</pre>


<h2 id="Blocks">Blocks</h2>

<p>
A <i>block</i> is a possibly empty sequence of declarations and statements
within matching brace brackets.
</p>

<pre class="ebnf">
Block = "{" StatementList "}" .
StatementList = { Statement ";" } .
</pre>

<p>
In addition to explicit blocks in the source code, there are implicit blocks:
</p>

<ol>

		if err := w.Close(); err != nil {
			t.Fatalf("Unable to write archive: %s", err)
		}

		// TODO: We may want to check if the archive roundtrips. This would require
		// taking into account addition of the two zero trailer blocks that Writer.Close
		// appends.
	})

	return paxHdrs, nil
}

// readHeader reads the next block header and assumes that the underlying reader
// is already aligned to a block boundary. It returns the raw block of the
// header in case further processing is required.
//
// The err will be set to io.EOF only when one of the following occurs:
//   - Exactly 0 bytes are read and EOF is hit.
//   - Exactly 1 block of zeros is read and EOF is hit.

</p>

<h2 id="Blocks">Blocks</h2>

<p>
A <i>block</i> is a possibly empty sequence of declarations and statements
within matching brace brackets.
</p>

<pre class="ebnf">
Block = "{" StatementList "}" .
StatementList = { Statement ";" } .
</pre>

<p>
In addition to explicit blocks in the source code, there are implicit blocks:
</p>

<ol>

		// Write the initial GNU header.
		var blk block
		gnu := blk.toGNU()
		sparse := gnu.sparse()
		copy(gnu.realSize(), size)
		sps = populateSparseMap(sparse, sps)
		if format != FormatUnknown {
			blk.setFormat(format)
		}
		out = append(out, blk[:]...)

		// Write extended sparse blocks.
		for len(sps) > 0 {
			var blk block
			sps = populateSparseMap(blk.toSparse(), sps)

					sa.IsExtended()[0] = 1
				}
				return sp
			}
			sp2 := formatSPD(spd, blk.GNU().Sparse())
			for len(sp2) > 0 {
				var spHdr block
				sp2 = formatSPD(sp2, spHdr.Sparse())
				spb = append(spb, spHdr[:]...)
			}

			// Update size fields in the header block.
			realSize := hdr.Size
			hdr.Size = 0 // Encoded size; does not account for encoded sparse map
			for _, s := range spd {
				hdr.Size += s.Length

			b.Write(buf[:1])
		}
	}
}

func BenchmarkBufferWriteBlock(b *testing.B) {
	block := make([]byte, 1024)
	for _, n := range []int{1 << 12, 1 << 16, 1 << 20} {
		b.Run(fmt.Sprintf("N%d", n), func(b *testing.B) {
			b.ReportAllocs()
			for i := 0; i < b.N; i++ {
				var bb Buffer
				for bb.Len() < n {
					bb.Write(block)
				}
			}
		})
	}
}

func BenchmarkBufferAppendNoCopy(b *testing.B) {

pkg syscall (darwin-arm64), const LOCK_EX = 2
pkg syscall (darwin-arm64), const LOCK_EX ideal-int
pkg syscall (darwin-arm64), const LOCK_NB = 4
pkg syscall (darwin-arm64), const LOCK_NB ideal-int
pkg syscall (darwin-arm64), const LOCK_SH = 1
pkg syscall (darwin-arm64), const LOCK_SH ideal-int
pkg syscall (darwin-arm64), const LOCK_UN = 8
pkg syscall (darwin-arm64), const LOCK_UN ideal-int

pkg syscall (freebsd-arm64), const LOCK_EX = 2
pkg syscall (freebsd-arm64), const LOCK_EX ideal-int
pkg syscall (freebsd-arm64), const LOCK_NB = 4
pkg syscall (freebsd-arm64), const LOCK_NB ideal-int
pkg syscall (freebsd-arm64), const LOCK_SH = 1
pkg syscall (freebsd-arm64), const LOCK_SH ideal-int
pkg syscall (freebsd-arm64), const LOCK_UN = 8
pkg syscall (freebsd-arm64), const LOCK_UN ideal-int

pkg syscall (freebsd-riscv64), const SYS_CLOCK_GETCPUCLOCKID2 = 247 #53466
pkg syscall (freebsd-riscv64), const SYS_CLOCK_GETCPUCLOCKID2 ideal-int #53466
pkg syscall (freebsd-riscv64), const SYS_CLOCK_GETRES = 234 #53466
pkg syscall (freebsd-riscv64), const SYS_CLOCK_GETRES ideal-int #53466
pkg syscall (freebsd-riscv64), const SYS_CLOCK_GETTIME = 232 #53466
pkg syscall (freebsd-riscv64), const SYS_CLOCK_GETTIME ideal-int #53466