[Bf-blender-cvs] [a5e9f024f21] master: Fix T77289: Crash when typing negative numbers

[Hans Goudey]

Commit: a5e9f024f21c76fd53c4734f287f043c3bc0beca
Author: Hans Goudey
Date:   Wed Jun 3 00:37:26 2020 -0400
Branches: master
https://developer.blender.org/rBa5e9f024f21c76fd53c4734f287f043c3bc0beca

Fix T77289: Crash when typing negative numbers

This was caused by an oversight in rB45dbc38a8b15. When the next operation
character is found the offset is shifted in the original string. The remaining
length has to be recalculated with that offset before shifting the remaining
characters to make room for the ")".

===================================================================

M	source/blender/blenkernel/intern/unit.c

===================================================================

diff --git a/source/blender/blenkernel/intern/unit.c b/source/blender/blenkernel/intern/unit.c
index 77e51f9d8c0..bb895304b84 100644
--- a/source/blender/blenkernel/intern/unit.c
+++ b/source/blender/blenkernel/intern/unit.c
@@ -716,7 +716,7 @@ static bool ch_is_op(char op)
 /**
  * Helper function for #unit_distribute_negatives to find the next negative to distribute.
  *
- * \note This unecessarily skips the next space if it comes right after the "-" 
+ * \note This unecessarily skips the next space if it comes right after the "-"
  * just to make a more predictable output.
  */
 static char *find_next_negative(const char *str, const char *remaining_str)
@@ -742,7 +742,7 @@ static char *find_next_negative(const char *str, const char *remaining_str)
 /**
  * Helper function for #unit_distribute_negatives to find the next operation, including "-".
  *
- * \note This unecessarily skips the space before the operation character 
+ * \note This unecessarily skips the space before the operation character
  * just to make a more predictable output.
  */
 static char *find_next_op(const char *str, char *remaining_str, int len_max)
@@ -793,12 +793,9 @@ static bool unit_distribute_negatives(char *str, const int len_max)
 
   char *remaining_str = str;
   int remaining_str_len = len_max;
-  int ofs = 0;
   while ((remaining_str = find_next_negative(str, remaining_str)) != NULL) {
-    ofs = (int)(remaining_str - str);
-
     /* Exit early in the unlikely situation that we've run out of length to add the parentheses. */
-    remaining_str_len = len_max - ofs;
+    remaining_str_len = len_max - (int)(remaining_str - str);
     if (remaining_str_len <= 2) {
       return changed;
     }
@@ -811,13 +808,13 @@ static bool unit_distribute_negatives(char *str, const int len_max)
 
     /* Add the ')' before the next operation or at the end. */
     remaining_str = find_next_op(str, remaining_str + 1, remaining_str_len);
-    memmove(remaining_str + 1, remaining_str, remaining_str_len - 3);
+    remaining_str_len = len_max - (int)(remaining_str - str);
+    memmove(remaining_str + 1, remaining_str, remaining_str_len - 1);
     *remaining_str = ')';
 
     /* Only move forward by 1 even though we added two characters. Minus signs need to be able to
      * apply to the next block of values too. */
     remaining_str += 1;
-    remaining_str_len -= 1;
   }
 
   return changed;