forked from Imagelibrary/binutils-gdb
de1ab01e8e
Changes in 1.2.10 (2 Jan 2017) - Avoid warnings on snprintf() return value - Fix bug in deflate_stored() for zero-length input - Fix bug in gzwrite.c that produced corrupt gzip files - Remove files to be installed before copying them in Makefile.in - Add warnings when compiling with assembler code Changes in 1.2.9 (31 Dec 2016) - Fix contrib/minizip to permit unzipping with desktop API [Zouzou] - Improve contrib/blast to return unused bytes - Assure that gzoffset() is correct when appending - Improve compress() and uncompress() to support large lengths - Fix bug in test/example.c where error code not saved - Remedy Coverity warning [Randers-Pehrson] - Improve speed of gzprintf() in transparent mode - Fix inflateInit2() bug when windowBits is 16 or 32 - Change DEBUG macro to ZLIB_DEBUG - Avoid uninitialized access by gzclose_w() - Allow building zlib outside of the source directory - Fix bug that accepted invalid zlib header when windowBits is zero - Fix gzseek() problem on MinGW due to buggy _lseeki64 there - Loop on write() calls in gzwrite.c in case of non-blocking I/O - Add --warn (-w) option to ./configure for more compiler warnings - Reject a window size of 256 bytes if not using the zlib wrapper - Fix bug when level 0 used with Z_HUFFMAN or Z_RLE - Add --debug (-d) option to ./configure to define ZLIB_DEBUG - Fix bugs in creating a very large gzip header - Add uncompress2() function, which returns the input size used - Assure that deflateParams() will not switch functions mid-block - Dramatically speed up deflation for level 0 (storing) - Add gzfread(), duplicating the interface of fread() - Add gzfwrite(), duplicating the interface of fwrite() - Add deflateGetDictionary() function - Use snprintf() for later versions of Microsoft C - Fix *Init macros to use z_ prefix when requested - Replace as400 with os400 for OS/400 support [Monnerat] - Add crc32_z() and adler32_z() functions with size_t lengths - Update Visual Studio project files [AraHaan]
Overview
========
This directory contains an update to the ZLib interface unit,
distributed by Borland as a Delphi supplemental component.
The original ZLib unit is Copyright (c) 1997,99 Borland Corp.,
and is based on zlib version 1.0.4. There are a series of bugs
and security problems associated with that old zlib version, and
we recommend the users to update their ZLib unit.
Summary of modifications
========================
- Improved makefile, adapted to zlib version 1.2.1.
- Some field types from TZStreamRec are changed from Integer to
Longint, for consistency with the zlib.h header, and for 64-bit
readiness.
- The zlib_version constant is updated.
- The new Z_RLE strategy has its corresponding symbolic constant.
- The allocation and deallocation functions and function types
(TAlloc, TFree, zlibAllocMem and zlibFreeMem) are now cdecl,
and _malloc and _free are added as C RTL stubs. As a result,
the original C sources of zlib can be compiled out of the box,
and linked to the ZLib unit.
Suggestions for improvements
============================
Currently, the ZLib unit provides only a limited wrapper around
the zlib library, and much of the original zlib functionality is
missing. Handling compressed file formats like ZIP/GZIP or PNG
cannot be implemented without having this functionality.
Applications that handle these formats are either using their own,
duplicated code, or not using the ZLib unit at all.
Here are a few suggestions:
- Checksum class wrappers around adler32() and crc32(), similar
to the Java classes that implement the java.util.zip.Checksum
interface.
- The ability to read and write raw deflate streams, without the
zlib stream header and trailer. Raw deflate streams are used
in the ZIP file format.
- The ability to read and write gzip streams, used in the GZIP
file format, and normally produced by the gzip program.
- The ability to select a different compression strategy, useful
to PNG and MNG image compression, and to multimedia compression
in general. Besides the compression level
TCompressionLevel = (clNone, clFastest, clDefault, clMax);
which, in fact, could have used the 'z' prefix and avoided
TColor-like symbols
TCompressionLevel = (zcNone, zcFastest, zcDefault, zcMax);
there could be a compression strategy
TCompressionStrategy = (zsDefault, zsFiltered, zsHuffmanOnly, zsRle);
- ZIP and GZIP stream handling via TStreams.
--
Cosmin Truta <cosmint@cs.ubbcluj.ro>