From 5c3a47c7201ebe7fbbd240fa926dc70f53cd01da Mon Sep 17 00:00:00 2001
From: halleyscometsw <halleyscometsw@51a99a44-fe44-0410-b1ba-c3e57ba2b86b>
Date: Fri, 25 Jul 2008 19:02:29 +0000
Subject: [PATCH] add coding_PSX_badflags

git-svn-id: https://vgmstream.svn.sourceforge.net/svnroot/vgmstream@374 51a99a44-fe44-0410-b1ba-c3e57ba2b86b
---
 src/coding/coding.h      |  2 ++
 src/coding/psx_decoder.c | 36 ++++++++++++++++++++++++++++++++++++
 src/vgmstream.c          | 15 ++++++++++++++-
 src/vgmstream.h          |  1 +
 4 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/src/coding/coding.h b/src/coding/coding.h
index 2f2594e5..b5f1a958 100644
--- a/src/coding/coding.h
+++ b/src/coding/coding.h
@@ -34,6 +34,8 @@ void decode_psx(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing,
 
 void decode_invert_psx(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do);
 
+void decode_psx_badflags(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do);
+
 void decode_xa(VGMSTREAM * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do, int channel);
 void init_get_high_nibble(VGMSTREAM * vgmstream);
 
diff --git a/src/coding/psx_decoder.c b/src/coding/psx_decoder.c
index 9df0e028..95f60588 100644
--- a/src/coding/psx_decoder.c
+++ b/src/coding/psx_decoder.c
@@ -94,3 +94,39 @@ void decode_invert_psx(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelsp
 	stream->adpcm_history1_32=hist1;
 	stream->adpcm_history2_32=hist2;
 }
+
+/* some TAITO games have garbage (?) in their flags, this decoder
+ * just ignores that byte */
+void decode_psx_badflags(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do) {
+
+	int predict_nr, shift_factor, sample;
+	int32_t hist1=stream->adpcm_history1_32;
+	int32_t hist2=stream->adpcm_history2_32;
+
+	short scale;
+	int i;
+	int32_t sample_count;
+
+	int framesin = first_sample/28;
+
+	predict_nr = read_8bit(stream->offset+framesin*16,stream->streamfile) >> 4;
+	shift_factor = read_8bit(stream->offset+framesin*16,stream->streamfile) & 0xf;
+	first_sample = first_sample % 28;
+	
+	for (i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
+        short sample_byte = (short)read_8bit(stream->offset+(framesin*16)+2+i/2,stream->streamfile);
+
+        scale = ((i&1 ?
+                    sample_byte >> 4 :
+                    sample_byte & 0x0f)<<12);
+
+        sample=(int)((scale >> shift_factor)+hist1*VAG_f[predict_nr][0]+hist2*VAG_f[predict_nr][1]);
+
+		outbuf[sample_count] = clamp16(sample);
+		hist2=hist1;
+		hist1=sample;
+	}
+	stream->adpcm_history1_32=hist1;
+	stream->adpcm_history2_32=hist2;
+}
+
diff --git a/src/vgmstream.c b/src/vgmstream.c
index b7b05ada..cd6e7fc9 100644
--- a/src/vgmstream.c
+++ b/src/vgmstream.c
@@ -436,6 +436,7 @@ int get_vgmstream_samples_per_frame(VGMSTREAM * vgmstream) {
         case coding_NGC_AFC:
             return 16;
         case coding_PSX:
+        case coding_PSX_badflags:
         case coding_invert_PSX:
 		case coding_XA:
             return 28;
@@ -491,6 +492,7 @@ int get_vgmstream_frame_size(VGMSTREAM * vgmstream) {
         case coding_NGC_AFC:
             return 9;
         case coding_PSX:
+        case coding_PSX_badflags:
         case coding_invert_PSX:
             return 16;
 		case coding_XA:
@@ -629,6 +631,13 @@ void decode_vgmstream(VGMSTREAM * vgmstream, int samples_written, int samples_to
                         samples_to_do);
             }
             break;
+        case coding_PSX_badflags:
+            for (chan=0;chan<vgmstream->channels;chan++) {
+                decode_psx_badflags(&vgmstream->ch[chan],buffer+samples_written*vgmstream->channels+chan,
+                        vgmstream->channels,vgmstream->samples_into_block,
+                        samples_to_do);
+            }
+            break;
         case coding_invert_PSX:
             for (chan=0;chan<vgmstream->channels;chan++) {
                 decode_invert_psx(&vgmstream->ch[chan],buffer+samples_written*vgmstream->channels+chan,
@@ -777,7 +786,8 @@ int vgmstream_do_loop(VGMSTREAM * vgmstream) {
                     vgmstream->meta_type == meta_DSP_RS03 ||
                     vgmstream->meta_type == meta_DSP_CSTR || 
 					vgmstream->coding_type == coding_PSX ||
-                    vgmstream->coding_type == coding_invert_PSX) {
+                    vgmstream->coding_type == coding_invert_PSX ||
+                    vgmstream->coding_type == coding_PSX_badflags) {
                 int i;
                 for (i=0;i<vgmstream->channels;i++) {
                     vgmstream->loop_ch[i].adpcm_history1_16 = vgmstream->ch[i].adpcm_history1_16;
@@ -921,6 +931,9 @@ void describe_vgmstream(VGMSTREAM * vgmstream, char * desc, int length) {
         case coding_PSX:
             snprintf(temp,TEMPSIZE,"Playstation 4-bit ADPCM");
             break;
+        case coding_PSX_badflags:
+            snprintf(temp,TEMPSIZE,"Playstation 4-bit ADPCM with bad flags");
+            break;
         case coding_invert_PSX:
             snprintf(temp,TEMPSIZE,"Inverted (?) Playstation 4-bit ADPCM");
             break;
diff --git a/src/vgmstream.h b/src/vgmstream.h
index cf07c64d..8863e167 100644
--- a/src/vgmstream.h
+++ b/src/vgmstream.h
@@ -44,6 +44,7 @@ typedef enum {
     coding_NGC_AFC,         /* NGC ADPCM, called AFC */
 	coding_PSX,				/* PSX & PS2 ADPCM */
     coding_invert_PSX,      /* PSX ADPCM with first byte of frame inverted */
+    coding_PSX_badflags,    /* with garbage in the flags byte */
 	coding_XA,				/* PSX CD-XA */
 	coding_XBOX,			/* XBOX IMA */
 	coding_EAXA,			/* EA/XA ADPCM */