shithub: ips

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refactor and add ipsdiff

--- a/ips.c

+++ /dev/null

@@ -1,97 +1,0 @@

-#include <u.h>

-#include <libc.h>

-#include <bio.h>

-

-#define GET2(p) (u16int)(p)[1] | (u16int)(p)[0]<<8

-#define GET3(p) (u16int)(p)[2] | (u16int)(p)[1]<<8 | (u16int)(p[0])<<16

-

-enum{

-	Hdrsz = 3 + 2,

-	RLEsz = 2 + 1,

-};

-

-static uchar section[Hdrsz + 0xFFFF + RLEsz];

-static Biobuf *ips;

-

-static int

-readsect(u32int *off, u16int *sz)

-{

-	u16int count;

-	uchar val;

-

-	if(Bread(ips, section, 3) != 3)

-		sysfatal("short read of off: %r");

-	if(memcmp(section, "EOF", 3) == 0)

-		return 0;

-	if(Bread(ips, section + 3, 2) != 2)

-		sysfatal("short read of size: %r");

-	*off = GET3(section);

-

-	*sz = GET2(section + 3);

-	if(*sz == 0){

-		if(Bread(ips, section + Hdrsz + 0xFFFF, RLEsz) != RLEsz)

-			sysfatal("short read of RLE: %r");

-		count = GET2(section + Hdrsz + 0xFFFF);

-		val = section[Hdrsz + 0xFFFF + 2];

-		memset(section + Hdrsz, val, count);

-		*sz = count;

-	} else if(Bread(ips, section + Hdrsz, *sz) != *sz)

-		sysfatal("short read of data: %r");

-	return 1;

-}

-

-void

-usage(void)

-{

-	fprint(2, "usage: %s patch.ips <file.orig >file.new\n", argv0);

-	exits("usage");

-}

-

-void

-main(int argc, char **argv)

-{

-	ulong dot, x;

-	long n;

-	uchar buf[8192];

-	u32int off;

-	u16int sz;

-

-	ARGBEGIN{

-	default:

-		usage();

-	}ARGEND;

-	if(argc < 1)

-		usage();

-

-	ips = Bopen(argv[0], OREAD);

-	if(ips == nil)

-		sysfatal("open: %r");

-

-	if(Bread(ips, buf, 5) != 5)

-		sysfatal("short read on magic: %r");

-	if(memcmp(buf, "PATCH", 5) != 0)

-		sysfatal("bad magic");

-

-	if(readsect(&off, &sz) == 0)

-		sysfatal("not a single section");

-

-	for(dot = 0; (n = read(0, buf, sizeof buf)) > 0; dot += n){

-		while(off < dot+n){

-			if(off < dot)

-				sysfatal("skipped region");

-			if(off + sz > dot + n){

-				x = (dot + n) - off;

-				memcpy(buf + (off - dot), section + Hdrsz, x);

-				memmove(section + Hdrsz, section + Hdrsz + x, sz - x);

-				sz -= x;

-				off += x;

-				break;

-			}

-			memcpy(buf + (off - dot), section + Hdrsz, sz);

-			if(readsect(&off, &sz) == 0)

-				break;

-		}

-		write(1, buf, n);

-	}

-	exits(nil);

-}

--- /dev/null

+++ b/ipsdiff.c

@@ -1,0 +1,121 @@

+#include <u.h>

+#include <libc.h>

+#include <bio.h>

+

+#define PUT2(p, u) (p)[0] = (u)>>8, (p)[1] = (u)

+#define PUT3(p, u) (p)[0] = (u)>>16, (p)[1] = (u)>>8, (p)[2] = (u)

+

+Biobuf *ips;

+typedef struct Bin Bin;

+struct Bin{

+	int fd;

+	long dot;

+	long n, off;

+	uchar data[0xFFFF];

+};

+

+static Bin base, modded;

+static int dump = 0;

+

+static long

+slurp(Bin *b)

+{

+	long n;

+

+	n = readn(b->fd, b->data + b->off, sizeof b->data - b->off);

+	if(n < 0)

+		sysfatal("read: %r");

+	b->n = b->off + n;

+	return n;

+}

+

+static void

+emit(u32int off, uchar *data, u16int size)

+{

+	uchar buf[3 + 2];

+

+	if(size == 0)

+		return;

+	PUT3(buf, off);

+	PUT2(buf+3, size);

+	if(dump)

+		fprint(2, "%ud %ud\n", off, size);

+	if(Bwrite(ips, buf, sizeof buf) != sizeof buf)

+		sysfatal("Bwrite: %r");

+	if(Bwrite(ips, data, size) != size)

+		sysfatal("Bwrite: %r");

+}

+

+static void

+diff(Bin *a, Bin *b)

+{

+	uchar *ap, *bp;

+	uchar *ac, *bc;

+	uchar *ae, *be;

+	int x;

+

+	ap = a->data;

+	bp = b->data;

+	ae = a->data + a->n;

+	be = b->data + b->n;

+

+	if(a->n != b->n)

+		sysfatal("desync: %ld %ld", a->n, a->n);

+

+	while(ap < ae && bp < be){

+		if(*ap == *bp){

+			ap++;

+			bp++;

+			continue;

+		}

+		// FIXME: better way of expanding diff context

+		x = 32;

+		for(ac = ap, bc = bp; ac < ae && bc < be; ac++, bc++){

+			if(--x <= 0 && *ac == *bc)

+				break;

+		}

+		emit(a->dot + (ap - a->data), bp, bc - bp);

+		ap = ac;

+		bp = bc;

+	}

+	a->dot += a->n;

+	b->dot += b->n;

+}

+

+void

+usage(void)

+{

+	fprint(2, "usage: %s base modified >patch.ips", argv0);

+	exits("usage");

+}

+

+void

+main(int argc, char **argv)

+{

+	ARGBEGIN{

+	case 'd':

+		dump++;

+		break;

+	default:

+		usage();

+	}ARGEND;

+	if(argc < 2)

+		usage();

+

+	ips = Bfdopen(1, OWRITE);

+	if(ips == nil)

+		sysfatal("Bfdopen: %r");

+	Bwrite(ips, "PATCH", 5);

+

+	base.fd = open(argv[0], OREAD);

+	modded.fd = open(argv[1], OREAD);

+	if(base.fd < 0 || modded.fd < 0)

+		sysfatal("open: %r");

+

+	while(slurp(&base) != 0 && slurp(&modded) != 0)

+		diff(&base, &modded);

+

+	Bwrite(ips, "EOF", 3);

+	Bflush(ips);

+	exits(nil);

+}

--- /dev/null

+++ b/ipspatch.c

@@ -1,0 +1,102 @@

+#include <u.h>

+#include <libc.h>

+#include <bio.h>

+

+#define GET2(p) (u16int)(p)[1] | (u16int)(p)[0]<<8

+#define GET3(p) (u16int)(p)[2] | (u16int)(p)[1]<<8 | (u16int)(p[0])<<16

+

+enum{

+	Hdrsz = 3 + 2,

+	RLEsz = 2 + 1,

+};

+

+static uchar section[Hdrsz + 0xFFFF + RLEsz];

+static Biobuf *ips;

+static int dump = 0;

+

+static int

+readsect(u32int *off, u16int *sz)

+{

+	u16int count;

+	uchar val;

+

+	if(Bread(ips, section, 3) != 3)

+		sysfatal("short read of off: %r");

+	if(memcmp(section, "EOF", 3) == 0)

+		return 0;

+	if(Bread(ips, section + 3, 2) != 2)

+		sysfatal("short read of size: %r");

+	*off = GET3(section);

+

+	*sz = GET2(section + 3);

+	if(*sz == 0){

+		if(Bread(ips, section + Hdrsz + 0xFFFF, RLEsz) != RLEsz)

+			sysfatal("short read of RLE: %r");

+		count = GET2(section + Hdrsz + 0xFFFF);

+		val = section[Hdrsz + 0xFFFF + 2];

+		memset(section + Hdrsz, val, count);

+		*sz = count;

+	} else if(Bread(ips, section + Hdrsz, *sz) != *sz)

+		sysfatal("short read of data: %r");

+	//fprint(2, "%ud %ud\n", *off, *sz);

+	return 1;

+}

+

+void

+usage(void)

+{

+	fprint(2, "usage: %s patch.ips <file.orig >file.new\n", argv0);

+	exits("usage");

+}

+

+void

+main(int argc, char **argv)

+{

+	ulong dot, x;

+	long n;

+	uchar buf[8192];

+	u32int off;

+	u16int sz;

+

+	ARGBEGIN{

+	case 'd':

+		dump++;

+		break;

+	default:

+		usage();

+	}ARGEND;

+	if(argc < 1)

+		usage();

+

+	ips = Bopen(argv[0], OREAD);

+	if(ips == nil)

+		sysfatal("open: %r");

+

+	if(Bread(ips, buf, 5) != 5)

+		sysfatal("short read on magic: %r");

+	if(memcmp(buf, "PATCH", 5) != 0)

+		sysfatal("bad magic");

+

+	if(readsect(&off, &sz) == 0)

+		sysfatal("not a single section");

+

+	for(dot = 0; (n = read(0, buf, sizeof buf)) > 0; dot += n){

+		while(off < dot+n){

+			if(off < dot)

+				sysfatal("skipped region");

+			if(off + sz > dot + n){

+				x = (dot + n) - off;

+				memcpy(buf + (off - dot), section + Hdrsz, x);

+				memmove(section + Hdrsz, section + Hdrsz + x, sz - x);

+				sz -= x;

+				off += x;

+				break;

+			}

+			memcpy(buf + (off - dot), section + Hdrsz, sz);

+			if(readsect(&off, &sz) == 0)

+				break;

+		}

+		write(1, buf, n);

+	}

+	exits(nil);

+}

--- a/mkfile

+++ b/mkfile

@@ -1,8 +1,8 @@

 </$objtype/mkfile

 BIN=$home/bin/$objtype

-TARG=ips

-OFILES=\

-	ips.$O\

+TARG=\

+	ipsdiff\

+	ipspatch\

-</sys/src/cmd/mkone

+</sys/src/cmd/mkmany