t.Fatalf("entry %d, Next(): got %v, want %v", i, err, nil)
				}
				buf := make([]byte, tc.cnt)
				if _, err := io.ReadFull(tr, buf); err != nil {
					t.Fatalf("entry %d, ReadFull(): got %v, want %v", i, err, nil)
				}
				if string(buf) != tc.output {
					t.Fatalf("entry %d, ReadFull(): got %q, want %q", i, string(buf), tc.output)
				}
			}

			if _, err := tr.Next(); err != io.EOF {

	// first read just those 4 bytes to see if it exists.
	if _, err := io.ReadFull(r, buf[:4]); err != nil {
		return err
	}
	off := 0
	maybeSig := readBuf(buf[:4])
	if maybeSig.uint32() != dataDescriptorSignature {
		// No data descriptor signature. Keep these four
		// bytes.
		off += 4
	}
	if _, err := io.ReadFull(r, buf[off:12]); err != nil {
		return err
	}
	b := readBuf(buf[:12])

// Read reads data into p.
// It returns the number of bytes read into p.
// The bytes are taken from at most one Read on the underlying [Reader],
// hence n may be less than len(p).
// To read exactly len(p) bytes, use io.ReadFull(b, p).
// If the underlying [Reader] can return a non-zero count with io.EOF,
// then this Read method can do so as well; see the [io.Reader] docs.
func (b *Reader) Read(p []byte) (n int, err error) {
	n = len(p)

cryptographically secure random // bytes. It is intended for use in APIs that expose a rand io.Reader. func ReadWithReader(r io.Reader, b []byte) error { if _, ok := r.(DefaultReader); ok { Read(b) return nil } fips140.RecordNonApproved() _, err := io.ReadFull(r, b) return err } golang.org/fips140@v1.26.0/fips140/v1.26.0/drbg/rand_test.go // Copyright 2025 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package...