Add check when calling free/seek/reset codec

It's possible to set a "coding" that triggers calls to the above while
codec_data is still null, when using special layouts like AAX

src/coding/at3plus_decoder.c

@@ -51,6 +51,7 @@ void decode_at3plus(VGMSTREAM * vgmstream, sample * outbuf, int channelspacing,
 
 void reset_at3plus(VGMSTREAM *vgmstream) {
     maiatrac3plus_codec_data *data = vgmstream->codec_data;
+    if (!data) return;
 
     if (data->handle)
         Atrac3plusDecoder_closeContext(data->handle);
@@ -62,6 +63,8 @@ void seek_at3plus(VGMSTREAM *vgmstream, int32_t num_sample) {
     int blocks_to_skip = num_sample / 2048;
     int samples_to_discard = num_sample % 2048;
     maiatrac3plus_codec_data *data = (maiatrac3plus_codec_data *)(vgmstream->codec_data);
+    if (!data) return;
+
     vgmstream->loop_ch[0].offset =
         vgmstream->loop_ch[0].channel_start_offset +
         vgmstream->interleave_block_size * blocks_to_skip;

src/coding/atrac9_decoder.c

@@ -152,6 +152,7 @@ decode_fail:
 
 void reset_atrac9(VGMSTREAM *vgmstream) {
     atrac9_codec_data *data = vgmstream->codec_data;
+    if (!data) return;
 
     if (!data->handle)
         goto fail;
@@ -184,6 +185,7 @@ fail:
 
 void seek_atrac9(VGMSTREAM *vgmstream, int32_t num_sample) {
     atrac9_codec_data *data = vgmstream->codec_data;
+    if (!data) return;
 
     reset_atrac9(vgmstream);
 
@@ -196,8 +198,7 @@ void seek_atrac9(VGMSTREAM *vgmstream, int32_t num_sample) {
 }
 
 void free_atrac9(atrac9_codec_data *data) {
-    if (!data)
+    if (!data) return;
-        return;
 
     if (data->handle) Atrac9ReleaseHandle(data->handle);
     free(data->data_buffer);

src/coding/ea_mt_decoder.c

@@ -534,6 +534,8 @@ static void flush_ea_mt_internal(VGMSTREAM *vgmstream, int is_start) {
     int i;
     size_t bytes;
 
+    if (!data) return;
+
     /* the decoder needs to be notified when offsets change */
     for (i = 0; i < vgmstream->channels; i++) {
         UTKContext *ctx = data->utk_context[i];

src/coding/ffmpeg_decoder.c

@@ -706,6 +706,7 @@ end:
 
 void reset_ffmpeg(VGMSTREAM *vgmstream) {
     ffmpeg_codec_data *data = (ffmpeg_codec_data *) vgmstream->codec_data;
+    if (!data) return;
 
     if (data->formatCtx) {
         avformat_seek_file(data->formatCtx, data->streamIndex, 0, 0, 0, AVSEEK_FLAG_ANY);
@@ -733,6 +734,7 @@ void reset_ffmpeg(VGMSTREAM *vgmstream) {
 void seek_ffmpeg(VGMSTREAM *vgmstream, int32_t num_sample) {
     ffmpeg_codec_data *data = (ffmpeg_codec_data *) vgmstream->codec_data;
     int64_t ts;
+    if (!data) return;
 
     /* Start from 0 and discard samples until loop_start (slower but not too noticeable).
      * Due to various FFmpeg quirks seeking to a sample is erratic in many formats (would need extra steps). */

src/coding/g719_decoder.c

@@ -53,6 +53,7 @@ void decode_g719(VGMSTREAM * vgmstream, sample * outbuf, int channelspacing, int
 void reset_g719(VGMSTREAM *vgmstream) {
     g719_codec_data *data = vgmstream->codec_data;
     int i;
+    if (!data) return;
 
     for (i = 0; i < vgmstream->channels; i++)
     {

src/coding/g7221_decoder.c

@@ -52,6 +52,7 @@ void decode_g7221(VGMSTREAM * vgmstream, sample * outbuf, int channelspacing, in
 void reset_g7221(VGMSTREAM *vgmstream) {
     g7221_codec_data *data = vgmstream->codec_data;
     int i;
+    if (!data) return;
 
     for (i = 0; i < vgmstream->channels; i++)
     {

src/coding/hca_decoder.c

@@ -2,7 +2,6 @@
 
 void decode_hca(hca_codec_data * data, sample * outbuf, int32_t samples_to_do, int channels) {
 	int samples_done = 0;
-
 	int32_t samples_remain = clHCA_samplesPerBlock - data->sample_ptr;
     
     void *hca_data = NULL;
@@ -84,7 +83,8 @@ void decode_hca(hca_codec_data * data, sample * outbuf, int32_t samples_to_do, i
 
 void reset_hca(VGMSTREAM *vgmstream) {
     hca_codec_data *data = vgmstream->codec_data;
-    /*clHCA *hca = (clHCA *)(data + 1);*/
+    if (!data) return;
+
     data->curblock = 0;
     data->sample_ptr = clHCA_samplesPerBlock;
     data->samples_discard = 0;
@@ -92,6 +92,8 @@ void reset_hca(VGMSTREAM *vgmstream) {
 
 void loop_hca(VGMSTREAM *vgmstream) {
     hca_codec_data *data = (hca_codec_data *)(vgmstream->codec_data);
+    if (!data) return;
+
     data->curblock = data->info.loopStart;
     data->sample_ptr = clHCA_samplesPerBlock;
     data->samples_discard = 0;

src/coding/mp4_aac_decoder.c

@@ -86,6 +86,8 @@ void decode_mp4_aac(mp4_aac_codec_data * data, sample * outbuf, int32_t samples_
 
 void reset_mp4_aac(VGMSTREAM *vgmstream) {
     mp4_aac_codec_data *data = vgmstream->codec_data;
+    if (!data) return;
+
     data->sampleId = 0;
     data->sample_ptr = data->samples_per_frame;
     data->samples_discard = 0;
@@ -93,6 +95,8 @@ void reset_mp4_aac(VGMSTREAM *vgmstream) {
 
 void seek_mp4_aac(VGMSTREAM *vgmstream, int32_t num_sample) {
     mp4_aac_codec_data *data = (mp4_aac_codec_data *)(vgmstream->codec_data);
+    if (!data) return;
+
     data->sampleId = 0;
     data->sample_ptr = data->samples_per_frame;
     data->samples_discard = num_sample;

src/coding/mpeg_decoder.c

@@ -500,6 +500,7 @@ void free_mpeg(mpeg_codec_data *data) {
 void reset_mpeg(VGMSTREAM *vgmstream) {
     off_t input_offset;
     mpeg_codec_data *data = vgmstream->codec_data;
+    if (!data) return;
 
     /* reset multistream */ //todo check if stream offsets are properly reset
 
@@ -524,6 +525,7 @@ void reset_mpeg(VGMSTREAM *vgmstream) {
 void seek_mpeg(VGMSTREAM *vgmstream, int32_t num_sample) {
     off_t input_offset;
     mpeg_codec_data *data = vgmstream->codec_data;
+    if (!data) return;
 
     /* seek multistream */
     if (!data->custom) {

src/coding/ogg_vorbis_decoder.c

@@ -22,15 +22,21 @@ void decode_ogg_vorbis(ogg_vorbis_codec_data * data, sample * outbuf, int32_t sa
 
 
 void reset_ogg_vorbis(VGMSTREAM *vgmstream) {
+    OggVorbis_File *ogg_vorbis_file;
     ogg_vorbis_codec_data *data = vgmstream->codec_data;
-    OggVorbis_File *ogg_vorbis_file = &(data->ogg_vorbis_file);
+    if (!data) return;
+
+    ogg_vorbis_file = &(data->ogg_vorbis_file);
 
     ov_pcm_seek(ogg_vorbis_file, 0);
 }
 
 void seek_ogg_vorbis(VGMSTREAM *vgmstream, int32_t num_sample) {
+    OggVorbis_File *ogg_vorbis_file;
     ogg_vorbis_codec_data *data = (ogg_vorbis_codec_data *)(vgmstream->codec_data);
-    OggVorbis_File *ogg_vorbis_file = &(data->ogg_vorbis_file);
+    if (!data) return;
+
+    ogg_vorbis_file = &(data->ogg_vorbis_file);
 
     ov_pcm_seek_lap(ogg_vorbis_file, num_sample);
 }

src/coding/vorbis_custom_decoder.c

@@ -207,6 +207,7 @@ void free_vorbis_custom(vorbis_custom_codec_data * data) {
 
 void reset_vorbis_custom(VGMSTREAM *vgmstream) {
     vorbis_custom_codec_data *data = vgmstream->codec_data;
+    if (!data) return;
 
     /* Seeking is provided by the Ogg layer, so with custom vorbis we'd need seek tables instead.
      * To avoid having to parse different formats we'll just discard until the expected sample */
@@ -216,6 +217,7 @@ void reset_vorbis_custom(VGMSTREAM *vgmstream) {
 
 void seek_vorbis_custom(VGMSTREAM *vgmstream, int32_t num_sample) {
     vorbis_custom_codec_data *data = vgmstream->codec_data;
+    if (!data) return;
 
     /* Seeking is provided by the Ogg layer, so with custom vorbis we'd need seek tables instead.
      * To avoid having to parse different formats we'll just discard until the expected sample */