From bdfe87c0f11c152e95cb9034d50cd97e94e7be72 Mon Sep 17 00:00:00 2001
From: Stepan Moskovchenko <stevenm@rockbox.org>
Date: Mon, 5 Nov 2007 05:35:10 +0000
Subject: MIDI: Make seeking neater by moving it into another file. Will be
 more useful later.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@15467 a1c6a512-1295-4272-9138-f99709370657
---
 apps/plugins/midi/midiplay.c  | 58 +++--------------------------------
 apps/plugins/midi/sequencer.c | 71 ++++++++++++++++++++++++++++++++++++++-----
 apps/plugins/midi/sequencer.h |  3 ++
 3 files changed, 70 insertions(+), 62 deletions(-)

diff --git a/apps/plugins/midi/midiplay.c b/apps/plugins/midi/midiplay.c
index c69c8b1ad6..cc8746308f 100644
--- a/apps/plugins/midi/midiplay.c
+++ b/apps/plugins/midi/midiplay.c
@@ -108,7 +108,6 @@ int numberOfSamples IBSS_ATTR; /* the number of samples in the current tick */
 int playingTime IBSS_ATTR;  /* How many seconds into the file have we been playing? */
 int samplesThisSecond IBSS_ATTR;    /* How many samples produced during this second so far? */
 
-
 long bpm IBSS_ATTR;
 
 int32_t gmbuf[BUF_SIZE*NBUF];
@@ -123,6 +122,7 @@ enum plugin_status plugin_start(struct plugin_api* api, void* parameter)
 {
     int retval = 0;
 
+
     PLUGIN_IRAM_INIT(api)
 
     rb = api;
@@ -317,66 +317,16 @@ static int midimain(void * filename)
                     /* Rewinding is tricky. Basically start the file over */
                     /* but run through the tracks without the synth running */
                     rb->pcm_play_stop();
-
-                    int desiredTime = playingTime - 5;  /* Rewind 5 sec */
-
-                    if(desiredTime < 0)
-                        desiredTime = 0;
-
-                    /* Set controllers to default values */
-                    resetControllers();
-
-                    /* Set the tempo to defalt */
-                    bpm=mf->div*1000000/tempo;
-                    numberOfSamples=SAMPLE_RATE/bpm;
-
-
-                    /* Reset the tracks to start */
-                    rewindFile();
-
-                    /* Reset the time counter to 0 */
-                    playingTime = 0;
-                    samplesThisSecond = 0;
-
-                    /* Quickly run through any initial things that occur before notes */
-                    do
-                    {
-                        notesUsed = 0;
-                        for(a=0; a<MAX_VOICES; a++)
-                            if(voices[a].isUsed == 1)
-                                notesUsed++;
-                        tick();
-                    } while(notesUsed == 0);
-
-                    /* Reset the time counter to 0 */
-                    playingTime = 0;
-                    samplesThisSecond = 0;
-
-
-
-                    /* Tick until goal is reached */
-                    while(playingTime < desiredTime)
-                        tick();
-
+                    seekBackward(5);
                     rb->pcm_play_data(&get_more, NULL, 0);
+
                     break;
                 }
 
                 case BTN_RIGHT:
                 {
-                    /* Skip 5 seconds forward */
-                    /* Skipping forward is easy */
-                    /* Should skip length be retrieved from the RB settings? */
-                    int samp = 5*SAMPLE_RATE;
-
-                    /* Have the issue where numberOfSamples changes within this tick */
-                    int tickCount = samp / numberOfSamples;
-                    int a=0;
-
                     rb->pcm_play_stop();
-
-                    for(a=0; a<tickCount; a++)
-                        tick();
+                    seekForward(5);
                     rb->pcm_play_data(&get_more, NULL, 0);
                     break;
                 }
diff --git a/apps/plugins/midi/sequencer.c b/apps/plugins/midi/sequencer.c
index b9cc83f9ad..4e6c15fba6 100644
--- a/apps/plugins/midi/sequencer.c
+++ b/apps/plugins/midi/sequencer.c
@@ -142,7 +142,6 @@ const uint32_t pitchTbl[] ICONST_ATTR={
 
 static void findDelta(struct SynthObject * so, int ch, int note)
 {
-
     struct GWaveform * wf = patchSet[chPat[ch]]->waveforms[patchSet[chPat[ch]]->noteTable[note]];
     so->wf=wf;
     unsigned int delta= 0;
@@ -152,14 +151,8 @@ static void findDelta(struct SynthObject * so, int ch, int note)
     so->delta = delta;
 }
 
-static inline void setPW(int ch, int msb, int lsb)
+static inline void computeDeltas(int ch)
 {
-    chPW[ch] = msb<<2|lsb>>5;
-
-    int totalBend = (chPW[ch]-256) * chPBDepth[ch];
-    chPBNoteOffset[ch] = totalBend >> 8;
-    chPBFractBend[ch] = pitchTbl[(totalBend & 0xFF) + 256];
-
     int a=0;
     for(a = 0; a<MAX_VOICES; a++)
     {
@@ -170,6 +163,17 @@ static inline void setPW(int ch, int msb, int lsb)
     }
 }
 
+static inline void setPW(int ch, int msb, int lsb)
+{
+    chPW[ch] = msb<<2|lsb>>5;
+
+    int totalBend = (chPW[ch]-256) * chPBDepth[ch];
+    chPBNoteOffset[ch] = totalBend >> 8;
+    chPBFractBend[ch] = pitchTbl[(totalBend & 0xFF) + 256];
+
+    computeDeltas(ch);
+}
+
 inline void pressNote(int ch, int note, int vol)
 {
     static int lastKill = 0;
@@ -376,7 +380,58 @@ void rewindFile(void)
     }
 }
 
+
 int tick(void) ICODE_ATTR;
+
+void seekBackward(int nsec)
+{
+    int notesUsed = 0, a=0;
+    int desiredTime = playingTime - nsec;  /* Rewind 5 sec */
+
+    if(desiredTime < 0)
+        desiredTime = 0;
+
+    /* Set controllers to default values */
+    resetControllers();
+
+    /* Set the tempo to defalt */
+    bpm=mf->div*1000000/tempo;
+    numberOfSamples=SAMPLE_RATE/bpm;
+
+
+    /* Reset the tracks to start */
+    rewindFile();
+
+    /* Reset the time counter to 0 */
+    playingTime = 0;
+    samplesThisSecond = 0;
+
+    /* Quickly run through any initial things that occur before notes */
+    do
+    {
+        notesUsed = 0;
+        for(a=0; a<MAX_VOICES; a++)
+            if(voices[a].isUsed == 1)
+                notesUsed++;
+        tick();
+    } while(notesUsed == 0);
+
+    /* Reset the time counter to 0 */
+    playingTime = 0;
+    samplesThisSecond = 0;
+
+    /* Tick until goal is reached */
+    while(playingTime < desiredTime)
+        tick();
+}
+
+
+void seekForward(int nsec)
+{
+    int desiredTime = playingTime + nsec;
+    while(tick() && playingTime < desiredTime);
+}
+
 int tick(void)
 {
     if(mf==NULL)
diff --git a/apps/plugins/midi/sequencer.h b/apps/plugins/midi/sequencer.h
index 8cb190442c..0c90d70604 100644
--- a/apps/plugins/midi/sequencer.h
+++ b/apps/plugins/midi/sequencer.h
@@ -23,5 +23,8 @@ int tick(void);
 void pressNote(int ch, int note, int vol);
 void rewindFile(void);
 
+void seekForward(int nSec);
+void seekBackward(int nSec);
+
 extern long tempo;
 
-- 
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