Re: To cast or not to cast?
- From: "Ilya Tumanov [MS]" <ilyatum@xxxxxxxxxxxxxxxxxxxx>
- Date: Sun, 10 Apr 2005 16:59:49 -0700
It won't, but managed array (retrieved from SQL CE) should be already
allocated.
Best regards,
Ilya
This posting is provided "AS IS" with no warranties, and confers no rights.
"<ctacke/>" <ctacke_AT_OpenNETCF_com> wrote in message
news:O13JLjhPFHA.2252@xxxxxxxxxxxxxxxxxxxxxxx
> Though fixed won't allocate any memory for you, so you're still where you
> were before.
>
> -Chris
>
>
> ""Ilya Tumanov [MS]"" <ilyatum@xxxxxxxxxxxxxxxxxxxx> wrote in message
> news:MFm$3ThPFHA.1564@xxxxxxxxxxxxxxxxxxxxxxxx
>> You don't need to do anything to pin memory with fixed(), fixed() will do
>> it for you:
>>
>> fixed(void *ArrayPointer = MyManagedArray) {
>> // MyManagedArray is pinned within fixed block and ArrayPointer points to
>> it.
>> // Assign it to IntPtr (might need some casting) and call native function
>> within this block.
>> }
>>
>> // MyManagedArray in longer pinned...
>>
>> Best regards,
>>
>> Ilya
>>
>> This posting is provided "AS IS" with no warranties, and confers no
>> rights.
>> --------------------
>>> From: "Jeremy" <jezonline@xxxxxxxxxxx>
>>> References: <umEpDi8OFHA.3880@xxxxxxxxxxxxxxxxxxxx>
>> <64$0lp9OFHA.1564@xxxxxxxxxxxxxxxxxxxxx>
>> <#t8wc#BPFHA.1268@xxxxxxxxxxxxxxxxxxxx>
>> <tz30okGPFHA.920@xxxxxxxxxxxxxxxxxxxxx>
>> <eTuV9uUPFHA.2568@xxxxxxxxxxxxxxxxxxxx>
>> <SN73xxVPFHA.920@xxxxxxxxxxxxxxxxxxxxx>
>> <#Hr63aWPFHA.3336@xxxxxxxxxxxxxxxxxxxx>
>> <VMZf79WPFHA.920@xxxxxxxxxxxxxxxxxxxxx>
>>> Subject: Re: To cast or not to cast?
>>> Date: Sun, 10 Apr 2005 20:37:43 +0100
>>> Lines: 335
>>> X-Priority: 3
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>> microsoft.public.dotnet.framework.compactframework:26681
>>> X-Tomcat-NG: microsoft.public.dotnet.framework.compactframework
>>>
>>> I did a little bit of research because I'm a newbie regarding
>>> pointers/memory allocation. I found an interesting post by Brian Smith:
>>>
>> http://groups-beta.google.com/group/microsoft.public.dotnet.framework.compac
>> tframework/browse_frm/thread/d628847ac90ac8a3/b92cb386364174f7?q=unmanaged+a
>> llocate+memory&rnum=10#b92cb386364174f7
>>>
>>> I supose I could use LocalAlloc to allocate memory. The post seems to be
>>> similar to my problem but I still don't understand how to pin managed
>> memory
>>> (by using Fixed()?), and have a pointer point to the byte array (which
>>> is
>>> probably what I would want to do) ?
>>>
>>> your help is really appreciated!
>>>
>>> ""Ilya Tumanov [MS]"" <ilyatum@xxxxxxxxxxxxxxxxxxxx> wrote in message
>>> news:VMZf79WPFHA.920@xxxxxxxxxxxxxxxxxxxxxxxx
>>> > Creating a new pointer is not enough. You need to allocate memory and
>>> > assign value pointing to it to the pointer.
>>> > You might allocate native memory via P/Invoke (which you would have to
>>> free
>>> > at some point).
>>> > Or, you can obtain a pointer to a managed array you already have.
>>> > Before you pass this pointer to a native code, you have to pin managed
>>> > memory so GC won't move the array.
>>> > You can use GCHandle class for it or you can use unsafe code.
>>> > I would recommend using Fixed() with unsafe pointer. That would pin
>>> > and
>>> > unpin the array automatically.
>>> > GCHandle has a bug (returns incorrect pointer - there's a workaround)
>> and
>>> > it's not automatic.
>>> >
>>> > Best regards,
>>> >
>>> > Ilya
>>> >
>>> > This posting is provided "AS IS" with no warranties, and confers no
>>> rights.
>>> >
>>> > --------------------
>>> > > From: "Jeremy" <jezonline@xxxxxxxxxxx>
>>> > > References: <umEpDi8OFHA.3880@xxxxxxxxxxxxxxxxxxxx>
>>> > <64$0lp9OFHA.1564@xxxxxxxxxxxxxxxxxxxxx>
>>> > <#t8wc#BPFHA.1268@xxxxxxxxxxxxxxxxxxxx>
>>> > <tz30okGPFHA.920@xxxxxxxxxxxxxxxxxxxxx>
>>> > <eTuV9uUPFHA.2568@xxxxxxxxxxxxxxxxxxxx>
>>> > <SN73xxVPFHA.920@xxxxxxxxxxxxxxxxxxxxx>
>>> > > Subject: Re: To cast or not to cast?
>>> > > Date: Sun, 10 Apr 2005 01:46:03 +0100
>>> > > Lines: 240
>>> > > X-Priority: 3
>>> > > X-MSMail-Priority: Normal
>>> > > X-Newsreader: Microsoft Outlook Express 6.00.2800.1478
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>>> > > Message-ID: <#Hr63aWPFHA.3336@xxxxxxxxxxxxxxxxxxxx>
>>> > > Newsgroups: microsoft.public.dotnet.framework.compactframework
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>>> > > Path:
>>> > > TK2MSFTNGXA01.phx.gbl!TK2MSFTNGP08.phx.gbl!TK2MSFTNGP10.phx.gbl
>>> > > Xref: TK2MSFTNGXA01.phx.gbl
>>> > microsoft.public.dotnet.framework.compactframework:26658
>>> > > X-Tomcat-NG: microsoft.public.dotnet.framework.compactframework
>>> > >
>>> > > Okay, so I used the 1040 length, it doesn't seem to complain, which
>>> > > is
>>> > good
>>> > > news I guess. To make sure it stores the data correctly I'm trying
>>> > > to
>>> > > retrieve it and feed it back to the biometric template matching
>> method.
>>> > >
>>> > > Because it takes IntPtr's for BiometricData and Signature, I tried
>>> > creating
>>> > > new pointers and marshal copy the content that I retrieved earlier
>> into
>>> > > these pointers. I failed. I tried the following:
>>> > >
>>> > > System.IntPtr BiometricDataPtr;//create new pointer
>>> > > BiometricData = (byte[])bioData[8];//BiometricData is an array of
>>> > > type
>>> > byte
>>> > > Marshal.Copy(BiometricData, 0, BiometricDataPtr, 1040);//copy
>>> > > content
>> of
>>> > > BiometricData in an IntPtr
>>> > >
>>> > > "Use of unassigned local variable 'BiometricDataPtr'."
>>> > > Obvsiously it's unused, it's meant to point to something... what am
>>> > > I
>>> > > missing here?
>>> > >
>>> > > ""Ilya Tumanov [MS]"" <ilyatum@xxxxxxxxxxxxxxxxxxxx> wrote in
>>> > > message
>>> > > news:SN73xxVPFHA.920@xxxxxxxxxxxxxxxxxxxxxxxx
>>> > > > You should not guess the length, you should know it. It might be
>> fixed
>>> > or
>>> > > > native code could return it somehow.
>>> > > > Most likely you're correct and FirstBIRSample.Length contains this
>>> size.
>>> > > > You should check out the documentation for the function you're
>> calling
>>> > to
>>> > > > make sure it's correct.
>>> > > >
>>> > > > If value of a pointer is 0, it's null pointer. It means this
>>> > > > pointer
>>> is
>>> > > not
>>> > > > valid and points to nothing.
>>> > > > Since no data is available, you could store it as DBNull.
>>> > > >
>>> > > > Best regards,
>>> > > >
>>> > > > Ilya
>>> > > >
>>> > > > This posting is provided "AS IS" with no warranties, and confers
>>> > > > no
>>> > > rights.
>>> > > >
>>> > > > --------------------
>>> > > > > From: "Jeremy" <jezonline@xxxxxxxxxxx>
>>> > > > > References: <umEpDi8OFHA.3880@xxxxxxxxxxxxxxxxxxxx>
>>> > > > <64$0lp9OFHA.1564@xxxxxxxxxxxxxxxxxxxxx>
>>> > > > <#t8wc#BPFHA.1268@xxxxxxxxxxxxxxxxxxxx>
>>> > > > <tz30okGPFHA.920@xxxxxxxxxxxxxxxxxxxxx>
>>> > > > > Subject: Re: To cast or not to cast?
>>> > > > > Date: Sat, 9 Apr 2005 22:32:29 +0100
>>> > > > > Lines: 159
>>> > > > > X-Priority: 3
>>> > > > > X-MSMail-Priority: Normal
>>> > > > > X-Newsreader: Microsoft Outlook Express 6.00.2800.1478
>>> > > > > X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1478
>>> > > > > Message-ID: <eTuV9uUPFHA.2568@xxxxxxxxxxxxxxxxxxxx>
>>> > > > > Newsgroups: microsoft.public.dotnet.framework.compactframework
>>> > > > > NNTP-Posting-Host: host-84-9-101-26.bulldogdsl.com 84.9.101.26
>>> > > > > Path:
>>> TK2MSFTNGXA01.phx.gbl!TK2MSFTNGP08.phx.gbl!TK2MSFTNGP14.phx.gbl
>>> > > > > Xref: TK2MSFTNGXA01.phx.gbl
>>> > > > microsoft.public.dotnet.framework.compactframework:26653
>>> > > > > X-Tomcat-NG: microsoft.public.dotnet.framework.compactframework
>>> > > > >
>>> > > > > Thanks a lot for that! Before going to the UInt16 problem, I
>> better
>>> > try
>>> > > to
>>> > > > > solve that IntPtr problem.
>>> > > > >
>>> > > > > Managed to use Marshal.Copy. Not sure how I should 'guess' the
>>> length
>>> > of
>>> > > > the
>>> > > > > Byte array to copy to. When I type FirstBIRSample.BiometricData
>>> (which
>>> > > is
>>> > > > > the IntPtr) in the command window, it returns to me: 2372256 -
>>> > > > > is
>>> this
>>> > > the
>>> > > > > size?
>>> > > > > I 'assumed' the size would be 1040 (which is stored in
>>> > > > > FirstBIRSample.Length).
>>> > > > >
>>> > > > > Second Part: Seems like the FirstBIRSample.Signature (also a
>>> pointer)
>>> > is
>>> > > > 0,
>>> > > > > how should I store this?
>>> > > > >
>>> > > > > Thanks so much!
>>> > > > >
>>> > > > > ""Ilya Tumanov [MS]"" <ilyatum@xxxxxxxxxxxxxxxxxxxx> wrote in
>>> message
>>> > > > > news:tz30okGPFHA.920@xxxxxxxxxxxxxxxxxxxxxxxx
>>> > > > > > While storing UInt16 as Int is OK, it will take more space.
>>> > > > > > The
>>> > > problem
>>> > > > > > you're having is caused by range check. You might consider
>>> > > > > > using
>>> > > > > > unchecked() to disable it.
>>> > > > > >
>>> > > > > > System.Runtime.InteropServices.Marshal class allows you to
>>> > > > > > copy
>>> data
>>> > > > from
>>> > > > > > the pointer to the array. Look into Copy() methods of that
>> class.
>>> > > > > >
>>> > > > > > Best regards,
>>> > > > > >
>>> > > > > > Ilya
>>> > > > > >
>>> > > > > > This posting is provided "AS IS" with no warranties, and
>>> > > > > > confers
>>> no
>>> > > > > rights.
>>> > > > > > --------------------
>>> > > > > > > From: "Jeremy" <jezonline@xxxxxxxxxxx>
>>> > > > > > > References: <umEpDi8OFHA.3880@xxxxxxxxxxxxxxxxxxxx>
>>> > > > > > <64$0lp9OFHA.1564@xxxxxxxxxxxxxxxxxxxxx>
>>> > > > > > > Subject: Re: To cast or not to cast?
>>> > > > > > > Date: Fri, 8 Apr 2005 10:44:39 +0100
>>> > > > > > > Lines: 91
>>> > > > > > > X-Priority: 3
>>> > > > > > > X-MSMail-Priority: Normal
>>> > > > > > > X-Newsreader: Microsoft Outlook Express 6.00.2800.1478
>>> > > > > > > X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1478
>>> > > > > > > Message-ID: <#t8wc#BPFHA.1268@xxxxxxxxxxxxxxxxxxxx>
>>> > > > > > > Newsgroups:
>>> > > > > > > microsoft.public.dotnet.framework.compactframework
>>> > > > > > > NNTP-Posting-Host: host-84-9-101-26.bulldogdsl.com
>>> > > > > > > 84.9.101.26
>>> > > > > > > Path:
>>> > > TK2MSFTNGXA01.phx.gbl!TK2MSFTNGP08.phx.gbl!TK2MSFTNGP14.phx.gbl
>>> > > > > > > Xref: TK2MSFTNGXA01.phx.gbl
>>> > > > > > microsoft.public.dotnet.framework.compactframework:26572
>>> > > > > > > X-Tomcat-NG:
>> microsoft.public.dotnet.framework.compactframework
>>> > > > > > >
>>> > > > > > > Thanks so much for the replies Alex and Ilya!
>>> > > > > > >
>>> > > > > > > I changed the types in sql. It wasn't happy with Uint16
>>> > > > > > > mapped
>>> to
>>> > > > > smallint
>>> > > > > > > (sql says value is either too small or too large), so I just
>>> went
>>> > > for
>>> > > > an
>>> > > > > > > int.
>>> > > > > > >
>>> > > > > > > Not sure how to retrieve the data data an IntPtr is pointing
>> to
>>> > > > though.
>>> > > > > > How
>>> > > > > > > can I get that data as a byte array?
>>> > > > > > >
>>> > > > > > > thanks so much again!
>>> > > > > > >
>>> > > > > > > ""Ilya Tumanov [MS]"" <ilyatum@xxxxxxxxxxxxxxxxxxxx> wrote
>>> > > > > > > in
>>> > > message
>>> > > > > > > news:64$0lp9OFHA.1564@xxxxxxxxxxxxxxxxxxxxxxxx
>>> > > > > > > >
>>> > > > > > >
>>> > > > > >
>>> > > > >
>>> > > >
>>> > >
>>> >
>>>
>> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/
>>> > > > > > > > frlrfsystemdatasqldbtypeclasstopic.asp
>>> > > > > > > >
>>> > > > > > > > UInt32: Int will do. Signed and Unsigned integers are
>> actually
>>> > the
>>> > > > > same;
>>> > > > > > > > just cast them to the right type.
>>> > > > > > > > UInt16: SmallInt, see warning above
>>> > > > > > > > Byte: TinyInt
>>> > > > > > > > BioAPI_*: look up underlying type definition and use it.
>> Enums
>>> > are
>>> > > > > Int32
>>> > > > > > > by
>>> > > > > > > > default.
>>> > > > > > > > IntPtr: it's Int32, so store it as Int.
>>> > > > > > > >
>>> > > > > > > > Note, however, it's probably pointless to store pointers
>>> > > > > > > > in
>>> the
>>> > > data
>>> > > > > > base.
>>> > > > > > > > Pointer itself is not important, most likely you need to
>> store
>>> > > > > whatever
>>> > > > > > > > it's pointing to.
>>> > > > > > > >
>>> > > > > > > > Best regards,
>>> > > > > > > >
>>> > > > > > > > Ilya
>>> > > > > > > >
>>> > > > > > > > This posting is provided "AS IS" with no warranties, and
>>> confers
>>> > > no
>>> > > > > > > rights.
>>> > > > > > > >
>>> > > > > > > > --------------------
>>> > > > > > > > > From: "Jeremy" <jezonline@xxxxxxxxxxx>
>>> > > > > > > > > Subject: To cast or not to cast?
>>> > > > > > > > > Date: Fri, 8 Apr 2005 00:21:17 +0100
>>> > > > > > > > > Lines: 25
>>> > > > > > > > > X-Priority: 3
>>> > > > > > > > > X-MSMail-Priority: Normal
>>> > > > > > > > > X-Newsreader: Microsoft Outlook Express 6.00.2800.1478
>>> > > > > > > > > X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1478
>>> > > > > > > > > Message-ID: <umEpDi8OFHA.3880@xxxxxxxxxxxxxxxxxxxx>
>>> > > > > > > > > Newsgroups:
>>> microsoft.public.dotnet.framework.compactframework
>>> > > > > > > > > NNTP-Posting-Host: host-84-9-101-26.bulldogdsl.com
>>> 84.9.101.26
>>> > > > > > > > > Path:
>>> > > > > TK2MSFTNGXA01.phx.gbl!TK2MSFTNGP08.phx.gbl!tk2msftngp13.phx.gbl
>>> > > > > > > > > Xref: TK2MSFTNGXA01.phx.gbl
>>> > > > > > > > microsoft.public.dotnet.framework.compactframework:26546
>>> > > > > > > > > X-Tomcat-NG:
>>> > microsoft.public.dotnet.framework.compactframework
>>> > > > > > > > >
>>> > > > > > > > > Hi,
>>> > > > > > > > >
>>> > > > > > > > > I'm trying to convert the following types into types
>>> > > > > > > > > that
>> I
>>> > can
>>> > > > > insert
>>> > > > > > > in
>>> > > > > > > > an
>>> > > > > > > > > SQL database (via a webservice). None of these however
>>> > > > > > > > > are
>>> > > > accepted
>>> > > > > by
>>> > > > > > > Sql
>>> > > > > > > > > (i.e., there is no OleDbType for them). I could only use
>>> > integer
>>> > > > > type
>>> > > > > > > for
>>> > > > > > > > > UInt32, that's about it. I'm totally unsure about the
>> other
>>> > > types.
>>> > > > > > What
>>> > > > > > > > I've
>>> > > > > > > > > tried doing so far is casting them prior to sending them
>> to
>>> > the
>>> > > > > > > > webservice.
>>> > > > > > > > > When inserting them I get errors though. Would anyone
>>> > know/could
>>> > > > > point
>>> > > > > > > me
>>> > > > > > > > to
>>> > > > > > > > > types that I could use? Any help would be really
>>> appreciated,
>>> > > i'm
>>> > > > > > lost!
>>> > > > > > > > >
>>> > > > > > > > > Thanks so much!
>>> > > > > > > > >
>>> > > > > > > > >
>>> > > > > > > > > System.UInt32 Length;
>>> > > > > > > > > System.Byte HeaderVersion;
>>> > > > > > > > > BioAPI_BIR_DATA_TYPE Type;
>>> > > > > > > > > System.UInt16 FormatOwner;
>>> > > > > > > > > System.UInt16 FormatID;
>>> > > > > > > > > System.Byte Quality; /*INT8 BioAPI_QUALITY*/
>>> > > > > > > > > BioAPI_BIR_PURPOSE Purpose;
>>> > > > > > > > > BioAPI_BIR_AUTH_FACTORS FactorsMask;
>>> > > > > > > > > System.IntPtr BiometricData;
>>> > > > > > > > > System.IntPtr Signature;
>>> > > > > > > > >
>>> > > > > > > > >
>>> > > > > > > > >
>>> > > > > > > >
>>> > > > > > >
>>> > > > > > >
>>> > > > > > >
>>> > > > > >
>>> > > > >
>>> > > > >
>>> > > > >
>>> > > >
>>> > >
>>> > >
>>> > >
>>> >
>>>
>>>
>>>
>>
>
>
.
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- From: Jeremy
- RE: To cast or not to cast?
- From: "Ilya Tumanov [MS]"
- Re: To cast or not to cast?
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- From: "Ilya Tumanov [MS]"
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- From: "Ilya Tumanov [MS]"
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