diff options
author | Hans Goudey <h.goudey@me.com> | 2022-09-12 18:38:31 +0300 |
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committer | Hans Goudey <h.goudey@me.com> | 2022-09-12 19:04:52 +0300 |
commit | 225b5a3491d9593639a80c9a34bcc017862eb2b2 (patch) | |
tree | 9efa12a3587569f6b8a2cac6391ab8ebd040118c | |
parent | e37f3388b1563591153fc82259cf549f7942dcf0 (diff) |
BLI: Add utility functions to generic spans
Generally we don't want to do per-element operations on these spans
because of the overhead of the runtime type system, but these operations
on the whole span avoid ugly pointer arithmetic in other areas.
-rw-r--r-- | source/blender/blenlib/BLI_generic_span.hh | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/source/blender/blenlib/BLI_generic_span.hh b/source/blender/blenlib/BLI_generic_span.hh index 143ab235d2e..e7a08988c46 100644 --- a/source/blender/blenlib/BLI_generic_span.hh +++ b/source/blender/blenlib/BLI_generic_span.hh @@ -100,6 +100,34 @@ class GSpan { { return this->slice(range.start(), range.size()); } + + GSpan drop_front(const int64_t n) const + { + BLI_assert(n >= 0); + const int64_t new_size = std::max<int64_t>(0, size_ - n); + return GSpan(*type_, POINTER_OFFSET(data_, type_->size() * n), new_size); + } + + GSpan drop_back(const int64_t n) const + { + BLI_assert(n >= 0); + const int64_t new_size = std::max<int64_t>(0, size_ - n); + return GSpan(*type_, data_, new_size); + } + + GSpan take_front(const int64_t n) const + { + BLI_assert(n >= 0); + const int64_t new_size = std::min<int64_t>(size_, n); + return GSpan(*type_, data_, new_size); + } + + GSpan take_back(const int64_t n) const + { + BLI_assert(n >= 0); + const int64_t new_size = std::min<int64_t>(size_, n); + return GSpan(*type_, POINTER_OFFSET(data_, type_->size() * (size_ - new_size)), new_size); + } }; /** @@ -199,6 +227,35 @@ class GMutableSpan { return this->slice(range.start(), range.size()); } + GMutableSpan drop_front(const int64_t n) const + { + BLI_assert(n >= 0); + const int64_t new_size = std::max<int64_t>(0, size_ - n); + return GMutableSpan(*type_, POINTER_OFFSET(data_, type_->size() * n), new_size); + } + + GMutableSpan drop_back(const int64_t n) const + { + BLI_assert(n >= 0); + const int64_t new_size = std::max<int64_t>(0, size_ - n); + return GMutableSpan(*type_, data_, new_size); + } + + GMutableSpan take_front(const int64_t n) const + { + BLI_assert(n >= 0); + const int64_t new_size = std::min<int64_t>(size_, n); + return GMutableSpan(*type_, data_, new_size); + } + + GMutableSpan take_back(const int64_t n) const + { + BLI_assert(n >= 0); + const int64_t new_size = std::min<int64_t>(size_, n); + return GMutableSpan( + *type_, POINTER_OFFSET(data_, type_->size() * (size_ - new_size)), new_size); + } + /** * Copy all values from another span into this span. This invokes undefined behavior when the * destination contains uninitialized data and T is not trivially copy constructible. |