Author: sveinung
Date: Thu Oct 8 17:42:50 2015
New Revision: 30031
URL: http://svn.gna.org/viewcvs/freeciv?rev=30031&view=rev
Log:
path finding: add backtrack convenience function
The new function pf_path_backtrack() is like pf_path_advance() except that
it removes from the end of the path.
See patch #6396
Modified:
trunk/common/aicore/path_finding.c
trunk/common/aicore/path_finding.h
Modified: trunk/common/aicore/path_finding.c
URL:
http://svn.gna.org/viewcvs/freeciv/trunk/common/aicore/path_finding.c?rev=30031&r1=30030&r2=30031&view=diff
==============================================================================
--- trunk/common/aicore/path_finding.c (original)
+++ trunk/common/aicore/path_finding.c Thu Oct 8 17:42:50 2015
@@ -3441,6 +3441,38 @@
return TRUE;
}
+/**************************************************************************
+ Remove the part of a path following a given tile.
+ If given tile is on the path more than once then the last occurrence
+ will be the one used.
+ If tile is not on the path at all, returns FALSE and path is not changed
+ at all.
+**************************************************************************/
+bool pf_path_backtrack(struct pf_path *path, struct tile *ptile)
+{
+ int i;
+ struct pf_position *new_positions;
+
+ fc_assert_ret_val(path->length > 0, FALSE);
+
+ for (i = path->length - 1; path->positions[i].tile != ptile; i--) {
+ if (i <= 0) {
+ return FALSE;
+ }
+ }
+
+ fc_assert_ret_val(i >= 0, FALSE);
+
+ path->length = i + 1;
+ new_positions = fc_malloc(sizeof(*path->positions) * path->length);
+ memcpy(new_positions, path->positions,
+ path->length * sizeof(*path->positions));
+ free(path->positions);
+ path->positions = new_positions;
+
+ return TRUE;
+}
+
/****************************************************************************
Get the last position of the path.
****************************************************************************/
Modified: trunk/common/aicore/path_finding.h
URL:
http://svn.gna.org/viewcvs/freeciv/trunk/common/aicore/path_finding.h?rev=30031&r1=30030&r2=30031&view=diff
==============================================================================
--- trunk/common/aicore/path_finding.h (original)
+++ trunk/common/aicore/path_finding.h Thu Oct 8 17:42:50 2015
@@ -494,6 +494,7 @@
struct pf_path *pf_path_concat(struct pf_path *dest_path,
const struct pf_path *src_path);
bool pf_path_advance(struct pf_path *path, struct tile *ptile);
+bool pf_path_backtrack(struct pf_path *path, struct tile *ptile);
const struct pf_position *pf_path_last_position(const struct pf_path *path);
void pf_path_print_real(const struct pf_path *path, enum log_level level,
const char *file, const char *function, int line);
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