string: test cleanups

Tests printed too much output on broken string function
and the output was not entirely useful.

Added a new header file with some common logic for
printing buffers nicely.

In str* tests len now means string length (not buffer
size which was confusing).

1 files changed, 50 insertions, 0 deletions

diff --git a/string/test/stringtest.h b/string/test/stringtest.h
new file mode 100644
index 0000000..b9c034a
--- /dev/null
+++ b/string/test/stringtest.h
@@ -0,0 +1,50 @@
+/*
+ * Common string test code.
+ *
+ * Copyright (c) 2020, Arm Limited.
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <ctype.h>
+#include <stdio.h>
+
+/* Accounting errors for a test case.  */
+static int err_count;
+#define ERR_LIMIT 10
+#define ERR(...) (err_count++, printf(__VA_ARGS__))
+
+static inline void quotechar(unsigned char c)
+{
+	if (isprint(c))
+		putchar(c);
+	else
+		printf("\\x%02x", c);
+}
+
+/* quoted print around at or the entire string if at < 0.  */
+static void quoteat(const char *prefix, const void *p, int len, int at)
+{
+	static const int CTXLEN = 15;
+	int i;
+	const char *pre="\"";
+	const char *post="\"";
+	const char *s = p;
+	if (at > CTXLEN) {
+		s += at - CTXLEN;
+		len -= at - CTXLEN;
+		pre = "...\"";
+	}
+	if (at >= 0 && len > 2*CTXLEN + 1) {
+		len = 2*CTXLEN + 1;
+		post = "\"...";
+	}
+	printf("%4s: %s", prefix, pre);
+	for (i = 0; i < len; i++)
+		quotechar(s[i]);
+	printf("%s\n", post);
+}
+
+static inline void quote(const char *prefix, const void *p, int len)
+{
+	quoteat(prefix, p, len, -1);
+}