From 0417e54bec27aed35421a53271aaf0484adc892e Mon Sep 17 00:00:00 2001 From: Ben Wagner Date: Fri, 22 Jul 2022 16:22:19 -0400 Subject: [PATCH] [base] Build outlines in amortized constant time. When resizing the loader's points and contours, resize them to at least 1.5 times their current size. The code currently only reserves as much space as is currently required, leading to O(n^2) runtime when adding points one at a time. This change does not attempt to ever shrink the loader's point and contour storage since this was not attempted previously either. The 1.5 multiple was chosen as a trade-off between potentially unused space and the runtime. * src/base/ftgloader.c (FT_GlyphLoader_CheckPoints): Implement it. Fixes #1173. --- src/base/ftgloadr.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/src/base/ftgloadr.c b/src/base/ftgloadr.c index 90cc09c02..b2cdabfbd 100644 --- a/src/base/ftgloadr.c +++ b/src/base/ftgloadr.c @@ -212,7 +212,7 @@ FT_Outline* current = &loader->current.outline; FT_Bool adjust = 0; - FT_UInt new_max, old_max; + FT_UInt new_max, old_max, min_new_max; error = FT_GlyphLoader_CreateExtra( loader ); @@ -226,14 +226,19 @@ if ( new_max > old_max ) { - new_max = FT_PAD_CEIL( new_max, 8 ); - if ( new_max > FT_OUTLINE_POINTS_MAX ) { error = FT_THROW( Array_Too_Large ); goto Exit; } + min_new_max = old_max + ( old_max >> 1 ); + if ( new_max < min_new_max ) + new_max = min_new_max; + new_max = FT_PAD_CEIL( new_max, 8 ); + if ( new_max > FT_OUTLINE_POINTS_MAX ) + new_max = FT_OUTLINE_POINTS_MAX; + if ( FT_RENEW_ARRAY( base->points, old_max, new_max ) || FT_RENEW_ARRAY( base->tags, old_max, new_max ) ) goto Exit; @@ -265,14 +270,19 @@ n_contours; if ( new_max > old_max ) { - new_max = FT_PAD_CEIL( new_max, 4 ); - if ( new_max > FT_OUTLINE_CONTOURS_MAX ) { error = FT_THROW( Array_Too_Large ); goto Exit; } + min_new_max = old_max + ( old_max >> 1 ); + if ( new_max < min_new_max ) + new_max = min_new_max; + new_max = FT_PAD_CEIL( new_max, 4 ); + if ( new_max > FT_OUTLINE_CONTOURS_MAX ) + new_max = FT_OUTLINE_CONTOURS_MAX; + if ( FT_RENEW_ARRAY( base->contours, old_max, new_max ) ) goto Exit;