initial commit

This commit is contained in:
Timon Ringwald 2022-04-19 14:35:10 +02:00
commit 094acf98ca
5 changed files with 117 additions and 0 deletions

9
errors.go Normal file
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package bufr
import (
"git.tordarus.net/Tordarus/adverr"
)
var (
ErrNothingToUnread = adverr.NewErrTmpl("ErrNothingToUnread", "Unreading failed because there wasn't any Read yet")
)

8
go.mod Normal file
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module git.tordarus.net/Tordarus/bufr
go 1.18
require (
git.tordarus.net/Tordarus/adverr v0.2.0
git.tordarus.net/Tordarus/dstruct v0.0.2
)

4
go.sum Normal file
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git.tordarus.net/Tordarus/adverr v0.2.0 h1:kLYjR2/Vb2GHiSAMvAv+WPNaHR9BRphKanf8H/pCZdA=
git.tordarus.net/Tordarus/adverr v0.2.0/go.mod h1:XRf0+7nhOkIEr0gi9DUG4RvV2KaOFB0fYPDaR1KLenw=
git.tordarus.net/Tordarus/dstruct v0.0.2 h1:oFaZO7YXQeHjxL4DmMaZ+Eb4MvP23dX8GAXs0Z6VQKo=
git.tordarus.net/Tordarus/dstruct v0.0.2/go.mod h1:RvLL2G4lUCGzwr8KaBGQRi3qlMG0WTgGhcVN6iyZZuw=

81
reader.go Normal file
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package bufr
import (
"bufio"
"io"
"strings"
"git.tordarus.net/Tordarus/dstruct"
)
type Reader struct {
buf *dstruct.Stack[rune]
src *bufio.Reader
}
func NewReader(r io.Reader) *Reader {
return &Reader{
buf: new(dstruct.Stack[rune]),
src: bufio.NewReader(r),
}
}
// Rune returns the next rune in r
func (r *Reader) Rune() (rune, error) {
rn, _, err := r.src.ReadRune()
if err == nil {
r.buf.Push(rn)
}
return rn, err
}
// UnreadRune unreads the last rune.
// The next read will include the unread rune.
// It returns ErrNothingToUnread if there wasn't any read yet
func (r *Reader) UnreadRune() error {
if r.buf.Empty() {
return ErrNothingToUnread.New()
}
if err := r.src.UnreadRune(); err == nil {
r.buf.Pop()
} else {
r.src = prependRune(r.buf.Pop(), r.src)
}
return nil
}
// UnreadString calls UnreadRune for each rune in str
// The actual runes are irrelevant.
// Only the rune count of str determines the amount of UnreadRune calls.
// The first error occured will be returned immediately.
func (r *Reader) UnreadString(str string) error {
for range str {
err := r.UnreadRune()
if err != nil {
return err
}
}
return nil
}
// StringWhile reads runes and calls f for each one.
// It returns all runes as a string for which f returned true.
// It stops when f returns false or an error occured.
// The rune for which f returned false will not be unread.
func (r *Reader) StringWhile(f func(rn rune) bool) (string, error) {
s := new(strings.Builder)
var err error
for rn, err := r.Rune(); err == nil && f(rn); rn, err = r.Rune() {
s.WriteRune(rn)
}
return s.String(), err
}
// StringUntil is a shorthand for r.StringWhile(func(rn rune) bool { return !f(rn) })
func (r *Reader) StringUntil(f func(rn rune) bool) (string, error) {
return r.StringWhile(func(rn rune) bool { return !f(rn) })
}

15
utils.go Normal file
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package bufr
import (
"bufio"
"io"
"strings"
)
func prependString(str string, r io.Reader) *bufio.Reader {
return bufio.NewReader(io.MultiReader(strings.NewReader(str), r))
}
func prependRune(rn rune, r io.Reader) *bufio.Reader {
return prependString(string(rn), r)
}