/// Rope-like data structure for joining many small strings into one big string.
const Joiner = @This();
const string = @import("string_types.zig").string;
const Allocator = @import("std").mem.Allocator;
const assert = @import("std").debug.assert;
const copy = @import("std").mem.copy;
const Env = @import("./env.zig");
const ObjectPool = @import("./pool.zig").ObjectPool;
const default_allocator = @import("./global.zig").default_allocator;
const Joinable = struct {
offset: u31 = 0,
needs_deinit: bool = false,
allocator: std.mem.Allocator = undefined,
slice: []const u8 = "",
pub const Pool = ObjectPool(Joinable, null, true, 4);
};
last_byte: u8 = 0,
len: usize = 0,
use_pool: bool = true,
node_allocator: std.mem.Allocator = undefined,
head: ?*Joinable.Pool.Node = null,
tail: ?*Joinable.Pool.Node = null,
pub fn done(this: *Joiner, allocator: std.mem.Allocator) ![]u8 {
if (this.head == null) {
var out: []u8 = &[_]u8{};
return out;
}
var slice = try allocator.alloc(u8, this.len);
var remaining = slice;
var el_ = this.head;
while (el_) |join| {
const to_join = join.data.slice[join.data.offset..];
@memcpy(remaining.ptr, to_join.ptr, to_join.len);
remaining = remaining[@minimum(remaining.len, to_join.len)..];
var prev = join;
el_ = join.next;
if (prev.data.needs_deinit) {
prev.data.allocator.free(prev.data.slice);
prev.data = Joinable{};
}
if (this.use_pool) prev.release();
}
return slice[0 .. slice.len - remaining.len];
}
pub fn lastByte(this: *const Joiner) u8 {
if (this.tail) |tail| {
const slice = tail.data.slice[tail.data.offset..];
return if (slice.len > 0) slice[slice.len - 1] else 0;
}
return 0;
}
pub fn append(this: *Joiner, slice: string, offset: u32, allocator: ?std.mem.Allocator) void {
const data = slice[offset..];
this.len += @truncate(u32, data.len);
var new_tail = if (this.use_pool)
Joinable.Pool.get(default_allocator)
else
(this.node_allocator.create(Joinable.Pool.Node) catch unreachable);
new_tail.* = .{
.allocator = default_allocator,
.data = Joinable{
.offset = @truncate(u31, offset),
.allocator = allocator orelse undefined,
.needs_deinit = allocator != null,
.slice = slice,
},
};
var tail = this.tail orelse {
this.tail = new_tail;
this.head = new_tail;
return;
};
tail.next = new_tail;
this.tail = new_tail;
}
const std = @import("std");
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Jarred Sumner