fixed dependencies

vendor/github.com/go-pdf/fpdf/rbuf.go

@@ -0,0 +1,72 @@
+// Copyright ©2021 The go-pdf Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package fpdf
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+)
+
+type rbuffer struct {
+	p []byte
+	c int
+}
+
+// newRBuffer returns a new buffer populated with the contents of the specified Reader
+func newRBuffer(r io.Reader) (b *rbuffer, err error) {
+	buf := new(bytes.Buffer)
+	_, err = buf.ReadFrom(r)
+	b = &rbuffer{p: buf.Bytes()}
+	return
+}
+
+func (r *rbuffer) Read(p []byte) (int, error) {
+	if r.c >= len(r.p) {
+		return 0, io.EOF
+	}
+	n := copy(p, r.p[r.c:])
+	r.c += n
+	return n, nil
+}
+
+func (r *rbuffer) ReadByte() (byte, error) {
+	if r.c >= len(r.p) {
+		return 0, io.EOF
+	}
+	v := r.p[r.c]
+	r.c++
+	return v, nil
+}
+
+func (r *rbuffer) u8() uint8 {
+	if r.c >= len(r.p) {
+		panic(io.ErrShortBuffer)
+	}
+	v := r.p[r.c]
+	r.c++
+	return v
+}
+
+func (r *rbuffer) u32() uint32 {
+	const n = 4
+	if r.c+n >= len(r.p) {
+		panic(io.ErrShortBuffer)
+	}
+	beg := r.c
+	r.c += n
+	v := binary.BigEndian.Uint32(r.p[beg:])
+	return v
+}
+
+func (r *rbuffer) i32() int32 {
+	return int32(r.u32())
+}
+
+func (r *rbuffer) Next(n int) []byte {
+	c := r.c
+	r.c += n
+	return r.p[c:r.c]
+}