159 lines
5.0 KiB
Plaintext
159 lines
5.0 KiB
Plaintext
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Known bugs and suggested enhancements in libpng-1.0.1
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1. March 13, 1998 -- BUG -- pngtrans.c:
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row_info->channels should be updated --
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row_info->color_type should be updated --
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STATUS: I think this is all fixed in libpng-1.0.1a but needs
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to be tested.
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2. March 14, 1998 -- ENHANCEMENT -- Glenn
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We should add the G>GA, G>GX, G>AG, and G>XG transformations
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in png_do_read_filler()
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STATUS: Implemented in libpng-1.0.1a
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3. March 14, 1998 -- BUG? -- Greg Roelofs
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pngrtran.c: if-test for channels/FILLER may be incorrect
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STATUS: Under investigation. Appears to be working correctly
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in libpng-1.0.1c.
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4. March 15, 1998 -- BUG -- Kevin Bracey
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pngwtran.c:
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line 306: loop should count to row_info->width, not to
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row_info->width*row_info->channnels
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STATUS: Fixed in libpng-1.0.1a
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5. March 15, 1998 -- OPTIMIZATION -- Kevin Bracey
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Loops need to be optimized everywhere
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a. Make them count down instead of up -- Kevin Bracey
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Optimizing compilers don't need this, and making
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the change would be error prone -- Tom Lane, Glenn R-P
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Question whether i-- or --i is better.
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STATUS: Under investigation.
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b. Remove products and structure members from loop tests -- Glenn R-P
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Can be accomplished without messing with loop guts. This
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was shown to be effective on optimized SGI compiler:
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replace
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png_uint_32 i;
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for(i=0; i < s->a*s->b; i++)
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with
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png_uint_32 i, istop;
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istop = s->a*s->b;
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for(i=0; i<istop; i++)
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STATUS: Mostly done in libpng-1.0.1a, done for all important loops.
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More done in libpng-1.0.1b.
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c. Replace abs() with intrinsic ternary operations in Paeth
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filtering -- Glenn R-P
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STATUS: Done in libpng-1.0.1a
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(can be restored to original behavior with #define PNG_USE_ABS)
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d. In pngwutil.c, make separate simple loops to use when filter
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heuristic sums aren't needed. -- Glenn R-P
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STATUS: Done in libpng-1.0.1a
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6. April 6, 1998 -- BUG -- bug in pngset.c (rowbytes too large) -- Bob Dellaca
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pngset.c has a bug, introduced in version 0.99c, that sets rowbytes
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too large when writing an image with bit_depth < 8
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STATUS: Fixed in libpng-1.0.1a
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7. April 10, 1998 -- BUG -- pngwutil weighted filtering bugs -- Glenn R-P
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pngwutil.c has some bugs in the experimental weighted filter
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algorithm (PNG_FILTER_XXX should be PNG_FILTER_VALUE_XXX in
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several places)
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STATUS: Andreas concurs. Fixed in libpng-1.0.1a
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8. April 10, 1998 -- ENHANCEMENT -- run-time selection of malloc function
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-- Bob Dellaca
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pngmem.c currently provides a compile-time option to replace
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png_malloc() and png_free(). It's been requested that these
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be made possible at run time, via calls to new png_set_malloc_fn()
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and png_set_free_fn() functions.
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STATUS: Under consideration
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9. April 11, 1998 -- BUG -- incorrect truncation of tRNS data in
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illegal PNG file where tRNS precedes PLTE -- Larry Reeve
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There is a misplaced pngrutil code block that truncates tRNS if it has
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more than num_palette entries -- test was done before num_palette was
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defined. Although the PNG file is illegal, it shouldn't crash apps.
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There is a simple fix; just moving the test to the point after
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num_palette has been defined.
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STATUS: Fixed in libpng-1.0.1a
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10. April 16, 1998 -- BUG -- incorrect operation of png_convert_to_rfc1123
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with 31st day of the month -- Steve Eddins
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The "ptime->date % 31" is wrong, should be "ptime->date % 32".
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STATUS: Fixed in libpng-1.0.1a
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11. April 21, 1998 -- ENHANCEMENT -- relocation of composite macros
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png_composite() and png_composite_16() relocated to png.h
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STATUS: Done in libpng-1.0.1b
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12. April 22, 1998 -- ENHANCEMENT -- makefile.sco
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Mike Hopkirk contributed a makefile for SCO osr5 and sco UW7
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STATUS: Added to libpng-1.0.1b distribution
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13: April 30, 1998 -- ENHANCEMENT -- warnings
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When people define out some of the read transformations and then
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try to use them, the request is silently ignored. It was suggested
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that a warning be issued in such cases.
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STATUS: Done in libpng-1.0.1b
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14. May 2, 1998 -- BUG -- incorrect mask for filler bytes
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In pngrtran.c, png_do_filler(), the masks for hi_filler and low_filler
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should be 0xff instead of 0xf
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STATUS: Fixed in libpng-1.0.1c
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15. May 3, 1998 -- BUG -- buffer overflow in png_do_read_filler()
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In pngrutil.c, max_pixel_depth needs to be set to 32 when using
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png_do_read_filler with palette images.
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STATUS: Fixed in libpng-1.0.1c (see also items 1 and 3 above).
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16. May 3, 1998 -- BUG -- type definitions wrong on error functions -- Tom Lane
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In png_create_xxx_struct(), the error functions should have typedef
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png_voidp instead of (void *). Needs to be corrected in the functions,
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the prototypes in png.h, the example.c file, and libpng.txt and libpng.3
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STATUS: Fixed in libpng-1.0.1c
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