SDL: SDL_rwops.c: stdio_seek - skip API call for RW_SEEK_CUR with 0 offset

From 2824d138b9dcc2c113c8057d0ef377e3edfb24be Mon Sep 17 00:00:00 2001
From: ds-sloth <[EMAIL REDACTED]>
Date: Fri, 16 Aug 2024 17:12:34 -0400
Subject: [PATCH] SDL_rwops.c: stdio_seek - skip API call for RW_SEEK_CUR with
 0 offset

Reference Issue #10556.
---
 src/file/SDL_rwops.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/file/SDL_rwops.c b/src/file/SDL_rwops.c
index 444bf4af3d5c5..8d2042cc0534c 100644
--- a/src/file/SDL_rwops.c
+++ b/src/file/SDL_rwops.c
@@ -369,6 +369,7 @@ stdio_size(SDL_RWops * context)
 static Sint64 SDLCALL stdio_seek(SDL_RWops *context, Sint64 offset, int whence)
 {
     int stdiowhence;
+    SDL_bool is_noop;
 
     switch (whence) {
     case RW_SEEK_SET:
@@ -390,7 +391,10 @@ static Sint64 SDLCALL stdio_seek(SDL_RWops *context, Sint64 offset, int whence)
     }
 #endif
 
-    if (fseek(context->hidden.stdio.fp, (fseek_off_t)offset, stdiowhence) == 0) {
+    /* don't make a possibly-costly API call for the noop seek from SDL_RWtell */
+    is_noop = (whence == RW_SEEK_CUR) && (offset == 0);
+
+    if (is_noop || fseek(context->hidden.stdio.fp, (fseek_off_t)offset, stdiowhence) == 0) {
         Sint64 pos = ftell(context->hidden.stdio.fp);
         if (pos < 0) {
             return SDL_SetError("Couldn't get stream offset");