package bytes_test

import (
	. "bytes"
	"fmt"
	"internal/testenv"
	"io"
	"math/rand"
	"strconv"
	"testing"
	"unicode/utf8"
)

const N = 10000       // make this bigger for a larger (and slower) test
var testString string // test data for write tests
var testBytes []byte  // test data; same as testString but as a slice.

type negativeReader struct{}

	//go:cgo_import_dynamic _ _ "libpthread.so.0"
	//go:cgo_import_dynamic _ _ "libc.so.6"

In the end, the compiled Go package, which will eventually be
presented to cmd/link as part of a larger program, contains:

	_go_.o        # gc-compiled object for _cgo_gotypes.go, _cgo_import.go, *.cgo1.go
	_all.o        # gcc-compiled object for _cgo_export.c, *.cgo2.c

	//
	// While this format is compatible with most tar readers,
	// the format has several limitations making it unsuitable for some usages.
	// Most notably, it cannot support sparse files, files larger than 8GiB,
	// filenames larger than 256 characters, and non-ASCII filenames.
	//
	// Reference:
	//	http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13_06
	FormatUSTAR

field, [`Policies`](/pkg/crypto/x509/#Certificate.Policies), which supports
certificate policy OIDs with components larger than 31 bits. By default this
field is only used during parsing, when it is populated with policy OIDs, but
not used during marshaling. It can be used to marshal these larger OIDs, instead
of the existing PolicyIdentifiers field, by using the
[`x509usepolicies` setting.](/pkg/crypto/x509/#CreateCertificate).

		s.err = err
	}
}

// Buffer sets the initial buffer to use when scanning
// and the maximum size of buffer that may be allocated during scanning.
// The maximum token size must be less than the larger of max and cap(buf).
// If max <= cap(buf), [Scanner.Scan] will use this buffer only and do no allocation.
//
// By default, [Scanner.Scan] uses an internal buffer and sets the
// maximum token size to [MaxScanTokenSize].

MOVQ	g(CX), AX     // Move g into AX.
MOVQ	g_m(AX), BX   // Move g.m into BX.
</pre>

<p>
Register <code>BP</code> is callee-save.
The assembler automatically inserts <code>BP</code> save/restore when frame size is larger than zero.
Using <code>BP</code> as a general purpose register is allowed,
however it can interfere with sampling-based profiling.
</p>

<h3 id="arm">ARM</h3>

<p>

	n := len(b) * count

	if len(b) == 0 {
		return []byte{}
	}

	// Past a certain chunk size it is counterproductive to use
	// larger chunks as the source of the write, as when the source
	// is too large we are basically just thrashing the CPU D-cache.
	// So if the result length is larger than an empirically-found
	// limit (8KB), we stop growing the source string once the limit

		hdr.Size = n
	}

	// Read the sparse map according to the appropriate format.
	if is1x0 {
		return readGNUSparseMap1x0(tr.curr)
	}
	return readGNUSparseMap0x1(hdr.PAXRecords)
}

// mergePAX merges paxHdrs into hdr for all relevant fields of Header.
func mergePAX(hdr *Header, paxHdrs map[string]string) (err error) {
	for k, v := range paxHdrs {
		if v == "" {
			continue // Keep the original USTAR value
		}

</p>

<p>
Reads of memory locations larger than a single machine word
are encouraged but not required to meet the same semantics
as word-sized memory locations,
observing a single allowed write <i>w</i>.
For performance reasons,
implementations may instead treat larger operations
as a set of individual machine-word-sized operations
in an unspecified order.

			break
		}
	}
	if got, want := scanner.Err(), ErrBadReadCount; got != want {
		t.Errorf("scanner.Err: got %v, want %v", got, want)
	}
}

// largeReader returns an invalid count that is larger than the number
// of bytes requested.
type largeReader struct{}

func (largeReader) Read(p []byte) (int, error) {
	return len(p) + 1, nil
}