var RandomSeed		# The seed for the random number generator
 
###############################################################
#
# Returns a random number
#
# Usage:
# 	Push Seed (or previously generated number)
#	Call RandomNumber
#	Pop Generated Random Number
Function RandomNumber
	Exch $R0
 
	IntOp $R0 $R0 * "13"
	IntOp $R0 $R0 + "3"
	IntOp $R0 $R0 % "1048576" # Values goes from 0 to 1048576 (2^20)
 
	Exch $R0
FunctionEnd
 
####################################################
#
# Returns a random number between 0 and MaxValue-1
#
# Usage:
# 	Push Seed (or previously generated number)
#	Push MaxValue
#	Call RandomNumber
#	Pop Generated Random Number
#	Pop NewSeed
Function LimitedRandomNumber
	Exch $R0
	Exch
	Exch $R1
	Push $R2
	Push $R3
 
	StrLen $R2 $R0
	Push $R1
RandLoop:
	Call RandomNumber
	Pop $R1	#Random Number
	IntCmp $R1 $R0 0 NewRnd
	StrLen $R3 $R1	
	IntOp $R3 $R3 - $R2
	IntOp $R3 $R3 / "2"
	StrCpy $R3 $R1 $R2 $R3
	IntCmp $R3 $R0 0 RndEnd
NewRnd:
	Push $R1
	Goto RandLoop
RndEnd:
	StrCpy $R0 $R3
	IntOp $R0 $R0 + "0" #removes initial 0's
	Pop $R3
	Pop $R2
	Exch $R1
	Exch
	Exch $R0
FunctionEnd

###################################################
# 
# Downloads a file from a list of mirrors
# (the fist mirror is selected at random)
#
# Usage:
# 	Push Mirror1
# 	[Push Mirror2]
# 	...
# 	[Push Mirror10]
#	Push NumMirrors		# 10 Max
#	Push FileName
#	Call DownloadFromRandomMirror
#	Pop Return
#
#	Returns the last NSISdl result
Function DownloadFromRandomMirror
	Exch $R1 #File name
	Exch
	Exch $R0 #Number of Mirrors
	Push $0
	Exch 3
	Pop $0	#Mirror 1
	IntCmpU "2" $R0 0 0 +4
		Push $1
		Exch 4
		Pop $1	#Mirror 2
	IntCmpU "3" $R0 0 0 +4
		Push $2
		Exch 5
		Pop $2	#Mirror 3
	IntCmpU "4" $R0 0 0 +4
		Push $3
		Exch 6
		Pop $3	#Mirror 4
	IntCmpU "5" $R0 0 0 +4
		Push $4
 
		Exch 7
		Pop $4	#Mirror 5
	IntCmpU "6" $R0 0 0 +4
		Push $5
		Exch 8
		Pop $5	#Mirror 6
	IntCmpU "7" $R0 0 0 +4
		Push $6
		Exch 9
		Pop $6	#Mirror 7
	IntCmpU "8" $R0 0 0 +4
		Push $7
		Exch 10
		Pop $7	#Mirror 8
	IntCmpU "9" $R0 0 0 +4
		Push $8
		Exch 11
		Pop $8	#Mirror 9
	IntCmpU "10" $R0 0 0 +4
		Push $9
		Exch 12
		Pop $9	#Mirror 10
	Push $R4
	Push $R2
	Push $R3
	Push $R5
	Push $R6
 
	StrCmp $RandomSeed "" 0 +2
		StrCpy $RandomSeed $HWNDPARENT   #init RandomSeed
 
	Push $RandomSeed
	Push $R0
	Call LimitedRandomNumber
	Pop $R3
	Pop $RandomSeed
 
	StrCpy $R5 "0"
MirrorsStart:
	IntOp $R5 $R5 + "1"
	StrCmp $R3 "0" 0 +3
		StrCpy $R2 $0
		Goto MirrorsEnd
	StrCmp $R3 "1" 0 +3
		StrCpy $R2 $1
		Goto MirrorsEnd
	StrCmp $R3 "2" 0 +3
		StrCpy $R2 $2
		Goto MirrorsEnd
	StrCmp $R3 "3" 0 +3
		StrCpy $R2 $3
		Goto MirrorsEnd
	StrCmp $R3 "4" 0 +3
		StrCpy $R2 $4
		Goto MirrorsEnd
	StrCmp $R3 "5" 0 +3
		StrCpy $R2 $5
		Goto MirrorsEnd
	StrCmp $R3 "6" 0 +3
		StrCpy $R2 $6
		Goto MirrorsEnd
	StrCmp $R3 "7" 0 +3
		StrCpy $R2 $7
		Goto MirrorsEnd
	StrCmp $R3 "8" 0 +3
		StrCpy $R2 $8
		Goto MirrorsEnd
	StrCmp $R3 "9" 0 +3
		StrCpy $R2 $9
		Goto MirrorsEnd
	StrCmp $R3 "10" 0 +3
		StrCpy $R2 $10
		Goto MirrorsEnd
 
MirrorsEnd:
	IntOp $R6 $R3 + "1"
	DetailPrint "Downloading from mirror $R6: $R2"
 
	NSISdl::download "$R2" "$R1"
	Pop $R4
	StrCmp $R4 "success" Success
	StrCmp $R4 "cancel" DownloadCanceled
	IntCmp $R5 $R0 NoSuccess
	DetailPrint "Download failed (error $R4), trying with other mirror"
	IntOp $R3 $R3 + "1"
	IntCmp $R3 $R0 0 MirrorsStart
	StrCpy $R3 "0"
	Goto MirrorsStart
 
DownloadCanceled:
	DetailPrint "Download Canceled: $R2"
	Goto End
NoSuccess:		
	DetailPrint "Download Failed: $R1"
	Goto End
Success:
	DetailPrint "Download completed."
End:
	Pop $R6
	Pop $R5
	Pop $R3
	Pop $R2
	Push $R4
	Exch
	Pop $R4
	Exch 2
	Pop $R1
	Exch 2
	Pop $0
	Exch
 
	IntCmpU "2" $R0 0 0 +4
		Exch 2	
		Pop $1
		Exch
	IntCmpU "3" $R0 0 0 +4
		Exch 2	
		Pop $2
		Exch
	IntCmpU "4" $R0 0 0 +4
		Exch 2	
		Pop $3
		Exch
	IntCmpU "5" $R0 0 0 +4
		Exch 2	
		Pop $4
		Exch
	IntCmpU "6" $R0 0 0 +4
		Exch 2	
		Pop $5
		Exch
	IntCmpU "7" $R0 0 0 +4
		Exch 2	
		Pop $6
		Exch
	IntCmpU "8" $R0 0 0 +4
		Exch 2	
		Pop $7
		Exch
	IntCmpU "9" $R0 0 0 +4
		Exch 2	
		Pop $8
		Exch
	IntCmpU "10" $R0 0 0 +4
		Exch 2	
		Pop $9
		Exch
	Pop $R0
FunctionEnd