/// <summary>
/// Attempts to read the next value as an OCTET STRING with a specified tag, returning the contents
/// as a <see cref="ReadOnlyMemory{T}"/> over the original data.
/// </summary>
/// <param name="expectedTag">The tag to check for before reading.</param>
/// <param name="contents">
/// On success, receives a <see cref="ReadOnlyMemory{T}"/> over the original data
/// corresponding to the value of the OCTET STRING.
/// </param>
/// <returns>
/// <see langword="true"/> and advances the reader if the OCTET STRING value had a primitive encoding,
/// <see langword="false"/> and does not advance the reader if it had a constructed encoding.
/// </returns>
/// <exception cref="AsnContentException">
/// the next value does not have the correct tag.
///
/// -or-
///
/// the length encoding is not valid under the current encoding rules.
///
/// -or-
///
/// the contents are not valid under the current encoding rules.
/// </exception>
/// <exception cref="ArgumentException">
/// <paramref name="expectedTag"/>.<see cref="Asn1Tag.TagClass"/> is
/// <see cref="TagClass.Universal"/>, but
/// <paramref name="expectedTag"/>.<see cref="Asn1Tag.TagValue"/> is not correct for
/// the method.
/// </exception>
/// <seealso cref="TryReadOctetString"/>
public bool TryReadPrimitiveOctetString(out ReadOnlyMemory <byte> contents, Asn1Tag?expectedTag = null)
{
bool ret = AsnDecoder.TryReadPrimitiveOctetString(
_data.Span,
RuleSet,
out ReadOnlySpan <byte> span,
out int consumed,
expectedTag);
if (ret)
{
contents = AsnDecoder.Slice(_data, span);
_data = _data.Slice(consumed);
}
else
{
contents = default;
}
return(ret);
}
/// <summary>
/// Write a single value which has already been encoded.
/// </summary>
/// <param name="value">The value to write.</param>
/// <remarks>
/// This method only checks that the tag and length are encoded according to the current ruleset,
/// and that the end of the value is the end of the input. The contents are not evaluated for
/// semantic meaning.
/// </remarks>
/// <exception cref="ArgumentException">
/// <paramref name="value"/> could not be read under the current encoding rules.
///
/// -or-
///
/// <paramref name="value"/> has data beyond the end of the first value.
/// </exception>
public void WriteEncodedValue(ReadOnlySpan <byte> value)
{
// Is it legal under the current rules?
bool read = AsnDecoder.TryReadEncodedValue(
value,
RuleSet,
out _,
out _,
out _,
out int consumed);
if (!read || consumed != value.Length)
{
throw new ArgumentException(
SR.Argument_WriteEncodedValue_OneValueAtATime,
nameof(value));
}
EnsureWriteCapacity(value.Length);
value.CopyTo(_buffer.AsSpan(_offset));
_offset += value.Length;
}
/// <summary>
/// Reads the next value as a BIT STRING with a specified tag, copying the value
/// into a provided destination buffer.
/// </summary>
/// <param name="destination">The buffer in which to write.</param>
/// <param name="unusedBitCount">
/// On success, receives the number of bits in the last byte which were reported as
/// "unused" by the writer.
/// </param>
/// <param name="bytesWritten">
/// On success, receives the number of bytes written to <paramref name="destination"/>.
/// </param>
/// <param name="expectedTag">
/// The tag to check for before reading, or <see langword="null"/> for the default tag (Universal 1).
/// </param>
/// <returns>
/// <see langword="true"/> and advances the reader if <paramref name="destination"/> had sufficient
/// length to receive the value, otherwise
/// <see langword="false"/> and the reader does not advance.
/// </returns>
/// <exception cref="AsnContentException">
/// the next value does not have the correct tag.
///
/// -or-
///
/// the length encoding is not valid under the current encoding rules.
///
/// -or-
///
/// the contents are not valid under the current encoding rules.
/// </exception>
/// <exception cref="ArgumentException">
/// <paramref name="expectedTag"/>.<see cref="Asn1Tag.TagClass"/> is
/// <see cref="TagClass.Universal"/>, but
/// <paramref name="expectedTag"/>.<see cref="Asn1Tag.TagValue"/> is not correct for
/// the method.
/// </exception>
/// <seealso cref="TryReadPrimitiveBitString"/>
/// <seealso cref="ReadBitString"/>
public bool TryReadBitString(
Span <byte> destination,
out int unusedBitCount,
out int bytesWritten,
Asn1Tag?expectedTag = null)
{
bool ret = AsnDecoder.TryReadBitString(
_data.Span,
destination,
RuleSet,
out unusedBitCount,
out int consumed,
out bytesWritten,
expectedTag);
if (ret)
{
_data = _data.Slice(consumed);
}
return(ret);
}
/// <summary>
/// Reads the next value as a character with a specified tag, returning the contents
/// as an unprocessed <see cref="ReadOnlyMemory{T}"/> over the original data.
/// </summary>
/// <param name="expectedTag">The tag to check for before reading.</param>
/// <param name="contents">
/// On success, receives a <see cref="ReadOnlyMemory{T}"/> over the original data
/// corresponding to the value of the character string.
/// </param>
/// <returns>
/// <see langword="true"/> and advances the reader if the character string value had a primitive encoding,
/// <see langword="false"/> and does not advance the reader if it had a constructed encoding.
/// </returns>
/// <remarks>
/// This method does not determine if the string used only characters defined by the encoding.
/// </remarks>
/// <exception cref="AsnContentException">
/// the next value does not have the correct tag.
///
/// -or-
///
/// the length encoding is not valid under the current encoding rules.
///
/// -or-
///
/// the contents are not valid under the current encoding rules.
/// </exception>
/// <exception cref="ArgumentException">
/// <paramref name="expectedTag"/>.<see cref="Asn1Tag.TagClass"/> is
/// <see cref="TagClass.Universal"/>, but
/// <paramref name="expectedTag"/>.<see cref="Asn1Tag.TagValue"/> is not a character
/// string tag type.
/// </exception>
/// <seealso cref="TryReadCharacterStringBytes"/>
public bool TryReadPrimitiveCharacterStringBytes(
Asn1Tag expectedTag,
out ReadOnlyMemory <byte> contents)
{
bool ret = AsnDecoder.TryReadPrimitiveCharacterStringBytes(
_data.Span,
RuleSet,
expectedTag,
out ReadOnlySpan <byte> span,
out int consumed);
if (ret)
{
contents = AsnDecoder.Slice(_data, span);
_data = _data.Slice(consumed);
}
else
{
contents = default;
}
return(ret);
}
internal ReadOnlySpan <byte> PeekEncodedValue()
{
AsnDecoder.ReadEncodedValue(_span, _ruleSet, out _, out _, out int consumed);
return(_span.Slice(0, consumed));
}
/// <summary>
/// Reads the next value as an OCTET STRING with tag UNIVERSAL 4, returning the value
/// in a byte array.
/// </summary>
/// <param name="expectedTag">
/// The tag to check for before reading, or <see langword="null"/> for the default tag (Universal 4).
/// </param>
/// <returns>
/// A copy of the value in a newly allocated, precisely sized, array.
/// </returns>
/// <exception cref="AsnContentException">
/// the next value does not have the correct tag.
///
/// -or-
///
/// the length encoding is not valid under the current encoding rules.
///
/// -or-
///
/// the contents are not valid under the current encoding rules.
/// </exception>
/// <exception cref="ArgumentException">
/// <paramref name="expectedTag"/>.<see cref="Asn1Tag.TagClass"/> is
/// <see cref="TagClass.Universal"/>, but
/// <paramref name="expectedTag"/>.<see cref="Asn1Tag.TagValue"/> is not correct for
/// the method.
/// </exception>
/// <seealso cref="TryReadPrimitiveOctetString"/>
/// <seealso cref="TryReadOctetString"/>
public byte[] ReadOctetString(Asn1Tag?expectedTag = null)
{
byte[] ret = AsnDecoder.ReadOctetString(_data.Span, RuleSet, out int consumed, expectedTag);
_data = _data.Slice(consumed);
return(ret);
}