Fix the bug that was causing the last byte of the stream to be returned incorrectly, as well as undo jm's reversion, which can cause ec_dec_tell() to operate incorrectly at the end of the stream.

A few other minor updates are included as well.

git-svn-id: http://svn.xiph.org/trunk/ghost@14427 0101bb08-14d6-0310-b084-bc0e0c8e3800

libentcode/ectest.c

@@ -1,3 +1,4 @@
+#include <stdlib.h>
 #include <stdio.h>
 #include <math.h>
 #include "probenc.h"
@@ -139,6 +140,32 @@ int main(int _argc,char **_argv){
      ldexp(nbits2,-4),ldexp(nbits,-4));
   }
   ec_byte_writeclear(&buf);
-  fprintf(stderr,"All tests passed.\n");
+  fprintf(stderr,"Testing random streams...\n");
+  srand(0);
+  for(i=0;i<1024;i++){
+    unsigned *data;
+    int       j;
+    ft=rand()/((RAND_MAX>>9)+1)+512;
+    sz=rand()/((RAND_MAX>>9)+1);
+    data=(unsigned *)malloc(sz*sizeof(*data));
+    ec_byte_writeinit(&buf);
+    ec_enc_init(&enc,&buf);
+    for(j=0;j<sz;j++){
+      data[j]=rand()%ft;
+      ec_enc_uint(&enc,data[j],ft);
+    }
+    ec_enc_done(&enc);
+    ec_byte_readinit(&buf,ec_byte_get_buffer(&buf),ec_byte_bytes(&buf));
+    ec_dec_init(&dec,&buf);
+    for(j=0;j<sz;j++){
+      sym=ec_dec_uint(&dec,ft);
+      if(sym!=data[j]){
+        fprintf(stderr,
+         "Decoded %i instead of %i with ft of %i at position %i of %i.\n",
+         sym,data[j],ft,j,sz);
+      }
+    }
+    ec_byte_writeclear(&buf);
+  }
   return 0;
 }

libentcode/mfrngdec.c

@@ -138,25 +138,26 @@ static int ec_dec_in(ec_dec *_this){
   ret=ec_byte_read1(_this->buf);
   if(ret<0){
     unsigned char *buf;
-    long           bytes;
-    bytes=ec_byte_bytes(_this->buf);
+    long           i;
+    i=ec_byte_bytes(_this->buf);
     buf=ec_byte_get_buffer(_this->buf);
     /*Breaking abstraction: don't do this at home, kids.*/
-    if(_this->buf->storage==bytes){
-      ec_byte_adv1(_this->buf);
-      if(bytes>0){
-        unsigned char *p;
-        p=buf+bytes;
-        /*If we end in a string of 0 or more EC_FOF_RSV1 bytes preceded by a
-           zero, return an extra EC_FOF_RSV1 byte.*/
-        do p--;
-        while(p>buf&&p[0]==EC_FOF_RSV1);
-        if(!p[0])return EC_FOF_RSV1;
-      }
+    if(_this->buf->storage==i&&i>0){
+      unsigned char *buf;
+      buf=ec_byte_get_buffer(_this->buf);
+      /*If we end in a string of 0 or more EC_FOF_RSV1 bytes preceded by a
+         zero, return an extra EC_FOF_RSV1 byte.*/
+      do i--;
+      while(i>0&&buf[i]==EC_FOF_RSV1);
+      if(!buf[i])ret=EC_FOF_RSV1;
+      else ret=0;
     }
-    return 0;
+    else ret=0;
+    /*Needed to make sure the above conditional only triggers once, and to keep
+       oc_dec_tell() operating correctly.*/
+    ec_byte_adv1(_this->buf);
   }
-  else return ret;
+  return ret;
 }
 
 /*Normalizes the contents of dif and rng so that rng lies entirely in the

libentcode/mfrngenc.c

@@ -169,25 +169,26 @@ void ec_enc_done(ec_enc *_this){
   }
   /*If we have a buffered byte...*/
   if(_this->rem>=0){
-    unsigned char *p;
     unsigned char *buf;
+    long           i;
     /*Flush it into the output buffer.*/
     ec_enc_carry_out(_this,0);
     _this->rem=-1;
     /*We may be able to drop some redundant bytes from the end.*/
     buf=ec_byte_get_buffer(_this->buf);
-    p=buf+ec_byte_bytes(_this->buf)-1;
+    i=ec_byte_bytes(_this->buf);
     /*Strip trailing zeros.*/
-    while(p>=buf&&!p[0])p--;
+    do i--;
+    while(i>0&&!buf[i]);
     /*Strip one trailing EC_FOF_RSV1 byte if the buffer ends in a string of
        consecutive EC_FOF_RSV1 bytes preceded by one (or more) zeros.*/
-    if(p>buf&&p[0]==EC_FOF_RSV1){
-      unsigned char *q;
-      q=p;
-      do q--;
-      while(q>buf&&q[0]==EC_FOF_RSV1);
-      if(!q[0])p--;
+    if(i>0&&buf[i]==EC_FOF_RSV1){
+      long j;
+      j=i;
+      do j--;
+      while(j>0&&buf[j]==EC_FOF_RSV1);
+      if(!buf[j])i--;
     }
-    ec_byte_writetrunc(_this->buf,p+1-buf);
+    ec_byte_writetrunc(_this->buf,i+1);
   }
 }

libentcode/rangedec.c

@@ -110,6 +110,7 @@
   }*/
 
 
+#include <stdio.h>
 
 /*Gets the next byte of input.
   After all the bytes in the current packet have been consumed, and the extra
@@ -121,25 +122,26 @@ static int ec_dec_in(ec_dec *_this){
   ret=ec_byte_read1(_this->buf);
   if(ret<0){
     unsigned char *buf;
-    long           bytes;
-    bytes=ec_byte_bytes(_this->buf);
+    long           i;
+    i=ec_byte_bytes(_this->buf);
     buf=ec_byte_get_buffer(_this->buf);
     /*Breaking abstraction: don't do this at home, kids.*/
-    if(_this->buf->storage==bytes){
-      ec_byte_adv1(_this->buf);
-      if(bytes>0){
-        unsigned char *p;
-        p=buf+bytes;
-        /*If we end in a string of 0 or more EC_FOF_RSV1 bytes preceded by a
-           zero, return an extra EC_FOF_RSV1 byte.*/
-        do p--;
-        while(p>buf&&p[0]==EC_FOF_RSV1);
-        if(!p[0])return EC_FOF_RSV1;
-      }
+    if(_this->buf->storage==i&&i>0){
+      unsigned char *buf;
+      buf=ec_byte_get_buffer(_this->buf);
+      /*If we end in a string of 0 or more EC_FOF_RSV1 bytes preceded by a
+         zero, return an extra EC_FOF_RSV1 byte.*/
+      do i--;
+      while(i>0&&buf[i]==EC_FOF_RSV1);
+      if(!buf[i])ret=EC_FOF_RSV1;
+      else ret=0;
     }
-    return 0;
+    else ret=0;
+    /*Needed to make sure the above conditional only triggers once, and to keep
+       oc_dec_tell() operating correctly.*/
+    ec_byte_adv1(_this->buf);
   }
-  else return ret;
+  return ret;
 }
 
 /*Normalizes the contents of dif and rng so that rng lies entirely in the

libentcode/rangeenc.c

@@ -79,12 +79,10 @@ void ec_enc_init(ec_enc *_this,ec_byte_buffer *_buf){
 }
 
 void ec_encode(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _ft){
-  unsigned r;
-  unsigned s;
+  ec_uint32 r;
   r=_this->rng/_ft;
   if(_fl>0){
-    s=r*(_ft-_fl);
-    _this->low+=_this->rng-s;
+    _this->low+=_this->rng-r*(_ft-_fl);
     _this->rng=r*(_fh-_fl);
   }
   else _this->rng-=r*(_ft-_fh);
@@ -141,25 +139,26 @@ void ec_enc_done(ec_enc *_this){
   }
   /*If we have a buffered byte...*/
   if(_this->rem>=0){
-    unsigned char *p;
     unsigned char *buf;
+    long           i;
     /*Flush it into the output buffer.*/
     ec_enc_carry_out(_this,0);
     _this->rem=-1;
     /*We may be able to drop some redundant bytes from the end.*/
     buf=ec_byte_get_buffer(_this->buf);
-    p=buf+ec_byte_bytes(_this->buf)-1;
+    i=ec_byte_bytes(_this->buf);
     /*Strip trailing zeros.*/
-    while(p>=buf&&!p[0])p--;
+    do i--;
+    while(i>0&&!buf[i]);
     /*Strip one trailing EC_FOF_RSV1 byte if the buffer ends in a string of
        consecutive EC_FOF_RSV1 bytes preceded by one (or more) zeros.*/
-    if(p>buf&&p[0]==EC_FOF_RSV1){
-      unsigned char *q;
-      q=p;
-      do q--;
-      while(q>buf&&q[0]==EC_FOF_RSV1);
-      if(!q[0])p--;
+    if(i>0&&buf[i]==EC_FOF_RSV1){
+      long j;
+      j=i;
+      do j--;
+      while(j>0&&buf[j]==EC_FOF_RSV1);
+      if(!buf[j])i--;
     }
-    ec_byte_writetrunc(_this->buf,p+1-buf);
+    ec_byte_writetrunc(_this->buf,i+1);
   }
 }