📄 zlibh.pas
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available input is skipped. No output is provided.
inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
if no more input was provided, Z_DATA_ERROR if no flush point has been found,
or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
case, the application may save the current current value of total_in which
indicates where valid compressed data was found. In the error case, the
application may repeatedly call inflateSync, providing more input each time,
until success or end of the input data.
*}
{$EXTERNALSYM inflateCopy}
function inflateCopy(var dest: TZStreamRec;
var source: TZStreamRec): Integer;
cdecl;
{*
Sets the destination stream as a complete copy of the source stream.
This function can be useful when randomly accessing a large stream. The
first pass through the stream can periodically record the inflate state,
allowing restarting inflate at those points when randomly accessing the
stream.
inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
(such as zalloc being NULL). msg is left unchanged in both source and
destination.
*}
{$EXTERNALSYM inflateReset}
function inflateReset(var strm: TZStreamRec): Integer;
cdecl;
{*
This function is equivalent to inflateEnd followed by inflateInit,
but does not free and reallocate all the internal decompression state.
The stream will keep attributes that may have been set by inflateInit2.
inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
stream state was inconsistent (such as zalloc or state being NULL).
*}
{$EXTERNALSYM inflateBackInit}
function inflateBackInit(var strm: TZStreamRec;
windowBits: Integer;
window: PByte): Integer; // macro
{*
Initialize the internal stream state for decompression using inflateBack()
calls. The fields zalloc, zfree and opaque in strm must be initialized
before the call. If zalloc and zfree are Z_NULL, then the default library-
derived memory allocation routines are used. windowBits is the base two
logarithm of the window size, in the range 8..15. window is a caller
supplied buffer of that size. Except for special applications where it is
assured that deflate was used with small window sizes, windowBits must be 15
and a 32K byte window must be supplied to be able to decompress general
deflate streams.
See inflateBack() for the usage of these routines.
inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
the paramaters are invalid, Z_MEM_ERROR if the internal state could not
be allocated, or Z_VERSION_ERROR if the version of the library does not
match the version of the header file.
*}
type
{$EXTERNALSYM in_func}
in_func = function(p1: Pointer; p2: PByte):UnsignedInt;
{$EXTERNALSYM out_func}
out_func = function (p1: Pointer; p2: PByte; p3:UnsignedInt): Longint;
TFNInFunc = in_func;
TFNOutFunc = out_func;
{$EXTERNALSYM inflateBack}
function inflateBack(var strm: TZStreamRec;
input:TFNInFunc;
in_desc: Pointer;
ouput:TFNOutFunc;
out_desc: Pointer): Integer; // OS: CHECKTHIS - should the parameter names
// be the same as in PHs translation? They
// are wrong there, but in/out are reserved
// words in Delphi
cdecl;
{*
inflateBack() does a raw inflate with a single call using a call-back
interface for input and output. This is more efficient than inflate() for
file i/o applications in that it avoids copying between the output and the
sliding window by simply making the window itself the output buffer. This
function trusts the application to not change the output buffer passed by
the output function, at least until inflateBack() returns.
inflateBackInit() must be called first to allocate the internal state
and to initialize the state with the user-provided window buffer.
inflateBack() may then be used multiple times to inflate a complete, raw
deflate stream with each call. inflateBackEnd() is then called to free
the allocated state.
A raw deflate stream is one with no zlib or gzip header or trailer.
This routine would normally be used in a utility that reads zip or gzip
files and writes out uncompressed files. The utility would decode the
header and process the trailer on its own, hence this routine expects
only the raw deflate stream to decompress. This is different from the
normal behavior of inflate(), which expects either a zlib or gzip header and
trailer around the deflate stream.
inflateBack() uses two subroutines supplied by the caller that are then
called by inflateBack() for input and output. inflateBack() calls those
routines until it reads a complete deflate stream and writes out all of the
uncompressed data, or until it encounters an error. The function's
parameters and return types are defined above in the in_func and out_func
typedefs. inflateBack() will call in(in_desc, &buf) which should return the
number of bytes of provided input, and a pointer to that input in buf. If
there is no input available, in() must return zero--buf is ignored in that
case--and inflateBack() will return a buffer error. inflateBack() will call
out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
should return zero on success, or non-zero on failure. If out() returns
non-zero, inflateBack() will return with an error. Neither in() nor out()
are permitted to change the contents of the window provided to
inflateBackInit(), which is also the buffer that out() uses to write from.
The length written by out() will be at most the window size. Any non-zero
amount of input may be provided by in().
For convenience, inflateBack() can be provided input on the first call by
setting strm->next_in and strm->avail_in. If that input is exhausted, then
in() will be called. Therefore strm->next_in must be initialized before
calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
must also be initialized, and then if strm->avail_in is not zero, input will
initially be taken from strm->next_in[0 .. strm->avail_in - 1].
The in_desc and out_desc parameters of inflateBack() is passed as the
first parameter of in() and out() respectively when they are called. These
descriptors can be optionally used to pass any information that the caller-
supplied in() and out() functions need to do their job.
On return, inflateBack() will set strm->next_in and strm->avail_in to
pass back any unused input that was provided by the last in() call. The
return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
if in() or out() returned an error, Z_DATA_ERROR if there was a format
error in the deflate stream (in which case strm->msg is set to indicate the
nature of the error), or Z_STREAM_ERROR if the stream was not properly
initialized. In the case of Z_BUF_ERROR, an input or output error can be
distinguished using strm->next_in which will be Z_NULL only if in() returned
an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
out() returning non-zero. (in() will always be called before out(), so
strm->next_in is assured to be defined if out() returns non-zero.) Note
that inflateBack() cannot return Z_OK.
*}
{$EXTERNALSYM inflateBackEnd}
function inflateBackEnd(var strm: TZStreamRec): Integer;
cdecl;
{*
All memory allocated by inflateBackInit() is freed.
inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
state was inconsistent.
*}
{$EXTERNALSYM zlibCompileFlags}
function zlibCompileFlags():uLong;
cdecl;
{* Return flags indicating compile-time options.
Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1.0: size of uInt
3.2: size of uLong
5.4: size of voidpf (pointer)
7.6: size of z_off_t
Compiler, assembler, and debug options:
8: DEBUG
9: ASMV or ASMINF -- use ASM code
10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
11: 0 (reserved)
One-time table building (smaller code, but not thread-safe if true):
12: BUILDFIXED -- build static block decoding tables when needed
13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
14,15: 0 (reserved)
Library content (indicates missing functionality):
16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
deflate code when not needed)
17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
and decode gzip streams (to avoid linking crc code)
18-19: 0 (reserved)
Operation variations (changes in library functionality):
20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
21: FASTEST -- deflate algorithm with only one, lowest compression level
22,23: 0 (reserved)
The sprintf variant used by gzprintf (zero is best):
24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
26: 0 = returns value, 1 = void -- 1 means inferred string length returned
Remainder:
27-31: 0 (reserved)
*}
{* utility functions *}
{*
The following utility functions are implemented on top of the
basic stream-oriented functions. To simplify the interface, some
default options are assumed (compression level and memory usage,
standard memory allocation functions). The source code of these
utility functions can easily be modified if you need special options.
*}
{$EXTERNALSYM compress}
function compress(dest: PBytef;
var destLen:uLongf;
{const} source: PBytef;
sourceLen:uLong): Integer;
cdecl;
{*
Compresses the source buffer into the destination buffer. sourceLen is
the byte length of the source buffer. Upon entry, destLen is the total
size of the destination buffer, which must be at least the value returned
by compressBound(sourceLen). Upon exit, destLen is the actual size of the
compressed buffer.
This function can be used to compress a whole file at once if the
input file is mmap'ed.
compress returns Z_OK if success, Z_MEM_ERROR if there was not
enough memory, Z_BUF_ERROR if there was not enough room in the output
buffer.
*}
{$EXTERNALSYM compress2}
function compress2(dest: PBytef;
var destLen:uLongf;
{const} source: PBytef;
sourceLen:uLong;
level: Integer): Integer;
cdecl;
{*
Compresses the source buffer into the destination buffer. The level
parameter has the same meaning as in deflateInit. sourceLen is the byte
length of the source buffer. Upon entry, destLen is the total size of the
destination buffer, which must be at least the value returned by
compressBound(sourceLen). Upon exit, destLen is the actual size of the
compressed buffer.
compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
memory, Z_BUF_ERROR if there was not enough room in the output buffer,
Z_STREAM_ERROR if the level parameter is invalid.
*}
{$EXTERNALSYM compressBound}
function compressBound(sourceLen:uLong):uLong;
cdecl;
{*
compressBound() returns an upper bound on the compressed size after
compress() or compress2() on sourceLen bytes. It would be used before
a compress() or compress2() call to allocate the destination buffer.
*}
{$EXTERNALSYM uncompress}
function uncompress(dest: PBytef;
var destLen:uLongf;
{const} source: PBytef;
sourceLen:uLong): Integer;
cdecl;
{*
Decompresses the source buffer into the destination buffer. sourceLen is
the byte length of the source buffer. Upon entry, destLen is the total
size of the destination buffer, which must be large enough to hold the
entire uncompressed data. (The size of the uncompressed data must have
been saved previously by the compressor and transmitted to the decompressor
by some mechanism outside the scope of this compression library.)
Upon exit, destLen is the actual size of the compressed buffer.
This function can be used to decompress a whole file at once if the
input file is mmap'ed.
uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
enough memory, Z_BUF_ERROR if there was not enough room in the output
buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
*}
(*
type
gzFile = voidp;
function gzopen(path: PChar; mode: PChar):gzFile;
{*
Opens a gzip (.gz) file for reading or writing. The mode parameter
is as in fopen ("rb" or "wb") but can also include a compression level
("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
Huffman only compression as in "wb1h", or 'R' for run-length encoding
as in "wb1R". (See the description of deflateInit2 for more information
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