audio/mp3: Move main_data_* to Go

audio/mp3/decode_notjs.go

@@ -60,19 +60,6 @@ func Get_Byte() C.unsigned {
 	return C.unsigned(b)
 }
 
-//export Get_Bytes
-func Get_Bytes(num C.unsigned, data *C.unsigned) C.unsigned {
-	s := C.unsigned(0)
-	for i := 0; i < int(num); i++ {
-		v := Get_Byte()
-		if v == eof {
-			return eof
-		}
-		*(*C.unsigned)(unsafe.Pointer(uintptr(unsafe.Pointer(data)) + uintptr(i)*unsafe.Sizeof(s))) = v
-	}
-	return C.OK
-}
-
 func getBytes(num int) ([]int, error) {
 	r := make([]int, num)
 	for i := 0; i < num; i++ {

audio/mp3/maindata.go

@@ -0,0 +1,137 @@
+// 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"
+import "C"
+
+import (
+	"fmt"
+)
+
+/* Bit reservoir for main data */
+type mainData struct {
+	// Large static data
+	vec [2 * 1024]int
+	// Pointer into the reservoir
+	ptr []int
+	// Index into the current byte(0-7)
+	idx int
+	// Number of bytes in reservoir(0-1024)
+	top int
+
+	pos int
+}
+
+var theMainData mainData
+
+//export Get_Main_Data
+func Get_Main_Data(size C.unsigned, begin C.unsigned) C.int {
+	if size > 1500 {
+		g_error = fmt.Errorf("size = %d", size)
+	}
+	/* Check that there's data available from previous frames if needed */
+	if int(begin) > theMainData.top {
+		// No,there is not,so we skip decoding this frame,but we have to
+		// read the main_data bits from the bitstream in case they are needed
+		// for decoding the next frame.
+		b, err := getBytes(int(size))
+		if err != nil {
+			g_error = err
+			return C.ERROR
+		}
+		copy(theMainData.vec[theMainData.top:], b)
+		/* Set up pointers */
+		theMainData.ptr = theMainData.vec[0:]
+		theMainData.pos = 0
+		theMainData.idx = 0
+		theMainData.top += int(size)
+		return C.ERROR
+	}
+	/* Copy data from previous frames */
+	for i := 0; i < int(begin); i++ {
+		theMainData.vec[i] = theMainData.vec[theMainData.top-int(begin)+i]
+	}
+	/* Read the main_data from file */
+	b, err := getBytes(int(size))
+	if err != nil {
+		g_error = err
+		return C.ERROR
+	}
+	copy(theMainData.vec[begin:], b)
+	/* Set up pointers */
+	theMainData.ptr = theMainData.vec[0:]
+	theMainData.pos = 0
+	theMainData.idx = 0
+	theMainData.top = int(begin) + int(size)
+	return C.OK
+}
+
+//export Get_Main_Bit
+func Get_Main_Bit() C.unsigned {
+	tmp := uint(theMainData.ptr[0]) >> (7 - uint(theMainData.idx))
+	tmp &= 0x01
+	theMainData.ptr = theMainData.ptr[(theMainData.idx+1)>>3:]
+	theMainData.pos += (theMainData.idx + 1) >> 3
+	theMainData.idx = (theMainData.idx + 1) & 0x07
+	return C.unsigned(tmp)
+}
+
+//export Get_Main_Bits
+func Get_Main_Bits(num C.unsigned) C.unsigned {
+	if num == 0 {
+		return 0
+	}
+	/* Form a word of the next four bytes */
+	b := make([]int, 4)
+	for i := range b {
+		if len(theMainData.ptr) > i {
+			b[i] = theMainData.ptr[i]
+		}
+	}
+	tmp := (uint32(b[0]) << 24) | (uint32(b[1]) << 16) | (uint32(b[2]) << 8) | (uint32(b[3]) << 0)
+
+	/* Remove bits already used */
+	tmp = tmp << uint(theMainData.idx)
+
+	/* Remove bits after the desired bits */
+	tmp = tmp >> (32 - num)
+
+	/* Update pointers */
+	theMainData.ptr = theMainData.ptr[(theMainData.idx+int(num))>>3:]
+	theMainData.pos += (theMainData.idx + int(num)) >> 3
+	theMainData.idx = (theMainData.idx + int(num)) & 0x07
+
+	/* Done */
+	return C.unsigned(tmp)
+}
+
+//export Get_Main_Pos
+func Get_Main_Pos() C.unsigned {
+	pos := theMainData.pos
+	pos *= 8               /* Multiply by 8 to get number of bits */
+	pos += theMainData.idx /* Add current bit index */
+	return C.unsigned(pos)
+}
+
+//export Set_Main_Pos
+func Set_Main_Pos(bit_pos C.unsigned) C.int {
+	theMainData.ptr = theMainData.vec[bit_pos>>3:]
+	theMainData.pos = int(bit_pos) >> 3
+	theMainData.idx = int(bit_pos) & 0x7
+	return C.OK
+}

audio/mp3/pdmp3.c

@@ -109,14 +109,10 @@ static void dmp_samples(t_mpeg1_main_data *md,int gr,int ch,int type);
 #define dmp_samples(...) do{}while(0)
 #endif
 
-static int Get_Main_Data(unsigned main_data_size,unsigned main_data_begin);
 static int Read_Audio_L3(void);
 static int Read_CRC(void);
 static int Read_Header(void) ;
 static int Read_Main_L3(void);
-static int Set_Main_Pos(unsigned bit_pos);
-
-static unsigned Get_Main_Pos(void);
 
 static void audio_write(unsigned *samples,unsigned nsamples,int sample_rate);
 static void audio_write_raw(unsigned *samples,unsigned nsamples);
@@ -456,12 +452,7 @@ static const float ci[8]={-0.6,-0.535,-0.33,-0.185,-0.095,-0.041,-0.0142,-0.0037
 };
 
 
-static unsigned hsynth_init = 1,synth_init = 1,
+static unsigned hsynth_init = 1,synth_init = 1;
-  /* Bit reservoir for main data */
-  g_main_data_vec[2*1024],/* Large static data */
-  *g_main_data_ptr,/* Pointer into the reservoir */
-  g_main_data_idx,/* Index into the current byte(0-7) */
-  g_main_data_top = 0;/* Number of bytes in reservoir(0-1024) */
 
 /* Scale factor band indices
  *
@@ -659,43 +650,6 @@ int Decode_L3(void){
   return(OK);   /* Done */
 }
 
-/** Description: This function assembles the main data buffer with data from
-*              this frame and the previous two frames into a local buffer
-*              used by the Get_Main_Bits function.
-* Parameters: main_data_begin indicates how many bytes from previous
-*             frames that should be used. main_data_size indicates the number
-*             of data bytes in this frame.
-* Return value: Status
-* Author: Krister Lagerström(krister@kmlager.com) **/
-static int Get_Main_Data(unsigned main_data_size,unsigned main_data_begin){
-  int i,start_pos;
-
-  if(main_data_size > 1500) ERR("main_data_size = %d\n",main_data_size);
-  /* Check that there's data available from previous frames if needed */
-  if(main_data_begin > g_main_data_top) {
-    /* No,there is not,so we skip decoding this frame,but we have to
-     * read the main_data bits from the bitstream in case they are needed
-     * for decoding the next frame. */
-   (void) Get_Bytes(main_data_size,&(g_main_data_vec[g_main_data_top]));
-    /* Set up pointers */
-    g_main_data_ptr = &(g_main_data_vec[0]);
-    g_main_data_idx = 0;
-    g_main_data_top += main_data_size;
-    return(ERROR);    /* This frame cannot be decoded! */
-  }
-  for(i = 0; i < main_data_begin; i++) {  /* Copy data from previous frames */
-    g_main_data_vec[i] = g_main_data_vec[g_main_data_top - main_data_begin + i];
-  }
-  start_pos = Get_Filepos();
-  /* Read the main_data from file */
- (void) Get_Bytes(main_data_size,&(g_main_data_vec[main_data_begin]));
-  /* Set up pointers */
-  g_main_data_ptr = &(g_main_data_vec[0]);
-  g_main_data_idx = 0;
-  g_main_data_top = main_data_begin + main_data_size;
-  return(OK);  /* Done */
-}
-
 /**Description: Reads audio and main data from bitstream into a buffer. main
 *  data is taken from this frame and up to 2 previous frames.
 * Parameters: None
@@ -1013,77 +967,6 @@ static int Read_Main_L3(void){
   return(OK);  /* Done */
 }
 
-/**Description: sets position of next bit to be read from main data bitstream.
-* Parameters: Bit position. 0 = start,8 = start of byte 1,etc.
-* Return value: OK or ERROR if bit_pos is past end of main data for this frame.
-* Author: Krister Lagerström(krister@kmlager.com) **/
-static int Set_Main_Pos(unsigned bit_pos){
-
-  g_main_data_ptr = &(g_main_data_vec[bit_pos >> 3]);
-  g_main_data_idx = bit_pos & 0x7;
-
-  return(OK);
-
-}
-
-/**Description: gets one bit from the local buffer which contains main_data.
-* Parameters: None
-* Return value: The bit is returned in the LSB of the return value.
-* Author: Krister Lagerström(krister@kmlager.com) **/
-unsigned Get_Main_Bit(void){
-  unsigned tmp;
-
-  tmp = g_main_data_ptr[0] >>(7 - g_main_data_idx);
-  tmp &= 0x01;
-  g_main_data_ptr +=(g_main_data_idx + 1) >> 3;
-  g_main_data_idx =(g_main_data_idx + 1) & 0x07;
-  return(tmp);  /* Done */
-}
-
-/**Description: reads 'number_of_bits' from local buffer containing main_data.
-* Parameters: number_of_bits to read(max 24)
-* Return value: The bits are returned in the LSB of the return value.
-*
-******************************************************************************/
-unsigned Get_Main_Bits(unsigned number_of_bits){
-  unsigned tmp;
-
-
-  if(number_of_bits == 0) return(0);
-
-  /* Form a word of the next four bytes */
-  tmp =(g_main_data_ptr[0] << 24) |(g_main_data_ptr[1] << 16) |
-       (g_main_data_ptr[2] <<  8) |(g_main_data_ptr[3] <<  0);
-
-  /* Remove bits already used */
-  tmp = tmp << g_main_data_idx;
-
-  /* Remove bits after the desired bits */
-  tmp = tmp >>(32 - number_of_bits);
-
-  /* Update pointers */
-  g_main_data_ptr +=(g_main_data_idx + number_of_bits) >> 3;
-  g_main_data_idx =(g_main_data_idx + number_of_bits) & 0x07;
-
-  /* Done */
-  return(tmp);
-
-}
-
-/**Description: returns pos. of next bit to be read from main data bitstream.
-* Parameters: None
-* Return value: Bit position.
-* Author: Krister Lagerström(krister@kmlager.com) **/
-static unsigned Get_Main_Pos(void){
-  unsigned pos;
-  
-  pos =((size_t) g_main_data_ptr) -((size_t) &(g_main_data_vec[0]));
-  pos /= 4; /* Divide by four to get number of bytes */
-  pos *= 8;    /* Multiply by 8 to get number of bits */
-  pos += g_main_data_idx;  /* Add current bit index */
-  return(pos);
-}
-
 /**Description: TBD
 * Parameters: TBD
 * Return value: TBD
@@ -1099,7 +982,7 @@ static void Error(const char *s,int e){
 * Author: Krister Lagerström(krister@kmlager.com) **/
 static void Decode_L3_Init_Song(void){
   hsynth_init = synth_init = 1;
-  g_main_data_top = 0; /* Clear bit reservoir */
+  //g_main_data_top = 0; /* Clear bit reservoir */
 }
 
 /**Description: Does inverse modified DCT and windowing.

audio/mp3/pdmp3.h

@@ -21,8 +21,14 @@ int Decode_L3(void);
 int Read_Frame(void);
 size_t writeToWriter(void* data, int size);
 
+int Get_Main_Data(unsigned main_data_size,unsigned main_data_begin);
 unsigned Get_Main_Bit(void);
 unsigned Get_Main_Bits(unsigned number_of_bits);
+unsigned Get_Main_Pos(void);
+int Set_Main_Pos(unsigned bit_pos);
+unsigned Get_Main_Bit(void);
+unsigned Get_Main_Bits(unsigned number_of_bits);
+
 void Get_Sideinfo(unsigned sideinfo_size);
 unsigned Get_Side_Bits(unsigned number_of_bits);