Tremor on Mona のデバッグ

まずは Linux 上での動きを見る。

svn checkout

svn co  -r13614 http://svn.xiph.org/trunk/Tremor tremor-test

Makefile

TARGET  = tremor-test

SOURCES =    \
main.c       \
bitwise.c    \
block.c      \
codebook.c   \
floor0.c     \
floor1.c     \
framing.c    \
info.c       \
mapping0.c   \
mdct.c       \
registry.c   \
res012.c     \
sharedbook.c \
synthesis.c  \
vorbisfile.c \
window.c


CFLAGS = -g -idirafter . -Wall

OBJECTS = $(SOURCES:.c=.o)

all : $(TARGET)

$(TARGET): $(OBJECTS)
$(CC) $(OBJECTS) -o $(TARGET)

.SUFFIXES: .c .o
.c.o:
$(CC) $(CFLAGS) $(INCLUDE) -c $< -o $@

depend:
$(CC) -MM $(INCLUDE) $(CFLAGS) $(SOURCES) > dependencies

clean :
rm -f $(OBJECTS) $(TARGET)

-include dependencies

test code

#include <stdio.h>
#include <ivorbisfile.h>

int main(int ac,char **av) {
    OggVorbis_File vf;
    FILE* fp = fopen("./A.OGG", "rb");
    if (NULL == fp) {
        fprintf(stderr, "file open error\n");
        return -1;
    }
    if (ov_open(fp, &vf, NULL, 0) < 0) {
        fprintf(stderr,"Input does not appear to be an Ogg bitstream.\n");
        return -1;
    }

    char **ptr=ov_comment(&vf,-1)->user_comments;
    vorbis_info *vi=ov_info(&vf,-1);
    while(*ptr){
        fprintf(stderr, "%s\n",*ptr);
        ++ptr;
    }
    fprintf(stderr, "\nBitstream is %d channel, %ldHz\n", vi->channels, vi->rate);
    fprintf(stderr, "\nDecoded length: %ld samples\n",
            (long)ov_pcm_total(&vf, -1));
    fprintf(stderr, "Encoded by: %s\n\n", ov_comment(&vf, -1)->vendor);
    return 0;
}

execute

sewashi% ./tremor-test
TITLE=Lepidoptera
ARTIST=Epoq
ALBUM=Kahvi Collective
DATE=2002
COMMENT=http://www.kahvi.org

Bitstream is 2 channel, 44100Hz

Decoded length: 13343346 samples
Encoded by: Xiph.Org libVorbis I 20020717

ふむ。うまく動いています。
全く同じコードを Mona で動かすと。 ov_open が OV_EREAD が返ります。

fseek ?

.mjt さんに fseek かもねと言われていたので調べる。
Linux と Mona で発行された fseek を比べる。

static int _fseek64_wrap(FILE *f,ogg_int64_t off,int whence){
  if(f==NULL)return(-1);
  int ret = fseek(f,off,whence);
  printf("fseek off=%d whence=%d ret=%d\n", off & 0xffffffff, whence, ret);
  return ret;
}

Linux上の fseek

fseek off=0 whence=0 ret=1
fseek off=0 whence=0 ret=2
fseek off=4356968 whence=0 ret=0
fseek off=4355944 whence=0 ret=0
fseek off=4354920 whence=0 ret=0
fseek off=4355037 whence=0 ret=0
fseek off=4355037 whence=0 ret=0
fseek off=4355038 whence=0 ret=0
fseek off=4422 whence=0 ret=0
fseek off=4357992 whence=0 ret=0
fseek off=4356968 whence=0 ret=0
fseek off=4355944 whence=0 ret=0
fseek off=4354920 whence=0 ret=0
fseek off=4355037 whence=0 ret=0
fseek off=0 whence=0 ret=0

Mona上の fseek

fseek off=0 whence=0 ret=1
fseek off=0 whence=0 ret=2
fseek off=4356968 whence=0 ret=0
fseek off=4355944 whence=0 ret=0
fseek off=4354920 whence=0 ret=0
fseek off=4355037 whence=0 ret=0
fseek off=4355037 whence=0 ret=0
fseek off=4355038 whence=0 ret=0

どうも fseek ではなさそうだ。

ドキュメント

んー。しょうがないドキュメント読むか。（先に読めよ）。

OV_EREAD - A read from media returned an error.

メディアエラーではないのは明らかなので深追いするしかなさそう。
途中までは read 出来ている気配なので fread を trace してみるか。

fread

Linux

sewashi% ./tremor-test
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=907
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=907
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=906
fread 1 1024 ret=0
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=907
fread 1 1024 ret=1024

Mona

fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=907
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=907
fread 1 1024 ret=1024
fread 1 1024 ret=1024
fread 1 1024 ret=906
fread 1 1024 ret=-1

結論

ファイルが読めないときに、fread が返す値が違う。
次の日記に続く。