pos/is4c-nf/scale-drivers/drivers/NewMagellan/Newtonsoft.Json/Linq/JsonPath/ArraySliceFilter.cs
using System;
using System.Collections.Generic;
using System.Globalization;
using Newtonsoft.Json.Utilities;
namespace Newtonsoft.Json.Linq.JsonPath
{
internal class ArraySliceFilter : PathFilter
{
public int? Start { get; set; }
public int? End { get; set; }
public int? Step { get; set; }
public override IEnumerable<JToken> ExecuteFilter(IEnumerable<JToken> current, bool errorWhenNoMatch)
{
if (Step == 0)
throw new JsonException("Step cannot be zero.");
foreach (JToken t in current)
{
JArray a = t as JArray;
if (a != null)
{
// set defaults for null arguments
int stepCount = Step ?? 1;
int startIndex = Start ?? ((stepCount > 0) ? 0 : a.Count - 1);
int stopIndex = End ?? ((stepCount > 0) ? a.Count : -1);
// start from the end of the list if start is negitive
if (Start < 0) startIndex = a.Count + startIndex;
// end from the start of the list if stop is negitive
if (End < 0) stopIndex = a.Count + stopIndex;
// ensure indexes keep within collection bounds
startIndex = Math.Max(startIndex, (stepCount > 0) ? 0 : int.MinValue);
startIndex = Math.Min(startIndex, (stepCount > 0) ? a.Count : a.Count - 1);
stopIndex = Math.Max(stopIndex, -1);
stopIndex = Math.Min(stopIndex, a.Count);
bool positiveStep = (stepCount > 0);
if (IsValid(startIndex, stopIndex, positiveStep))
{
for (int i = startIndex; IsValid(i, stopIndex, positiveStep); i += stepCount)
{
yield return a[i];
}
}
else
{
if (errorWhenNoMatch)
throw new JsonException("Array slice of {0} to {1} returned no results.".FormatWith(CultureInfo.InvariantCulture,
Start != null ? Start.Value.ToString(CultureInfo.InvariantCulture) : "*",
End != null ? End.Value.ToString(CultureInfo.InvariantCulture) : "*"));
}
}
else
{
if (errorWhenNoMatch)
throw new JsonException("Array slice is not valid on {0}.".FormatWith(CultureInfo.InvariantCulture, t.GetType().Name));
}
}
}
private bool IsValid(int index, int stopIndex, bool positiveStep)
{
if (positiveStep)
return (index < stopIndex);
return (index > stopIndex);
}
}
}