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StreamToStringANSI

function StreamToStringANSI(M : TStream) : string

Example​

procedure ScriptEvent(var Value: variant);
var
  Buffer: TMemoryStream;
begin
  Buffer := TMemoryStream.Create;
  try
    StringToStreamANSI('Fictional order 1001', Buffer);
    Value := StreamToStringANSI(Buffer);
  finally
    Buffer.Free;
  end;
end;

Usage​

StreamToStringANSI reads an entire stream from the beginning and decodes it with the system ANSI encoding.

Parameters

NameTypeDescription
MTStreamExisting readable, seekable caller-owned stream. Its current position is ignored.

Returns

The code-page-decoded Velox string. Empty input returns an empty string.

Errors

Nil-object, seek, read, allocation and encoding failures propagate. No previous position is restored.

Usage notes

Use ANSI only for a legacy contract that names the expected code page operationally. Prefer UTF-8 for new interchange formats.

Additional Technical Info​

StreamToStringANSI reads all bytes from a stream and decodes them with Delphi TEncoding.ANSI. On Windows the process-wide singleton captures the machine's active ANSI code page through GetACP on first use; it is not UTF-8 and no encoding identifier is read from the stream.

The example round-trips fictional ASCII-range text. It is source-reviewed and is not executed by the documentation workflow.

Implementation

The Velox wrapper calls the shared MemoryStreamToString helper with the installed singleton TEncoding.ANSI. The helper rewinds the stream, narrows its size to LongInt, allocates and reads that byte count, then calls GetString on the entire array. Because an encoding is supplied, GetBufferEncoding is not called.

Edge cases and quirks

  • A BOM is treated as ordinary encoded bytes; it is not detected or removed.
  • Results for byte values above ASCII depend on the captured Windows system ANSI code page. The same bytes can decode differently on another Velox host whose system code page differs; switching service accounts on the same configured host does not select a different code page through this function.
  • The current Delphi MBCS decoder calls the operating-system conversion with permissive flags. Invalid or unmappable data follows that code page's conversion/failure behaviour and must not be used as validation.
  • The helper ignores a short Read result and includes any zero-filled unread tail in the decoding input.
  • The stream is rewound and left after the bytes read. Sizes outside signed LongInt are unsupported.

Side effects

Mutates M.Position; it does not mutate or free the stream.

Performance and concurrency

The complete bytes and decoded string coexist in memory. The call is synchronous and does not coordinate concurrent stream access. The encoding singleton is process-wide and stable after its thread-safe first creation.

Related entries

External references

Created 2026-07-15