add basename and dirname

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 102 insertions, 0 deletions

diff --git a/src/libgen.c b/src/libgen.c
new file mode 100644
index 0000000..f8c338b
--- /dev/null
+++ b/src/libgen.c
@@ -0,0 +1,102 @@
+/**
+ * slibc — Yet another C library
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 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.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <string.h>
+#include <libgen.h>
+#include <stddef.h>
+
+
+
+/**
+ * Get the basename of a filename.
+ * 
+ * This is a GNU extension, include <libgen.h>
+ * to override it with the XPG-compliant implementation.
+ * 
+ * @param   filename  The filename.
+ * @return            The basename, it is either a substring
+ *                    of `filename` or, if `filename` is `NULL`
+ *                    or is empty, a statically allocationed string,
+ *                    so it must not freed or edited.
+ */
+char* __gnu_basename(const char* filename)
+{
+  char* r = filename;
+  char last = '/';
+  if (filename == NULL)
+    return ".";
+  while (*filename)
+    {
+      if ((*filename != '/') && (last == '/'))
+	r = filename;
+      last = *filename++;
+    }
+  return r;
+}
+
+
+/**
+ * Get the basename of a filename, remove
+ * trailing slashes.
+ * 
+ * @param   filename  The filename, may be edited by this function.
+ * @return            The basename, it is either a substring
+ *                    of `filename` or, if `filename` is `NULL`
+ *                    or is empty, a statically allocationed string,
+ *                    so it must not freed or edited.
+ */
+char* __xpg_basename(char* filename)
+{
+  char* r = __gnu_basename(filename);
+  char* p;
+  if (strcmp("."))
+    for (p = r + 1; *p; p++)
+      if (p == '/')
+	*p = 0;
+  return r;
+}
+
+
+/**
+ * Get the dirname of a filename.
+ * 
+ * @param   filename  The filename, may be edited by this function.
+ * @return            The dirname, it is either a substring
+ *                    of `filename` or, if `filename` is `NULL`
+ *                    or does no contain a non-trailing slash,
+ *                    a statically allocationed string, so it
+ *                    must not freed or edited.
+ */
+char* dirname(char* filename)
+{
+  int have_nonslash = 0;
+  char* last_slash = NULL;
+  char c, d;
+  if ((filename == NULL) || (!*filename))
+    return ".";
+  for (; (c = *filename); filename++)
+    {
+      d = filename[1];
+      have_nonslash |= c - '/';
+      if ((c == '/') && d && (d != '/'))
+	last_slash = filename;
+    }
+  if (!have_nonslash)      return "/";
+  if (last_slash == NULL)  return ".";
+  return *last_slash = 0, filename;
+}
+