diff options
Diffstat (limited to 'page.go')
| -rw-r--r-- | page.go | 31 |
1 files changed, 25 insertions, 6 deletions
@@ -145,12 +145,33 @@ func (a pgids) merge(b pgids) pgids { // Return the opposite slice if one is nil. if len(a) == 0 { return b - } else if len(b) == 0 { + } + if len(b) == 0 { return a } + merged := make(pgids, len(a)+len(b)) + mergepgids(merged, a, b) + return merged +} + +// merge copies the sorted union of a and b into dst. +// If dst is too small, it panics. +func mergepgids(dst, a, b pgids) { + if len(dst) < len(a)+len(b) { + panic(fmt.Errorf("mergepgids bad len %d < %d + %d", len(dst), len(a), len(b))) + } + // Copy in the opposite slice if one is nil. + if len(a) == 0 { + copy(dst, b) + return + } + if len(b) == 0 { + copy(dst, a) + return + } - // Create a list to hold all elements from both lists. - merged := make(pgids, 0, len(a)+len(b)) + // Merged will hold all elements from both lists. + merged := dst[:0] // Assign lead to the slice with a lower starting value, follow to the higher value. lead, follow := a, b @@ -172,7 +193,5 @@ func (a pgids) merge(b pgids) pgids { } // Append what's left in follow. - merged = append(merged, follow...) - - return merged + _ = append(merged, follow...) } |