Add BrotliCopyPreloadedSymbols function.

Add a single trivial use to avoid complier warning.

PiperOrigin-RevId: 671098230

c/dec/decode.c

diff --git a/c/dec/decode.c b/c/dec/decode.c
index 220c7e8..7790f92 100644
--- a/c/dec/decode.c
+++ b/c/dec/decode.c
@@ -1899,6 +1899,22 @@
     }                                             \
   }
 
+/* Reads up to limit symbols from br and copies them into ringbuffer,
+   starting from pos. Caller must ensure that this is safe. */
+static BROTLI_INLINE void BrotliCopyPreloadedSymbols(BrotliBitReader* br,
+                                                     brotli_reg_t* bits,
+                                                     brotli_reg_t* value,
+                                                     BrotliDecoderState* s,
+                                                     int pos,
+                                                     int limit) {
+      int pos_limit = pos + limit;
+      for (; pos < pos_limit; pos++) {
+        s->ringbuffer[pos] =
+            (uint8_t)ReadPreloadedSymbol(s->literal_htree, br, bits, value);
+        BROTLI_LOG_ARRAY_INDEX(s->ringbuffer, pos);
+      }
+}
+
 static BROTLI_INLINE BrotliDecoderErrorCode ProcessCommandsInternal(
     int safe, BrotliDecoderState* s) {
   int pos = s->pos;
@@ -1969,8 +1985,7 @@
         goto NextLiteralBlock;
       }
       if (!safe) {
-        s->ringbuffer[pos] =
-            (uint8_t)ReadPreloadedSymbol(s->literal_htree, br, &bits, &value);
+        BrotliCopyPreloadedSymbols(br, &bits, &value, s, pos, 1);
       } else {
         brotli_reg_t literal;
         if (!SafeReadSymbol(s->literal_htree, br, &literal)) {