• bitwise.c
  • /********************************************************************
     *                                                                  *
     * THIS FILE IS PART OF THE Ogg CONTAINER SOURCE CODE.              *
     * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
     * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
     * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
     *                                                                  *
     * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2014             *
     * by the Xiph.Org Foundation http://www.xiph.org/                  *
     *                                                                  *
     ********************************************************************
    
      function: packing variable sized words into an octet stream
    
     ********************************************************************/
    
    /* We're 'LSb' endian; if we write a word but read individual bits,
       then we'll read the lsb first */
    
    #include <string.h>
    #include <stdlib.h>
    #include <limits.h>
    #include <ogg/ogg.h>
    
    #define BUFFER_INCREMENT 256
    
    static const unsigned long mask[]=
    {0x00000000,0x00000001,0x00000003,0x00000007,0x0000000f,
     0x0000001f,0x0000003f,0x0000007f,0x000000ff,0x000001ff,
     0x000003ff,0x000007ff,0x00000fff,0x00001fff,0x00003fff,
     0x00007fff,0x0000ffff,0x0001ffff,0x0003ffff,0x0007ffff,
     0x000fffff,0x001fffff,0x003fffff,0x007fffff,0x00ffffff,
     0x01ffffff,0x03ffffff,0x07ffffff,0x0fffffff,0x1fffffff,
     0x3fffffff,0x7fffffff,0xffffffff };
    
    static const unsigned int mask8B[]=
    {0x00,0x80,0xc0,0xe0,0xf0,0xf8,0xfc,0xfe,0xff};
    
    void oggpack_writeinit(oggpack_buffer *b){
      memset(b,0,sizeof(*b));
      b->ptr=b->buffer=_ogg_malloc(BUFFER_INCREMENT);
      b->buffer[0]='\0';
      b->storage=BUFFER_INCREMENT;
    }
    
    void oggpackB_writeinit(oggpack_buffer *b){
      oggpack_writeinit(b);
    }
    
    int oggpack_writecheck(oggpack_buffer *b){
      if(!b->ptr || !b->storage)return -1;
      return 0;
    }
    
    int oggpackB_writecheck(oggpack_buffer *b){
      return oggpack_writecheck(b);
    }
    
    void oggpack_writetrunc(oggpack_buffer *b,long bits){
      long bytes=bits>>3;
      if(b->ptr){
        bits-=bytes*8;
        b->ptr=b->buffer+bytes;
        b->endbit=bits;
        b->endbyte=bytes;
        *b->ptr&=mask[bits];
      }
    }
    
    void oggpackB_writetrunc(oggpack_buffer *b,long bits){
      long bytes=bits>>3;
      if(b->ptr){
        bits-=bytes*8;
        b->ptr=b->buffer+bytes;
        b->endbit=bits;
        b->endbyte=bytes;
        *b->ptr&=mask8B[bits];
      }
    }
    
    /* Takes only up to 32 bits. */
    void oggpack_write(oggpack_buffer *b,unsigned long value,int bits){
      if(bits<0 || bits>32) goto err;
      if(b->endbyte>=b->storage-4){
        void *ret;
        if(!b->ptr)return;
        if(b->storage>LONG_MAX-BUFFER_INCREMENT) goto err;
        ret=_ogg_realloc(b->buffer,b->storage+BUFFER_INCREMENT);
        if(!ret) goto err;
        b->buffer=ret;
        b->storage+=BUFFER_INCREMENT;
        b->ptr=b->buffer+b->endbyte;
      }
    
      value&=mask[bits];
      bits+=b->endbit;
    
      b->ptr[0]|=value<<b->endbit;
    
      if(bits>=8){
        b->ptr[1]=(unsigned char)(value>>(8-b->endbit));
        if(bits>=16){
          b->ptr[2]=(unsigned char)(value>>(16-b->endbit));
          if(bits>=24){
            b->ptr[3]=(unsigned char)(value>>(24-b->endbit));
            if(bits>=32){
              if(b->endbit)
                b->ptr[4]=(unsigned char)(value>>(32-b->endbit));
              else
                b->ptr[4]=0;
            }
          }
        }
      }
    
      b->endbyte+=bits/8;
      b->ptr+=bits/8;
      b->endbit=bits&7;
      return;
     err:
      oggpack_writeclear(b);
    }
    
    /* Takes only up to 32 bits. */
    void oggpackB_write(oggpack_buffer *b,unsigned long value,int bits){
      if(bits<0 || bits>32) goto err;
      if(b->endbyte>=b->storage-4){
        void *ret;
        if(!b->ptr)return;
        if(b->storage>LONG_MAX-BUFFER_INCREMENT) goto err;
        ret=_ogg_realloc(b->buffer,b->storage+BUFFER_INCREMENT);
        if(!ret) goto err;
        b->buffer=ret;
        b->storage+=BUFFER_INCREMENT;
        b->ptr=b->buffer+b->endbyte;
      }
    
      value=(value&mask[bits])<<(32-bits);
      bits+=b->endbit;
    
      b->ptr[0]|=value>>(24+b->endbit);
    
      if(bits>=8){
        b->ptr[1]=(unsigned char)(value>>(16+b->endbit));
        if(bits>=16){
          b->ptr[2]=(unsigned char)(value>>(8+b->endbit));
          if(bits>=24){
            b->ptr[3]=(unsigned char)(value>>(b->endbit));
            if(bits>=32){
              if(b->endbit)
                b->ptr[4]=(unsigned char)(value<<(8-b->endbit));
              else
                b->ptr[4]=0;
            }
          }
        }
      }
    
      b->endbyte+=bits/8;
      b->ptr+=bits/8;
      b->endbit=bits&7;
      return;
     err:
      oggpack_writeclear(b);
    }
    
    void oggpack_writealign(oggpack_buffer *b){
      int bits=8-b->endbit;
      if(bits<8)
        oggpack_write(b,0,bits);
    }
    
    void oggpackB_writealign(oggpack_buffer *b){
      int bits=8-b->endbit;
      if(bits<8)
        oggpackB_write(b,0,bits);
    }
    
    static void oggpack_writecopy_helper(oggpack_buffer *b,
                                         void *source,
                                         long bits,
                                         void (*w)(oggpack_buffer *,
                                                   unsigned long,
                                                   int),
                                         int msb){
      unsigned char *ptr=(unsigned char *)source;
    
      long bytes=bits/8;
      long pbytes=(b->endbit+bits)/8;
      bits-=bytes*8;
    
      /* expand storage up-front */
      if(b->endbyte+pbytes>=b->storage){
        void *ret;
        if(!b->ptr) goto err;
        if(b->storage>b->endbyte+pbytes+BUFFER_INCREMENT) goto err;
        b->storage=b->endbyte+pbytes+BUFFER_INCREMENT;
        ret=_ogg_realloc(b->buffer,b->storage);
        if(!ret) goto err;
        b->buffer=ret;
        b->ptr=b->buffer+b->endbyte;
      }
    
      /* copy whole octets */
      if(b->endbit){
        int i;
        /* unaligned copy.  Do it the hard way. */
        for(i=0;i<bytes;i++)
          w(b,(unsigned long)(ptr[i]),8);
      }else{
        /* aligned block copy */
        memmove(b->ptr,source,bytes);
        b->ptr+=bytes;
        b->endbyte+=bytes;
        *b->ptr=0;
      }
    
      /* copy trailing bits */
      if(bits){
        if(msb)
          w(b,(unsigned long)(ptr[bytes]>>(8-bits)),bits);
        else
          w(b,(unsigned long)(ptr[bytes]),bits);
      }
      return;
     err:
      oggpack_writeclear(b);
    }
    
    void oggpack_writecopy(oggpack_buffer *b,void *source,long bits){
      oggpack_writecopy_helper(b,source,bits,oggpack_write,0);
    }
    
    void oggpackB_writecopy(oggpack_buffer *b,void *source,long bits){
      oggpack_writecopy_helper(b,source,bits,oggpackB_write,1);
    }
    
    void oggpack_reset(oggpack_buffer *b){
      if(!b->ptr)return;
      b->ptr=b->buffer;
      b->buffer[0]=0;
      b->endbit=b->endbyte=0;
    }
    
    void oggpackB_reset(oggpack_buffer *b){
      oggpack_reset(b);
    }
    
    void oggpack_writeclear(oggpack_buffer *b){
      if(b->buffer)_ogg_free(b->buffer);
      memset(b,0,sizeof(*b));
    }
    
    void oggpackB_writeclear(oggpack_buffer *b){
      oggpack_writeclear(b);
    }
    
    void oggpack_readinit(oggpack_buffer *b,unsigned char *buf,int bytes){
      memset(b,0,sizeof(*b));
      b->buffer=b->ptr=buf;
      b->storage=bytes;
    }
    
    void oggpackB_readinit(oggpack_buffer *b,unsigned char *buf,int bytes){
      oggpack_readinit(b,buf,bytes);
    }
    
    /* Read in bits without advancing the bitptr; bits <= 32 */
    long oggpack_look(oggpack_buffer *b,int bits){
      unsigned long ret;
      unsigned long m;
    
      if(bits<0 || bits>32) return -1;
      m=mask[bits];
      bits+=b->endbit;
    
      if(b->endbyte >= b->storage-4){
        /* not the main path */
        if(b->endbyte > b->storage-((bits+7)>>3)) return -1;
        /* special case to avoid reading b->ptr[0], which might be past the end of
            the buffer; also skips some useless accounting */
        else if(!bits)return(0L);
      }
    
      ret=b->ptr[0]>>b->endbit;
      if(bits>8){
        ret|=b->ptr[1]<<(8-b->endbit);
        if(bits>16){
          ret|=b->ptr[2]<<(16-b->endbit);
          if(bits>24){
            ret|=b->ptr[3]<<(24-b->endbit);
            if(bits>32 && b->endbit)
              ret|=b->ptr[4]<<(32-b->endbit);
          }
        }
      }
      return(m&ret);
    }
    
    /* Read in bits without advancing the bitptr; bits <= 32 */
    long oggpackB_look(oggpack_buffer *b,int bits){
      unsigned long ret;
      int m=32-bits;
    
      if(m<0 || m>32) return -1;
      bits+=b->endbit;
    
      if(b->endbyte >= b->storage-4){
        /* not the main path */
        if(b->endbyte > b->storage-((bits+7)>>3)) return -1;
        /* special case to avoid reading b->ptr[0], which might be past the end of
            the buffer; also skips some useless accounting */
        else if(!bits)return(0L);
      }
    
      ret=b->ptr[0]<<(24+b->endbit);
      if(bits>8){
        ret|=b->ptr[1]<<(16+b->endbit);
        if(bits>16){
          ret|=b->ptr[2]<<(8+b->endbit);
          if(bits>24){
            ret|=b->ptr[3]<<(b->endbit);
            if(bits>32 && b->endbit)
              ret|=b->ptr[4]>>(8-b->endbit);
          }
        }
      }
      return ((ret&0xffffffff)>>(m>>1))>>((m+1)>>1);
    }
    
    long oggpack_look1(oggpack_buffer *b){
      if(b->endbyte>=b->storage)return(-1);
      return((b->ptr[0]>>b->endbit)&1);
    }
    
    long oggpackB_look1(oggpack_buffer *b){
      if(b->endbyte>=b->storage)return(-1);
      return((b->ptr[0]>>(7-b->endbit))&1);
    }
    
    void oggpack_adv(oggpack_buffer *b,int bits){
      bits+=b->endbit;
    
      if(b->endbyte > b->storage-((bits+7)>>3)) goto overflow;
    
      b->ptr+=bits/8;
      b->endbyte+=bits/8;
      b->endbit=bits&7;
      return;
    
     overflow:
      b->ptr=NULL;
      b->endbyte=b->storage;
      b->endbit=1;
    }
    
    void oggpackB_adv(oggpack_buffer *b,int bits){
      oggpack_adv(b,bits);
    }
    
    void oggpack_adv1(oggpack_buffer *b){
      if(++(b->endbit)>7){
        b->endbit=0;
        b->ptr++;
        b->endbyte++;
      }
    }
    
    void oggpackB_adv1(oggpack_buffer *b){
      oggpack_adv1(b);
    }
    
    /* bits <= 32 */
    long oggpack_read(oggpack_buffer *b,int bits){
      long ret;
      unsigned long m;
    
      if(bits<0 || bits>32) goto err;
      m=mask[bits];
      bits+=b->endbit;
    
      if(b->endbyte >= b->storage-4){
        /* not the main path */
        if(b->endbyte > b->storage-((bits+7)>>3)) goto overflow;
        /* special case to avoid reading b->ptr[0], which might be past the end of
            the buffer; also skips some useless accounting */
        else if(!bits)return(0L);
      }
    
      ret=b->ptr[0]>>b->endbit;
      if(bits>8){
        ret|=b->ptr[1]<<(8-b->endbit);
        if(bits>16){
          ret|=b->ptr[2]<<(16-b->endbit);
          if(bits>24){
            ret|=b->ptr[3]<<(24-b->endbit);
            if(bits>32 && b->endbit){
              ret|=b->ptr[4]<<(32-b->endbit);
            }
          }
        }
      }
      ret&=m;
      b->ptr+=bits/8;
      b->endbyte+=bits/8;
      b->endbit=bits&7;
      return ret;
    
     overflow:
     err:
      b->ptr=NULL;
      b->endbyte=b->storage;
      b->endbit=1;
      return -1L;
    }
    
    /* bits <= 32 */
    long oggpackB_read(oggpack_buffer *b,int bits){
      long ret;
      long m=32-bits;
    
      if(m<0 || m>32) goto err;
      bits+=b->endbit;
    
      if(b->endbyte+4>=b->storage){
        /* not the main path */
        if(b->endbyte > b->storage-((bits+7)>>3)) goto overflow;
        /* special case to avoid reading b->ptr[0], which might be past the end of
            the buffer; also skips some useless accounting */
        else if(!bits)return(0L);
      }
    
      ret=b->ptr[0]<<(24+b->endbit);
      if(bits>8){
        ret|=b->ptr[1]<<(16+b->endbit);
        if(bits>16){
          ret|=b->ptr[2]<<(8+b->endbit);
          if(bits>24){
            ret|=b->ptr[3]<<(b->endbit);
            if(bits>32 && b->endbit)
              ret|=b->ptr[4]>>(8-b->endbit);
          }
        }
      }
      ret=((ret&0xffffffffUL)>>(m>>1))>>((m+1)>>1);
    
      b->ptr+=bits/8;
      b->endbyte+=bits/8;
      b->endbit=bits&7;
      return ret;
    
     overflow:
     err:
      b->ptr=NULL;
      b->endbyte=b->storage;
      b->endbit=1;
      return -1L;
    }
    
    long oggpack_read1(oggpack_buffer *b){
      long ret;
    
      if(b->endbyte >= b->storage) goto overflow;
      ret=(b->ptr[0]>>b->endbit)&1;
    
      b->endbit++;
      if(b->endbit>7){
        b->endbit=0;
        b->ptr++;
        b->endbyte++;
      }
      return ret;
    
     overflow:
      b->ptr=NULL;
      b->endbyte=b->storage;
      b->endbit=1;
      return -1L;
    }
    
    long oggpackB_read1(oggpack_buffer *b){
      long ret;
    
      if(b->endbyte >= b->storage) goto overflow;
      ret=(b->ptr[0]>>(7-b->endbit))&1;
    
      b->endbit++;
      if(b->endbit>7){
        b->endbit=0;
        b->ptr++;
        b->endbyte++;
      }
      return ret;
    
     overflow:
      b->ptr=NULL;
      b->endbyte=b->storage;
      b->endbit=1;
      return -1L;
    }
    
    long oggpack_bytes(oggpack_buffer *b){
      return(b->endbyte+(b->endbit+7)/8);
    }
    
    long oggpack_bits(oggpack_buffer *b){
      return(b->endbyte*8+b->endbit);
    }
    
    long oggpackB_bytes(oggpack_buffer *b){
      return oggpack_bytes(b);
    }
    
    long oggpackB_bits(oggpack_buffer *b){
      return oggpack_bits(b);
    }
    
    unsigned char *oggpack_get_buffer(oggpack_buffer *b){
      return(b->buffer);
    }
    
    unsigned char *oggpackB_get_buffer(oggpack_buffer *b){
      return oggpack_get_buffer(b);
    }
    
    /* Self test of the bitwise routines; everything else is based on
       them, so they damned well better be solid. */
    
    #ifdef _V_SELFTEST
    #include <stdio.h>
    
    static int ilog(unsigned int v){
      int ret=0;
      while(v){
        ret++;
        v>>=1;
      }
      return(ret);
    }
    
    oggpack_buffer o;
    oggpack_buffer r;
    
    void report(char *in){
      fprintf(stderr,"%s",in);
      exit(1);
    }
    
    void cliptest(unsigned long *b,int vals,int bits,int *comp,int compsize){
      long bytes,i;
      unsigned char *buffer;
    
      oggpack_reset(&o);
      for(i=0;i<vals;i++)
        oggpack_write(&o,b[i],bits?bits:ilog(b[i]));
      buffer=oggpack_get_buffer(&o);
      bytes=oggpack_bytes(&o);
      if(bytes!=compsize)report("wrong number of bytes!\n");
      for(i=0;i<bytes;i++)if(buffer[i]!=comp[i]){
        for(i=0;i<bytes;i++)fprintf(stderr,"%x %x\n",(int)buffer[i],(int)comp[i]);
        report("wrote incorrect value!\n");
      }
      oggpack_readinit(&r,buffer,bytes);
      for(i=0;i<vals;i++){
        int tbit=bits?bits:ilog(b[i]);
        if(oggpack_look(&r,tbit)==-1)
          report("out of data!\n");
        if(oggpack_look(&r,tbit)!=(b[i]&mask[tbit]))
          report("looked at incorrect value!\n");
        if(tbit==1)
          if(oggpack_look1(&r)!=(b[i]&mask[tbit]))
            report("looked at single bit incorrect value!\n");
        if(tbit==1){
          if(oggpack_read1(&r)!=(b[i]&mask[tbit]))
            report("read incorrect single bit value!\n");
        }else{
        if(oggpack_read(&r,tbit)!=(b[i]&mask[tbit]))
          report("read incorrect value!\n");
        }
      }
      if(oggpack_bytes(&r)!=bytes)report("leftover bytes after read!\n");
    }
    
    void cliptestB(unsigned long *b,int vals,int bits,int *comp,int compsize){
      long bytes,i;
      unsigned char *buffer;
    
      oggpackB_reset(&o);
      for(i=0;i<vals;i++)
        oggpackB_write(&o,b[i],bits?bits:ilog(b[i]));
      buffer=oggpackB_get_buffer(&o);
      bytes=oggpackB_bytes(&o);
      if(bytes!=compsize)report("wrong number of bytes!\n");
      for(i=0;i<bytes;i++)if(buffer[i]!=comp[i]){
        for(i=0;i<bytes;i++)fprintf(stderr,"%x %x\n",(int)buffer[i],(int)comp[i]);
        report("wrote incorrect value!\n");
      }
      oggpackB_readinit(&r,buffer,bytes);
      for(i=0;i<vals;i++){
        int tbit=bits?bits:ilog(b[i]);
        if(oggpackB_look(&r,tbit)==-1)
          report("out of data!\n");
        if(oggpackB_look(&r,tbit)!=(b[i]&mask[tbit]))
          report("looked at incorrect value!\n");
        if(tbit==1)
          if(oggpackB_look1(&r)!=(b[i]&mask[tbit]))
            report("looked at single bit incorrect value!\n");
        if(tbit==1){
          if(oggpackB_read1(&r)!=(b[i]&mask[tbit]))
            report("read incorrect single bit value!\n");
        }else{
        if(oggpackB_read(&r,tbit)!=(b[i]&mask[tbit]))
          report("read incorrect value!\n");
        }
      }
      if(oggpackB_bytes(&r)!=bytes)report("leftover bytes after read!\n");
    }
    
    void copytest(int prefill, int copy){
      oggpack_buffer source_write;
      oggpack_buffer dest_write;
      oggpack_buffer source_read;
      oggpack_buffer dest_read;
      unsigned char *source;
      unsigned char *dest;
      long source_bytes,dest_bytes;
      int i;
    
      oggpack_writeinit(&source_write);
      oggpack_writeinit(&dest_write);
    
      for(i=0;i<(prefill+copy+7)/8;i++)
        oggpack_write(&source_write,(i^0x5a)&0xff,8);
      source=oggpack_get_buffer(&source_write);
      source_bytes=oggpack_bytes(&source_write);
    
      /* prefill */
      oggpack_writecopy(&dest_write,source,prefill);
    
      /* check buffers; verify end byte masking */
      dest=oggpack_get_buffer(&dest_write);
      dest_bytes=oggpack_bytes(&dest_write);
      if(dest_bytes!=(prefill+7)/8){
        fprintf(stderr,"wrong number of bytes after prefill! %ld!=%d\n",dest_bytes,(prefill+7)/8);
        exit(1);
      }
      oggpack_readinit(&source_read,source,source_bytes);
      oggpack_readinit(&dest_read,dest,dest_bytes);
    
      for(i=0;i<prefill;i+=8){
        int s=oggpack_read(&source_read,prefill-i<8?prefill-i:8);
        int d=oggpack_read(&dest_read,prefill-i<8?prefill-i:8);
        if(s!=d){
          fprintf(stderr,"prefill=%d mismatch! byte %d, %x!=%x\n",prefill,i/8,s,d);
          exit(1);
        }
      }
      if(prefill<dest_bytes){
        if(oggpack_read(&dest_read,dest_bytes-prefill)!=0){
          fprintf(stderr,"prefill=%d mismatch! trailing bits not zero\n",prefill);
          exit(1);
        }
      }
    
      /* second copy */
      oggpack_writecopy(&dest_write,source,copy);
    
      /* check buffers; verify end byte masking */
      dest=oggpack_get_buffer(&dest_write);
      dest_bytes=oggpack_bytes(&dest_write);
      if(dest_bytes!=(copy+prefill+7)/8){
        fprintf(stderr,"wrong number of bytes after prefill+copy! %ld!=%d\n",dest_bytes,(copy+prefill+7)/8);
        exit(1);
      }
      oggpack_readinit(&source_read,source,source_bytes);
      oggpack_readinit(&dest_read,dest,dest_bytes);
    
      for(i=0;i<prefill;i+=8){
        int s=oggpack_read(&source_read,prefill-i<8?prefill-i:8);
        int d=oggpack_read(&dest_read,prefill-i<8?prefill-i:8);
        if(s!=d){
          fprintf(stderr,"prefill=%d mismatch! byte %d, %x!=%x\n",prefill,i/8,s,d);
          exit(1);
        }
      }
    
      oggpack_readinit(&source_read,source,source_bytes);
      for(i=0;i<copy;i+=8){
        int s=oggpack_read(&source_read,copy-i<8?copy-i:8);
        int d=oggpack_read(&dest_read,copy-i<8?copy-i:8);
        if(s!=d){
          fprintf(stderr,"prefill=%d copy=%d mismatch! byte %d, %x!=%x\n",prefill,copy,i/8,s,d);
          exit(1);
        }
      }
    
      if(copy+prefill<dest_bytes){
        if(oggpack_read(&dest_read,dest_bytes-copy-prefill)!=0){
          fprintf(stderr,"prefill=%d copy=%d mismatch! trailing bits not zero\n",prefill,copy);
          exit(1);
        }
      }
    
      oggpack_writeclear(&source_write);
      oggpack_writeclear(&dest_write);
    
    
    }
    
    void copytestB(int prefill, int copy){
      oggpack_buffer source_write;
      oggpack_buffer dest_write;
      oggpack_buffer source_read;
      oggpack_buffer dest_read;
      unsigned char *source;
      unsigned char *dest;
      long source_bytes,dest_bytes;
      int i;
    
      oggpackB_writeinit(&source_write);
      oggpackB_writeinit(&dest_write);
    
      for(i=0;i<(prefill+copy+7)/8;i++)
        oggpackB_write(&source_write,(i^0x5a)&0xff,8);
      source=oggpackB_get_buffer(&source_write);
      source_bytes=oggpackB_bytes(&source_write);
    
      /* prefill */
      oggpackB_writecopy(&dest_write,source,prefill);
    
      /* check buffers; verify end byte masking */
      dest=oggpackB_get_buffer(&dest_write);
      dest_bytes=oggpackB_bytes(&dest_write);
      if(dest_bytes!=(prefill+7)/8){
        fprintf(stderr,"wrong number of bytes after prefill! %ld!=%d\n",dest_bytes,(prefill+7)/8);
        exit(1);
      }
      oggpackB_readinit(&source_read,source,source_bytes);
      oggpackB_readinit(&dest_read,dest,dest_bytes);
    
      for(i=0;i<prefill;i+=8){
        int s=oggpackB_read(&source_read,prefill-i<8?prefill-i:8);
        int d=oggpackB_read(&dest_read,prefill-i<8?prefill-i:8);
        if(s!=d){
          fprintf(stderr,"prefill=%d mismatch! byte %d, %x!=%x\n",prefill,i/8,s,d);
          exit(1);
        }
      }
      if(prefill<dest_bytes){
        if(oggpackB_read(&dest_read,dest_bytes-prefill)!=0){
          fprintf(stderr,"prefill=%d mismatch! trailing bits not zero\n",prefill);
          exit(1);
        }
      }
    
      /* second copy */
      oggpackB_writecopy(&dest_write,source,copy);
    
      /* check buffers; verify end byte masking */
      dest=oggpackB_get_buffer(&dest_write);
      dest_bytes=oggpackB_bytes(&dest_write);
      if(dest_bytes!=(copy+prefill+7)/8){
        fprintf(stderr,"wrong number of bytes after prefill+copy! %ld!=%d\n",dest_bytes,(copy+prefill+7)/8);
        exit(1);
      }
      oggpackB_readinit(&source_read,source,source_bytes);
      oggpackB_readinit(&dest_read,dest,dest_bytes);
    
      for(i=0;i<prefill;i+=8){
        int s=oggpackB_read(&source_read,prefill-i<8?prefill-i:8);
        int d=oggpackB_read(&dest_read,prefill-i<8?prefill-i:8);
        if(s!=d){
          fprintf(stderr,"prefill=%d mismatch! byte %d, %x!=%x\n",prefill,i/8,s,d);
          exit(1);
        }
      }
    
      oggpackB_readinit(&source_read,source,source_bytes);
      for(i=0;i<copy;i+=8){
        int s=oggpackB_read(&source_read,copy-i<8?copy-i:8);
        int d=oggpackB_read(&dest_read,copy-i<8?copy-i:8);
        if(s!=d){
          fprintf(stderr,"prefill=%d copy=%d mismatch! byte %d, %x!=%x\n",prefill,copy,i/8,s,d);
          exit(1);
        }
      }
    
      if(copy+prefill<dest_bytes){
        if(oggpackB_read(&dest_read,dest_bytes-copy-prefill)!=0){
          fprintf(stderr,"prefill=%d copy=%d mismatch! trailing bits not zero\n",prefill,copy);
          exit(1);
        }
      }
    
      oggpackB_writeclear(&source_write);
      oggpackB_writeclear(&dest_write);
    
    }
    
    int main(void){
      unsigned char *buffer;
      long bytes,i,j;
      static unsigned long testbuffer1[]=
        {18,12,103948,4325,543,76,432,52,3,65,4,56,32,42,34,21,1,23,32,546,456,7,
           567,56,8,8,55,3,52,342,341,4,265,7,67,86,2199,21,7,1,5,1,4};
      int test1size=43;
    
      static unsigned long testbuffer2[]=
        {216531625L,1237861823,56732452,131,3212421,12325343,34547562,12313212,
           1233432,534,5,346435231,14436467,7869299,76326614,167548585,
           85525151,0,12321,1,349528352};
      int test2size=21;
    
      static unsigned long testbuffer3[]=
        {1,0,14,0,1,0,12,0,1,0,0,0,1,1,0,1,0,1,0,1,0,1,0,1,0,1,0,0,1,1,1,1,1,0,0,1,
           0,1,30,1,1,1,0,0,1,0,0,0,12,0,11,0,1,0,0,1};
      int test3size=56;
    
      static unsigned long large[]=
        {2136531625L,2137861823,56732452,131,3212421,12325343,34547562,12313212,
           1233432,534,5,2146435231,14436467,7869299,76326614,167548585,
           85525151,0,12321,1,2146528352};
    
      int onesize=33;
      static int one[33]={146,25,44,151,195,15,153,176,233,131,196,65,85,172,47,40,
                        34,242,223,136,35,222,211,86,171,50,225,135,214,75,172,
                        223,4};
      static int oneB[33]={150,101,131,33,203,15,204,216,105,193,156,65,84,85,222,
                           8,139,145,227,126,34,55,244,171,85,100,39,195,173,18,
                           245,251,128};
    
      int twosize=6;
      static int two[6]={61,255,255,251,231,29};
      static int twoB[6]={247,63,255,253,249,120};
    
      int threesize=54;
      static int three[54]={169,2,232,252,91,132,156,36,89,13,123,176,144,32,254,
                          142,224,85,59,121,144,79,124,23,67,90,90,216,79,23,83,
                          58,135,196,61,55,129,183,54,101,100,170,37,127,126,10,
                          100,52,4,14,18,86,77,1};
      static int threeB[54]={206,128,42,153,57,8,183,251,13,89,36,30,32,144,183,
                             130,59,240,121,59,85,223,19,228,180,134,33,107,74,98,
                             233,253,196,135,63,2,110,114,50,155,90,127,37,170,104,
                             200,20,254,4,58,106,176,144,0};
    
      int foursize=38;
      static int four[38]={18,6,163,252,97,194,104,131,32,1,7,82,137,42,129,11,72,
                         132,60,220,112,8,196,109,64,179,86,9,137,195,208,122,169,
                         28,2,133,0,1};
      static int fourB[38]={36,48,102,83,243,24,52,7,4,35,132,10,145,21,2,93,2,41,
                            1,219,184,16,33,184,54,149,170,132,18,30,29,98,229,67,
                            129,10,4,32};
    
      int fivesize=45;
      static int five[45]={169,2,126,139,144,172,30,4,80,72,240,59,130,218,73,62,
                         241,24,210,44,4,20,0,248,116,49,135,100,110,130,181,169,
                         84,75,159,2,1,0,132,192,8,0,0,18,22};
      static int fiveB[45]={1,84,145,111,245,100,128,8,56,36,40,71,126,78,213,226,
                            124,105,12,0,133,128,0,162,233,242,67,152,77,205,77,
                            172,150,169,129,79,128,0,6,4,32,0,27,9,0};
    
      int sixsize=7;
      static int six[7]={17,177,170,242,169,19,148};
      static int sixB[7]={136,141,85,79,149,200,41};
    
      /* Test read/write together */
      /* Later we test against pregenerated bitstreams */
      oggpack_writeinit(&o);
    
      fprintf(stderr,"\nSmall preclipped packing (LSb): ");
      cliptest(testbuffer1,test1size,0,one,onesize);
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\nNull bit call (LSb): ");
      cliptest(testbuffer3,test3size,0,two,twosize);
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\nLarge preclipped packing (LSb): ");
      cliptest(testbuffer2,test2size,0,three,threesize);
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\n32 bit preclipped packing (LSb): ");
      oggpack_reset(&o);
      for(i=0;i<test2size;i++)
        oggpack_write(&o,large[i],32);
      buffer=oggpack_get_buffer(&o);
      bytes=oggpack_bytes(&o);
      oggpack_readinit(&r,buffer,bytes);
      for(i=0;i<test2size;i++){
        if(oggpack_look(&r,32)==-1)report("out of data. failed!");
        if(oggpack_look(&r,32)!=large[i]){
          fprintf(stderr,"%ld != %lu (%lx!=%lx):",oggpack_look(&r,32),large[i],
                  oggpack_look(&r,32),large[i]);
          report("read incorrect value!\n");
        }
        oggpack_adv(&r,32);
      }
      if(oggpack_bytes(&r)!=bytes)report("leftover bytes after read!\n");
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\nSmall unclipped packing (LSb): ");
      cliptest(testbuffer1,test1size,7,four,foursize);
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\nLarge unclipped packing (LSb): ");
      cliptest(testbuffer2,test2size,17,five,fivesize);
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\nSingle bit unclipped packing (LSb): ");
      cliptest(testbuffer3,test3size,1,six,sixsize);
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\nTesting read past end (LSb): ");
      oggpack_readinit(&r,(unsigned char *)"\0\0\0\0\0\0\0\0",8);
      for(i=0;i<64;i++){
        if(oggpack_read(&r,1)!=0){
          fprintf(stderr,"failed; got -1 prematurely.\n");
          exit(1);
        }
      }
      if(oggpack_look(&r,1)!=-1 ||
         oggpack_read(&r,1)!=-1){
          fprintf(stderr,"failed; read past end without -1.\n");
          exit(1);
      }
      oggpack_readinit(&r,(unsigned char *)"\0\0\0\0\0\0\0\0",8);
      if(oggpack_read(&r,30)!=0 || oggpack_read(&r,16)!=0){
          fprintf(stderr,"failed 2; got -1 prematurely.\n");
          exit(1);
      }
    
      if(oggpack_look(&r,18)!=0 ||
         oggpack_look(&r,18)!=0){
        fprintf(stderr,"failed 3; got -1 prematurely.\n");
          exit(1);
      }
      if(oggpack_look(&r,19)!=-1 ||
         oggpack_look(&r,19)!=-1){
        fprintf(stderr,"failed; read past end without -1.\n");
          exit(1);
      }
      if(oggpack_look(&r,32)!=-1 ||
         oggpack_look(&r,32)!=-1){
        fprintf(stderr,"failed; read past end without -1.\n");
          exit(1);
      }
      oggpack_writeclear(&o);
      fprintf(stderr,"ok.");
    
      /* this is partly glassbox; we're mostly concerned about the allocation boundaries */
    
      fprintf(stderr,"\nTesting aligned writecopies (LSb): ");
      for(i=0;i<71;i++)
        for(j=0;j<5;j++)
          copytest(j*8,i);
      for(i=BUFFER_INCREMENT*8-71;i<BUFFER_INCREMENT*8+71;i++)
        for(j=0;j<5;j++)
          copytest(j*8,i);
      fprintf(stderr,"ok.      ");
    
      fprintf(stderr,"\nTesting unaligned writecopies (LSb): ");
      for(i=0;i<71;i++)
        for(j=1;j<40;j++)
          if(j&0x7)
            copytest(j,i);
      for(i=BUFFER_INCREMENT*8-71;i<BUFFER_INCREMENT*8+71;i++)
        for(j=1;j<40;j++)
          if(j&0x7)
            copytest(j,i);
      
      fprintf(stderr,"ok.      \n");
    
    
      /********** lazy, cut-n-paste retest with MSb packing ***********/
    
      /* Test read/write together */
      /* Later we test against pregenerated bitstreams */
      oggpackB_writeinit(&o);
    
      fprintf(stderr,"\nSmall preclipped packing (MSb): ");
      cliptestB(testbuffer1,test1size,0,oneB,onesize);
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\nNull bit call (MSb): ");
      cliptestB(testbuffer3,test3size,0,twoB,twosize);
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\nLarge preclipped packing (MSb): ");
      cliptestB(testbuffer2,test2size,0,threeB,threesize);
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\n32 bit preclipped packing (MSb): ");
      oggpackB_reset(&o);
      for(i=0;i<test2size;i++)
        oggpackB_write(&o,large[i],32);
      buffer=oggpackB_get_buffer(&o);
      bytes=oggpackB_bytes(&o);
      oggpackB_readinit(&r,buffer,bytes);
      for(i=0;i<test2size;i++){
        if(oggpackB_look(&r,32)==-1)report("out of data. failed!");
        if(oggpackB_look(&r,32)!=large[i]){
          fprintf(stderr,"%ld != %lu (%lx!=%lx):",oggpackB_look(&r,32),large[i],
                  oggpackB_look(&r,32),large[i]);
          report("read incorrect value!\n");
        }
        oggpackB_adv(&r,32);
      }
      if(oggpackB_bytes(&r)!=bytes)report("leftover bytes after read!\n");
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\nSmall unclipped packing (MSb): ");
      cliptestB(testbuffer1,test1size,7,fourB,foursize);
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\nLarge unclipped packing (MSb): ");
      cliptestB(testbuffer2,test2size,17,fiveB,fivesize);
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\nSingle bit unclipped packing (MSb): ");
      cliptestB(testbuffer3,test3size,1,sixB,sixsize);
      fprintf(stderr,"ok.");
    
      fprintf(stderr,"\nTesting read past end (MSb): ");
      oggpackB_readinit(&r,(unsigned char *)"\0\0\0\0\0\0\0\0",8);
      for(i=0;i<64;i++){
        if(oggpackB_read(&r,1)!=0){
          fprintf(stderr,"failed; got -1 prematurely.\n");
          exit(1);
        }
      }
      if(oggpackB_look(&r,1)!=-1 ||
         oggpackB_read(&r,1)!=-1){
          fprintf(stderr,"failed; read past end without -1.\n");
          exit(1);
      }
      oggpackB_readinit(&r,(unsigned char *)"\0\0\0\0\0\0\0\0",8);
      if(oggpackB_read(&r,30)!=0 || oggpackB_read(&r,16)!=0){
          fprintf(stderr,"failed 2; got -1 prematurely.\n");
          exit(1);
      }
    
      if(oggpackB_look(&r,18)!=0 ||
         oggpackB_look(&r,18)!=0){
        fprintf(stderr,"failed 3; got -1 prematurely.\n");
          exit(1);
      }
      if(oggpackB_look(&r,19)!=-1 ||
         oggpackB_look(&r,19)!=-1){
        fprintf(stderr,"failed; read past end without -1.\n");
          exit(1);
      }
      if(oggpackB_look(&r,32)!=-1 ||
         oggpackB_look(&r,32)!=-1){
        fprintf(stderr,"failed; read past end without -1.\n");
          exit(1);
      }
      fprintf(stderr,"ok.");
      oggpackB_writeclear(&o);
    
      /* this is partly glassbox; we're mostly concerned about the allocation boundaries */
    
      fprintf(stderr,"\nTesting aligned writecopies (MSb): ");
      for(i=0;i<71;i++)
        for(j=0;j<5;j++)
          copytestB(j*8,i);
      for(i=BUFFER_INCREMENT*8-71;i<BUFFER_INCREMENT*8+71;i++)
        for(j=0;j<5;j++)
          copytestB(j*8,i);
      fprintf(stderr,"ok.      ");
    
      fprintf(stderr,"\nTesting unaligned writecopies (MSb): ");
      for(i=0;i<71;i++)
        for(j=1;j<40;j++)
          if(j&0x7)
            copytestB(j,i);
      for(i=BUFFER_INCREMENT*8-71;i<BUFFER_INCREMENT*8+71;i++)
        for(j=1;j<40;j++)
          if(j&0x7)
            copytestB(j,i);
      
      fprintf(stderr,"ok.      \n\n");
    
      return(0);
    }
    #endif  /* _V_SELFTEST */
    
    #undef BUFFER_INCREMENT