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 /source | |
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.
Diffstat (limited to 'source')
-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. |