added readonly flag option for hecdss open (#366)

* added readonly flag option for hecdss open

* Allow user to choose access, null/empty check filename

* update docstring

* fix memory leak in hecdss.c

Author: jeremiah-kang

heclib/hecdss/hecdss.c

@@ -4,7 +4,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-HECDSS_API const char *hec_dss_api_version() { return "0.4.0"; }
+HECDSS_API const char *hec_dss_api_version() { return "0.5.0"; }
 
 #if defined(__GNUC__) || defined(__sun__)
 #define MIN(a, b)                                                              \
@@ -166,11 +166,31 @@ void hec_dss_array_copy_int(int *destination, const long destinationSize,
   }
 }
 HECDSS_API int hec_dss_open(const char *filename, dss_file **dss) {
+  return hec_dss_open_ex(filename, dss, 0);
+}
+
+/*
+*				int access:  read/write access to the file
+*					0 - GENERAL_ACCESS:  Doesn't matter (no error if file doesn't have write permission)
+*					1 - READ_ACCESS:  Read only (will not allow writing to file)
+*					2 - MULTI_USER_ACCESS:  Read/Write permission with full mutil-user access
+*						(usually slow, but necessary for multiple processes)
+*					3 - SINGLE_USER_ADVISORY_ACCESS:  Read/Write permission with mutil-user advisory access
+*						(throws an error if file is read only).  Best (and default access)
+*					4 - EXCLUSIVE_ACCESS:  Exclusive write (used for squeezing).  Throws an error if not available.
+ */
+HECDSS_API int hec_dss_open_ex(const char *filename, dss_file **dss,
+                               int access) {
   dss_file *f = (dss_file *)malloc(sizeof(dss_file));
   if (f == NULL)
     return -1;
+  // readonly can only be from 0 to 4
+  if (access < 0 || access > 4) {
+    free(f);
+    return -1;
+  }
 
-  int status = hec_dss_zopen(f->ifltab, filename);
+  int status = zopenExtended(f->ifltab, filename, 0, access, 0, 0, 0);
   if (status != 0) {
     free(f);
     return status;

heclib/hecdss/hecdss.h

@@ -8,9 +8,10 @@
 
 
  This API is designed with perspective that the calling/client code is in charge
- of managing memory. The only exception is hec_dss_open(const char* filename,
- dss_file** dss).   hec_dss_open allocates one internal structure that must be
- freed by calling hec_dss_close;
+ of managing memory. The only exceptions are hec_dss_open(const char* filename,
+ dss_file** dss) and hec_dss_open_ex(const char* filename, dss_file** dss,
+ int readonly).  Each allocates one internal structure that must be freed by
+ calling hec_dss_close;
 
  For reading data: The client passes in pre-allocated arrays, with the size,
  then the API copies data into those arrays
@@ -73,12 +74,26 @@ HECDSS_API int hec_dss_CONSTANT_MAX_PATH_SIZE();
 
 /// <summary>
 /// use hec_dss_open to connect to a DSS file.
+/// Equivalent to hec_dss_open_ex(filename, dss, 0).
 /// </summary>
 /// <param name="filename">input: filename to open or create</param>
 /// <param name="dss">output: pointer to dss_file</param>
 /// <returns>zero if successful</returns>
 HECDSS_API int hec_dss_open(const char *filename, dss_file **dss);
 
+/// <summary>
+/// use hec_dss_open_ex to connect to a DSS file, access.
+///
+/// </summary>
+/// <param name="filename">input: filename to open; also created if readonly is
+/// zero and the file does not exist</param>
+/// <param name="dss">output: pointer to dss_file</param>
+/// <param name="access">input: zero to open with read/write access
+/// (identical to hec_dss_open), non-zero to open read-only</param>
+/// <returns>zero if successful</returns>
+HECDSS_API int hec_dss_open_ex(const char *filename, dss_file **dss,
+                               int access);
+
 /// <summary>
 /// use hec_dss_close to close the connection to a DSS file.
 /// This must be called when a program is done using a DSS file.

heclib/heclib_c/src/DssInterface/v6and7/zopenExtended.c

@@ -17,6 +17,12 @@
 int zopenExtended(long long *ifltab, const char *dssFilename, int fileVersion,
 			 int access, int maxExpectedPathnames, int hashSize, int binSize)
 {
+
+	if (!dssFilename || strlen(dssFilename) <=0 ) {
+		return zerrorProcessing(ifltab, DSS_FUNCTION_zopen_ID, zdssErrorCodes.NULL_FILENAME,
+			0, 0, zdssErrorSeverity.INVALID_ARGUMENT, "", "");
+	}
+	
 	int version;
 
 	version = zgetFileVersion(dssFilename);