1 files changed, 155 insertions, 0 deletions
diff --git a/newlib/libc/sys/go32/fixpath.c b/newlib/libc/sys/go32/fixpath.c
new file mode 100644
index 00000000000..e7d61fddd1a
--- /dev/null
+++ b/newlib/libc/sys/go32/fixpath.c
@@ -0,0 +1,155 @@
+/*
+  (c) Copyright 1992 Eric Backus
+
+  This software may be used freely so long as this copyright notice is
+  left intact.  There is no warrantee on this software.
+*/
+
+#include "dos.h"		/* For intdos() */
+#include <errno.h>		/* For errno */
+#include <string.h>		/* For strlen() */
+
+int
+_get_default_drive(void)
+{
+    union REGS	regs;
+
+    regs.h.ah = 0x19;		/* DOS Get Default Drive call */
+    regs.h.al = 0;
+    (void) intdos(&regs, &regs);
+    return regs.h.al;
+}
+
+static char *
+get_current_directory(char *out, int drive_number)
+{
+    union REGS	regs;
+
+    regs.h.ah = 0x47;
+    regs.h.dl = drive_number + 1;
+    regs.x.si = (unsigned long) (out + 1);
+    (void) intdos(&regs, &regs);
+    if (regs.x.cflag != 0)
+    {
+	errno = regs.x.ax;
+	return out;
+    }
+    else
+    {
+	/* Root path, don't insert "/", it'll be added later */
+	if (*(out + 1) != '\0')
+	    *out = '/';
+	else
+	    *out = '\0';
+	return out + strlen(out);
+    }
+}
+
+static int
+is_slash(int c)
+{
+    return c == '/' || c == '\\';
+}
+
+static int
+is_term(int c)
+{
+    return c == '/' || c == '\\' || c == '\0';
+}
+
+/* Takes as input an arbitrary path.  Fixes up the path by:
+   1. Removing consecutive slashes
+   2. Removing trailing slashes
+   3. Making the path absolute if it wasn't already
+   4. Removing "." in the path
+   5. Removing ".." entries in the path (and the directory above them)
+   6. Adding a drive specification if one wasn't there
+   7. Converting all slashes to '/'
+ */
+void
+_fixpath(const char *in, char *out)
+{
+    int		drive_number;
+    const char	*ip = in;
+    char	*op = out;
+
+    /* Add drive specification to output string */
+    if (*(ip + 1) == ':' && ((*ip >= 'a' && *ip <= 'z') ||
+			     (*ip >= 'A' && *ip <= 'Z')))
+    {
+	if (*ip >= 'a' && *ip <= 'z')
+	    drive_number = *ip - 'a';
+	else
+	    drive_number = *ip - 'A';
+	*op++ = *ip++;
+	*op++ = *ip++;
+    }
+    else
+    {
+	drive_number = _get_default_drive();
+	*op++ = drive_number + 'a';
+	*op++ = ':';
+    }
+
+    /* Convert relative path to absolute */
+    if (!is_slash(*ip))
+	op = get_current_directory(op, drive_number);
+
+    /* Step through the input path */
+    while (*ip)
+    {
+	/* Skip input slashes */
+	if (is_slash(*ip))
+	{
+	    ip++;
+	    continue;
+	}
+
+	/* Skip "." and output nothing */
+	if (*ip == '.' && is_term(*(ip + 1)))
+	{
+	    ip++;
+	    continue;
+	}
+
+	/* Skip ".." and remove previous output directory */
+	if (*ip == '.' && *(ip + 1) == '.' && is_term(*(ip + 2)))
+	{
+	    ip += 2;
+	    /* Don't back up over drive spec */
+	    if (op > out + 2)
+		/* This requires "/" to follow drive spec */
+		while (!is_slash(*--op));
+	    continue;
+	}
+
+	/* Copy path component from in to out */
+	*op++ = '/';
+	while (!is_term(*ip)) *op++ = *ip++;
+    }
+
+    /* If root directory, insert trailing slash */
+    if (op == out + 2) *op++ = '/';
+
+    /* Null terminate the output */
+    *op = '\0';
+}
+
+#ifdef	TEST
+#include <stdio.h>
+
+int
+main(int argc, char **argv)
+{
+    char	path[90];
+    int		i;
+
+    for (i = 1; i < argc; i++)
+    {
+	_fixpath(argv[i], path);
+	(void) printf("'%s' -> '%s'\n", argv[i], path);
+    }
+
+    return 0;
+}
+#endif