v/vlib/strings/builder.v

135 lines
2.5 KiB
V
Raw Normal View History

2020-02-03 05:00:36 +01:00
// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
2019-06-23 04:21:30 +02:00
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
2019-09-14 22:48:30 +02:00
module strings
2019-06-22 20:20:28 +02:00
2019-10-24 11:47:21 +02:00
pub struct Builder {
2020-05-09 15:16:48 +02:00
// TODO
pub mut:
2019-12-19 22:29:37 +01:00
buf []byte
str_calls int
2019-12-19 22:29:37 +01:00
len int
initial_size int = 1
2019-06-22 20:20:28 +02:00
}
pub fn new_builder(initial_size int) Builder {
2019-12-19 22:29:37 +01:00
return Builder{
//buf: make(0, initial_size)
buf: []byte{cap: initial_size}
2020-05-18 21:38:06 +02:00
str_calls: 0
len: 0
initial_size: initial_size
2019-06-22 20:20:28 +02:00
}
}
2020-05-17 13:51:18 +02:00
pub fn (mut b Builder) write_bytes(bytes byteptr, howmany int) {
2019-12-11 17:20:46 +01:00
b.buf.push_many(bytes, howmany)
b.len += howmany
}
2020-05-17 13:51:18 +02:00
pub fn (mut b Builder) write_b(data byte) {
2019-12-06 21:02:09 +01:00
b.buf << data
2019-12-08 12:11:19 +01:00
b.len++
2019-12-06 21:02:09 +01:00
}
[inline]
2020-05-17 13:51:18 +02:00
pub fn (mut b Builder) write(s string) {
2019-12-24 18:54:43 +01:00
if s == '' {
return
}
2019-10-10 00:15:19 +02:00
b.buf.push_many(s.str, s.len)
2019-12-19 22:29:37 +01:00
// for c in s {
// b.buf << c
// }
// b.buf << []byte(s) // TODO
2019-06-22 20:20:28 +02:00
b.len += s.len
}
2020-05-17 13:51:18 +02:00
pub fn (mut b Builder) go_back(n int) {
2020-03-10 23:21:26 +01:00
b.buf.trim(b.buf.len-n)
b.len -= n
}
2020-03-10 23:21:26 +01:00
fn bytes2string(b []byte) string {
mut copy := b.clone()
copy << `\0`
res := tos(copy.data, copy.len-1)
return res
}
2020-06-17 00:59:33 +02:00
pub fn (mut b Builder) cut_last(n int) string {
res := bytes2string( b.buf[b.len-n..] )
2020-06-17 00:59:33 +02:00
b.buf.trim(b.buf.len-n)
b.len -= n
return res
2020-06-17 00:59:33 +02:00
}
/*
pub fn (mut b Builder) cut_to(pos int) string {
res := bytes2string( b.buf[pos..] )
2020-06-17 00:59:33 +02:00
b.buf.trim(pos)
b.len = pos
return res
2020-06-17 00:59:33 +02:00
}
*/
2020-05-17 13:51:18 +02:00
pub fn (mut b Builder) go_back_to(pos int) {
2020-04-28 13:15:37 +02:00
b.buf.trim(pos)
b.len = pos
}
[inline]
2020-05-17 13:51:18 +02:00
pub fn (mut b Builder) writeln(s string) {
2019-12-19 22:29:37 +01:00
// for c in s {
// b.buf << c
// }
2019-10-10 00:15:19 +02:00
b.buf.push_many(s.str, s.len)
2019-12-19 22:29:37 +01:00
// b.buf << []byte(s) // TODO
2019-06-22 20:20:28 +02:00
b.buf << `\n`
b.len += s.len + 1
}
2020-03-21 07:01:06 +01:00
// buf == 'hello world'
// last_n(5) returns 'world'
2020-03-21 07:04:53 +01:00
pub fn (b &Builder) last_n(n int) string {
2020-03-21 07:01:06 +01:00
if n > b.len {
return ''
}
return bytes2string( b.buf[b.len-n..] )
2020-03-21 07:01:06 +01:00
}
// buf == 'hello world'
// after(6) returns 'world'
2020-03-21 07:04:53 +01:00
pub fn (b &Builder) after(n int) string {
2020-03-21 07:01:06 +01:00
if n >= b.len {
return ''
}
return bytes2string( b.buf[n..] )
2020-03-21 07:01:06 +01:00
}
// NB: in order to avoid memleaks and additional memory copies, after a call to b.str(),
// the builder b will be empty. The returned string *owns* the accumulated data so far.
2020-05-17 13:51:18 +02:00
pub fn (mut b Builder) str() string {
b.str_calls++
if b.str_calls > 1 {
panic('builder.str() should be called just once.\n' +
'If you want to reuse a builder, call b.free() first.')
}
2019-11-17 00:22:43 +01:00
b.buf << `\0`
s := tos(b.buf.data, b.len)
2020-07-01 17:04:30 +02:00
bis := b.initial_size
2020-06-28 13:56:38 +02:00
//free(b.buf.data)
2020-07-01 17:04:30 +02:00
b.buf = []byte{cap: bis}
b.len = 0
return s
2019-06-22 20:20:28 +02:00
}
2020-05-17 13:51:18 +02:00
pub fn (mut b Builder) free() {
2019-12-19 22:29:37 +01:00
unsafe{
free(b.buf.data)
}
//b.buf = []byte{cap: b.initial_size}
b.len = 0
b.str_calls = 0
2019-06-24 22:34:21 +02:00
}