hash reorg.

* new package hash defining interfaces Hash and Hash32.
* adler32 and crc32 return Hash32 instead of specific types.
* adler32 and crc32 provide non-allocating methods for single slices.
* sha1 and md5 move to crypto, return Hash.
* sum.go, a simple test program, moves to /usr/rsc.
* refresh Make.deps

R=r
DELTA=1908  (935 added, 923 deleted, 50 changed)
OCL=29095
CL=29135

14 files changed, 160 insertions, 93 deletions

diff --git a/src/lib/Make.deps b/src/lib/Make.deps
index d75dbf22e5..30083f2631 100644
--- a/src/lib/Make.deps
+++ b/src/lib/Make.deps
@@ -3,6 +3,8 @@ bufio.install: io.install os.install utf8.install
 container/vector.install:
 crypto/aes.install: os.install
 crypto/block.install: fmt.install io.install os.install
+crypto/md5.install: hash.install os.install
+crypto/sha1.install: hash.install os.install
 exec.install: os.install strings.install
 exvar.install: fmt.install http.install io.install log.install strconv.install sync.install
 flag.install: fmt.install os.install strconv.install
@@ -12,11 +14,9 @@ go/doc.install: container/vector.install fmt.install go/ast.install go/token.ins
 go/parser.install: container/vector.install fmt.install go/ast.install go/scanner.install go/token.install io.install os.install
 go/scanner.install: go/token.install strconv.install unicode.install utf8.install
 go/token.install: strconv.install
-hash/adler32.install: os.install
-hash/crc32.install: os.install
-hash/md5.install: os.install
-hash/sha1.install: os.install
-hash/sum.install: flag.install fmt.install hash/adler32.install hash/crc32.install hash/md5.install hash/sha1.install io.install os.install
+hash.install: io.install
+hash/adler32.install: hash.install os.install
+hash/crc32.install: hash.install os.install
 http.install: bufio.install fmt.install io.install log.install net.install os.install path.install strconv.install strings.install utf8.install
 io.install: os.install sync.install
 json.install: container/vector.install fmt.install io.install math.install reflect.install strconv.install strings.install utf8.install
diff --git a/src/lib/Makefile b/src/lib/Makefile
index 75c6758d36..d258e1adbc 100644
--- a/src/lib/Makefile
+++ b/src/lib/Makefile
@@ -19,6 +19,8 @@ DIRS=\
 	container/vector\
 	crypto/aes\
 	crypto/block\
+	crypto/md5\
+	crypto/sha1\
 	exec\
 	exvar\
 	flag\
@@ -28,11 +30,9 @@ DIRS=\
 	go/parser\
 	go/scanner\
 	go/token\
+	hash\
 	hash/adler32\
 	hash/crc32\
-	hash/md5\
-	hash/sha1\
-	hash/sum\
 	http\
 	io\
 	json\
@@ -65,6 +65,9 @@ TEST=\
 	bufio\
 	container/vector\
 	crypto/aes\
+	crypto/block\
+	crypto/md5\
+	crypto/sha1\
 	exec\
 	exvar\
 	flag\
@@ -73,8 +76,6 @@ TEST=\
 	go/scanner\
 	hash/adler32\
 	hash/crc32\
-	hash/md5\
-	hash/sha1\
 	http\
 	io\
 	json\
diff --git a/src/lib/hash/md5/Makefile b/src/lib/crypto/md5/Makefile
index f9320faaf5..8867b84a52 100644
--- a/src/lib/hash/md5/Makefile
+++ b/src/lib/crypto/md5/Makefile
@@ -5,7 +5,7 @@
 # DO NOT EDIT.  Automatically generated by gobuild.
 # gobuild -m >Makefile
 
-D=/hash/
+D=/crypto/
 
 O_arm=5
 O_amd64=6
diff --git a/src/lib/hash/md5/md5.go b/src/lib/crypto/md5/md5.go
index de8d34d33f..f8b8dda2fb 100644
--- a/src/lib/hash/md5/md5.go
+++ b/src/lib/crypto/md5/md5.go
@@ -5,7 +5,13 @@
 // This package implements the MD5 hash algorithm as defined in RFC 1321.
 package md5
 
-import "os"
+import (
+	"hash";
+	"os";
+)
+
+// The size of an MD5 checksum in bytes.
+const Size = 16;
 
 const (
 	_Chunk = 64;
@@ -16,29 +22,35 @@ const (
 	_Init3 = 0x10325476;
 )
 
-// Digest represents the partial evaluation of a checksum.
-type Digest struct {
+// digest represents the partial evaluation of a checksum.
+type digest struct {
 	s [4]uint32;
 	x [_Chunk]byte;
 	nx int;
 	len uint64;
 }
 
-// NewDigest creates a new Digest.
-func NewDigest() *Digest {
-	d := new(Digest);
+func (d *digest) Reset() {
 	d.s[0] = _Init0;
 	d.s[1] = _Init1;
 	d.s[2] = _Init2;
 	d.s[3] = _Init3;
+}
+
+// New returns a Hash computing the SHA1 checksum.
+func New() hash.Hash {
+	d := new(digest);
+	d.Reset();
 	return d;
 }
 
-func _Block(dig *Digest, p []byte) int
+func (d *digest) Size() int {
+	return Size;
+}
+
+func _Block(dig *digest, p []byte) int
 
-// Write updates the Digest with the incremental checksum generated by p.
-// It returns the number of bytes written; err is always nil.
-func (d *Digest) Write(p []byte) (nn int, err os.Error) {
+func (d *digest) Write(p []byte) (nn int, err os.Error) {
 	nn = len(p);
 	d.len += uint64(nn);
 	if d.nx > 0 {
@@ -67,9 +79,7 @@ func (d *Digest) Write(p []byte) (nn int, err os.Error) {
 	return;
 }
 
-// Sum returns the MD5 checksum of the data written to the Digest
-// in the form of an array of 16 bytes in big-endian order.
-func (d *Digest) Sum() []byte {
+func (d *digest) Sum() []byte {
 	// Padding.  Add a 1 bit and 0 bits until 56 bytes mod 64.
 	len := d.len;
 	var tmp [64]byte;
diff --git a/src/lib/hash/md5/md5_test.go b/src/lib/crypto/md5/md5_test.go
index 80271978d3..e557742cc7 100644
--- a/src/lib/hash/md5/md5_test.go
+++ b/src/lib/crypto/md5/md5_test.go
@@ -6,7 +6,7 @@ package md5
 
 import (
 	"fmt";
-	"hash/md5";
+	"crypto/md5";
 	"io";
 	"testing";
 )
@@ -53,7 +53,7 @@ var golden = []md5Test {
 func TestGolden(t *testing.T) {
 	for i := 0; i < len(golden); i++ {
 		g := golden[i];
-		c := NewDigest();
+		c := New();
 		io.WriteString(c, g.in);
 		s := fmt.Sprintf("%x", c.Sum());
 		if s != g.out {
diff --git a/src/lib/hash/md5/md5block.go b/src/lib/crypto/md5/md5block.go
index 0fc210a2cf..2776c8795c 100644
--- a/src/lib/hash/md5/md5block.go
+++ b/src/lib/crypto/md5/md5block.go
@@ -8,7 +8,7 @@
 
 package md5
 
-import "hash/md5"
+import "crypto/md5"
 
 // table[i] = int((1<<32) * abs(sin(i+1 radians))).
 var table = []uint32 {
@@ -90,7 +90,7 @@ var shift2 = []uint { 5, 9, 14, 20 };
 var shift3 = []uint { 4, 11, 16, 23 };
 var shift4 = []uint { 6, 10, 15, 21 };
 
-func _Block(dig *Digest, p []byte) int {
+func _Block(dig *digest, p []byte) int {
 	a := dig.s[0];
 	b := dig.s[1];
 	c := dig.s[2];
diff --git a/src/lib/hash/sha1/Makefile b/src/lib/crypto/sha1/Makefile
index 0f09259b48..f4e1ea0dd5 100644
--- a/src/lib/hash/sha1/Makefile
+++ b/src/lib/crypto/sha1/Makefile
@@ -5,7 +5,7 @@
 # DO NOT EDIT.  Automatically generated by gobuild.
 # gobuild -m >Makefile
 
-D=/hash/
+D=/crypto/
 
 O_arm=5
 O_amd64=6
diff --git a/src/lib/hash/sha1/sha1.go b/src/lib/crypto/sha1/sha1.go
index 2b83eb9b0c..c5f702264f 100644
--- a/src/lib/hash/sha1/sha1.go
+++ b/src/lib/crypto/sha1/sha1.go
@@ -5,7 +5,13 @@
 // This package implements the SHA1 hash algorithm as defined in RFC 3174.
 package sha1
 
-import "os"
+import (
+	"hash";
+	"os";
+)
+
+// The size of a SHA1 checksum in bytes.
+const Size = 20;
 
 const (
 	_Chunk = 64;
@@ -17,30 +23,36 @@ const (
 	_Init4 = 0xC3D2E1F0;
 )
 
-// Digest represents the partial evaluation of a checksum.
-type Digest struct {
+// digest represents the partial evaluation of a checksum.
+type digest struct {
 	h [5]uint32;
 	x [_Chunk]byte;
 	nx int;
 	len uint64;
 }
 
-// NewDigest creates a new Digest.
-func NewDigest() *Digest {
-	d := new(Digest);
+func (d *digest) Reset() {
 	d.h[0] = _Init0;
 	d.h[1] = _Init1;
 	d.h[2] = _Init2;
 	d.h[3] = _Init3;
 	d.h[4] = _Init4;
+}
+
+// New returns a Hash computing the SHA1 checksum.
+func New() hash.Hash {
+	d := new(digest);
+	d.Reset();
 	return d;
 }
 
-func _Block(dig *Digest, p []byte) int
+func (d *digest) Size() int {
+	return Size;
+}
+
+func _Block(dig *digest, p []byte) int
 
-// Write updates the Digest with the incremental checksum generated by p.
-// It returns the number of bytes written; err is always nil.
-func (d *Digest) Write(p []byte) (nn int, err os.Error) {
+func (d *digest) Write(p []byte) (nn int, err os.Error) {
 	nn = len(p);
 	d.len += uint64(nn);
 	if d.nx > 0 {
@@ -69,9 +81,7 @@ func (d *Digest) Write(p []byte) (nn int, err os.Error) {
 	return;
 }
 
-// Sum returns the SHA-1 checksum of the data written to the Digest
-// in the form of an array of 20 bytes in big-endian order.
-func (d *Digest) Sum() []byte {
+func (d *digest) Sum() []byte {
 	// Padding.  Add a 1 bit and 0 bits until 56 bytes mod 64.
 	len := d.len;
 	var tmp [64]byte;
diff --git a/src/lib/hash/sha1/sha1_test.go b/src/lib/crypto/sha1/sha1_test.go
index 103b218e9b..3ac9a47ec2 100644
--- a/src/lib/hash/sha1/sha1_test.go
+++ b/src/lib/crypto/sha1/sha1_test.go
@@ -8,7 +8,7 @@ package sha1
 
 import (
 	"fmt";
-	"hash/sha1";
+	"crypto/sha1";
 	"io";
 	"testing";
 )
@@ -55,7 +55,7 @@ var golden = []sha1Test {
 func TestGolden(t *testing.T) {
 	for i := 0; i < len(golden); i++ {
 		g := golden[i];
-		c := NewDigest();
+		c := New();
 		io.WriteString(c, g.in);
 		s := fmt.Sprintf("%x", c.Sum());
 		if s != g.out {
diff --git a/src/lib/hash/sha1/sha1block.go b/src/lib/crypto/sha1/sha1block.go
index 51bfd6d092..01ddd9506a 100644
--- a/src/lib/hash/sha1/sha1block.go
+++ b/src/lib/crypto/sha1/sha1block.go
@@ -8,7 +8,7 @@
 
 package sha1
 
-import "hash/sha1"
+import "crypto/sha1"
 
 const (
 	_K0 = 0x5A827999;
@@ -17,7 +17,7 @@ const (
 	_K3 = 0xCA62C1D6;
 )
 
-func _Block(dig *Digest, p []byte) int {
+func _Block(dig *digest, p []byte) int {
 	var w [80]uint32;
 
 	n := 0;
diff --git a/src/lib/hash/adler32/adler32.go b/src/lib/hash/adler32/adler32.go
index 2b3bd6f85a..fbf9177f89 100644
--- a/src/lib/hash/adler32/adler32.go
+++ b/src/lib/hash/adler32/adler32.go
@@ -11,28 +11,42 @@
 //	significant-byte first (network) order.
 package adler32
 
-import "os"
+import (
+	"hash";
+	"os";
+)
 
 const (
 	mod = 65521;
 )
 
-// Digest represents the partial evaluation of a checksum.
-type Digest struct {
+// The size of an Adler-32 checksum in bytes.
+const Size = 4;
+
+// digest represents the partial evaluation of a checksum.
+type digest struct {
 	// invariant: (a < mod && b < mod) || a <= b
 	// invariant: a + b + 255 <= 0xffffffff
 	a, b uint32;
 }
 
-// NewDigest creates a new Digest.
-func NewDigest() *Digest {
-	return &Digest{1, 0};
+func (d *digest) Reset() {
+	d.a, d.b = 1, 0;
+}
+
+// New returns a new Hash32 computing the Adler-32 checksum.
+func New() hash.Hash32 {
+	d := new(digest);
+	d.Reset();
+	return d;
+}
+
+func (d *digest) Size() int {
+	return Size;
 }
 
-// Write updates the Digest with the incremental checksum generated by p.
-// It returns the number of bytes written; err is always nil.
-func (d *Digest) Write(p []byte) (nn int, err os.Error) {
-	a, b := d.a, d.b;
+// Add p to the running checksum a, b.
+func update(a, b uint32, p []byte) (aa, bb uint32) {
 	for i := 0; i < len(p); i++ {
 		a += uint32(p[i]);
 		b += a;
@@ -45,13 +59,11 @@ func (d *Digest) Write(p []byte) (nn int, err os.Error) {
 			// invariant: a + b + 255 <= 2 * b + 255 <= 0xffffffff
 		}
 	}
-	d.a, d.b = a, b;
-	return len(p), nil
+	return a, b;
 }
 
-// Sum32 returns the 32-bit Adler-32 checksum of the data written to the Digest.
-func (d *Digest) Sum32() uint32 {
-	a, b := d.a, d.b;
+// Return the 32-bit checksum corresponding to a, b.
+func finish(a, b uint32) uint32 {
 	if b >= mod {
 		a %= mod;
 		b %= mod;
@@ -59,9 +71,16 @@ func (d *Digest) Sum32() uint32 {
 	return b<<16 | a;
 }
 
-// Sum returns the 32-bit Adler-32 checksum of the data written to the Digest
-// in the form of an array of 4 bytes in big-endian order.
-func (d *Digest) Sum() []byte {
+func (d *digest) Write(p []byte) (nn int, err os.Error) {
+	d.a, d.b = update(d.a, d.b, p);
+	return len(p), nil;
+}
+
+func (d *digest) Sum32() uint32 {
+	return finish(d.a, d.b);
+}
+
+func (d *digest) Sum() []byte {
 	p := make([]byte, 4);
 	s := d.Sum32();
 	p[0] = byte(s>>24);
@@ -70,3 +89,8 @@ func (d *Digest) Sum() []byte {
 	p[3] = byte(s);
 	return p;
 }
+
+// Checksum returns the Adler-32 checksum of data.
+func Checksum(data []byte) uint32 {
+	return finish(update(1, 0, data));
+}
diff --git a/src/lib/hash/adler32/adler32_test.go b/src/lib/hash/adler32/adler32_test.go
index 90c0f6d39e..ce49a110bb 100644
--- a/src/lib/hash/adler32/adler32_test.go
+++ b/src/lib/hash/adler32/adler32_test.go
@@ -53,7 +53,7 @@ var golden = []_Adler32Test {
 func TestGolden(t *testing.T) {
 	for i := 0; i < len(golden); i++ {
 		g := golden[i];
-		c := NewDigest();
+		c := New();
 		io.WriteString(c, g.in);
 		s := c.Sum32();
 		if s != g.out {
diff --git a/src/lib/hash/crc32/crc32.go b/src/lib/hash/crc32/crc32.go
index 57fa6af816..7fc3966aea 100644
--- a/src/lib/hash/crc32/crc32.go
+++ b/src/lib/hash/crc32/crc32.go
@@ -6,7 +6,13 @@
 // See http://en.wikipedia.org/wiki/Cyclic_redundancy_check for information.
 package crc32
 
-import "os"
+import (
+	"hash";
+	"os";
+)
+
+// The size of a CRC-32 checksum in bytes.
+const Size = 4;
 
 // Predefined polynomials.
 const (
@@ -26,12 +32,11 @@ const (
 )
 
 // Table is a 256-word table representing the polynomial for efficient processing.
-// TODO(rsc): Change to [256]uint32 once 6g can handle it.
-type Table []uint32
+type Table [256]uint32
 
 // MakeTable returns the Table constructed from the specified polynomial.
-func MakeTable(poly uint32) Table {
-	t := make(Table, 256);
+func MakeTable(poly uint32) *Table {
+	t := new(Table);
 	for i := 0; i < 256; i++ {
 		crc := uint32(i);
 		for j := 0; j < 8; j++ {
@@ -49,44 +54,51 @@ func MakeTable(poly uint32) Table {
 // IEEETable is the table for the IEEE polynomial.
 var IEEETable = MakeTable(IEEE);
 
-// Digest represents the partial evaluation of a checksum.
-type Digest struct {
+// digest represents the partial evaluation of a checksum.
+type digest struct {
 	crc uint32;
-	tab Table;
+	tab *Table;
+}
+
+// New creates a new Hash computing the CRC-32 checksum
+// using the polynomial represented by the Table.
+func New(tab *Table) hash.Hash32 {
+	return &digest{0, tab};
+}
+
+// NewIEEE creates a new Hash computing the CRC-32 checksum
+// using the IEEE polynomial.
+func NewIEEE() hash.Hash32 {
+	return New(IEEETable);
 }
 
-// NewDigest creates a new Digest for the checksum based on
-// the polynomial represented by the Table.
-func NewDigest(tab Table) *Digest {
-	return &Digest{0, tab};
+func (d *digest) Size() int {
+	return Size;
 }
 
-// NewIEEEDigest creates a new Digest for the checksum based on
-// the IEEE polynomial.
-func NewIEEEDigest() *Digest {
-	return NewDigest(IEEETable);
+func (d *digest) Reset() {
+	d.crc = 0;
 }
 
-// Write updates the Digest with the incremental checksum generated by p.
-// It returns the number of bytes written; err is always nil.
-func (d *Digest) Write(p []byte) (n int, err os.Error) {
-	crc := d.crc ^ 0xFFFFFFFF;
-	tab := d.tab;
+func update(crc uint32, tab *Table, p []byte) uint32 {
+	crc ^= 0xFFFFFFFF;
 	for i := 0; i < len(p); i++ {
 		crc = tab[byte(crc) ^ p[i]] ^ (crc >> 8);
 	}
-	d.crc = crc ^ 0xFFFFFFFF;
+	crc ^= 0xFFFFFFFF;
+	return crc;
+}
+
+func (d *digest) Write(p []byte) (n int, err os.Error) {
+	d.crc = update(d.crc, d.tab, p);
 	return len(p), nil;
 }
 
-// Sum32 returns the CRC-32 checksum of the data written to the Digest.
-func (d *Digest) Sum32() uint32 {
+func (d *digest) Sum32() uint32 {
 	return d.crc
 }
 
-// Sum returns the CRC-32 checksum of the data written to the Digest
-// in the form of an array of 4 bytes in big-endian order.
-func (d *Digest) Sum() []byte {
+func (d *digest) Sum() []byte {
 	p := make([]byte, 4);
 	s := d.Sum32();
 	p[0] = byte(s>>24);
@@ -96,4 +108,14 @@ func (d *Digest) Sum() []byte {
 	return p;
 }
 
+// Checksum returns the CRC-32 checksum of data
+// using the polynomial represented by the Table.
+func Checksum(data []byte, tab *Table) uint32 {
+	return update(0, tab, data);
+}
 
+// ChecksumIEEE returns the CRC-32 checksum of data
+// using the IEEE polynomial.
+func ChecksumIEEE(data []byte) uint32 {
+	return update(0, IEEETable, data);
+}
diff --git a/src/lib/hash/crc32/crc32_test.go b/src/lib/hash/crc32/crc32_test.go
index 2d675468d0..c037da600e 100644
--- a/src/lib/hash/crc32/crc32_test.go
+++ b/src/lib/hash/crc32/crc32_test.go
@@ -52,7 +52,7 @@ var golden = []_Crc32Test {
 func TestGolden(t *testing.T) {
 	for i := 0; i < len(golden); i++ {
 		g := golden[i];
-		c := NewIEEEDigest();
+		c := NewIEEE();
 		io.WriteString(c, g.in);
 		s := c.Sum32();
 		if s != g.out {