129 lines
3.0 KiB
Zig
129 lines
3.0 KiB
Zig
const io = @import("./io.zig");
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const math = @import("./math.zig");
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pub const ByteStack = Stack(io.Byte);
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pub fn Stack(comptime Value: type) type {
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return struct {
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allocator: io.Allocator,
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capacity: usize,
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values: []Value,
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const Self = @This();
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pub fn clear(self: *Self) void {
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self.values = self.values[0 .. 0];
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}
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pub fn free(self: *Self) void {
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if (self.capacity == 0) {
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return;
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}
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self.allocator.deallocate(self.values.ptr[0 .. self.capacity]);
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self.values = &.{};
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}
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pub fn grow(self: *Self, growth_amount: usize) io.AllocationError!void {
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const grown_capacity = self.capacity + growth_amount;
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const buffer = try self.allocator.reallocate(null, @sizeOf(Value) * grown_capacity);
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errdefer self.allocator.deallocate(buffer);
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if (self.capacity != 0) {
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io.copy(buffer, io.bytes_of(self.values));
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self.allocator.deallocate(self.values.ptr[0 .. self.capacity]);
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}
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self.values = @as([*]Value, @ptrCast(@alignCast(buffer)))[0 .. self.values.len];
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self.capacity = grown_capacity;
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}
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pub fn is_empty(self: Self) bool {
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return self.values.len == 0;
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}
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pub fn make(allocator: io.Allocator) Self {
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return .{
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.allocator = allocator,
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.capacity = 0,
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.values = &.{},
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};
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}
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pub fn pack(self: *Self) io.AllocationError!void {
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const packed_size = self.values.len;
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const buffer = try self.allocator.reallocate(null, @sizeOf(Value) * self.values.len);
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io.copy(buffer, io.bytes_of(self.values));
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if (self.capacity != 0) {
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self.allocator.deallocate(self.values.ptr[0 .. self.capacity]);
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}
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self.values = @as([*]Value, @ptrCast(@alignCast(buffer)))[0 .. packed_size];
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self.capacity = packed_size;
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}
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pub fn peek(self: Self) ?Value {
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if (self.values.len == 0) {
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return null;
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}
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return self.values[self.values.len - 1];
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}
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pub fn pop(self: *Self) ?Value {
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if (self.values.len == 0) {
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return null;
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}
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const last_index = self.values.len - 1;
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defer self.values = self.values[0 .. last_index];
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return self.values[last_index];
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}
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pub fn push_all(self: *Self, values: []const Value) io.AllocationError!void {
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const new_length = self.values.len + values.len;
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if (new_length > self.capacity) {
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try self.grow(values.len + values.len);
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}
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const offset_index = self.values.len;
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self.values = self.values.ptr[0 .. new_length];
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for (0 .. values.len) |index| {
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self.values[offset_index + index] = values[index];
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}
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}
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pub fn push_one(self: *Self, value: Value) io.AllocationError!void {
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if (self.values.len == self.capacity) {
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try self.grow(@max(1, self.capacity));
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}
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const offset_index = self.values.len;
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self.values = self.values.ptr[0 .. self.values.len + 1];
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self.values[offset_index] = value;
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}
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};
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}
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pub fn stack_as_writer(self: *ByteStack) io.Writer {
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return io.Writer.bind(ByteStack, self, write_stack);
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}
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fn write_stack(stack: *ByteStack, bytes: []const io.Byte) ?usize {
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stack.push_all(bytes) catch return null;
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return bytes.len;
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}
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