Several fixes to let gmtgravmag3d pass in memory data via modified -T…

… option. (#8680)

* Modify option -T to use modifiers.

Let both input xyz file and vertices (new -T+v<file>) be readable by externals.

* Save number of columns read when requesrec reading a file with unknown n cols.

* Change KEYs to allow -F from externals.

Change syntax of -T option

* Update the -T docs.

doc/rst/source/supplements/potential/gmtgravmag3d.rst

@@ -12,7 +12,7 @@ Synopsis
 
 .. include:: ../../common_SYN_OPTs.rst_
 
-**gmt gravmag3d** *xyz_file* |-T|\ **v**\ *vert_file* OR |-T|\ **r\|s**\ *raw_file* OR |-M|\ **+s**\ *body,params*
+**gmt gravmag3d** *xyz_file* |-T|\ **+v**\ *vert_file* OR |-T|\ **+r\|+s**\ *raw_file* OR |-M|\ **+s**\ *body,params*
 [ |-C|\ *density* ]
 [ |-E|\ *thickness* ]
 [ |-F|\ *xy_file* ]
@@ -97,15 +97,15 @@ Required Arguments (not all)
 
 .. _-T:
 
-**-Tv**\ *vert_file* (must have when passing a *xyz_file*) OR **-Tr\|s**\ *raw_file*
-    Gives names of a xyz and vertex (**-Tv**\ *vert_file*) files defining a close surface.
+**-T+v**\ *vert_file* (must have when passing a *xyz_file*) OR **-T+r\|+s**\ *raw_file*
+    Gives names of a xyz and vertex (**-T+v**\ *vert_file*) files defining a closed surface.
     The file formats correspond to the output of the :doc:`triangulate </triangulate>` program.
     The *xyz* file can have 3, 4, 5, 6 or 8 columns. In first case (3 columns) the magnetization (or density) are
     assumed constant (controlled by |-C| or |-H|). Following cases are: 4 columns -> 4rth col magnetization intensity;
     5 columns: mag, mag dip; 6 columns: mag, mag dec, mag dip; 8 columns: field dec, field dip, mag, mag dec, mag dip.
-    When n columns > 3 the third argument of the |-H| option is ignored. A *raw* format (selected by the **-Tr** option)
+    When n columns > 3 the third argument of the |-H| option is ignored. A *raw* format (selected with the **-T+r** option)
     is a file with N rows (one per triangle) and 9 columns corresponding to the *x, y, z* coordinates of each of the three
-    vertex of each triangle. Alternatively, the **-Ts** option indicates that the surface file is in the ASCII STL
+    vertex of each triangle. Alternatively, the **-T+s** option indicates that the surface file is in the ASCII STL
     (Stereo Lithographic) format. These two type of files are used to provide a closed surface.
 
 Optional Arguments

src/gmt_api.c

@@ -10315,7 +10315,7 @@ GMT_LOCAL void gmtapi_get_record_init (struct GMTAPI_CTRL *API) {
 	}
 }
 
-void * GMT_Get_Record (void *V_API, unsigned int mode, int *retval) {
+void *GMT_Get_Record(void *V_API, unsigned int mode, int *retval) {
 	/* Retrieves the next data record from the virtual input source and
 	 * returns the number of columns found via *retval (unless retval == NULL).
 	 * If current record is a segment header then we return 0.
@@ -10348,7 +10348,10 @@ void * GMT_Get_Record (void *V_API, unsigned int mode, int *retval) {
 		record = API->api_get_record (API, mode, &n_fields);
 	} while (API->get_next_record);
 
-	if (!(n_fields == EOF || n_fields == GMT_IO_NEXT_FILE)) API->current_rec[GMT_IN]++;	/* Increase record count, unless EOF */
+	if (!(n_fields == EOF || n_fields == GMT_IO_NEXT_FILE)) {	/* Increase record count, unless EOF */
+		API->current_rec[GMT_IN]++;
+		if (GMT->current.io.variable_in_columns) GMT->current.io.n_numerical_cols = (unsigned int)n_fields;	/* Keep track of this */
+	}
 
 	if (retval) *retval = n_fields;	/* Requested we return the number of fields found */
 	return (record);		/* Return pointer to current record */
@@ -13461,6 +13464,10 @@ struct GMT_RESOURCE * GMT_Encode_Options (void *V_API, const char *module_name,
 	else if (!strncmp (module, "gravprisms", 10U) && (opt = GMT_Find_Option (API, 'C', *head))) {
 		deactivate_input = true;    /* Turn off implicit input since none is in effect */
 	}
+	/* 1z. Check if gmtgravmag3d is producing grids or datasets */
+	else if (!strncmp (module, "gmtgravmag3d", 12U)) {
+		//type = (opt = GMT_Find_Option (API, 'F', *head)) ? 'D' : 'G';	/* Giving -F<file> means compute over a line, else grid */
+	}
 
 	/* 2a. Get the option key array for this module */
 	key = gmtapi_process_keys (API, keys, type, *head, n_per_family, &n_keys);	/* This is the array of keys for this module, e.g., "<D{,GG},..." */