From 9e8d7389dc43cc9e53a71a3e8e30f87020367187 Mon Sep 17 00:00:00 2001
From: Martijn van Beurden <mvanb1@gmail.com>
Date: Wed, 18 May 2022 11:04:45 +0200
Subject: [PATCH] Fix initialization of decoder fuzzer

The decoder fuzzer initialized before setting up. This is now swapped
without upsetting the way the datasource is queried
---
 oss-fuzz/fuzzer_decoder.cc | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/oss-fuzz/fuzzer_decoder.cc b/oss-fuzz/fuzzer_decoder.cc
index ee4fdea1..da88c3df 100644
--- a/oss-fuzz/fuzzer_decoder.cc
+++ b/oss-fuzz/fuzzer_decoder.cc
@@ -171,22 +171,12 @@ namespace FLAC {
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
     fuzzing::datasource::Datasource ds(data, size);
     FLAC::Decoder::FuzzerStream decoder(ds);
+    bool use_ogg = true;
 
     try {
-        {
-            ::FLAC__StreamDecoderInitStatus ret;
-
-            if ( ds.Get<bool>() ) {
-                ret = decoder.init();
-            } else {
-                ret = decoder.init_ogg();
-            }
-
-            if ( ret != FLAC__STREAM_DECODER_INIT_STATUS_OK ) {
-                goto end;
-            }
+        if ( ds.Get<bool>() ) {
+            use_ogg = false;
         }
-
         if ( ds.Get<bool>() ) {
 #ifdef FUZZER_DEBUG
             printf("set_ogg_serial_number\n");
@@ -245,6 +235,18 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
 #endif
             decoder.set_metadata_ignore_all();
         }
+        {
+            ::FLAC__StreamDecoderInitStatus ret;
+            if ( !use_ogg ) {
+                ret = decoder.init();
+            } else {
+                ret = decoder.init_ogg();
+            }
+
+            if ( ret != FLAC__STREAM_DECODER_INIT_STATUS_OK ) {
+                goto end;
+            }
+        }
 
         while ( ds.Get<bool>() ) {
             switch ( ds.Get<uint8_t>() ) {