1 files changed, 189 insertions, 0 deletions
diff --git a/common/buffer/get.go b/common/buffer/get.go
new file mode 100644
index 0000000..4f27b70
--- /dev/null
+++ b/common/buffer/get.go
@@ -0,0 +1,189 @@
+package buffer
+
+import (
+	"encoding/binary"
+	"math"
+	"strings"
+)
+
+func (b *Buffer) ReadByte() (byte, error) {
+	if b.off+1 > len(b.buf) {
+		return 0, ErrBadRead
+	}
+
+	r := b.buf[b.off]
+	b.off += 1
+	return r, nil
+}
+
+func (b *Buffer) GetBytes(n int) ([]byte, error) {
+	if b.off+n > len(b.buf) {
+		return nil, ErrBadRead
+	}
+
+	r := b.buf[b.off : b.off+n]
+	b.off += n
+	return r, nil
+}
+
+func (b *Buffer) GetUint8() (uint8, error) {
+	if b.off+1 > len(b.buf) {
+		return 0, ErrBadRead
+	}
+
+	r := b.buf[b.off]
+	b.off++
+	return r, nil
+}
+
+func (b *Buffer) GetInt8() (int8, error) {
+	r, err := b.GetUint8()
+	if err != nil {
+		return 0, err
+	}
+
+	return int8(r), nil
+}
+
+func (b *Buffer) GetInt16() (int16, error) {
+	r, err := b.GetUint16()
+	if err != nil {
+		return 0, err
+	}
+
+	return int16(r), nil
+}
+
+func (b *Buffer) GetUint16() (uint16, error) {
+	if b.off+2 > len(b.buf) {
+		return 0, ErrBadRead
+	}
+
+	r := binary.LittleEndian.Uint16(b.buf[b.off : b.off+2])
+	b.off += 2
+	return r, nil
+}
+
+func (b *Buffer) GetInt32() (int32, error) {
+	r, err := b.GetUint32()
+	if err != nil {
+		return 0, err
+	}
+
+	return int32(r), nil
+}
+
+func (b *Buffer) GetUint32() (uint32, error) {
+	if b.off+4 > len(b.buf) {
+		return 0, ErrBadRead
+	}
+
+	r := binary.LittleEndian.Uint32(b.buf[b.off : b.off+4])
+	b.off += 4
+	return r, nil
+}
+
+func (b *Buffer) GetFloat32() (float32, error) {
+	r, err := b.GetUint32()
+	if err != nil {
+		return 0, err
+	}
+
+	return math.Float32frombits(r), nil
+}
+
+func (b *Buffer) GetAngle8() (float32, error) {
+	r, err := b.ReadByte()
+	if err != nil {
+		return 0, err
+	}
+
+	return float32(int8(r)) * (360.0 / 256), nil
+}
+
+func (b *Buffer) GetAngle16() (float32, error) {
+	r, err := b.GetUint16()
+	if err != nil {
+		return 0, err
+	}
+
+	return float32(r) * (360.0 / 65536), nil
+}
+
+func (b *Buffer) GetCoord16() (float32, error) {
+	r, err := b.GetInt16()
+	if err != nil {
+		return 0, err
+	}
+
+	return float32(r) / 8.0, nil
+}
+
+func (b *Buffer) GetCoord32() (float32, error) {
+	return b.GetFloat32()
+}
+
+func (b *Buffer) GetString() (string, error) {
+	var str strings.Builder
+
+	for b.off < b.Len() {
+		r, err := b.ReadByte()
+		if err != nil {
+			return "", err
+		}
+
+		if r == 0xff {
+			continue
+		}
+
+		if r == 0x00 {
+			break
+		}
+
+		str.WriteByte(r)
+	}
+
+	return str.String(), nil
+}
+
+func (b *Buffer) PeekInt32() (int32, error) {
+	if b.off+4 > len(b.buf) {
+		return 0, ErrBadRead
+	}
+
+	return int32(binary.LittleEndian.Uint32(b.buf[b.off : b.off+4])), nil
+}
+
+func (b *Buffer) PeekBytes(n int) ([]byte, error) {
+	if b.off+n > len(b.buf) {
+		return nil, ErrBadRead
+	}
+
+	return b.buf[b.off : b.off+n], nil
+}
+
+func (b *Buffer) PeekBytesAt(off, size int) ([]byte, error) {
+	if off+size > len(b.buf) {
+		return nil, ErrBadRead
+	}
+
+	return b.buf[off : off+size], nil
+}
+
+func (b *Buffer) Skip(n int) error {
+	if b.off+n > len(b.buf) {
+		return ErrBadRead
+	}
+
+	b.off += n
+	return nil
+}
+
+func (b *Buffer) Seek(n int) error {
+	if n > len(b.buf) {
+		return ErrBadRead
+	}
+
+	b.off = n
+	return nil
+}