PNG_PASS_COL_SHIFT   56 contrib/libtests/pngunknown.c #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
PNG_PASS_COL_SHIFT   85 contrib/libtests/pngvalid.c #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
PNG_PASS_COL_SHIFT 2605 png.h          #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)