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audio/mp3: Move Read_Frame to Go

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This commit is contained in:
Hajime Hoshi 2017-06-17 02:43:13 +09:00
parent b08897a4e5
commit 73190062da
4 changed files with 64 additions and 90 deletions
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29
audio/mp3/decode_notjs.go
View File

@ -37,29 +37,6 @@ var (
writer io.Writer
)
//export Read_CRC
func Read_CRC() C.int {
buf := make([]int, 2)
n := 0
var err error
for n < 2 && err == nil {
nn, err2 := getBytes(buf[n:])
n += nn
err = err2
}
if err == io.EOF {
if n < 2 {
return C.ERROR
}
return C.OK
}
if err != nil {
g_error = err
return C.ERROR
}
return C.OK
}
func getByte() (uint8, error) {
for len(readerCache) == 0 && !readerEOF {
buf := make([]uint8, 4096)
@ -117,13 +94,17 @@ func decode(r io.Reader, w io.Writer) error {
reader = r
writer = w
for Get_Filepos() != eof {
if C.Read_Frame() == C.OK {
err := readFrame()
if err == nil {
C.Decode_L3()
continue
}
if Get_Filepos() == eof {
break
}
if err != nil {
return err
}
return errors.New("mp3: not enough maindata to decode frame")
}
return g_error

45
audio/mp3/pdmp3.c
View File

@ -204,43 +204,6 @@ int Decode_L3(void){
return(OK); /* Done */
}
/**Description: Search for next frame and read it into buffer. Main data in
this frame is saved for two frames since it might be needed by them.
* Parameters: None
* Return value: OK if a frame is successfully read,ERROR otherwise.
* Author: Krister Lagerström(krister@kmlager.com) **/
int Read_Frame(void){
unsigned first = 0;
if(Get_Filepos() == 0) Decode_L3_Init_Song();
/* Try to find the next frame in the bitstream and decode it */
if(Read_Header() != OK) return(ERROR);
#ifdef DEBUG
{ static int framenum = 0;
printf("\nFrame %d\n",framenum++);
dmp_fr(&g_frame_header);
}
DBG("Starting decode,Layer: %d,Rate: %6d,Sfreq: %05d",
g_frame_header.layer,
g_mpeg1_bitrates[g_frame_header.layer - 1][g_frame_header.bitrate_index],
g_sampling_frequency[g_frame_header.sampling_frequency]);
#endif
/* Get CRC word if present */
if((g_frame_header.protection_bit==0)&&(Read_CRC()!=OK)) return(ERROR);
if(g_frame_header.layer == 3) { /* Get audio data */
Read_Audio_L3(); /* Get side info */
dmp_si(&g_frame_header,&g_side_info); /* DEBUG */
/* If there's not enough main data in the bit reservoir,
* signal to calling function so that decoding isn't done! */
/* Get main data(scalefactors and Huffman coded frequency data) */
if(Read_Main_L3() != OK) return(ERROR);
}else{
ERR("Only layer 3(!= %d) is supported!\n",g_frame_header.layer);
return(ERROR);
}
return(OK);
}
/**Description: TBD
* Parameters: TBD
* Return value: TBD
@ -250,14 +213,6 @@ static void Error(const char *s,int e){
exit(e);
}
/**Description: reinit decoder before playing new song,or seeking current song.
* Parameters: None
* Return value: None
* Author: Krister Lagerström(krister@kmlager.com) **/
static void Decode_L3_Init_Song(void){
synth_init = 1;
}
/**Description: output audio data
* Parameters: Pointers to the samples,the number of samples
* Return value: None

1
audio/mp3/pdmp3.h
View File

@ -86,7 +86,6 @@ t_sf_band_indices;
unsigned Get_Filepos(void);
int Decode_L3(void);
int Read_Frame(void);
size_t writeToWriter(void* data, int size);
unsigned Get_Main_Pos(void);

79
audio/mp3/read.go
View File

@ -28,6 +28,52 @@ import (
"io"
)
func readCRC() error {
buf := make([]int, 2)
n := 0
var err error
for n < 2 && err == nil {
nn, err2 := getBytes(buf[n:])
n += nn
err = err2
}
if err == io.EOF {
if n < 2 {
return fmt.Errorf("mp3: unexpected EOF at readCRC")
}
return nil
}
if err != nil {
return err
}
return nil
}
func readFrame() error {
if err := readHeader(); err != nil {
return err
}
/* Get CRC word if present */
if C.g_frame_header.protection_bit == 0 {
if err := readCRC(); err != nil {
return err
}
}
if C.g_frame_header.layer == 3 { /* Get audio data */
Read_Audio_L3() /* Get side info */
/* If there's not enough main data in the bit reservoir,
* signal to calling function so that decoding isn't done! */
/* Get main data(scalefactors and Huffman coded frequency data) */
if Read_Main_L3() != C.OK {
// TODO: Fix this
return fmt.Errorf("mp3: Read_Main_L3")
}
} else {
return fmt.Errorf("mp3: Only layer 3(!= %d) is supported!", C.g_frame_header.layer)
}
return nil
}
func isHeader(header uint32) bool {
const C_SYNC = 0xffe00000
if (header & C_SYNC) != C_SYNC {
@ -44,8 +90,7 @@ func isHeader(header uint32) bool {
return true
}
//export Read_Header
func Read_Header() C.int {
func readHeader() error {
/* Get the next four bytes from the bitstream */
buf := make([]int, 4)
n := 0
@ -56,10 +101,10 @@ func Read_Header() C.int {
err = err2
}
if n < 4 {
if err != io.EOF {
g_error = err
if err == io.EOF {
return fmt.Errorf("mp3: unexpected EOF at readHeader")
}
return C.ERROR
return err
}
b1 := uint32(buf[0])
b2 := uint32(buf[1])
@ -75,10 +120,10 @@ func Read_Header() C.int {
/* Get one new byte from the bitstream */
b, err := getByte()
if err != nil {
if err != io.EOF {
g_error = err
if err == io.EOF {
return fmt.Errorf("mp3: unexpected EOF at readHeader")
}
return C.ERROR
return err
}
b4 = uint32(b)
header = (b1 << 24) | (b2 << 16) | (b3 << 8) | (b4 << 0)
@ -100,33 +145,27 @@ func Read_Header() C.int {
C.g_frame_header.emphasis = C.uint((header & 0x00000003) >> 0)
/* Check for invalid values and impossible combinations */
if C.g_frame_header.id != 3 {
g_error = fmt.Errorf("mp3: ID must be 3\nHeader word is 0x%08x at file pos %d",
return fmt.Errorf("mp3: ID must be 3\nHeader word is 0x%08x at file pos %d",
header, C.Get_Filepos())
return C.ERROR
}
if C.g_frame_header.bitrate_index == 0 {
g_error = fmt.Errorf("mp3: Free bitrate format NIY!\nHeader word is 0x%08x at file pos %d",
return fmt.Errorf("mp3: Free bitrate format NIY!\nHeader word is 0x%08x at file pos %d",
header, Get_Filepos())
return C.ERROR
//exit(1);
}
if C.g_frame_header.bitrate_index == 15 {
g_error = fmt.Errorf("mp3: bitrate_index = 15 is invalid!\nHeader word is 0x%08x at file pos %d",
return fmt.Errorf("mp3: bitrate_index = 15 is invalid!\nHeader word is 0x%08x at file pos %d",
header, Get_Filepos())
return C.ERROR
}
if C.g_frame_header.sampling_frequency == 3 {
g_error = fmt.Errorf("mp3: sampling_frequency = 3 is invalid! Header word is 0x%08x at file pos %d",
return fmt.Errorf("mp3: sampling_frequency = 3 is invalid! Header word is 0x%08x at file pos %d",
header, Get_Filepos())
return C.ERROR
}
if C.g_frame_header.layer == 0 {
g_error = fmt.Errorf("mp3: layer = 0 is invalid! Header word is 0x%08x at file pos %d",
return fmt.Errorf("mp3: layer = 0 is invalid! Header word is 0x%08x at file pos %d",
header, Get_Filepos())
return C.ERROR
}
C.g_frame_header.layer = 4 - C.g_frame_header.layer
return C.OK
return nil
}
func readHuffman(part_2_start, gr, ch int) error {