Merge pull request #95 from saxbophone/josh/93-resume-from-saved-progress

Fix a bug where plot_spiral() would always start from line 0

Author: saxbophone

saxbospiral/solve.c

@@ -243,7 +243,8 @@ sxbp_status_t sxbp_resize_spiral(
  * index of the highest line to plot to and a pointer to a callback function,
  * calculate the length needed for each line in the spiral up to this index
  * (to avoid line overlap) and store these in a the spiral struct that is
- * pointed to by the pointer
+ * pointed to by the pointer. If the spiral has some lines already solved, the
+ * algorithm will start at the next unsolved line.
  * the function pointer can be NULL, if it is not then it will be called every
  * time a new line of the spiral is solved. The function should be of return
  * type void and take three arguments: a pointer to a spiral_t struct, an
@@ -261,8 +262,8 @@ sxbp_status_t sxbp_plot_spiral(
     sxbp_status_t result = {{0, 0, 0}, 0};
     // get index of highest line to plot
     uint64_t max_index = (max_line > spiral->size) ? spiral->size : max_line;
-    // calculate the length of each line
-    for(size_t i = 0; i < max_index; i++) {
+    // calculate the length of each line within range solved_count -> max_index
+    for(size_t i = spiral->solved_count; i < max_index; i++) {
         result = sxbp_resize_spiral(spiral, i, 1, perfection_threshold);
         // catch and return error if any
         if(result.diagnostic != SXBP_OPERATION_OK) {

saxbospiral/solve.h

@@ -30,7 +30,8 @@ sxbp_status_t sxbp_resize_spiral(
  * index of the highest line to plot to and a pointer to a callback function,
  * calculate the length needed for each line in the spiral up to this index
  * (to avoid line overlap) and store these in a the spiral struct that is
- * pointed to by the pointer
+ * pointed to by the pointer. If the spiral has some lines already solved, the
+ * algorithm will start at the next unsolved line.
  * the function pointer can be NULL, if it is not then it will be called every
  * time a new line of the spiral is solved. The function should be of return
  * type void and take three arguments: a pointer to a spiral_t struct, an