如何解码 ASN.1 架构中的 TS32297 标头以获得 BER

Question

I am trying to write asn.1 schema for IMS cdrs having file header and repeating cdr headers(TS 32297 headers) but not able to decode these headers
In a specification shared by the client these headers are defined like this:

FileHeader ::= SEQUENCE
{   fileLength                          [0] INTEGER     (SIZE(4) CODE("DEC")) OPTIONAL,
    headerlength                        [1] INTEGER (SIZE (3) CODE ("DEC")) OPTIONAL,
    highreleaseIdentifier               [2] OCTET STRING (SIZE (1)CODE ("LEFT")) OPTIONAL,
    lowreleaseIdentifier                    [3] OCTET STRING (SIZE (1)CODE ("LEFT")) OPTIONAL,
    fileTimestamp                   [4] OCTET STRING (SIZE (4)CODE ("LEFT")) OPTIONAL,
    lastcdrTimestamp                    [5] OCTET STRING (SIZE (4)CODE ("LEFT")) OPTIONAL,
    dataRecordIdentifier                [6] OCTET STRING (SIZE (8)CODE ("LEFT")) OPTIONAL,  
    totalCdr                    [10] OCTET STRING (SIZE (4)CODE ("LEFT")) OPTIONAL,
    filesequencenumber                  [11] OCTET STRING (SIZE (4)CODE ("LEFT")) OPTIONAL,
    filecloserReason                [12] IMPLICIT   FilecloserReason (SIZE (4)CODE("DEC")) OPTIONAL,
    ipnodeaddress                       [13] OCTET STRING (SIZE (20)CODE ("LEFT")) OPTIONAL,
    lostCdrindicator                [14] OCTET STRING (SIZE (1)CODE ("LEFT")) OPTIONAL,
    lengthCdrFilter                     [15] INTEGER (SIZE (2)CODE ("LEFT")) OPTIONAL,
    cdrroutingFilter                [16] OCTET STRING (SIZE (5)CODE ("LEFT")) OPTIONAL  
}
CDRHeader ::= SEQUENCE
{       
    cDRLength                       [0] INTEGER     (SIZE(2) CODE("DEC")) OPTIONAL,
    releaseIdentifier           [1] IMPLICIT  OCTET STRING (SIZE (1)CODE ("LEFT")) OPTIONAL, -- This comprises of Release Id and Version Id 
    dataRecordIdentifier        [2] IMPLICIT  OCTET STRING (SIZE (1)CODE ("LEFT")) OPTIONAL, -- It comprises of Data Record Number and TS Number 
    releaseIdentifierextension  [3] IMPLICIT  ReleaseIdentifierextension (SIZE (1)CODE("DEC")) OPTIONAL 
}

但是 ASNVE1 无法理解这些 CODE("DEC")/CODE ("LEFT")，因此无法编译此 asn 规范。

请建议如何修改标头的 ASN 架构

Answer 1

您的规格无效

1. CODE 不是有效的约束
2. 如果它是一个有效的约束，那么你需要一个逻辑运算符来将它与 SIZE 约束结合起来

您可以删除所有的 CODE("DEC") 和 CODE ("LEFT")

Answer 2

你不能做你想做的事。 TS 32.297 标头未在 ASN.1 中指定并且不符合 ASN.1 编码。 如果您使用Objective System 的ASN1VE 工具查看此数据，它可以解析标题然后显示ASN.1 数据，但您必须告诉它您的数据有32.297 个标题。 然后使用描述 ASN.1 编码数据的未修改 ASN.1 模式。