diff options
Diffstat (limited to 'absl/types/span.h')
| -rw-r--r-- | absl/types/span.h | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/absl/types/span.h b/absl/types/span.h index d365f17d..0ca30d1d 100644 --- a/absl/types/span.h +++ b/absl/types/span.h @@ -458,10 +458,20 @@ class Span { // Span::subspan() // - // Returns a `Span` starting at element `pos` and of length `len`, with - // proper bounds checking to ensure `len` does not exceed the ptr+size of the - // original array. (Spans whose `len` would point past the end of the array - // will throw a `std::out_of_range`.) + // Returns a `Span` starting at element `pos` and of length `len`. Both `pos` + // and `len` are of type `size_type` and thus non-negative. Parameter `pos` + // must be <= size(). Any `len` value that points past the end of the span + // will be trimmed to at most size() - `pos`. A default `len` value of `npos` + // ensures the returned subspan continues until the end of the span. + // + // Examples: + // + // std::vector<int> vec = {10, 11, 12, 13}; + // absl::MakeSpan(vec).subspan(1, 2); // {11, 12} + // absl::MakeSpan(vec).subspan(2, 8); // {12, 13} + // absl::MakeSpan(vec).subspan(1); // {11, 12, 13} + // absl::MakeSpan(vec).subspan(4); // {} + // absl::MakeSpan(vec).subspan(5); // throws std::out_of_range constexpr Span subspan(size_type pos = 0, size_type len = npos) const { return (pos <= len_) ? Span(ptr_ + pos, span_internal::Min(len_ - pos, len)) |