cc79022c128caab81ba5686174b0085ce480259f
kent
  Wed Oct 27 17:53:19 2010 -0700
Adding new function pathRelativeToFile
diff --git src/lib/filePath.c src/lib/filePath.c
index 9972139..50019dd 100644
--- src/lib/filePath.c
+++ src/lib/filePath.c
@@ -1,110 +1,131 @@
 /* filePath - stuff to handle file name parsing. */
 #include "common.h"
 #include "filePath.h"
 
 static char const rcsid[] = "$Id: filePath.c,v 1.3 2008/09/17 17:56:37 kent Exp $";
 
 void undosPath(char *path)
 /* Convert '\' to '/' in path. */
 {
 subChar(path, '\\', '/');
 }
 
 void splitPath(char *path, char dir[PATH_LEN], char name[FILENAME_LEN],
 	       char extension[FILEEXT_LEN])
 /* Split a full path into components.  The dir component will include the
  * trailing / if any.  The extension component will include the starting
  * . if any.   Pass in NULL for dir, name, or extension if you don't care about
  * that part. */
 {
 char *dirStart, *nameStart, *extStart, *extEnd;
 int dirSize, nameSize, extSize;
 
 undosPath(path);
 dirStart = path;
 nameStart = strrchr(path,'/');
 if (nameStart == NULL)
     nameStart = path;
 else
     nameStart += 1;
 extStart = strrchr(nameStart, '.');
 if (extStart == NULL)
     extStart = nameStart + strlen(nameStart);
 extEnd = extStart + strlen(extStart);
 if ((dirSize = (nameStart - dirStart)) >= PATH_LEN)
     errAbort("Directory too long in %s", path);
 if ((nameSize = (extStart - nameStart)) >= FILENAME_LEN)
     errAbort("Name too long in %s", path);
 if ((extSize = (extEnd - extStart)) >= FILEEXT_LEN)
     errAbort("Extension too long in %s", path);
 if (dir != NULL)
     {
     memcpy(dir, dirStart, dirSize);
     dir[dirSize] = 0;
     }
 if (name != NULL)
     {
     memcpy(name, nameStart, nameSize);
     name[nameSize] = 0;
     }
 if (extension != NULL)
     {
     memcpy(extension, extStart, extSize);
     extension[extSize] = 0;
     }
 }
 
 static char *findSlashBefore(char *start, char *e)
 /* Return first slash before s (but not before start) */
 {
 while (--e >= start)
     {
     if (*e == '/')
          return e;
     }
 return start;
 }
 
 char *expandRelativePath(char *baseDir, char *relPath)
 /* Expand relative path to more absolute one. */
 {
+if (relPath[0] == '/')
+   // hey, it's absolute actually... 
+   return cloneString(relPath);
+
 char *e = baseDir + strlen(baseDir);
 int slashCount;
 char *rel = relPath;
 char *result;
 int size, baseSize;
 undosPath(baseDir);
 undosPath(relPath);
 slashCount = countChars(baseDir, '/');
 if (baseDir[0] == 0)
     slashCount = -1;
 while (startsWith("../", rel))
     {
     if (slashCount < 0)
         {
 	warn("More ..'s in \"%s\" than directories in \"%s\"", relPath, baseDir);
 	return NULL;
 	}
     else if (slashCount == 0)
         e = baseDir;
     else
         e = findSlashBefore(baseDir, e);
     slashCount -= 1;
     rel += 3;
     }
 baseSize = e - baseDir;
 size = strlen(rel) + 1;
 if (baseSize > 0)
     size += baseSize + 1;
 if (baseSize > 0)
     {
     result = needMem(size);
     memcpy(result, baseDir, baseSize);
     result[baseSize] = '/';
     strcpy(result + baseSize + 1, rel);
     }
 else
     result = cloneString(rel);
 return result;
 }
 
+char *pathRelativeToFile(char *baseFile, char *relPath)
+/* Given a base file name and a path relative to that, return
+ * relative path interpreted as if it were seen from the
+ * same directory holding the baseFile.  
+ *   An example of using this would be in processing include
+ * files.  In this case the baseFile would be the current
+ * source file, and the relPath would be from the include
+ * statement.  The returned result could then be used to
+ * open the include file. */
+{
+char dir[PATH_LEN];
+splitPath(baseFile, dir, NULL, NULL);
+int dirLen = strlen(dir);
+if (dirLen > 0 && dir[dirLen-1] == '/')
+     dir[dirLen-1] = 0;
+return expandRelativePath(dir, relPath);
+}