Add some doc and switch to the parallel gzip library

Former-commit-id: 2c1187001f989ba3de5895f516d4c8b54d52a4c4

pkg/obiutils/array.go

@@ -0,0 +1,40 @@
+package obiutils
+
+// Matrix is a generic type representing a matrix.
+type Matrix[T any] [][]T
+
+// Make2DArray generates a 2D array of type T with the specified number of rows and columns.
+//
+// Data is stored in a contiguous memory block in row-major order.
+//
+// Parameters:
+// - rows: the number of rows in the 2D array.
+// - cols: the number of columns in the 2D array.
+//
+// Return:
+// - Matrix[T]: the generated 2D array of type T.
+func Make2DArray[T any](rows, cols int) Matrix[T] {
+	matrix := make(Matrix[T], rows)
+	data := make([]T, cols*rows)
+	for i := 0; i < rows; i++ {
+		matrix[i] = data[i*cols : (i+1)*cols]
+	}
+	return matrix
+}
+
+// Row returns the i-th row of the matrix.
+//
+// Parameters:
+//
+//	i - the index of the row to retrieve.
+//
+// Return:
+//
+//	[]T - the i-th row of the matrix.
+func (matrix *Matrix[T]) Column(i int) []T {
+	r := make([]T, len(*matrix))
+	for j := 0; j < len(*matrix); j++ {
+		r[j] = (*matrix)[j][i]
+	}
+	return r
+}