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reader.go
80 lines (67 loc) · 1.33 KB
/
reader.go
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package terminfo
import (
"encoding/binary"
"errors"
"io"
)
type reader struct {
b []byte
i int
}
func newReader(b []byte) *reader {
return &reader{b, 0}
}
func (r *reader) len() int {
return len(r.b) - r.i
}
func (r *reader) isEmpty() bool {
return r.len() == 0
}
func (r *reader) align() {
if r.i%2 == 1 {
r.i += 1
}
}
func (r *reader) sliceUnsafe(off int) []byte {
return r.b[r.i+off:]
}
func (r *reader) slice(off int) ([]byte, error) {
if r.len() < off {
return nil, io.ErrUnexpectedEOF
}
return r.sliceUnsafe(off), nil
}
func (r *reader) readBytes(n int) ([]byte, error) {
if r.len() < n {
return nil, io.ErrUnexpectedEOF
}
r.i += n
return r.b[r.i-n : r.i], nil
}
func (r *reader) readInts(n, byteSize int) ([]int, error) {
r.align()
if r.len() < n*byteSize {
return nil, io.ErrUnexpectedEOF
}
rst := make([]int, n)
switch byteSize {
case 2:
for i := 0; i < n; i++ {
rst[i] = int(int16(binary.LittleEndian.Uint16(r.sliceUnsafe(i * 2))))
}
case 4:
for i := 0; i < n; i++ {
rst[i] = int(int32(binary.LittleEndian.Uint32(r.sliceUnsafe(i * 4))))
}
default:
return nil, errors.New("Illegal byteSize")
}
r.i += n * byteSize
return rst, nil
}
func (r *reader) readInt16s(n int) ([]int, error) {
return r.readInts(n, 2)
}
func (r *reader) readInt32s(n int) ([]int, error) {
return r.readInts(n, 4)
}