Consolidate some of the stray integer parsers

There are several ad-hoc int/uint parsers scattered around the code,
add a single helper function for that task and replace the multiple
instances. A simple white-box test case is added for the utility
function.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

3 files changed, 173 insertions, 2 deletions

diff --git a/lib/util/Makemodule.am b/lib/util/Makemodule.am
index 6386066..9b2065a 100644
--- a/lib/util/Makemodule.am
+++ b/lib/util/Makemodule.am
@@ -9,7 +9,8 @@ libutil_a_SOURCES = include/util/util.h include/util/str_table.h \
 	lib/util/src/canonicalize_name.c lib/util/src/filename_sane.c \
 	lib/util/src/source_date_epoch.c lib/util/src/file_cmp.c \
 	lib/util/src/hex_decode.c lib/util/src/base64_decode.c \
-	lib/util/src/get_line.c lib/util/src/split_line.c
+	lib/util/src/get_line.c lib/util/src/split_line.c \
+	lib/util/src/parse_int.c
 libutil_a_CFLAGS = $(AM_CFLAGS)
 libutil_a_CPPFLAGS = $(AM_CPPFLAGS)
 
@@ -83,11 +84,14 @@ test_get_line_LDADD = libutil.a libio.a libcompat.a
 test_split_line_SOURCES = lib/util/test/split_line.c
 test_split_line_LDADD = libutil.a libcompat.a
 
+test_parse_int_SOURCES = lib/util/test/parse_int.c
+test_parse_int_LDADD = libutil.a libcompat.a
+
 LIBUTIL_TESTS = \
 	test_str_table test_rbtree test_xxhash test_threadpool test_ismemzero \
 	test_canonicalize_name test_filename_sane test_filename_sane_w32 \
 	test_sdate_epoch test_hex_decode test_base64_decode test_get_line \
-	test_split_line
+	test_split_line test_parse_int
 
 check_PROGRAMS += $(LIBUTIL_TESTS)
 TESTS += $(LIBUTIL_TESTS)
diff --git a/lib/util/src/parse_int.c b/lib/util/src/parse_int.c
new file mode 100644
index 0000000..1bca528
--- /dev/null
+++ b/lib/util/src/parse_int.c
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * alloc.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include "util/parse.h"
+#include "sqfs/error.h"
+
+#include <ctype.h>
+
+int parse_uint(const char *in, size_t len, size_t *diff,
+	       sqfs_u64 vmin, sqfs_u64 vmax, sqfs_u64 *out)
+{
+	/* init result */
+	if (diff != NULL)
+		*diff = 0;
+	*out = 0;
+
+	/* sequence has at least 1 digit */
+	if (len == 0 || !isdigit(*in))
+		return SQFS_ERROR_CORRUPTED;
+
+	/* parse sequence */
+	while (len > 0 && isdigit(*in)) {
+		sqfs_u64 x = *(in++) - '0';
+		--len;
+
+		if (diff != NULL)
+			++(*diff);
+
+		if ((*out) >= (0xFFFFFFFFFFFFFFFFULL / 10ULL))
+			return SQFS_ERROR_OVERFLOW;
+
+		(*out) *= 10;
+
+		if ((*out) > (0xFFFFFFFFFFFFFFFFULL - x))
+			return SQFS_ERROR_OVERFLOW;
+
+		(*out) += x;
+	}
+
+	/* range check */
+	if ((vmin != vmax) && ((*out < vmin) || (*out > vmax)))
+		return SQFS_ERROR_OUT_OF_BOUNDS;
+
+	/* if diff is not used, entire  must have been processed */
+	if (diff == NULL && (len > 0 && *in != '\0'))
+		return SQFS_ERROR_CORRUPTED;
+
+	return 0;
+}
+
+
+int parse_int(const char *in, size_t len, size_t *diff,
+	      sqfs_s64 vmin, sqfs_s64 vmax, sqfs_s64 *out)
+{
+	bool negative = false;
+	sqfs_u64 temp;
+	int ret;
+
+	if (len > 0 && *in == '-') {
+		++in;
+		--len;
+		negative = true;
+	}
+
+	ret = parse_uint(in, len, diff, 0, 0, &temp);
+	if (ret)
+		return ret;
+
+	if (temp >= 0x7FFFFFFFFFFFFFFFULL)
+		return SQFS_ERROR_OVERFLOW;
+
+	if (negative) {
+		if (diff != NULL)
+			(*diff) += 1;
+		*out = -((sqfs_s64)temp);
+	} else {
+		*out = (sqfs_s64)temp;
+	}
+
+	if (vmin != vmax && ((*out < vmin) || (*out > vmax)))
+		return SQFS_ERROR_OUT_OF_BOUNDS;
+
+	return 0;
+}
diff --git a/lib/util/test/parse_int.c b/lib/util/test/parse_int.c
new file mode 100644
index 0000000..2bd5a7c
--- /dev/null
+++ b/lib/util/test/parse_int.c
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * parse_int.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+#include "util/parse.h"
+#include "util/test.h"
+#include "sqfs/error.h"
+
+int main(int argc, char **argv)
+{
+	sqfs_s64 s_out;
+	sqfs_u64 out;
+	size_t diff;
+	int ret;
+	(void)argc; (void)argv;
+
+	/* must begin with a digit */
+	ret = parse_uint("a1234", -1, &diff, 0, 0, &out);
+	TEST_EQUAL_I(ret, SQFS_ERROR_CORRUPTED);
+
+	/* can end with a non-digit... */
+	ret = parse_uint("1234a", -1, &diff, 0, 0, &out);
+	TEST_EQUAL_I(ret, 0);
+	TEST_EQUAL_UI(out, 1234);
+	TEST_EQUAL_UI(diff, 4);
+
+	/* ...unless diff is NULL */
+	ret = parse_uint("1234a", -1, NULL, 0, 0, &out);
+	TEST_EQUAL_I(ret, SQFS_ERROR_CORRUPTED);
+
+	/* numeric overflow is cought */
+	ret = parse_uint("18446744073709551616", -1, NULL, 0, 0, &out);
+	TEST_EQUAL_I(ret, SQFS_ERROR_OVERFLOW);
+
+	/* buffer length is adherered to */
+	ret = parse_uint("18446744073709551616", 5, NULL, 0, 0, &out);
+	TEST_EQUAL_I(ret, 0);
+	TEST_EQUAL_UI(out, 18446);
+
+	ret = parse_uint("18446744073709551616", 5, &diff, 0, 0, &out);
+	TEST_EQUAL_I(ret, 0);
+	TEST_EQUAL_UI(diff, 5);
+	TEST_EQUAL_UI(out, 18446);
+
+	/* if vmin/vmax differ, check the range */
+	ret = parse_uint("1234", -1, NULL, 0, 1000, &out);
+	TEST_EQUAL_I(ret, SQFS_ERROR_OUT_OF_BOUNDS);
+
+	ret = parse_uint("1234", -1, NULL, 0, 2000, &out);
+	TEST_EQUAL_I(ret, 0);
+	TEST_EQUAL_UI(out, 1234);
+
+	ret = parse_uint("1234", -1, NULL, 2000, 3000, &out);
+	TEST_EQUAL_I(ret, SQFS_ERROR_OUT_OF_BOUNDS);
+
+	/* int version accepts '-' prefix */
+	ret = parse_int("1234", -1, NULL, 0, 0, &s_out);
+	TEST_EQUAL_I(ret, 0);
+	TEST_EQUAL_I(s_out, 1234);
+
+	ret = parse_int("-1234", -1, NULL, 0, 0, &s_out);
+	TEST_EQUAL_I(ret, 0);
+	TEST_EQUAL_I(s_out, -1234);
+
+	ret = parse_int("- 1234", -1, NULL, 0, 0, &s_out);
+	TEST_EQUAL_I(ret, SQFS_ERROR_CORRUPTED);
+
+	ret = parse_int("+1234", -1, NULL, 0, 0, &s_out);
+	TEST_EQUAL_I(ret, SQFS_ERROR_CORRUPTED);
+
+	ret = parse_int("-1234", -1, NULL, -1000, 1000, &s_out);
+	TEST_EQUAL_I(ret, SQFS_ERROR_OUT_OF_BOUNDS);
+
+	return EXIT_SUCCESS;
+}