BLI_path: remove FILE_MAX limit on BLI_path_frame{_range} functions

- Use BLI_str_replace_range to avoid a temporary string copy.
- Also add a buffer size argument to BLI_path_frame_range.

source/blender/blenkernel/intern/writeavi.c

@@ -164,13 +164,13 @@ static void filepath_avi(char *filepath, const RenderData *rd, bool preview, con
 
   if (rd->scemode & R_EXTENSION) {
     if (!BLI_path_extension_check(filepath, ".avi")) {
-      BLI_path_frame_range(filepath, sfra, efra, 4);
+      BLI_path_frame_range(filepath, FILE_MAX, sfra, efra, 4);
       BLI_strncat(filepath, ".avi", FILE_MAX);
     }
   }
   else {
     if (BLI_path_frame_check_chars(filepath)) {
-      BLI_path_frame_range(filepath, sfra, efra, 4);
+      BLI_path_frame_range(filepath, FILE_MAX, sfra, efra, 4);
     }
   }
 

source/blender/blenkernel/intern/writeffmpeg.c

@@ -1406,7 +1406,7 @@ static void ffmpeg_filepath_get(FFMpegContext *context,
     if (*fe == NULL) {
       BLI_strncat(string, autosplit, FILE_MAX);
 
-      BLI_path_frame_range(string, sfra, efra, 4);
+      BLI_path_frame_range(string, FILE_MAX, sfra, efra, 4);
       BLI_strncat(string, *exts, FILE_MAX);
     }
     else {
@@ -1417,7 +1417,7 @@ static void ffmpeg_filepath_get(FFMpegContext *context,
   }
   else {
     if (BLI_path_frame_check_chars(string)) {
-      BLI_path_frame_range(string, sfra, efra, 4);
+      BLI_path_frame_range(string, FILE_MAX, sfra, efra, 4);
     }
 
     BLI_strncat(string, autosplit, FILE_MAX);

source/blender/blenlib/BLI_path_util.h

@@ -446,7 +446,8 @@ bool BLI_path_frame(char *path, size_t path_maxncpy, int frame, int digits) ATTR
  * with sta and end as decimal integers, with leading zeroes as necessary, to make digits
  * digits each, with a hyphen in-between.
  */
-bool BLI_path_frame_range(char *path, int sta, int end, int digits) ATTR_NONNULL(1);
+bool BLI_path_frame_range(char *path, size_t path_maxncpy, int sta, int end, int digits)
+    ATTR_NONNULL(1);
 /**
  * Get the frame from a filename formatted by blender's frame scheme
  */

source/blender/blenlib/intern/path_util.c

@@ -45,6 +45,14 @@ static int BLI_path_unc_prefix_len(const char *path);
 static bool BLI_path_is_abs_win32(const char *path);
 #endif /* WIN32 */
 
+/**
+ * The maximum number of `#` characters expanded for #BLI_path_frame & #BLI_path_frame_range
+ * Typically 12 is enough and even 16 is very large.
+ * Use a much larger value so hitting the upper limit is not an issue.
+ * Exceeding this limit won't fail either, it will just not insert so many leading zeros.
+ */
+#define FILENAME_FRAME_CHARS_MAX FILE_MAX
+
 int BLI_path_sequence_decode(const char *path,
                              char *head,
                              const size_t head_maxncpy,
@@ -885,18 +893,19 @@ bool BLI_path_frame(char *path, size_t path_maxncpy, int frame, int digits)
     ensure_digits(path, digits);
   }
 
-  if (stringframe_chars(path, &ch_sta, &ch_end)) { /* Warning: `ch_end` is the last # +1. */
-    char tmp[FILE_MAX];
-    SNPRINTF(tmp, "%.*s%.*d%s", ch_sta, path, ch_end - ch_sta, frame, path + ch_end);
-    BLI_strncpy(path, tmp, path_maxncpy);
+  if (stringframe_chars(path, &ch_sta, &ch_end)) {
+    char frame_str[FILENAME_FRAME_CHARS_MAX + 1]; /* One for null. */
+    const int ch_span = MIN2(ch_end - ch_sta, FILENAME_FRAME_CHARS_MAX);
+    BLI_snprintf(frame_str, sizeof(frame_str), "%.*d", ch_span, frame);
+    BLI_str_replace_range(path, path_maxncpy, ch_sta, ch_end, frame_str);
     return true;
   }
   return false;
 }
 
-bool BLI_path_frame_range(char *path, int sta, int end, int digits)
+bool BLI_path_frame_range(char *path, size_t path_maxncpy, int sta, int end, int digits)
 {
-  BLI_string_debug_size_after_nil(path, FILE_MAX);
+  BLI_string_debug_size_after_nil(path, path_maxncpy);
 
   int ch_sta, ch_end;
 
@@ -904,18 +913,11 @@ bool BLI_path_frame_range(char *path, int sta, int end, int digits)
     ensure_digits(path, digits);
   }
 
-  if (stringframe_chars(path, &ch_sta, &ch_end)) { /* Warning: `ch_end` is the last # +1. */
-    char tmp[FILE_MAX];
-    SNPRINTF(tmp,
-             "%.*s%.*d-%.*d%s",
-             ch_sta,
-             path,
-             ch_end - ch_sta,
-             sta,
-             ch_end - ch_sta,
-             end,
-             path + ch_end);
-    BLI_strncpy(path, tmp, FILE_MAX);
+  if (stringframe_chars(path, &ch_sta, &ch_end)) {
+    char frame_str[(FILENAME_FRAME_CHARS_MAX * 2) + 1 + 1]; /* One for null, one for the '-' */
+    const int ch_span = MIN2(ch_end - ch_sta, FILENAME_FRAME_CHARS_MAX);
+    BLI_snprintf(frame_str, sizeof(frame_str), "%.*d-%.*d", ch_span, sta, ch_span, end);
+    BLI_str_replace_range(path, path_maxncpy, ch_sta, ch_end, frame_str);
     return true;
   }
   return false;

source/blender/blenlib/tests/BLI_path_util_test.cc

@@ -638,6 +638,15 @@ TEST(path_util, Frame)
     EXPECT_TRUE(ret);
     EXPECT_STREQ(path, "test_-0100");
   }
+
+  /* Ensure very large ranges work. */
+  {
+    char path[FILE_MAX * 2];
+    memset(path, '#', sizeof(path));
+    path[sizeof(path) - 1] = '\0';
+    ret = BLI_path_frame(path, sizeof(path), 123456789, 0);
+    EXPECT_TRUE(BLI_str_endswith(path, "0123456789"));
+  }
 }
 
 /** \} */
@@ -987,7 +996,7 @@ TEST(path_util, FrameCheckChars)
     char path[FILE_MAX]; \
     bool ret; \
     STRNCPY(path, input_path); \
-    ret = BLI_path_frame_range(path, sta, end, digits); \
+    ret = BLI_path_frame_range(path, sizeof(path), sta, end, digits); \
     if (expect_outpath == nullptr) { \
       EXPECT_FALSE(ret); \
     } \