more work on the huffman
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parent
99d8ce3484
commit
e099a7fdda
163
src/main.zig
163
src/main.zig
@ -21,8 +21,7 @@ fn usage() void {
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exit("", .{}, 1);
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}
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fn BitWalkerUint(T: anytype) type {
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fn BitWalkerUint(T: anytype, size: usize, reverse: bool) type {
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var typeInfo = @typeInfo(T);
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if (typeInfo == std.builtin.Type.Int) {
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@ -33,21 +32,51 @@ fn BitWalkerUint(T: anytype) type {
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@compileError("The integer needs to be unsigned");
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}
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var size = typeInfo.Int.bits;
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if (typeInfo.Int.bits < size) {
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@compileError("Int size needs to be the same or grater than the size");
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}
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return struct {
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t: T,
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value: T,
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// TODO this is probably wrong
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in_byte_position: u8,
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const Self = @This();
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fn init(value: T) Self {
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return Self {
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var start_value = 0;
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if (reverse) {
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start_value = size;
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}
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return Self{
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.t = value,
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.in_byte_position = 0,
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.in_byte_position = size,
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};
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}
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fn walkBit(self: *Self) ?u1 {
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if (reverse) {
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if (self.in_byte_position == 0)
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return null;
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} else {
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if (self.in_byte_position > size - 1)
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return null;
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}
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var mask = 1;
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for (0..self.in_byte_position) |_| {
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mask = @shlExact(mask, 1);
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}
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if (reverse) {
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self.in_byte_position -= 1;
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} else {
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self.in_byte_position += 1;
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}
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return self.value & mask;
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}
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};
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}
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@ -126,7 +155,7 @@ const BitWalker = struct {
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}
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};
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fn HuffmanGraph(valueType: type) type {
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fn HuffmanGraph(comptime valueType: type) type {
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return struct {
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const Node = struct {
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left: ?Node,
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@ -136,7 +165,6 @@ fn HuffmanGraph(valueType: type) type {
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allocator: mem.Allocator,
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fn init(allocator: mem.Allocator) !*Node {
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var node = try allocator.create(Node);
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node.left = null;
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node.right = null;
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@ -155,19 +183,96 @@ fn HuffmanGraph(valueType: type) type {
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}
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self.allocator.destory(self);
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}
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fn depth(self: *Node) usize {
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var d = 0;
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if (self.right) |r| {
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d = r.depth();
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}
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if (self.left) |l| {
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d = std.math.max(d, l.depth());
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}
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return d + 1;
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}
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};
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root: Node,
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root: *Node,
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allocator: mem.Allocator,
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stored_depth: ?usize = null,
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iterNode: *Node,
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const Self = @This();
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fn init(allocator: mem.Allocator) !Self {
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var root = try Node.init(allocator);
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return Self {
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root,
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return Self{
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.root = root,
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.iterNode = root,
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.allocator = allocator,
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};
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}
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fn addValue(self: *Self, code: u64, size: usize, value: valueType) !void {
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var walker = BitWalkerUint(u64, size, true).init(code);
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var curNode: *Node = self.node;
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while (walker.walkBit()) |bit| {
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if (bit == 1) {
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if (curNode.left) |nextNode| {
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curNode = nextNode;
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} else {
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curNode.left = try Node.init(self.allocator);
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curNode = curNode.left.?;
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}
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} else {
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if (curNode.right) |nextNode| {
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curNode = nextNode;
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} else {
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curNode.right = try Node.init(self.allocator);
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curNode = curNode.right.?;
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}
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}
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}
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curNode.value = value;
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self.stored_depth = null;
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}
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fn depth(self: *Self) usize {
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if (self.stored_depth) |d| {
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return d;
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}
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self.stored_depth = self.root.depth() - 1;
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return self.stored_depth.?;
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}
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fn iter(self: *Self, bit: u1) anyerror!?valueType {
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var node = self.iterNode;
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var nextNode: ?*Node = null;
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if (bit == 1) {
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nextNode = node.left;
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} else {
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nextNode = node.right;
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}
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if (nextNode) |new_node| {
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if (new_node.value) |value| {
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self.iterNode = self.root;
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return value;
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} else {
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self.iterNode = new_node;
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return null;
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}
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}
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return error.InvalidBitSequence;
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}
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fn deinit(self: *Self) void {
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self.root.deinit();
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}
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@ -178,15 +283,17 @@ const DynamicDecoder = struct {
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const Self = @This();
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len_to_read: usize,
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codes: [19]u3,
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codes: [19]u64,
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walker: *BitWalker,
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allocator: mem.Allocator,
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graph: HuffmanGraph(u64),
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fn init(walker: *BitWalker, len_to_read: usize, allocator: mem.Allocator) !Self {
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const list: [19]u8 = .{ 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
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var lenList: [19]u3 = .{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
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var bl_count: [7]u8 = .{0, 0, 0, 0, 0, 0, 0};
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var bl_count: [7]u3 = .{ 0, 0, 0, 0, 0, 0, 0 };
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var max: u8 = 0;
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for (0..(len_to_read + 4)) |i| {
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var data: u3 = @intCast(u3, try walker.walk(3));
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@ -195,36 +302,50 @@ const DynamicDecoder = struct {
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continue;
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}
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bl_count[data - 1] += 1;
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if (data > max) {
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max = data;
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}
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}
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var bl_count: []u8 = allocator.allocator(u8, max - 1);
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var next_code: [19]u64 = .{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
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var next_codes: [19]u3 = .{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
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var code = 0;
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var code: u64 = 0;
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bl_count[0] = 0;
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for (1..max) |bits| {
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code = (code + bl_count[bits-1]) << 1;
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code = @shlExact(code + bl_count[bits - 1], 1);
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next_code[bits] = code;
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}
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var codes: [19]u3 = .{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
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var codes: [19]u64 = .{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
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for (0..19) |n| {
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var len = lenList[n];
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if (len != 0) {
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codes = next_code[len];
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codes[n] = next_code[len];
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next_code[len] += 1;
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}
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}
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var graph = try HuffmanGraph(u64).init(allocator);
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for (0..19) |i| {
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if (lenList[i] == 0)
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continue;
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try graph.addValue(codes[i], lenList[i], list[i]);
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}
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return .{
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.len_to_read = len_to_read,
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.codes = codes,
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.walker = walker,
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.allocator = allocator,
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.graph = graph,
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};
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}
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fn deinit(self: *Self) void {
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self.graph.deinit();
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}
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};
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const LOCAL_FILE_HEADER_SIGNATURE = 0x04034b50;
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@ -326,7 +447,7 @@ const ZipFileHeader = struct {
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print("number of dist codes: {}", .{number_of_dist_codes});
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print("number_of_length_codes: {}", .{number_of_length_codes});
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var dynamic_decoder = try DynamicDecoder.init(&bitw, number_of_length_codes);
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var dynamic_decoder = try DynamicDecoder.init(&bitw, number_of_length_codes, self.allocator);
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_ = dynamic_decoder;
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