BufferedStreamReader

A simple, buffered TStreamReader replacement for Delphi.

Unlike the TStreamReader in the RTL, it can be used to process any remaining data after reading some text. Due to the BufferedStream it is also significantly faster than TStreamReader, especially for doing many small reads with large buffer sizes (>16KB).

Two classes are provided:

BufferedStreamReader class which takes a TStream and has methods to read text from the stream, as well as allowing for the unread (possibly binary) data to be processed further. It has methods to read a line, until a byte or string delimiter, or until the end of the stream.

BufferedStream class which acts as a read-only buffered TStream implementation which provides access to the buffer and has methods to fill and consume the buffer. The position is tracked according to the consumed bytes, so reading from the BufferedStream does not skip buffered data.

Dependencies

The BufferedStreamReader has a method ReadUntil taking a regular expression for matching the delimiter. This function relies on my RegularExpr library, which is a wrapper around PCRE using Delphi's own RegularExpressionsAPI unit, included in XE2 and above.

If you do not wish to use this dependency you can define BUFFEREDSTREAMREADER_NO_REGULAREXPR in your project.

The test and example projects assume that the BufferedStreamReader and RegularExpr libraries share the same root folder, if this is not the case remember to adjust the search paths in the respective project options.

Examples

ppm2png illustrates how to first parse an ASCII header and then convert the binary data immediately following the header using the BufferedStreamReader. The program converts PPM (Portable PixMaps) files to PNG files. The example requires the RegularExpr dependency, as described above.