nasmlib: add path-splitting functions

Some debugging formats may need to be able to split paths into
directory name and filename, at least.  This is kind of iffy, at least
across platforms, but that isn't really expected to be an issue in
practice... we hope.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 131 insertions, 0 deletions

diff --git a/nasmlib/path.c b/nasmlib/path.c
new file mode 100644
index 00000000..855440ea
--- /dev/null
+++ b/nasmlib/path.c
@@ -0,0 +1,131 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2017 The NASM Authors - All Rights Reserved
+ *   See the file AUTHORS included with the NASM distribution for
+ *   the specific copyright holders.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following
+ *   conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * 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.
+ *
+ *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * path.c - host operating system specific pathname manipulation functions
+ */
+
+#include "compiler.h"
+#include "nasmlib.h"
+#include "error.h"
+
+#if defined(unix) || defined(__unix) || defined(__unix__)
+# define separators "/"
+# define cleandirend "/"
+# define leaveonclean 1
+# define curdir "."
+#elif defined(__MSDOS__) || defined(__WINDOWS__) || \
+    defined(__OS2__) || defined(_WIN16) || defined(_WIN32)
+# define separators "/\\:"
+# define cleandirend "/\\"
+# define leaveonclean 2         /* Leave \\ at the start alone */
+# define curdir "."
+#elif defined(Macintosh)        /* MacOS classic? */
+# define separators ":"
+# define curdir ":"
+# define cleandirend ":"
+# define leaveonclean 0
+# define leave_leading 1
+#elif defined(__VMS)
+/*
+ * VMS filenames may have ;version at the end.  Assume we should count that
+ * as part of the filename anyway.
+ */
+# define separators ":]"
+# define curdir "[]"
+#else
+/* No idea what to do here, do nothing.  Feel free to add new ones. */
+# define curdir ""
+#endif
+
+static inline bool ismatch(const char *charset, char ch)
+{
+    const char *p;
+
+    for (p = charset; *p; p++) {
+        if (ch == *p)
+            return true;
+    }
+
+    return false;
+}
+
+static const char *first_filename_char(const char *path)
+{
+#ifdef separators
+    const char *p = path + strlen(path);
+
+    while (p > path) {
+        if (!ismatch(separators, p[-1]))
+            return p;
+        p--;
+    }
+
+    return p;
+#else
+    return path;
+#endif
+}
+
+/* Return the filename portion of a PATH as a new string */
+char *nasm_basename(const char *path)
+{
+    return nasm_strdup(first_filename_char(path));
+}
+
+/* Return the directory name portion of a PATH as a new string */
+char *nasm_dirname(const char *path)
+{
+    const char *p = first_filename_char(path);
+    const char *p0 = p;
+    (void)p0;                   /* Don't warn if unused */
+
+    if (p == path)
+        return nasm_strdup(curdir);
+
+#ifdef cleandirend
+    while (p > path+leaveonclean) {
+        if (ismatch(cleandirend, p[-1]))
+            break;
+        p--;
+    }
+#endif
+
+#ifdef leave_leading
+    /* If the directory contained ONLY separators, leave as-is */
+    if (p == path+leaveonclean)
+        p = p0;
+#endif
+
+    return nasm_strndup(path, p-path);
+}