// Copyright (c) 2006-2024, Timothy A. Davis, All Rights Reserved.
// SPDX-License-Identifier: LGPL-2.1+
// https://github.com/DrTimothyAldenDavis/SuiteSparse/tree/dev/CSparse/Source

/**
 * It sets the p[i] equal to the sum of c[0] through c[i-1].
 *
 * @param {Array}   ptr             The Sparse Matrix ptr array
 * @param {Array}   c               The Sparse Matrix ptr array
 * @param {Number}  n               The number of columns
 */
export function csCumsum(ptr, c, n) {
  // variables
  var i;
  var nz = 0;
  for (i = 0; i < n; i++) {
    // initialize ptr @ i
    ptr[i] = nz;
    // increment number of nonzeros
    nz += c[i];
    // also copy p[0..n-1] back into c[0..n-1]
    c[i] = ptr[i];
  }
  // finalize ptr
  ptr[n] = nz;
  // return sum (c [0..n-1])
  return nz;
}