Fix tell/seek operations

* Makefile (clean): descend into t as well.
* t/Makefile (clean): New goal.
* runcap.h (runcap_seek): Return off_t.
* seek.c (runcap_seek): Change return value.  Fix operation.
* tell.c (runcap_tell): Bugfix.
* t/rt.c: New option -r for testing seek.
* t/08seek.t: New testcase.
* t/09seek.t: New testcase.

8 files changed, 218 insertions, 13 deletions

diff --git a/Makefile b/Makefile
index e0a8f06..47bcf17 100644
--- a/Makefile
+++ b/Makefile
@@ -53,5 +53,8 @@ libruncap.a: $(OBJECTS)
 
-clean:
+clean: subdirs-clean
 	rm -f libruncap.a $(OBJECTS)
 
+subdirs-clean:
+	@$(MAKE) -C t clean
+
 install: install-lib install-headers install-man
diff --git a/runcap.h b/runcap.h
index 3ed907d..0ece8e7 100644
--- a/runcap.h
+++ b/runcap.h
@@ -92,3 +92,3 @@ ssize_t runcap_getline(struct runcap *rc, int stream, char **pstr, size_t *psize
 off_t runcap_tell(struct runcap *rc, int stream);
-int runcap_seek(struct runcap *rc, int stream, off_t off, int whence);
+off_t runcap_seek(struct runcap *rc, int stream, off_t off, int whence);
 
@@ -97,3 +97,3 @@ runcap_rewind(struct runcap *rc, int stream)
 {
-	return runcap_seek(rc, stream, 0, 0);
+	return runcap_seek(rc, stream, 0, 0) != 0;
 }	
diff --git a/seek.c b/seek.c
index dfa3d1d..acb42e9 100644
--- a/seek.c
+++ b/seek.c
@@ -21,3 +21,3 @@
 
-int
+off_t
 runcap_seek(struct runcap *rc, int sd, off_t off, int whence)
@@ -34,3 +34,3 @@ runcap_seek(struct runcap *rc, int sd, off_t off, int whence)
 	case SEEK_CUR:
-		off = cur;
+		off = cur + off;
 		break;
@@ -54,4 +54,4 @@ runcap_seek(struct runcap *rc, int sd, off_t off, int whence)
 
-	cur -= cap->sc_level;
-	
+	cur -= cap->sc_cur;
+
 	if (cur <= off && off <= cur + cap->sc_level) {
@@ -67,3 +67,3 @@ runcap_seek(struct runcap *rc, int sd, off_t off, int whence)
 	}
-	return 0;
+	return off;
 }
diff --git a/t/08seek.t b/t/08seek.t
new file mode 100755
index 0000000..c2312bd
--- /dev/null
+++ b/t/08seek.t
@@ -0,0 +1,43 @@
+#! ./testsuite
+# testsuite for runcap - run program and capture its output
+# Copyright (C) 2017 Sergey Poznyakoff
+#
+# Runcap is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Runcap is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with Runcap. If not, see <http://www.gnu.org/licenses/>.
+
+TC_TITLE seek
+
+TC_EXPECT out <<EOT
+res=0
+exit code: 0
+stdout: 71 lines, 4051 bytes
+stderr: 0 lines, 0 bytes
+READ 0:
+ the Rabbit-Hole
+
+Alice was beginning to get very tired of sitting by her sister on the
+bank, and of
+READ 1:
+ on the
+ba
+READ 2:
+nk, and of
+READ 3:
+tten up so
+EOT
+
+rt -r stdout:100:15:0\
+   -r stdout:10:-20:1\
+   -r stdout:10:0:1\
+   -r stdout:10:-20:2\
+   -- genout $testdir/INPUT
diff --git a/t/09seek.t b/t/09seek.t
new file mode 100755
index 0000000..87628f1
--- /dev/null
+++ b/t/09seek.t
@@ -0,0 +1,44 @@
+#! ./testsuite
+# testsuite for runcap - run program and capture its output
+# Copyright (C) 2017 Sergey Poznyakoff
+#
+# Runcap is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Runcap is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with Runcap. If not, see <http://www.gnu.org/licenses/>.
+
+TC_TITLE seek, short buffer
+
+TC_EXPECT out <<EOT
+res=0
+exit code: 0
+stdout: 71 lines, 4051 bytes
+stderr: 0 lines, 0 bytes
+READ 0:
+ the Rabbit-Hole
+
+Alice was beginning to get very tired of sitting by her sister on the
+bank, and of
+READ 1:
+ on the
+ba
+READ 2:
+nk, and of
+READ 3:
+tten up so
+EOT
+
+rt -s 16\
+   -r stdout:100:15:0\
+   -r stdout:10:-20:1\
+   -r stdout:10:0:1\
+   -r stdout:10:-20:2\
+   -- genout $testdir/INPUT
diff --git a/t/Makefile b/t/Makefile
index c24d98e..7a3bb62 100644
--- a/t/Makefile
+++ b/t/Makefile
@@ -16,3 +16,4 @@
 
-check: genout rt
+TESTPROGS=genout rt
+check: $(TESTPROGS)
 	@./testsuite
@@ -39,3 +40,5 @@ TESTSUITE =\
  05stdin.t\
- 06mon.t
+ 06mon.t\
+ 08seek.t\
+ 09seek.t
 
@@ -44,3 +47,3 @@ DISTDIR = $(TOPDISTDIR)/t
 DISTFILES = Makefile rt.c genout.c $(TESTSUITE) INPUT
-.PHONY: distdir
+.PHONY: distdir clean
 distdir:
@@ -49 +52,3 @@ distdir:
 
+clean:
+	rm -rf $(TESTPROGS) testsuite.log testsuite.dir
diff --git a/t/rt.c b/t/rt.c
index 9dbbfa8..12a3232 100644
--- a/t/rt.c
+++ b/t/rt.c
@@ -52,4 +52,9 @@ usage(int code)
 	fprintf(fp, "  -i                     inline read (use before -f)\n");
+	fprintf(fp, "  -n all|stderr|stdout   print lines from the requested capture\n");
 	fprintf(fp, "  -m                     monitors each line recevied from the program (see -S)\n");
 	fprintf(fp, "  -p PROGNAME            sets program name to use instead of COMMAND\n");
+	fprintf(fp, "  -r STREAM[:COUNT:OFF:WHENCE]\n");
+	fprintf(fp, "                         read and print COUNT bytes from STREAM (stdout or\n");
+	fprintf(fp, "                         stderr) starting from OFFset located using WHENCE\n");
+	fprintf(fp, "                         (0, 1, 2).\n");
 	fprintf(fp, "  -s SIZE                sets capture size (see -S)\n");
@@ -121,2 +126,90 @@ nl(struct runcap *rc, int stream)
 
+struct readreq
+{
+	int what;
+	unsigned long count;
+	long off;
+	int whence;
+};
+
+void
+readreq_parse(struct readreq *req, char *arg)
+{
+	char *s;
+	int i = 0;
+
+	s = strchr(arg, ':');
+	if (s)
+		*s = 0;
+	req->what = whatarg(arg);
+	req->count = 0;
+	req->off = 0;
+	req->whence = 0;
+	if (s)
+		*s++ = ':';
+
+	arg = s;
+	while (*arg) {
+		switch (i++) {
+		case 0:
+			req->count = strtoul(arg, &s, 10);
+			break;
+
+		case 1:
+			req->off = strtol(arg, &s, 10);
+			break;
+
+		case 2:
+			req->whence = strtol(arg, &s, 10);
+			if (!(0 <= req->whence && req->whence <= 2)) {
+				error("bad whence: %s", arg);
+				exit(1);
+			}
+			break;
+
+		default:
+			error("too many parts in argument: %s", arg);
+			exit(1);
+		}
+		
+		if (*s == ':')
+			arg = s + 1;
+		else if (*s) {
+			error("malformed argument: %s", arg);
+			exit(1);
+		} else
+			arg = s;
+	}
+}
+
+void
+readreq_do(struct runcap *rc, struct readreq *req)
+{
+	int res;
+	size_t i;
+	
+	if (runcap_seek(rc, req->what, req->off, req->whence) == -1) {
+		perror("runcap_seek");
+		exit(1);
+	}
+
+	if (req->count == 0) 
+		req->count = rc->rc_cap[req->what].sc_size;
+	
+	for (i = 0; i < req->count; i++) {
+		char c;
+		
+		res = runcap_getc(rc, req->what, &c);
+		if (res == 0) {
+			error("unexpected eof at byte %zu\n", i);
+			break;
+		}
+		if (res == -1) {
+			error("%s at byte %zu\n", strerror (errno), i);
+			break;
+		}
+		putchar(c);
+	}
+}
+	
 int
@@ -129,2 +222,4 @@ main(int argc, char **argv)
 	int numlines = WA_NONE;
+	struct readreq rq[10];
+	int rqn = 0, i;
 	
@@ -144,3 +239,3 @@ main(int argc, char **argv)
 		progname = argv[0];
-	while ((c = getopt(argc, argv, "?f:in:mp:S:s:t:")) != EOF) {
+	while ((c = getopt(argc, argv, "?f:in:mp:r:S:s:t:")) != EOF) {
 		switch (c) {
@@ -202,2 +297,10 @@ main(int argc, char **argv)
 			break;
+		case 'r':
+			/* -r WHAT:N[:OFF:WHENCE] */
+			if (rqn == sizeof(rq)/sizeof(rq[0])) {
+				error("too many read requests");
+				break;
+			}
+			readreq_parse(&rq[rqn++], optarg);
+			break;
 		case 'm':
@@ -279,3 +382,9 @@ main(int argc, char **argv)
 		nl(&rc, RUNCAP_STDERR);	
-	
+
+	for (i = 0; i < rqn; i++) {
+		printf("READ %d:\n", i);
+		readreq_do(&rc, &rq[i]);
+		putchar('\n');
+	}
+			
 	return 0;
diff --git a/tell.c b/tell.c
index d16110c..337e990 100644
--- a/tell.c
+++ b/tell.c
@@ -35,2 +35,3 @@ runcap_tell(struct runcap *rc, int sd)
 			return -1;
+		off -= cap->sc_level;
 	} else