[XML] properly handle normalizedString & token

[jkowalleck]

CycloneDX uses http://www.w3.org/2001/XMLSchema - which defines normalizedString as follows:

<xs:simpleType name="normalizedString" id="normalizedString">
  <xs:annotation>
    <xs:documentation source="http://www.w3.org/TR/xmlschema-2/#normalizedString"/>
  </xs:annotation>
  <xs:restriction base="xs:string">
    <xs:whiteSpace value="replace" id="normalizedString.whiteSpace"/>
  </xs:restriction>
</xs:simpleType>

normalizedString represents white space normalized strings. The ·value space· of normalizedString is the set of strings that do not contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters. The ·lexical space· of normalizedString is the set of strings that do not contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters. The ·base type· of normalizedString is string.

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CycloneDX uses http://www.w3.org/2001/XMLSchema - which defines token as follows:

<xs:simpleType name="token" id="token">
  <xs:annotation>
    <xs:documentation source="http://www.w3.org/TR/xmlschema-2/#token"/>
  </xs:annotation>
  <xs:restriction base="xs:normalizedString">
    <xs:whiteSpace value="collapse" id="token.whiteSpace"/>
  </xs:restriction>
</xs:simpleType>

token represents tokenized strings. The ·value space· of token is the set of strings that do not contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters, that have no leading or trailing spaces (#x20) and that have no internal sequences of two or more spaces. The ·lexical space· of token is the set of strings that do not contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters, that have no leading or trailing spaces (#x20) and that have no internal sequences of two or more spaces. The ·base type· of token is normalizedString.

---

therefore, on XML-normalization for normalizedString, the following chars must be replaced by space( ):

• carriage return: \r (#xD)
• line feed: \n (#xA)
• tab: \t (#x9)

Therefore, on XML-normalization for token, the following must aplpy:

• all from above
• consecutive spaces are collapsed to one space.
• leading and trialing spaces are truncated

Affected are only fields that are defined as normalizedString respective token in XML spec!
Other field MUST NOT be affected!

[jkowalleck]

possible solution:
modify the XML normalizers where needed, and call a to-be-written helper function that does the normalization.

[jkowalleck]

solution as done in TS?JS CycloneDX/cyclonedx-javascript-library#1116