audio/mp3: Move L3_Hybrid_Synthesis to Go

audio/mp3/imdct.go

@@ -17,17 +17,9 @@
 package mp3
 
 // #include "pdmp3.h"
-//
-// static float getFloatFromArray(float* arr, int index) {
-//   return arr[index];
-// }
-//
-// static void setFloatToArray(float* arr, int index, float value) {
-//   arr[index] = value;
-// }
 import "C"
 
-var imdctWin = [4][36]float32{
+var imdctWinData = [4][36]float32{
 	{
 		0.043619, 0.130526, 0.216440, 0.300706, 0.382683, 0.461749,
 		0.537300, 0.608761, 0.675590, 0.737277, 0.793353, 0.843391,
@@ -236,32 +228,28 @@ var cos_N36 = [18][36]float32{
 	},
 }
 
-//export IMDCT_Win
-func IMDCT_Win(in *C.float, out *C.float, blockType C.unsigned) {
-	for i := 0; i < 36; i++ {
-		C.setFloatToArray(out, C.int(i), 0)
-	}
+func imdctWin(in []float32, blockType int) []float32 {
+	out := make([]float32, 36)
 	if blockType == 2 {
 		N := 12
 		for i := 0; i < 3; i++ {
 			for p := 0; p < N; p++ {
 				sum := float32(0.0)
 				for m := 0; m < N/2; m++ {
-					sum += float32(C.getFloatFromArray(in, C.int(i+3*m))) * cos_N12[m][p]
+					sum += in[i+3*m] * cos_N12[m][p]
 				}
-				v := float32(C.getFloatFromArray(out, C.int(6*i+p+6)))
-				v += sum * imdctWin[blockType][p]
-				C.setFloatToArray(out, C.int(6*i+p+6), C.float(v))
+				out[6*i+p+6] += sum * imdctWinData[blockType][p]
 			}
 		}
-		return
+		return out
 	}
 	N := 36
 	for p := 0; p < N; p++ {
 		sum := float32(0.0)
 		for m := 0; m < N/2; m++ {
-			sum += float32(C.getFloatFromArray(in, C.int(m))) * cos_N36[m][p]
+			sum += in[m] * cos_N36[m][p]
 		}
-		C.setFloatToArray(out, C.int(p), C.float(sum*imdctWin[blockType][p]))
+		out[p] = sum * imdctWinData[blockType][p]
 	}
+	return out
 }

audio/mp3/l3.go

@@ -0,0 +1,48 @@
+// Copyright 2017 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !js
+
+package mp3
+
+// #include "pdmp3.h"
+//
+// extern unsigned hsynth_init, synth_init;
+// extern t_mpeg1_main_data g_main_data;
+// extern t_mpeg1_side_info g_side_info;
+import "C"
+
+var store = [2][32][18]float32{}
+
+//export L3_Hybrid_Synthesis
+func L3_Hybrid_Synthesis(gr C.unsigned, ch C.unsigned) {
+	for sb := 0; sb < 32; sb++ { /* Loop through all 32 subbands */
+		/* Determine blocktype for this subband */
+		bt := 0
+		if (C.g_side_info.win_switch_flag[gr][ch] == 1) &&
+			(C.g_side_info.mixed_block_flag[gr][ch] == 1) && (sb < 2) {
+			bt = int(C.g_side_info.block_type[gr][ch])
+		}
+		/* Do the inverse modified DCT and windowing */
+		in := make([]float32, 18)
+		for i := range in {
+			in[i] = float32(C.g_main_data.is[gr][ch][sb*18+i])
+		}
+		rawout := imdctWin(in, bt)
+		for i := 0; i < 18; i++ { /* Overlapp add with stored vector into main_data vector */
+			C.g_main_data.is[gr][ch][sb*18+i] = C.float(rawout[i] + store[ch][sb][i])
+			store[ch][sb][i] = rawout[i+18]
+		}
+	}
+}

audio/mp3/pdmp3.c

@@ -46,7 +46,6 @@ static void Decode_L3_Init_Song(void);
 static void Error(const char *s,int e);
 static void L3_Antialias(unsigned gr,unsigned ch);
 static void L3_Frequency_Inversion(unsigned gr,unsigned ch);
-static void L3_Hybrid_Synthesis(unsigned gr,unsigned ch);
 static void L3_Requantize(unsigned gr,unsigned ch);
 static void L3_Reorder(unsigned gr,unsigned ch);
 static void L3_Stereo(unsigned gr);
@@ -216,8 +215,7 @@ static const float powtab34[32] = {
 //},g_synth_n_win[64][32]={
 };
 
-
-static unsigned hsynth_init = 1,synth_init = 1;
+unsigned synth_init = 1;
 
 /* Scale factor band indices
  *
@@ -557,7 +555,7 @@ static void Error(const char *s,int e){
 * Return value: None
 * Author: Krister Lagerström(krister@kmlager.com) **/
 static void Decode_L3_Init_Song(void){
-  hsynth_init = synth_init = 1;
+  synth_init = 1;
 }
 
 /**Description: TBD
@@ -606,40 +604,6 @@ static void L3_Frequency_Inversion(unsigned gr,unsigned ch){
   return; /* Done */
 }
 
-/**Description: TBD
-* Parameters: TBD
-* Return value: TBD
-* Author: Krister Lagerström(krister@kmlager.com) **/
-static void L3_Hybrid_Synthesis(unsigned gr,unsigned ch){
-  unsigned sb,i,j,bt;
-  float rawout[36];
-  static float store[2][32][18];
-
-  if(hsynth_init) { /* Clear stored samples vector. OPT? use memset */
-    for(j = 0; j < 2; j++) {
-      for(sb = 0; sb < 32; sb++) {
-        for(i = 0; i < 18; i++) {
-          store[j][sb][i] = 0.0;
-        }
-      }
-    }
-    hsynth_init = 0;
-  } /* end if(hsynth_init) */
-  for(sb = 0; sb < 32; sb++) { /* Loop through all 32 subbands */
-    /* Determine blocktype for this subband */
-    bt =((g_side_info.win_switch_flag[gr][ch] == 1) &&
-     (g_side_info.mixed_block_flag[gr][ch] == 1) &&(sb < 2))
-      ? 0 : g_side_info.block_type[gr][ch];
-    /* Do the inverse modified DCT and windowing */
-    IMDCT_Win(&(g_main_data.is[gr][ch][sb*18]),rawout,bt);
-    for(i = 0; i < 18; i++) { /* Overlapp add with stored vector into main_data vector */
-      g_main_data.is[gr][ch][sb*18 + i] = rawout[i] + store[ch][sb][i];
-      store[ch][sb][i] = rawout[i + 18];
-    } /* end for(i... */
-  } /* end for(sb... */
-  return; /* Done */
-}
-
 /**Description: TBD
 * Parameters: TBD
 * Return value: TBD

audio/mp3/pdmp3.h

@@ -99,7 +99,7 @@ int Read_Audio_L3(void);
 static int Read_Header(void);
 void Read_Huffman(unsigned part_2_start,unsigned gr,unsigned ch);
 
-void IMDCT_Win(float* in, float* out,unsigned block_type);
+void L3_Hybrid_Synthesis(unsigned gr,unsigned ch);
 
 int Read_CRC(void);