src: major cleanups, introduce new eXtended Span class

- initial minimally invasive eXtended Span implementation
- rename ptr_diff to ptr_diff_bytes
- move some files to util subdir
- lots of cleanups
- start using the new checked pointers - this needs some real-world testing

src/util/snprintf.h

@@ -0,0 +1,84 @@
+/* snprintf.h --
+
+   This file is part of the UPX executable compressor.
+
+   Copyright (C) 1996-2022 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1996-2022 Laszlo Molnar
+   All Rights Reserved.
+
+   UPX and the UCL library are free software; you can redistribute them
+   and/or modify them under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of
+   the License, or (at your option) any later version.
+
+   This program 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 this program; see the file COPYING.
+   If not, write to the Free Software Foundation, Inc.,
+   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+   Markus F.X.J. Oberhumer              Laszlo Molnar
+   <markus@oberhumer.com>               <ezerotven+github@gmail.com>
+ */
+
+#pragma once
+#ifndef UPX_SNPRINTF_H__
+#define UPX_SNPRINTF_H__ 1
+
+/*************************************************************************
+// UPX version of string functions, with assertions and sane limits
+**************************************************************************/
+
+// info: snprintf() returns length and NOT size, but max_size is indeed size (incl NUL)
+
+int upx_safe_vsnprintf(char *str, upx_rsize_t max_size, const char *format, va_list ap);
+int upx_safe_snprintf(char *str, upx_rsize_t max_size, const char *format, ...)
+    attribute_format(3, 4);
+
+// malloc's *ptr
+int upx_safe_vasprintf(char **ptr, const char *format, va_list ap);
+int upx_safe_asprintf(char **ptr, const char *format, ...) attribute_format(2, 3);
+
+// returns a malloc'd pointer
+char *upx_safe_xprintf(const char *format, ...) attribute_format(1, 2);
+
+upx_rsize_t upx_safe_strlen(const char *);
+
+// globally redirect some functions
+#undef snprintf
+#undef sprintf
+#undef vsnprintf
+#define snprintf upx_safe_snprintf
+#define sprintf ERROR_sprintf_IS_DANGEROUS_USE_snprintf
+#define vsnprintf upx_safe_vsnprintf
+
+#undef strlen
+#define strlen upx_safe_strlen
+
+/*************************************************************************
+// some unsigned char string support functions
+**************************************************************************/
+
+inline unsigned char *strcpy(unsigned char *s1, const unsigned char *s2) {
+    return (unsigned char *) strcpy((char *) s1, (const char *) s2);
+}
+
+inline int strcmp(const unsigned char *s1, const unsigned char *s2) {
+    return strcmp((const char *) s1, (const char *) s2);
+}
+
+inline int strcasecmp(const unsigned char *s1, const unsigned char *s2) {
+    return strcasecmp((const char *) s1, (const char *) s2);
+}
+
+inline upx_rsize_t upx_safe_strlen(const unsigned char *s) {
+    return upx_safe_strlen((const char *) s);
+}
+
+#endif /* already included */
+
+/* vim:set ts=4 sw=4 et: */