flate

commit f03a6f1d3efa723e6af183b54c76fc37a9c2cf4c
parent 7e14ecf2e5698d7c6e25e8f0bda8987afc25065c
Author: nsz <nszabolcs@gmail.com>
Date:   Mon, 24 Aug 2009 08:44:52 +0200

sflate += pkzip stream
Diffstat:
sflate.c
 | 
166
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------

1 file changed, 145 insertions(+), 21 deletions(-)
diff --git a/sflate.c b/sflate.c
@@ -3,6 +3,28 @@
 #include <string.h>
 #include "flate.h"
 
+static void set32(uchar *p, uint n) {
+	p[0] = n >> 24;
+	p[1] = n >> 16;
+	p[2] = n >> 8;
+	p[3] = n;
+}
+
+static void set32le(uchar *p, uint n) {
+	p[0] = n;
+	p[1] = n >> 8;
+	p[2] = n >> 16;
+	p[3] = n >> 24;
+}
+
+static int check32(uchar *p, uint n) {
+	return n == ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
+}
+
+static int check32le(uchar *p, uint n) {
+	return n == (p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24));
+}
+
 enum {
 	ZlibCM    = 7 << 4,
 	ZlibCINFO = 8,
@@ -22,10 +44,7 @@ int deflate_zlib_header(uchar *p, int n) {
 int deflate_zlib_footer(uchar *p, int n, uint sum, uint len, uint zlen) {
 	if (n < 4)
 		return FlateErr;
-	p[0] = sum >> 24;
-	p[1] = sum >> 16;
-	p[2] = sum >> 8;
-	p[3] = sum;
+	set32(p, sum);
 	return 4;
 }
 
@@ -42,8 +61,7 @@ int inflate_zlib_header(uchar *p, int n) {
 }
 
 int inflate_zlib_footer(uchar *p, int n, uint sum, uint len, uint zlen) {
-	if (n < 4 ||
-	    sum != ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]))
+	if (n < 4 || !check32(p, sum))
 		return FlateErr;
 	return 4;
 }
@@ -62,12 +80,9 @@ enum {
 };
 
 int deflate_gzip_header(uchar *p, int n) {
-	int k;
-
 	if (n < 10)
 		return FlateErr;
-	for (k = 0; k < n; k++)
-		p[k] = 0;
+	memset(p, 0, 10);
 	p[0] = GZipID1;
 	p[1] = GZipID2;
 	p[2] = GZipCM;
@@ -79,14 +94,8 @@ int deflate_gzip_header(uchar *p, int n) {
 int deflate_gzip_footer(uchar *p, int n, uint sum, uint len, uint zlen) {
 	if (n < 8)
 		return FlateErr;
-	p[0] = sum;
-	p[1] = sum >> 8;
-	p[2] = sum >> 16;
-	p[3] = sum >> 24;
-	p[4] = len;
-	p[5] = len >> 8;
-	p[6] = len >> 16;
-	p[7] = len >> 24;
+	set32le(p, sum);
+	set32le(p+4, len);
 	return 8;
 }
 
@@ -127,14 +136,118 @@ int inflate_gzip_header(uchar *p, int n) {
 }
 
 int inflate_gzip_footer(uchar *p, int n, uint sum, uint len, uint zlen) {
-	if (n < 8 ||
-	    sum != (p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24)) ||
-	    len != (p[4] | (p[5] << 8) | (p[6] << 16) | (p[7] << 24)))
+	if (n < 8 || !check32le(p, sum) || !check32le(p+4, len))
 		return FlateErr;
 	return 8;
 }
 
 
+static char pkname[] = "sflate_stream";
+
+enum {
+	PKHeadID   = 0x04034b50,
+	PKDataID   = 0x08074b50,
+	PKDirID    = 0x02014b50,
+	PKFootID   = 0x06054b50,
+	PKVersion  = 20,
+	PKFlag     = 1 << 3,
+	PKMethod   = 8,
+	PKDate     = (2009 - 1980) << 25,
+	PKHeadSize = 30,
+	PKDirSize  = 46,
+	PKNameLen  = sizeof(pkname) - 1
+};
+
+int deflate_pkzip_header(uchar *p, int n) {
+	if (n < PKHeadSize + PKNameLen)
+		return FlateErr;
+	memset(p, 0, PKHeadSize);
+	set32le(p, PKHeadID);
+	set32le(p+4, PKVersion);
+	set32le(p+6, PKFlag);
+	set32le(p+8, PKMethod);
+	set32le(p+10, PKDate);
+	set32le(p+26, PKNameLen);
+	memcpy(p + PKHeadSize, pkname, PKNameLen);
+	return PKHeadSize + PKNameLen;
+}
+
+int deflate_pkzip_footer(uchar *p, int n, uint sum, uint len, uint zlen) {
+	if (n < PKDirSize + PKNameLen + 22)
+		return FlateErr;
+/*	if (n < 16 + PKDirSize + PKNameLen + 22)
+		return FlateErr;
+	set32le(p, PKDataID);
+	set32le(p+4, sum);
+	set32le(p+8, zlen);
+	set32le(p+12, len);
+	p += 16;
+*/
+	memset(p, 0, PKDirSize);
+	set32le(p, PKDirID);
+	set32le(p+4, PKVersion | (PKVersion << 16));
+	set32le(p+8, PKFlag);
+	set32le(p+10, PKMethod);
+	set32le(p+12, PKDate);
+	set32le(p+16, sum);
+	set32le(p+20, zlen);
+	set32le(p+24, len);
+	set32le(p+28, PKNameLen);
+	memcpy(p + PKDirSize, pkname, PKNameLen);
+	p += PKDirSize + PKNameLen;
+	memset(p, 0, 22);
+	set32le(p, PKFootID);
+	p[8] = p[10] = 1;
+	set32le(p+12, PKDirSize + PKNameLen);
+	set32le(p+16, zlen + PKHeadSize + PKNameLen);
+	return PKDirSize + PKNameLen + 22;
+/*	set32le(p+12, 16 + PKDirSize + PKNameLen);
+	set32le(p+16, zlen + PKHeadSize + PKNameLen);
+	return 16 + PKDirSize + PKNameLen + 22;
+*/
+}
+
+int inflate_pkzip_header(uchar *p, int n) {
+	int k = 30;
+
+	if (k > n)
+		return FlateErr;
+	if (!check32le(p, PKHeadID))
+		return FlateErr;
+	if ((p[4] | (p[5] << 8)) > PKVersion)
+		return FlateErr;
+	if ((p[8] | (p[9] << 8)) != PKMethod)
+		return FlateErr;
+	k += p[26] | (p[27] << 8);
+	k += p[28] | (p[29] << 8);
+	if (k > n)
+		return FlateErr;
+	return k;
+}
+
+int inflate_pkzip_footer(uchar *p, int n, uint sum, uint len, uint zlen) {
+	int k = PKDirSize + 22;
+
+	if (k > n)
+		return FlateErr;
+	if (check32le(p, PKDataID)) {
+		p += 16;
+		k += 16;
+		if (k > n)
+			return FlateErr;
+	}
+	if (!check32le(p, PKDirID))
+		return FlateErr;
+	if (!check32le(p+16, sum))
+		return FlateErr;
+	if (!check32le(p+20, zlen))
+		return FlateErr;
+	if (!check32le(p+24, len))
+		return FlateErr;
+	return k;
+}
+
+
 /* example usage */
 
 static int (*header)(uchar *, int);
@@ -343,6 +456,17 @@ int main(int argc, char *argv[]) {
 		n = call(stdin, stdout);
 		break;
 	case 'p':
+		if (comp == 'c') {
+			header = deflate_pkzip_header;
+			footer = deflate_pkzip_footer;
+		} else {
+			header = inflate_pkzip_header;
+			footer = inflate_pkzip_footer;
+		}
+		checksum = crc32;
+		crc32init();
+		n = call(stdin, stdout);
+		break;
 	default:
 		err = "uninplemented.";
 		n = FlateErr;