Add 'corebinutils/sh/' from commit '126b33a9db9b44a56f2c62d18346746ec1330766'

git-subtree-dir: corebinutils/sh
git-subtree-mainline: 96be0a182e0b889a9daf43c04a0b835aa604d280
git-subtree-split: 126b33a9db9b44a56f2c62d18346746ec1330766

1 files changed, 93 insertions, 0 deletions

diff --git a/corebinutils/sh/mystring.c b/corebinutils/sh/mystring.c
new file mode 100644
index 0000000000..efe2b811b3
--- /dev/null
+++ b/corebinutils/sh/mystring.c
@@ -0,0 +1,93 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2026 Project Tick. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * String functions.
+ *
+ *	equal(s1, s2)		Return true if strings are equal.
+ *	number(s)		Convert a string of digits to an integer.
+ *	is_number(s)		Return true if s is a string of digits.
+ */
+
+#include <stdlib.h>
+#include "shell.h"
+#include "syntax.h"
+#include "error.h"
+#include "mystring.h"
+
+
+char nullstr[1];		/* zero length string */
+
+/*
+ * equal - #defined in mystring.h
+ */
+
+
+/*
+ * Convert a string of digits to an integer, printing an error message on
+ * failure.
+ */
+
+int
+number(const char *s)
+{
+	if (! is_number(s))
+		error("Illegal number: %s", s);
+	return atoi(s);
+}
+
+
+
+/*
+ * Check for a valid number.  This should be elsewhere.
+ */
+
+int
+is_number(const char *p)
+{
+	const char *q;
+
+	if (*p == '\0')
+		return 0;
+	while (*p == '0')
+		p++;
+	for (q = p; *q != '\0'; q++)
+		if (! is_digit(*q))
+			return 0;
+	if (q - p > 10 ||
+	    (q - p == 10 && memcmp(p, "2147483647", 10) > 0))
+		return 0;
+	return 1;
+}