diff options
Diffstat (limited to 'libtiff/tif_fax3.h')
| -rw-r--r-- | libtiff/tif_fax3.h | 42 |
1 files changed, 33 insertions, 9 deletions
diff --git a/libtiff/tif_fax3.h b/libtiff/tif_fax3.h index d4ed4a21..224d5e2c 100644 --- a/libtiff/tif_fax3.h +++ b/libtiff/tif_fax3.h @@ -1,4 +1,4 @@ -/* $Header: /usr/people/sam/tiff/libtiff/RCS/tif_fax3.h,v 1.27 1996/01/10 19:33:22 sam Exp $ */ +/* $Header: /usr/people/sam/tiff/libtiff/RCS/tif_fax3.h,v 1.29 1996/02/09 22:51:07 sam Exp $ */ /* * Copyright (c) 1990-1996 Sam Leffler @@ -122,25 +122,49 @@ extern const TIFFFaxTabEnt TIFFFaxBlackTable[]; * data. In any event, we don't prescan and must watch for * running out of data since we can't permit the library to * scan past the end of the input data buffer. + * + * Finally, note that we must handle remaindered data at the end + * of a strip specially. The coder asks for a fixed number of + * bits when scanning for the next code. This may be more bits + * than are actually present in the data stream. If we appear + * to run out of data but still have some number of valid bits + * remaining then we makeup the requested amount with zeros and + * return successfully. If the returned data is incorrect then + * we should be called again and get a premature EOF error; + * otherwise we should get the right answer. */ #ifndef NeedBits8 #define NeedBits8(n,eoflab) do { \ if (BitsAvail < (n)) { \ - if (EndOfData()) goto eoflab; \ - BitAcc |= bitmap[*cp++]<<BitsAvail; \ - BitsAvail += 8; \ + if (EndOfData()) { \ + if (BitsAvail == 0) /* no valid bits */ \ + goto eoflab; \ + BitsAvail = (n); /* pad with zeros */ \ + } else { \ + BitAcc |= bitmap[*cp++]<<BitsAvail; \ + BitsAvail += 8; \ + } \ } \ } while (0) #endif #ifndef NeedBits16 #define NeedBits16(n,eoflab) do { \ if (BitsAvail < (n)) { \ - if (EndOfData()) goto eoflab; \ - BitAcc |= bitmap[*cp++]<<BitsAvail; \ - if ((BitsAvail += 8) < (n)) { \ - if (EndOfData()) goto eoflab; \ + if (EndOfData()) { \ + if (BitsAvail == 0) /* no valid bits */ \ + goto eoflab; \ + BitsAvail = (n); /* pad with zeros */ \ + } else { \ BitAcc |= bitmap[*cp++]<<BitsAvail; \ - BitsAvail += 8; \ + if ((BitsAvail += 8) < (n)) { \ + if (EndOfData()) { \ + /* NB: we know BitsAvail is non-zero here */ \ + BitsAvail = (n); /* pad with zeros */ \ + } else { \ + BitAcc |= bitmap[*cp++]<<BitsAvail; \ + BitsAvail += 8; \ + } \ + } \ } \ } \ } while (0) |