package tar

import "strings"

// Format represents the tar archive format.
//
// The original tar format was introduced in Unix V7.
// Since then, there have been multiple competing formats attempting to
// standardize or extend the V7 format to overcome its limitations.
// The most common formats are the USTAR, PAX, and GNU formats,
// each with their own advantages and limitations.
//
// The following table captures the capabilities of each format:

</li>

<li>
<code>R0.UXTB</code>
<br>
<code>R0.UXTB&lt;&lt;imm</code>:
<code>UXTB</code>: extract an 8-bit value from the low-order bits of <code>R0</code> and zero-extend it to the size of <code>R0</code>.
<code>R0.UXTB&lt;&lt;imm</code>: left shift the result of <code>R0.UXTB</code> by <code>imm</code> bits.
The <code>imm</code> value can be 0, 1, 2, 3, or 4.

with its array and with other slices of the same array; by contrast,
distinct arrays always represent distinct storage.
</p>
<p>
The array underlying a slice may extend past the end of the slice.
The <i>capacity</i> is a measure of that extent: it is the sum of
the length of the slice and the length of the array beyond the slice;
a slice of length up to that capacity can be created by

	//export MyFunction2
	func MyFunction2(arg1, arg2 int, arg3 string) (int64, *C.char) {...}

They will be available in the C code as:

	extern GoInt64 MyFunction(int arg1, int arg2, GoString arg3);
	extern struct MyFunction2_return MyFunction2(int arg1, int arg2, GoString arg3);

found in the _cgo_export.h generated header, after any preambles
copied from the cgo input files. Functions with multiple

	{"X13", "X13"},
	{"X14", "X14"},
	{"X15", "X15"},
	{"X2", "X2"},
	{"X3", "X3"},
	{"X4", "X4"},
	{"X5", "X5"},
	{"X6", "X6"},
	{"X7", "X7"},
	{"X8", "X8"},
	{"X9", "X9"},
	{"_expand_key_128<>(SB)", "_expand_key_128<>(SB)"},
	{"_seek<>(SB)", "_seek<>(SB)"},
	{"a2+16(FP)", "a2+16(FP)"},
	{"addr2+24(FP)", "addr2+24(FP)"},
	{"asmcgocall<>(SB)", "asmcgocall<>(SB)"},
	{"b+24(FP)", "b+24(FP)"},

			return false // Negative values are never okay
		case cur.Offset > math.MaxInt64-cur.Length:
			return false // Integer overflow with large length
		case cur.endOffset() > size:
			return false // Region extends beyond the actual size
		case pre.endOffset() > cur.Offset:
			return false // Regions cannot overlap and must be in order
		}
		pre = cur
	}
	return true
}

	FMOVS	0x44332211(R1), F2	// FMOVS	1144201745(R1), F2
	FMOVD	0x1000000(R1), F2	// FMOVD	16777216(R1), F2
	FMOVD	0x44332211(R1), F2	// FMOVD	1144201745(R1), F2

// shifted or extended register offset.
	MOVD	(R2)(R6.SXTW), R4               // 44c866f8
	MOVD	(R3)(R6), R5                    // 656866f8
	MOVD	(R3)(R6*1), R5                  // 656866f8
	MOVD	(R2)(R6), R4                    // 446866f8

	//
	// See http://mdfs.net/Docs/Comp/Archiving/Zip/ExtraField
	zip64ExtraID       = 0x0001 // Zip64 extended information
	ntfsExtraID        = 0x000a // NTFS
	unixExtraID        = 0x000d // UNIX
	extTimeExtraID     = 0x5455 // Extended timestamp
	infoZipUnixExtraID = 0x5855 // Info-ZIP Unix extension
)

// FileHeader describes a file within a ZIP file.

client or server to have an empty Content-Length header.
This behavior is controlled by the `httplaxcontentlength` setting.

Go 1.22 changed the behavior of ServeMux to accept extended
patterns and unescape both patterns and request paths by segment.
This behavior can be controlled by the
[`httpmuxgo121` setting](/pkg/net/http/#ServeMux).

		// If legacy MS-DOS timestamps are set, we can use the delta between
		// the legacy and extended versions to estimate timezone offset.
		//
		// A non-UTC timezone is always used (even if offset is zero).
		// Thus, FileHeader.Modified.Location() == time.UTC is useful for
		// determining whether extended timestamps are present.
		// This is necessary for users that need to do additional time