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Add a transparent write mode to gzopen() when 'T' is in the mode.

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This commit is contained in:
Mark Adler
2011-10-02 13:24:43 -07:00
parent 3c9d261809
commit 26a99cd895
5 changed files with 82 additions and 39 deletions
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26
zlib.h
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@@ -696,7 +696,7 @@ ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
be larger than the value returned by deflateBound() if flush options other
than Z_FINISH or Z_NO_FLUSH are used.
*/
ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
unsigned *pending,
int *bits));
@@ -706,7 +706,7 @@ ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
provided would be due to the available output space having being consumed.
The number of bits of output not provided are between 0 and 7, where they
await more bits to join them in order to fill out a full byte.
deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
stream state was inconsistent.
*/
@@ -1196,10 +1196,13 @@ ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
for fixed code compression as in "wb9F". (See the description of
deflateInit2 for more information about the strategy parameter.) Also "a"
can be used instead of "w" to request that the gzip stream that will be
written be appended to the file. "+" will result in an error, since reading
and writing to the same gzip file is not supported.
deflateInit2 for more information about the strategy parameter.) 'T' will
request transparent writing or appending with no compression and not using
the gzip format.
"a" can be used instead of "w" to request that the gzip stream that will
be written be appended to the file. "+" will result in an error, since
reading and writing to the same gzip file is not supported.
These functions, as well as gzip, will read and decode a sequence of gzip
streams in a file. The append function of gzopen() can be used to create
@@ -1209,7 +1212,9 @@ ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
will simply append a gzip stream to the existing file.
gzopen can be used to read a file which is not in gzip format; in this
case gzread will directly read from the file without decompression.
case gzread will directly read from the file without decompression. When
reading, this will be detected automatically by looking for the magic two-
byte gzip header.
gzopen returns NULL if the file could not be opened, if there was
insufficient memory to allocate the gzFile state, or if an invalid mode was
@@ -1440,6 +1445,13 @@ ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
cause buffers to be allocated to allow reading the file to determine if it
is a gzip file. Therefore if gzbuffer() is used, it should be called before
gzdirect().
When writing, gzdirect() returns true (1) if transparent writing was
requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
gzdirect() is not needed when writing. Transparent writing must be
explicitly requested, so the application already knows the answer. When
linking statically, using gzdirect() will include all of the zlib code for
gzip file reading and decompression, which may not be desired.)
*/
ZEXTERN int ZEXPORT gzclose OF((gzFile file));