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EnableExplicit

;{ StrFastConcat } 
	
	; v 1.0.0.5
	;   2017		(c) Luna Sole
	Structure STRFASTOBJ
		*Data
	EndStructure
	
	; Starts new concatenation. Lot of them may exists and be threaded
	; RETURN:		strfast object on success
	Procedure StrFastNew()
		Protected *StrFast.STRFASTOBJ = AllocateStructure(STRFASTOBJ)
		If *StrFast
			*StrFast\Data = AllocateMemory(4 + 10240*SizeOf(Character))
			If *StrFast\Data
				PokeL(*StrFast\Data, 0)      ; bytes 1-4 storing current len (chars)
				ProcedureReturn *StrFast
			Else
				FreeStructure(*StrFast)
			EndIf
		EndIf
	EndProcedure
	
	; Concatenate strings quite optimized way
	; *String		pointer to a string
	; Len			*String len (chars). If set, len is not calculated here, which brings some more speed in some cases
	; RETURN:		none
	Procedure StrFastAddEx (*StrFast.STRFASTOBJ, *String, Len = 0)
		Protected NewLenB, *FastLen.Long
		If *StrFast
			If Len <= 0
				Len = MemoryStringLength(*String)
			EndIf
			If Len
				*FastLen = *StrFast\Data
				NewLenB = (*FastLen\l + Len)*SizeOf(Character)
				If NewLenB > (MemorySize(*StrFast\Data)-4)
					; every time buffer size is set to required size*2. that GREATLY raises both memory overhead and speed, comparing to use of small/medium fixed step
					; idea stolen from @Karig variant ^^
					*StrFast\Data = ReAllocateMemory(*StrFast\Data, 4 + NewLenB*1.28, #PB_Memory_NoClear)
					*FastLen = *StrFast\Data
				EndIf
				CopyMemory(*String, *StrFast\Data+4 + *FastLen\l*SizeOf(Character), Len*SizeOf(Character))
				*FastLen\l + Len
			EndIf
		EndIf
	EndProcedure
	
	; Wrapper for a cases where pointer is not applicable.
	; It is much slower than StrFastAddEx(), but only comparing to it. Itself is still very fast.
	; String$		a string to add
	; Len			String$ len (chars). If set, len is not calculated here, which brings some more speed in some cases
	; RETURN:		none
	Procedure StrFastAdd(*StrFast.STRFASTOBJ, String$, Len = 0)
		StrFastAddEx(*StrFast, @String$, Len)
	EndProcedure
	
	; Returns concatenated string
	; RETURN:		string
	Procedure$ StrFastGet(*StrFast.STRFASTOBJ)
		If *StrFast
			ProcedureReturn PeekS(*StrFast\Data+4, PeekL(*StrFast\Data))
		EndIf
	EndProcedure
	
	; Release specified fast string
	; RETURN:		none
	Procedure StrFastFree(*StrFast.STRFASTOBJ)
		If *StrFast
			FreeMemory(*StrFast\Data)
			FreeStructure(*StrFast)
		EndIf
	EndProcedure
	
;}


;;; Example

; Allocate this fast stuff
Define FS = StrFastNew()

; 1) Typical usage
StrFastAdd(FS, "test ")
; 2) Sometime this is faster, when is reasonable
StrFastAdd(FS, "this ", 5)
; 3) Using pointer + fixed len, fastest option here
StrFastAddEx(FS, @"ssst++", 4)

; Get Result & Release
Debug StrFastGet(FS)
StrFastFree(FS)

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Structure STRFASTOBJ
  len.l
  Step.l
  *Data
EndStructure

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If NewLenB+8 > (MemorySize(*StrFast\Data))
	*StrFast\Data = ReAllocateMemory(*StrFast\Data, 8+NewLenB + *FastStepB\l)
	*FastLen = *StrFast\Data : *FastStepB = *StrFast\Data+4; ++
EndIf