github.com/vc42/parquet-go@v0.0.0-20240320194221-1a9adb5f23f5/array_go18.go (about)

     1  //go:build go1.18
     2  
     3  package parquet
     4  
     5  import (
     6  	"unsafe"
     7  
     8  	"github.com/vc42/parquet-go/internal/unsafecast"
     9  	"github.com/vc42/parquet-go/sparse"
    10  )
    11  
    12  func makeArray(base unsafe.Pointer, length int, offset uintptr) sparse.Array {
    13  	return sparse.UnsafeArray(base, length, offset)
    14  }
    15  
    16  func makeArrayOf[T any](s []T) sparse.Array {
    17  	var model T
    18  	return makeArray(unsafecast.PointerOf(s), len(s), unsafe.Sizeof(model))
    19  }
    20  
    21  func makeSlice[T any](a sparse.Array) []T {
    22  	return slice[T](a.Index(0), a.Len())
    23  }
    24  
    25  func slice[T any](p unsafe.Pointer, n int) []T {
    26  	return unsafe.Slice((*T)(p), n)
    27  }
    28  
    29  type sliceHeader struct {
    30  	base unsafe.Pointer
    31  	len  int
    32  	cap  int
    33  }