache_size);
+    var queue: std.SinglyLinkedList = .{};
+    for (caches.items) |item|
+        queue.prepend(&item.node);
+    return .{
+        .alloc = alloc,
+
+        .caches = caches,
+        .cache_queue = queue,
+    };
+}
+pub fn deinit(self: *SharedCache) void {
+    self.caches.deinit(self.alloc);
+}
+
+pub fn getCache(self: *SharedCache, io: Io) !*BufferNode {
+    self.queue_mut.lock(io);
+    const nxt = self.cache_queue.popFirst();
+    self.queue_mut.unlock(io);
+    if (nxt == null) {
+        const new = try self.caches.addOne(self.alloc);
+        new.* = .{
+            .node = .{},
+            .cache = undefined,
+        };
+        return new;
+    }
+    return @fieldParentPtr("node", nxt.?);
+}
+pub fn returnCache(self: *SharedCache, buf: *BufferNode) void {
+    self.cache_queue.prepend(buf);
+}