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Zero alloc strings
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//example for(int i=0;i<1000;i++) string newZeroGcString = NonAllocString.instance+"test"+23; | |
using System; | |
using System.Collections.Generic; | |
using System.Text; | |
public class NonAllocString | |
{ | |
private NonAllocString() | |
{ | |
} | |
public static NonAllocString instance | |
{ | |
get | |
{ | |
if (m_instance.Count > 0) | |
{ | |
var nonAllocString = m_instance.Pop(); | |
nonAllocString.generatedString = null; | |
return nonAllocString; | |
} | |
else | |
return new NonAllocString(); | |
} | |
} | |
static readonly Stack<NonAllocString> m_instance = new Stack<NonAllocString>(); | |
List<AnyValue> anyValues = new List<AnyValue>(); | |
public static NonAllocString operator +(NonAllocString a, object input) | |
{ | |
a.anyValues.Add(new AnyValue() {type = input?.GetType(), obj = input is NonAllocString d ? (string)d : input is string s ? s : input}); | |
return a; | |
} | |
public static NonAllocString operator +(NonAllocString a, int input) | |
{ | |
a.anyValues.Add(input); | |
return a; | |
} | |
public static NonAllocString operator +(NonAllocString a, float input) | |
{ | |
a.anyValues.Add(input); | |
return a; | |
} | |
public StringBuilder sb = new StringBuilder(); | |
public string GetString() | |
{ | |
sb.Clear(); | |
for (int i = 0; i < anyValues.Count; i++) | |
{ | |
if (anyValues[i].obj != null) | |
sb.Append(anyValues[i].obj); | |
else if (anyValues[i].type == typeof(int)) | |
sb.Append(anyValues[i].integer); | |
else if (anyValues[i].type == typeof(float)) | |
sb.Append(anyValues[i].float2); | |
} | |
return sb.ToString(); | |
} | |
public override string ToString() | |
{ | |
return anyValues.Count.ToString(); | |
} | |
public static implicit operator string(NonAllocString c) | |
{ | |
return c.Dispose(); | |
} | |
private string Dispose() | |
{ | |
if (!string.IsNullOrEmpty(generatedString)) | |
return generatedString; | |
var key = ArrayHash(); | |
string s; | |
if (!stringcache.TryGetValue(key, out s)) | |
s = stringcache[key] = GetString(); | |
m_instance.Push(this); | |
anyValues.Clear(); | |
return generatedString = s; | |
} | |
private string generatedString; | |
public static Dictionary<int, string> stringcache = new Dictionary<int, string>(); | |
public int ArrayHash() | |
{ | |
int key = 123; | |
for (int i = 0; i < anyValues.Count; i++) | |
{ | |
AnyValue o = anyValues[i]; | |
key = CombineHash(key, o.GetHashCode()); | |
} | |
return key; | |
} | |
public static int CombineHash(int h1, int h2) | |
{ | |
return ((h1 << 5) + h1) ^ h2; | |
} | |
struct AnyValue | |
{ | |
public Type type; | |
public object obj; | |
public int integer; | |
public float float2; | |
public static implicit operator int(AnyValue msg) | |
{ | |
return msg.integer; | |
} | |
public static implicit operator AnyValue(int c) | |
{ | |
return new AnyValue() {integer = c,type = typeof(int)}; | |
} | |
public static implicit operator float(AnyValue msg) | |
{ | |
return msg.float2; | |
} | |
public static implicit operator AnyValue(float c) | |
{ | |
return new AnyValue() {float2 = c, type = typeof(float)}; | |
} | |
public override int GetHashCode() | |
{ | |
if (obj != null) return CombineHash(type.GetHashCode(), obj.GetHashCode()); | |
if (type == typeof(int)) return CombineHash(integer.GetHashCode(), 2345); | |
if (type == typeof(float)) return CombineHash(float2.GetHashCode(), 4933); | |
throw new Exception("dad"); | |
} | |
} | |
} |
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