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author | Indrajith K L | 2022-12-03 17:00:20 +0530 |
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committer | Indrajith K L | 2022-12-03 17:00:20 +0530 |
commit | f5c4671bfbad96bf346bd7e9a21fc4317b4959df (patch) | |
tree | 2764fc62da58f2ba8da7ed341643fc359873142f /v_windows/v/vlib/strings/builder.v | |
download | cli-tools-windows-master.tar.gz cli-tools-windows-master.tar.bz2 cli-tools-windows-master.zip |
Diffstat (limited to 'v_windows/v/vlib/strings/builder.v')
-rw-r--r-- | v_windows/v/vlib/strings/builder.v | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/v_windows/v/vlib/strings/builder.v b/v_windows/v/vlib/strings/builder.v new file mode 100644 index 0000000..4616a19 --- /dev/null +++ b/v_windows/v/vlib/strings/builder.v @@ -0,0 +1,163 @@ +// Copyright (c) 2019-2021 Alexander Medvednikov. All rights reserved. +// Use of this source code is governed by an MIT license +// that can be found in the LICENSE file. +module strings + +// strings.Builder is used to efficiently append many strings to a large +// dynamically growing buffer, then use the resulting large string. Using +// a string builder is much better for performance/memory usage than doing +// constantly string concatenation. +pub type Builder = []byte + +// new_builder returns a new string builder, with an initial capacity of `initial_size` +pub fn new_builder(initial_size int) Builder { + return Builder([]byte{cap: initial_size}) +} + +// write_ptr writes `len` bytes provided byteptr to the accumulated buffer +[unsafe] +pub fn (mut b Builder) write_ptr(ptr &byte, len int) { + if len == 0 { + return + } + unsafe { b.push_many(ptr, len) } +} + +// write_rune appends a single rune to the accumulated buffer +[manualfree] +pub fn (mut b Builder) write_rune(r rune) { + mut buffer := [5]byte{} + res := unsafe { utf32_to_str_no_malloc(u32(r), &buffer[0]) } + if res.len == 0 { + return + } + unsafe { b.push_many(res.str, res.len) } +} + +// write_runes appends all the given runes to the accumulated buffer +pub fn (mut b Builder) write_runes(runes []rune) { + mut buffer := [5]byte{} + for r in runes { + res := unsafe { utf32_to_str_no_malloc(u32(r), &buffer[0]) } + if res.len == 0 { + continue + } + unsafe { b.push_many(res.str, res.len) } + } +} + +// write_b appends a single `data` byte to the accumulated buffer +pub fn (mut b Builder) write_b(data byte) { + b << data +} + +// write implements the Writer interface +pub fn (mut b Builder) write(data []byte) ?int { + if data.len == 0 { + return 0 + } + b << data + return data.len +} + +[inline] +pub fn (b &Builder) byte_at(n int) byte { + return unsafe { (&[]byte(b))[n] } +} + +// write appends the string `s` to the buffer +[inline] +pub fn (mut b Builder) write_string(s string) { + if s.len == 0 { + return + } + unsafe { b.push_many(s.str, s.len) } + // for c in s { + // b.buf << c + // } + // b.buf << []byte(s) // TODO +} + +// go_back discards the last `n` bytes from the buffer +pub fn (mut b Builder) go_back(n int) { + b.trim(b.len - n) +} + +// cut_last cuts the last `n` bytes from the buffer and returns them +pub fn (mut b Builder) cut_last(n int) string { + cut_pos := b.len - n + x := unsafe { (&[]byte(b))[cut_pos..] } + res := x.bytestr() + b.trim(cut_pos) + return res +} + +// cut_to cuts the string after `pos` and returns it. +// if `pos` is superior to builder length, returns an empty string +// and cancel further operations +pub fn (mut b Builder) cut_to(pos int) string { + if pos > b.len { + return '' + } + return b.cut_last(b.len - pos) +} + +// go_back_to resets the buffer to the given position `pos` +// NB: pos should be < than the existing buffer length. +pub fn (mut b Builder) go_back_to(pos int) { + b.trim(pos) +} + +// writeln appends the string `s`, and then a newline character. +[inline] +pub fn (mut b Builder) writeln(s string) { + // for c in s { + // b.buf << c + // } + if s.len > 0 { + unsafe { b.push_many(s.str, s.len) } + } + // b.buf << []byte(s) // TODO + b << byte(`\n`) +} + +// last_n(5) returns 'world' +// buf == 'hello world' +pub fn (b &Builder) last_n(n int) string { + if n > b.len { + return '' + } + x := unsafe { (&[]byte(b))[b.len - n..] } + return x.bytestr() +} + +// after(6) returns 'world' +// buf == 'hello world' +pub fn (b &Builder) after(n int) string { + if n >= b.len { + return '' + } + x := unsafe { (&[]byte(b))[n..] } + return x.bytestr() +} + +// str returns a copy of all of the accumulated buffer content. +// NB: after a call to b.str(), the builder b should not be +// used again, you need to call b.free() first, or just leave +// it to be freed by -autofree when it goes out of scope. +// The returned string *owns* its own separate copy of the +// accumulated data that was in the string builder, before the +// .str() call. +pub fn (mut b Builder) str() string { + b << byte(0) + bcopy := unsafe { &byte(memdup(b.data, b.len)) } + s := unsafe { bcopy.vstring_with_len(b.len - 1) } + b.trim(0) + return s +} + +// free is for manually freeing the contents of the buffer +[unsafe] +pub fn (mut b Builder) free() { + unsafe { free(b.data) } +} |