Fix Mines of Madness string compare bug

docs/changelog.txt

@@ -43,6 +43,8 @@ USERS
   counters or strings lists beyond 1 billion. Checks have been
   added to prevent them from expanding beyond 2^31 (please don't
   actually use this many counters/strings).
++ Fixed string comparison for pre-2.81 games that relied on
+  null-terminated string compares. This fixes Mines of Madness.
 + Fixed hlp2html bug where certain chars wouldn't be escaped and
   decreased the size of the output HTML files somewhat.
 + Fixed libxmp playback for S3Ms containing ADPCM4 samples. This

src/run_robot.c

@@ -1726,8 +1726,6 @@ void run_robot(context *ctx, int id, int x, int y)
         {
           struct string dest;
           struct string src;
-          int allow_wildcards = 0;
-          int exact_case = 0;
 
           // NOTE: versions prior to 2.92 did tr_msg here instead of above.
 
@@ -1756,19 +1754,31 @@ void run_robot(context *ctx, int id, int x, int y)
             src.length = tmp;
           }
 
-          // String equality extensions (2.91+)
-          if(mzx_world->version >= V291)
+          // Non-terminated string compares (2.81+)
+          if(mzx_world->version >= V281)
           {
-            if(comparison == EXACTLY_EQUAL || comparison == WILD_EXACTLY_EQUAL)
-              exact_case = 1;
+            boolean exact_case = false;
+            boolean wildcards = false;
 
-            if(comparison == WILD_EQUAL || comparison == WILD_EXACTLY_EQUAL)
-              allow_wildcards = 1;
-          }
+            // String equality extensions (2.91+)
+            if(mzx_world->version >= V291)
+            {
+              if(comparison == EXACTLY_EQUAL || comparison == WILD_EXACTLY_EQUAL)
+                exact_case = true;
 
-          src_value = 0;
-          dest_value = compare_strings(&dest, &src,
-           exact_case, allow_wildcards);
+              if(comparison == WILD_EQUAL || comparison == WILD_EXACTLY_EQUAL)
+                wildcards = true;
+            }
+
+            src_value = 0;
+            dest_value = compare_strings(&dest, &src, exact_case, wildcards);
+          }
+          // Null-terminated string compares (2.80X and prior).
+          else
+          {
+            src_value = 0;
+            dest_value = compare_strings_null_terminated(&dest, &src);
+          }
         }
         else
 

src/str.c

@@ -1768,7 +1768,7 @@ static int compare_wildcard(const char *str, size_t str_len,
 int compare_strings(struct string *A, struct string *B, boolean exact_case,
  boolean allow_wildcards)
 {
-  size_t cmp_length = (A->length < B->length) ? A->length : B->length;
+  size_t cmp_length = MIN(A->length, B->length);
   int res = 0;
 
   if(!allow_wildcards)
@@ -1802,6 +1802,30 @@ int compare_strings(struct string *A, struct string *B, boolean exact_case,
   return compare_wildcard(A->value, A->length, B->value, B->length, exact_case);
 }
 
+/**
+ * String comparison prior to 2.81 used strcasecmp, which worked because string
+ * values were guaranteed to be null terminated. Some games relied on this
+ * behavior by inserting nulls into strings (Mines of Madness). String values
+ * are not null terminated anymore, so approximate this with strncasecmp.
+ */
+int compare_strings_null_terminated(struct string *A, struct string *B)
+{
+  size_t cmp_length = MIN(A->length, B->length);
+  int res;
+
+  res = strncasecmp(A->value, B->value, cmp_length);
+  if(res)
+    return res;
+
+  if(A->length > B->length)
+    return A->value[cmp_length];
+
+  if(A->length < B->length)
+    return -B->value[cmp_length];
+
+  return 0;
+}
+
 // Create a new string from loading a save file. This skips find_string.
 struct string *load_new_string(struct string_list *string_list, int index,
  const char *name, int name_length, int str_length)

src/str.h

@@ -61,6 +61,7 @@ void dec_string_int(struct world *mzx_world, const char *name, int value,
  int id);
 int compare_strings(struct string *A, struct string *B, boolean exact_case,
  boolean allow_wildcards);
+int compare_strings_null_terminated(struct string *A, struct string *B);
 
 struct string *load_new_string(struct string_list *string_list, int index,
  const char *name, int name_length, int str_length);