[libpng15] Speed up png_combine_row() for interlaced images. This reduces the
generality of the code, allowing it to be optimized for Adam7 interlace. The masks passed to png_combine_row() are now generated internally, avoiding some code duplication and localizing the interlace handling somewhat.
This commit is contained in:
Glenn Randers-Pehrson
parent
4daae30174
commit
65c0339b5c
10
ANNOUNCE
10
ANNOUNCE
@ -1,5 +1,5 @@
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Libpng 1.5.6beta05 - October 6, 2011
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Libpng 1.5.6beta05 - October 7, 2011
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This is not intended to be a public release. It will be replaced
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within a few weeks by a public version or by another test version.
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@ -55,9 +55,11 @@ Version 1.5.6beta03 [September 28, 2011]
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Version 1.5.6beta04 [October 5, 2011]
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Fixed typo in Makefile.in and Makefile.am ("-M Wl" should be "-M -Wl")."
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Version 1.5.6beta05 [October 6, 2011]
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Replaced a short but frequently-used memcpy() in png_combine_row() with
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a loop.
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Version 1.5.6beta05 [October 7, 2011]
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Speed up png_combine_row() for interlaced images. This reduces the generality
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of the code, allowing it to be optimized for Adam7 interlace. The masks
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passed to png_combine_row() are now generated internally, avoiding
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some code duplication and localizing the interlace handling somewhat.
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Send comments/corrections/commendations to png-mng-implement at lists.sf.net:
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(subscription required; visit
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8
CHANGES
8
CHANGES
@ -3616,9 +3616,11 @@ Version 1.5.6beta03 [September 28, 2011]
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Version 1.5.6beta04 [October 5, 2011]
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Fixed typo in Makefile.in and Makefile.am ("-M Wl" should be "-M -Wl")."
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Version 1.5.6beta05 [October 6, 2011]
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Replaced a short but frequently-used memcpy() in png_combine_row() with
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a loop.
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Version 1.5.6beta05 [October 7, 2011]
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Speed up png_combine_row() for interlaced images. This reduces the generality
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of the code, allowing it to be optimized for Adam7 interlace. The masks
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passed to png_combine_row() are now generated internally, avoiding
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some code duplication and localizing the interlace handling somewhat.
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Send comments/corrections/commendations to png-mng-implement at lists.sf.net
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(subscription required; visit
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50
pngpriv.h
50
pngpriv.h
@ -44,6 +44,9 @@
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*/
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#include <stdlib.h>
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/* This is used to find 'offsetof', used below for alignment tests. */
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#include <stddef.h>
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#define PNGLIB_BUILD /*libpng is being built, not used*/
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#ifdef PNG_USER_CONFIG
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@ -321,6 +324,22 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
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# define png_memset memset
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# endif
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#endif
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/* These macros may need to be architecture dependent, they take a pointer and
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* an alignment requirement.
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*/
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#ifdef offsetof
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# define png_alignof(type) offsetof(struct{char c; type t;}, t)
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#endif
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/* This implicitly assumes alignment is always to a power of 2. */
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#ifdef png_alignof
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# define png_isaligned(ptr, type)\
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((((char*)ptr-(char*)0) & (png_alignof(type)-1)) == 0)
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#else
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# define png_isaligned(ptr, type) 0
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#endif
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/* End of memory model/platform independent support */
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/* End of 1.5.0beta36 move from pngconf.h */
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@ -823,17 +842,34 @@ PNG_EXTERN void png_write_finish_row PNGARG((png_structp png_ptr));
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PNG_EXTERN void png_write_start_row PNGARG((png_structp png_ptr));
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/* Combine a row of data, dealing with alpha, etc. if requested. 'row' is an
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* array of png_ptr->width pixels, 'mask' is a mask of the pixels to copy from
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* png_ptr->row_buf+1. 'mask' describes each block of 8 pixels - only the low 8
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* bits are used. This function is only ever used to write to row buffers
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* provided by the caller of the relevant libpng API and the row must have
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* already been transformed by the read transformations.
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* array of png_ptr->width pixels. If the image is not interlaced or this
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* is the final pass this just does a png_memcpy, otherwise the "display" flag
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* is used to determine whether to copy pixels that are not in the current pass.
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*
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* Because 'png_do_read_interlace' (below) replicates pixels this allows this
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* function to achieve the documented 'blocky' appearance during interlaced read
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* if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
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* are not changed if they are not in the current pass, when display is 0.
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*
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* 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
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*
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* The API always reads from the png_struct row buffer and always assumes that
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* it is full width (png_do_read_interlace has already been called.)
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*
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* This function is only ever used to write to row buffers provided by the
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* caller of the relevant libpng API and the row must have already been
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* transformed by the read transformations.
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*/
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PNG_EXTERN void png_combine_row PNGARG((png_structp png_ptr, png_bytep row,
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int mask));
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int display));
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#ifdef PNG_READ_INTERLACING_SUPPORTED
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/* Expand an interlaced row */
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/* Expand an interlaced row: the 'row_info' describes the pass data that has
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* been read in and must correspond to the pixels in 'row', the pixels are
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* expanded (moved apart) in 'row' to match the final layout, when doing this
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* the pixels are *replicated* to the intervening space. This is essential for
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* the correct operation of png_combine_row, above.
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*/
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PNG_EXTERN void png_do_read_interlace PNGARG((png_row_infop row_info,
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png_bytep row, int pass, png_uint_32 transformations));
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#endif
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31
pngread.c
31
pngread.c
@ -390,11 +390,6 @@ png_start_read_image(png_structp png_ptr)
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void PNGAPI
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png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
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{
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#ifdef PNG_READ_INTERLACING_SUPPORTED
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PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
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0xff};
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PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
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#endif
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int ret;
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png_row_info row_info;
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@ -474,8 +469,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
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if (png_ptr->row_number & 0x07)
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{
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if (dsp_row != NULL)
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png_combine_row(png_ptr, dsp_row,
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png_pass_dsp_mask[png_ptr->pass]);
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png_combine_row(png_ptr, dsp_row, 1/*display*/);
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png_read_finish_row(png_ptr);
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return;
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}
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@ -485,8 +479,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
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if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
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{
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if (dsp_row != NULL)
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png_combine_row(png_ptr, dsp_row,
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png_pass_dsp_mask[png_ptr->pass]);
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png_combine_row(png_ptr, dsp_row, 1/*display*/);
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png_read_finish_row(png_ptr);
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return;
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@ -497,8 +490,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
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if ((png_ptr->row_number & 0x07) != 4)
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{
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if (dsp_row != NULL && (png_ptr->row_number & 4))
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png_combine_row(png_ptr, dsp_row,
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png_pass_dsp_mask[png_ptr->pass]);
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png_combine_row(png_ptr, dsp_row, 1/*display*/);
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png_read_finish_row(png_ptr);
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return;
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@ -509,8 +501,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
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if ((png_ptr->row_number & 3) || png_ptr->width < 3)
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{
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if (dsp_row != NULL)
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png_combine_row(png_ptr, dsp_row,
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png_pass_dsp_mask[png_ptr->pass]);
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png_combine_row(png_ptr, dsp_row, 1/*display*/);
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png_read_finish_row(png_ptr);
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return;
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@ -521,8 +512,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
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if ((png_ptr->row_number & 3) != 2)
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{
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if (dsp_row != NULL && (png_ptr->row_number & 2))
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png_combine_row(png_ptr, dsp_row,
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png_pass_dsp_mask[png_ptr->pass]);
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png_combine_row(png_ptr, dsp_row, 1/*display*/);
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png_read_finish_row(png_ptr);
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return;
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@ -532,8 +522,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
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if ((png_ptr->row_number & 1) || png_ptr->width < 2)
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{
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if (dsp_row != NULL)
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png_combine_row(png_ptr, dsp_row,
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png_pass_dsp_mask[png_ptr->pass]);
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png_combine_row(png_ptr, dsp_row, 1/*display*/);
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png_read_finish_row(png_ptr);
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return;
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@ -651,20 +640,20 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
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png_ptr->transformations);
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if (dsp_row != NULL)
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png_combine_row(png_ptr, dsp_row, png_pass_dsp_mask[png_ptr->pass]);
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png_combine_row(png_ptr, dsp_row, 1/*display*/);
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if (row != NULL)
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png_combine_row(png_ptr, row, png_pass_mask[png_ptr->pass]);
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png_combine_row(png_ptr, row, 0/*row*/);
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}
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else
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#endif
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{
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if (row != NULL)
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png_combine_row(png_ptr, row, 0xff);
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png_combine_row(png_ptr, row, -1/*ignored*/);
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if (dsp_row != NULL)
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png_combine_row(png_ptr, dsp_row, 0xff);
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png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
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}
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png_read_finish_row(png_ptr);
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