zig/std/buffer.zig

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const debug = @import("debug.zig");
const mem = @import("mem.zig");
const Allocator = mem.Allocator;
const assert = debug.assert;
const ArrayList = @import("array_list.zig").ArrayList;
/// A buffer that allocates memory and maintains a null byte at the end.
pub const Buffer = struct {
list: ArrayList(u8),
/// Must deinitialize with deinit.
pub fn init(allocator: &Allocator, m: []const u8) -> %Buffer {
var self = %return initSize(allocator, m.len);
mem.copy(u8, self.list.items, m);
return self;
}
/// Must deinitialize with deinit.
pub fn initSize(allocator: &Allocator, size: usize) -> %Buffer {
var self = initNull(allocator);
%return self.resize(size);
return self;
}
/// Must deinitialize with deinit.
/// None of the other operations are valid until you do one of these:
/// * ::replaceContents
/// * ::replaceContentsBuffer
/// * ::resize
pub fn initNull(allocator: &Allocator) -> Buffer {
Buffer {
.list = ArrayList(u8).init(allocator),
}
}
/// Must deinitialize with deinit.
pub fn initFromBuffer(buffer: &const Buffer) -> %Buffer {
return Buffer.init(buffer.list.allocator, buffer.toSliceConst());
}
pub fn deinit(self: &Buffer) {
self.list.deinit();
}
pub fn toSlice(self: &Buffer) -> []u8 {
return self.list.toSlice()[0..self.len()];
}
pub fn toSliceConst(self: &const Buffer) -> []const u8 {
return self.list.toSliceConst()[0..self.len()];
}
pub fn resize(self: &Buffer, new_len: usize) -> %void {
%return self.list.resize(new_len + 1);
self.list.items[self.len()] = 0;
}
pub fn isNull(self: &const Buffer) -> bool {
return self.list.len == 0;
}
pub fn len(self: &const Buffer) -> usize {
return self.list.len - 1;
}
pub fn append(self: &Buffer, m: []const u8) -> %void {
const old_len = self.len();
%return self.resize(old_len + m.len);
mem.copy(u8, self.list.toSlice()[old_len..], m);
}
pub fn appendByte(self: &Buffer, byte: u8) -> %void {
%return self.resize(self.len() + 1);
self.list.items[self.len() - 1] = byte;
}
pub fn eql(self: &const Buffer, m: []const u8) -> bool {
mem.eql(u8, self.toSliceConst(), m)
}
pub fn startsWith(self: &const Buffer, m: []const u8) -> bool {
if (self.len() < m.len) return false;
return mem.eql(u8, self.list.items[0..m.len], m);
}
pub fn endsWith(self: &const Buffer, m: []const u8) -> bool {
const l = self.len();
if (l < m.len) return false;
const start = l - m.len;
return mem.eql(u8, self.list.items[start..l], m);
}
pub fn replaceContents(self: &const Buffer, m: []const u8) -> %void {
%return self.resize(m.len);
mem.copy(u8, self.list.toSlice(), m);
}
};
test "simple Buffer" {
const cstr = @import("cstr.zig");
var buf = %%Buffer.init(&debug.global_allocator, "");
assert(buf.len() == 0);
%%buf.append("hello");
%%buf.appendByte(' ');
%%buf.append("world");
assert(buf.eql("hello world"));
assert(mem.eql(u8, cstr.toSliceConst(buf.toSliceConst().ptr), buf.toSliceConst()));
var buf2 = %%Buffer.initFromBuffer(&buf);
assert(buf.eql(buf2.toSliceConst()));
assert(buf.startsWith("hell"));
assert(buf.endsWith("orld"));
%%buf2.resize(4);
assert(buf.startsWith(buf2.toSliceConst()));
}