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This commit was manufactured by cvs2svn to create branch 'zlib'.

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Cherrypick from master 2011-03-18 10:11:29 UTC Joel Sherrill <joel.sherrill@OARcorp.com> '2010-03-22	Joel Sherrill <joel.sherrill@oarcorp.com>':
    cpukit/zlib/doc/algorithm.txt
    cpukit/zlib/gzclose.c
    cpukit/zlib/gzguts.h
    cpukit/zlib/gzlib.c
    cpukit/zlib/gzread.c
    cpukit/zlib/gzwrite.c
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2011-03-18 10:11:30 +00:00
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1. Compression algorithm (deflate)
The deflation algorithm used by gzip (also zip and zlib) is a variation of
LZ77 (Lempel-Ziv 1977, see reference below). It finds duplicated strings in
the input data. The second occurrence of a string is replaced by a
pointer to the previous string, in the form of a pair (distance,
length). Distances are limited to 32K bytes, and lengths are limited
to 258 bytes. When a string does not occur anywhere in the previous
32K bytes, it is emitted as a sequence of literal bytes. (In this
description, `string' must be taken as an arbitrary sequence of bytes,
and is not restricted to printable characters.)
Literals or match lengths are compressed with one Huffman tree, and
match distances are compressed with another tree. The trees are stored
in a compact form at the start of each block. The blocks can have any
size (except that the compressed data for one block must fit in
available memory). A block is terminated when deflate() determines that
it would be useful to start another block with fresh trees. (This is
somewhat similar to the behavior of LZW-based _compress_.)
Duplicated strings are found using a hash table. All input strings of
length 3 are inserted in the hash table. A hash index is computed for
the next 3 bytes. If the hash chain for this index is not empty, all
strings in the chain are compared with the current input string, and
the longest match is selected.
The hash chains are searched starting with the most recent strings, to
favor small distances and thus take advantage of the Huffman encoding.
The hash chains are singly linked. There are no deletions from the
hash chains, the algorithm simply discards matches that are too old.
To avoid a worst-case situation, very long hash chains are arbitrarily
truncated at a certain length, determined by a runtime option (level
parameter of deflateInit). So deflate() does not always find the longest
possible match but generally finds a match which is long enough.
deflate() also defers the selection of matches with a lazy evaluation
mechanism. After a match of length N has been found, deflate() searches for
a longer match at the next input byte. If a longer match is found, the
previous match is truncated to a length of one (thus producing a single
literal byte) and the process of lazy evaluation begins again. Otherwise,
the original match is kept, and the next match search is attempted only N
steps later.
The lazy match evaluation is also subject to a runtime parameter. If
the current match is long enough, deflate() reduces the search for a longer
match, thus speeding up the whole process. If compression ratio is more
important than speed, deflate() attempts a complete second search even if
the first match is already long enough.
The lazy match evaluation is not performed for the fastest compression
modes (level parameter 1 to 3). For these fast modes, new strings
are inserted in the hash table only when no match was found, or
when the match is not too long. This degrades the compression ratio
but saves time since there are both fewer insertions and fewer searches.
2. Decompression algorithm (inflate)
2.1 Introduction
The key question is how to represent a Huffman code (or any prefix code) so
that you can decode fast. The most important characteristic is that shorter
codes are much more common than longer codes, so pay attention to decoding the
short codes fast, and let the long codes take longer to decode.
inflate() sets up a first level table that covers some number of bits of
input less than the length of longest code. It gets that many bits from the
stream, and looks it up in the table. The table will tell if the next
code is that many bits or less and how many, and if it is, it will tell
the value, else it will point to the next level table for which inflate()
grabs more bits and tries to decode a longer code.
How many bits to make the first lookup is a tradeoff between the time it
takes to decode and the time it takes to build the table. If building the
table took no time (and if you had infinite memory), then there would only
be a first level table to cover all the way to the longest code. However,
building the table ends up taking a lot longer for more bits since short
codes are replicated many times in such a table. What inflate() does is
simply to make the number of bits in the first table a variable, and then
to set that variable for the maximum speed.
For inflate, which has 286 possible codes for the literal/length tree, the size
of the first table is nine bits. Also the distance trees have 30 possible
values, and the size of the first table is six bits. Note that for each of
those cases, the table ended up one bit longer than the ``average'' code
length, i.e. the code length of an approximately flat code which would be a
little more than eight bits for 286 symbols and a little less than five bits
for 30 symbols.
2.2 More details on the inflate table lookup
Ok, you want to know what this cleverly obfuscated inflate tree actually
looks like. You are correct that it's not a Huffman tree. It is simply a
lookup table for the first, let's say, nine bits of a Huffman symbol. The
symbol could be as short as one bit or as long as 15 bits. If a particular
symbol is shorter than nine bits, then that symbol's translation is duplicated
in all those entries that start with that symbol's bits. For example, if the
symbol is four bits, then it's duplicated 32 times in a nine-bit table. If a
symbol is nine bits long, it appears in the table once.
If the symbol is longer than nine bits, then that entry in the table points
to another similar table for the remaining bits. Again, there are duplicated
entries as needed. The idea is that most of the time the symbol will be short
and there will only be one table look up. (That's whole idea behind data
compression in the first place.) For the less frequent long symbols, there
will be two lookups. If you had a compression method with really long
symbols, you could have as many levels of lookups as is efficient. For
inflate, two is enough.
So a table entry either points to another table (in which case nine bits in
the above example are gobbled), or it contains the translation for the symbol
and the number of bits to gobble. Then you start again with the next
ungobbled bit.
You may wonder: why not just have one lookup table for how ever many bits the
longest symbol is? The reason is that if you do that, you end up spending
more time filling in duplicate symbol entries than you do actually decoding.
At least for deflate's output that generates new trees every several 10's of
kbytes. You can imagine that filling in a 2^15 entry table for a 15-bit code
would take too long if you're only decoding several thousand symbols. At the
other extreme, you could make a new table for every bit in the code. In fact,
that's essentially a Huffman tree. But then you spend too much time
traversing the tree while decoding, even for short symbols.
So the number of bits for the first lookup table is a trade of the time to
fill out the table vs. the time spent looking at the second level and above of
the table.
Here is an example, scaled down:
The code being decoded, with 10 symbols, from 1 to 6 bits long:
A: 0
B: 10
C: 1100
D: 11010
E: 11011
F: 11100
G: 11101
H: 11110
I: 111110
J: 111111
Let's make the first table three bits long (eight entries):
000: A,1
001: A,1
010: A,1
011: A,1
100: B,2
101: B,2
110: -> table X (gobble 3 bits)
111: -> table Y (gobble 3 bits)
Each entry is what the bits decode as and how many bits that is, i.e. how
many bits to gobble. Or the entry points to another table, with the number of
bits to gobble implicit in the size of the table.
Table X is two bits long since the longest code starting with 110 is five bits
long:
00: C,1
01: C,1
10: D,2
11: E,2
Table Y is three bits long since the longest code starting with 111 is six
bits long:
000: F,2
001: F,2
010: G,2
011: G,2
100: H,2
101: H,2
110: I,3
111: J,3
So what we have here are three tables with a total of 20 entries that had to
be constructed. That's compared to 64 entries for a single table. Or
compared to 16 entries for a Huffman tree (six two entry tables and one four
entry table). Assuming that the code ideally represents the probability of
the symbols, it takes on the average 1.25 lookups per symbol. That's compared
to one lookup for the single table, or 1.66 lookups per symbol for the
Huffman tree.
There, I think that gives you a picture of what's going on. For inflate, the
meaning of a particular symbol is often more than just a letter. It can be a
byte (a "literal"), or it can be either a length or a distance which
indicates a base value and a number of bits to fetch after the code that is
added to the base value. Or it might be the special end-of-block code. The
data structures created in inftrees.c try to encode all that information
compactly in the tables.
Jean-loup Gailly Mark Adler
jloup@gzip.org madler@alumni.caltech.edu
References:
[LZ77] Ziv J., Lempel A., ``A Universal Algorithm for Sequential Data
Compression,'' IEEE Transactions on Information Theory, Vol. 23, No. 3,
pp. 337-343.
``DEFLATE Compressed Data Format Specification'' available in
http://www.ietf.org/rfc/rfc1951.txt

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/* gzclose.c -- zlib gzclose() function
* Copyright (C) 2004, 2010 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include "gzguts.h"
/* gzclose() is in a separate file so that it is linked in only if it is used.
That way the other gzclose functions can be used instead to avoid linking in
unneeded compression or decompression routines. */
int ZEXPORT gzclose(file)
gzFile file;
{
#ifndef NO_GZCOMPRESS
gz_statep state;
if (file == NULL)
return Z_STREAM_ERROR;
state = (gz_statep)file;
return state->mode == GZ_READ ? gzclose_r(file) : gzclose_w(file);
#else
return gzclose_r(file);
#endif
}

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/* gzguts.h -- zlib internal header definitions for gz* operations
* Copyright (C) 2004, 2005, 2010 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#ifdef _LARGEFILE64_SOURCE
# ifndef _LARGEFILE_SOURCE
# define _LARGEFILE_SOURCE
# endif
# ifdef _FILE_OFFSET_BITS
# undef _FILE_OFFSET_BITS
# endif
#endif
#define ZLIB_INTERNAL
#include <stdio.h>
#include "zlib.h"
#ifdef STDC
# include <string.h>
# include <stdlib.h>
# include <limits.h>
#endif
#include <fcntl.h>
#ifdef NO_DEFLATE /* for compatibility with old definition */
# define NO_GZCOMPRESS
#endif
#ifdef _MSC_VER
# include <io.h>
# define vsnprintf _vsnprintf
#endif
#ifndef local
# define local static
#endif
/* compile with -Dlocal if your debugger can't find static symbols */
/* gz* functions always use library allocation functions */
#ifndef STDC
extern voidp malloc OF((uInt size));
extern void free OF((voidpf ptr));
#endif
/* get errno and strerror definition */
#if defined UNDER_CE && defined NO_ERRNO_H
# include <windows.h>
# define zstrerror() gz_strwinerror((DWORD)GetLastError())
#else
# ifdef STDC
# include <errno.h>
# define zstrerror() strerror(errno)
# else
# define zstrerror() "stdio error (consult errno)"
# endif
#endif
/* MVS fdopen() */
#ifdef __MVS__
#pragma map (fdopen , "\174\174FDOPEN")
FILE *fdopen(int, const char *);
#endif
#ifdef _LARGEFILE64_SOURCE
# define z_off64_t off64_t
#else
# define z_off64_t z_off_t
#endif
/* default i/o buffer size -- double this for output when reading */
#define GZBUFSIZE 8192
/* gzip modes, also provide a little integrity check on the passed structure */
#define GZ_NONE 0
#define GZ_READ 7247
#define GZ_WRITE 31153
#define GZ_APPEND 1 /* mode set to GZ_WRITE after the file is opened */
/* values for gz_state how */
#define LOOK 0 /* look for a gzip header */
#define COPY 1 /* copy input directly */
#define GZIP 2 /* decompress a gzip stream */
/* internal gzip file state data structure */
typedef struct {
/* used for both reading and writing */
int mode; /* see gzip modes above */
int fd; /* file descriptor */
char *path; /* path or fd for error messages */
z_off64_t pos; /* current position in uncompressed data */
unsigned size; /* buffer size, zero if not allocated yet */
unsigned want; /* requested buffer size, default is GZBUFSIZE */
unsigned char *in; /* input buffer */
unsigned char *out; /* output buffer (double-sized when reading) */
unsigned char *next; /* next output data to deliver or write */
/* just for reading */
unsigned have; /* amount of output data unused at next */
int eof; /* true if end of input file reached */
z_off64_t start; /* where the gzip data started, for rewinding */
z_off64_t raw; /* where the raw data started, for seeking */
int how; /* 0: get header, 1: copy, 2: decompress */
int direct; /* true if last read direct, false if gzip */
/* just for writing */
int level; /* compression level */
int strategy; /* compression strategy */
/* seek request */
z_off64_t skip; /* amount to skip (already rewound if backwards) */
int seek; /* true if seek request pending */
/* error information */
int err; /* error code */
char *msg; /* error message */
/* zlib inflate or deflate stream */
z_stream strm; /* stream structure in-place (not a pointer) */
} gz_state;
typedef gz_state FAR *gz_statep;
/* shared functions */
ZEXTERN void ZEXPORT gz_error OF((gz_statep, int, const char *));
#if defined UNDER_CE && defined NO_ERRNO_H
ZEXTERN char ZEXPORT *gz_strwinerror OF((DWORD error));
#endif
/* GT_OFF(x), where x is an unsigned value, is true if x > maximum z_off64_t
value -- needed when comparing unsigned to z_off64_t, which is signed
(possible z_off64_t types off_t, off64_t, and long are all signed) */
#ifdef INT_MAX
# define GT_OFF(x) (sizeof(int) == sizeof(z_off64_t) && (x) > INT_MAX)
#else
ZEXTERN unsigned ZEXPORT gz_intmax OF((void));
# define GT_OFF(x) (sizeof(int) == sizeof(z_off64_t) && (x) > gz_intmax())
#endif

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/* gzlib.c -- zlib functions common to reading and writing gzip files
* Copyright (C) 2004, 2010 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include "gzguts.h"
#ifdef _LARGEFILE64_SOURCE
# define LSEEK lseek64
#else
# define LSEEK lseek
#endif
/* Local functions */
local void gz_reset OF((gz_statep));
local gzFile gz_open OF((const char *, int, const char *));
#if defined UNDER_CE && defined NO_ERRNO_H
/* Map the Windows error number in ERROR to a locale-dependent error message
string and return a pointer to it. Typically, the values for ERROR come
from GetLastError.
The string pointed to shall not be modified by the application, but may be
overwritten by a subsequent call to gz_strwinerror
The gz_strwinerror function does not change the current setting of
GetLastError. */
char ZEXPORT *gz_strwinerror (error)
DWORD error;
{
static char buf[1024];
wchar_t *msgbuf;
DWORD lasterr = GetLastError();
DWORD chars = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM
| FORMAT_MESSAGE_ALLOCATE_BUFFER,
NULL,
error,
0, /* Default language */
(LPVOID)&msgbuf,
0,
NULL);
if (chars != 0) {
/* If there is an \r\n appended, zap it. */
if (chars >= 2
&& msgbuf[chars - 2] == '\r' && msgbuf[chars - 1] == '\n') {
chars -= 2;
msgbuf[chars] = 0;
}
if (chars > sizeof (buf) - 1) {
chars = sizeof (buf) - 1;
msgbuf[chars] = 0;
}
wcstombs(buf, msgbuf, chars + 1);
LocalFree(msgbuf);
}
else {
sprintf(buf, "unknown win32 error (%ld)", error);
}
SetLastError(lasterr);
return buf;
}
#endif /* UNDER_CE && NO_ERRNO_H */
/* Reset gzip file state */
local void gz_reset(state)
gz_statep state;
{
if (state->mode == GZ_READ) { /* for reading ... */
state->have = 0; /* no output data available */
state->eof = 0; /* not at end of file */
state->how = LOOK; /* look for gzip header */
state->direct = 1; /* default for empty file */
}
state->seek = 0; /* no seek request pending */
gz_error(state, Z_OK, NULL); /* clear error */
state->pos = 0; /* no uncompressed data yet */
state->strm.avail_in = 0; /* no input data yet */
}
/* Open a gzip file either by name or file descriptor. */
local gzFile gz_open(path, fd, mode)
const char *path;
int fd;
const char *mode;
{
gz_statep state;
/* allocate gzFile structure to return */
state = malloc(sizeof(gz_state));
if (state == NULL)
return NULL;
state->size = 0; /* no buffers allocated yet */
state->want = GZBUFSIZE; /* requested buffer size */
state->msg = NULL; /* no error message yet */
/* interpret mode */
state->mode = GZ_NONE;
state->level = Z_DEFAULT_COMPRESSION;
state->strategy = Z_DEFAULT_STRATEGY;
while (*mode) {
if (*mode >= '0' && *mode <= '9')
state->level = *mode - '0';
else
switch (*mode) {
case 'r':
state->mode = GZ_READ;
break;
#ifndef NO_GZCOMPRESS
case 'w':
state->mode = GZ_WRITE;
break;
case 'a':
state->mode = GZ_APPEND;
break;
#endif
case '+': /* can't read and write at the same time */
free(state);
return NULL;
case 'b': /* ignore -- will request binary anyway */
break;
case 'f':
state->strategy = Z_FILTERED;
break;
case 'h':
state->strategy = Z_HUFFMAN_ONLY;
break;
case 'R':
state->strategy = Z_RLE;
break;
case 'F':
state->strategy = Z_FIXED;
default: /* could consider as an error, but just ignore */
;
}
mode++;
}
/* must provide an "r", "w", or "a" */
if (state->mode == GZ_NONE) {
free(state);
return NULL;
}
/* save the path name for error messages */
state->path = malloc(strlen(path) + 1);
if (state->path == NULL) {
free(state);
return NULL;
}
strcpy(state->path, path);
/* open the file with the appropriate mode (or just use fd) */
state->fd = fd != -1 ? fd :
open(path,
#ifdef O_LARGEFILE
O_LARGEFILE |
#endif
#ifdef O_BINARY
O_BINARY |
#endif
(state->mode == GZ_READ ?
O_RDONLY :
(O_WRONLY | O_CREAT | (
state->mode == GZ_WRITE ?
O_TRUNC :
O_APPEND))),
0666);
if (state->fd == -1) {
free(state);
return NULL;
}
if (state->mode == GZ_APPEND)
state->mode = GZ_WRITE; /* simplify later checks */
/* save the current position for rewinding (only if reading) */
if (state->mode == GZ_READ) {
state->start = LSEEK(state->fd, 0, SEEK_CUR);
if (state->start == -1) state->start = 0;
}
/* initialize stream */
gz_reset(state);
/* return stream */
return (gzFile)state;
}
/* -- see zlib.h -- */
gzFile ZEXPORT gzopen(path, mode)
const char *path;
const char *mode;
{
return gz_open(path, -1, mode);
}
/* -- see zlib.h -- */
gzFile ZEXPORT gzopen64(path, mode)
const char *path;
const char *mode;
{
return gz_open(path, -1, mode);
}
/* -- see zlib.h -- */
gzFile ZEXPORT gzdopen(fd, mode)
int fd;
const char *mode;
{
char *path; /* identifier for error messages */
gzFile gz;
if (fd == -1 || (path = malloc(7 + 3 * sizeof(int))) == NULL)
return NULL;
sprintf(path, "<fd:%d>", fd);
gz = gz_open(path, fd, mode);
free(path);
return gz;
}
/* -- see zlib.h -- */
int ZEXPORT gzbuffer(file, size)
gzFile file;
unsigned size;
{
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return -1;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return -1;
/* make sure we haven't already allocated memory */
if (state->size != 0)
return -1;
/* check and set requested size */
if (size == 0)
return -1;
state->want = size;
return 0;
}
/* -- see zlib.h -- */
int ZEXPORT gzrewind(file)
gzFile file;
{
gz_statep state;
/* get internal structure */
if (file == NULL)
return -1;
state = (gz_statep)file;
/* check that we're reading and that there's no error */
if (state->mode != GZ_READ || state->err != Z_OK)
return -1;
/* back up and start over */
if (LSEEK(state->fd, state->start, SEEK_SET) == -1)
return -1;
gz_reset(state);
return 0;
}
/* -- see zlib.h -- */
z_off64_t ZEXPORT gzseek64(file, offset, whence)
gzFile file;
z_off64_t offset;
int whence;
{
unsigned n;
z_off64_t ret;
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return -1;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return -1;
/* check that there's no error */
if (state->err != Z_OK)
return -1;
/* can only seek from start or relative to current position */
if (whence != SEEK_SET && whence != SEEK_CUR)
return -1;
/* normalize offset to a SEEK_CUR specification */
if (whence == SEEK_SET)
offset -= state->pos;
else if (state->seek)
offset += state->skip;
state->seek = 0;
/* if within raw area while reading, just go there */
if (state->mode == GZ_READ && state->how == COPY &&
state->pos + offset >= state->raw) {
ret = LSEEK(state->fd, offset, SEEK_CUR);
if (ret == -1)
return -1;
state->have = 0;
state->eof = 0;
state->seek = 0;
gz_error(state, Z_OK, NULL);
state->strm.avail_in = 0;
state->pos += offset;
return state->pos;
}
/* calculate skip amount, rewinding if needed for back seek when reading */
if (offset < 0) {
if (state->mode != GZ_READ) /* writing -- can't go backwards */
return -1;
offset += state->pos;
if (offset < 0) /* before start of file! */
return -1;
if (gzrewind(file) == -1) /* rewind, then skip to offset */
return -1;
}
/* if reading, skip what's in output buffer (one less gzgetc() check) */
if (state->mode == GZ_READ) {
n = GT_OFF(state->have) || (z_off64_t)state->have > offset ?
(unsigned)offset : state->have;
state->have -= n;
state->next += n;
state->pos += n;
offset -= n;
}
/* request skip (if not zero) */
if (offset) {
state->seek = 1;
state->skip = offset;
}
return state->pos + offset;
}
/* -- see zlib.h -- */
z_off_t ZEXPORT gzseek(file, offset, whence)
gzFile file;
z_off_t offset;
int whence;
{
z_off64_t ret;
ret = gzseek64(file, (z_off64_t)offset, whence);
return ret == (z_off_t)ret ? (z_off_t)ret : -1;
}
/* -- see zlib.h -- */
z_off64_t ZEXPORT gztell64(file)
gzFile file;
{
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return -1;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return -1;
/* return position */
return state->pos + (state->seek ? state->skip : 0);
}
/* -- see zlib.h -- */
z_off_t ZEXPORT gztell(file)
gzFile file;
{
z_off64_t ret;
ret = gztell64(file);
return ret == (z_off_t)ret ? (z_off_t)ret : -1;
}
/* -- see zlib.h -- */
z_off64_t ZEXPORT gzoffset64(file)
gzFile file;
{
z_off64_t offset;
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return -1;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return -1;
/* compute and return effective offset in file */
offset = LSEEK(state->fd, 0, SEEK_CUR);
if (offset == -1)
return -1;
if (state->mode == GZ_READ) /* reading */
offset -= state->strm.avail_in; /* don't count buffered input */
return offset;
}
/* -- see zlib.h -- */
z_off_t ZEXPORT gzoffset(file)
gzFile file;
{
z_off64_t ret;
ret = gzoffset64(file);
return ret == (z_off_t)ret ? (z_off_t)ret : -1;
}
/* -- see zlib.h -- */
int ZEXPORT gzeof(file)
gzFile file;
{
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return 0;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return 0;
/* return end-of-file state */
return state->mode == GZ_READ ? (state->eof && state->have == 0) : 0;
}
/* -- see zlib.h -- */
const char * ZEXPORT gzerror(file, errnum)
gzFile file;
int *errnum;
{
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return NULL;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return NULL;
/* return error information */
if (errnum != NULL)
*errnum = state->err;
return state->msg == NULL ? "" : state->msg;
}
/* -- see zlib.h -- */
void ZEXPORT gzclearerr(file)
gzFile file;
{
gz_statep state;
/* get internal structure and check integrity */
if (file == NULL)
return;
state = (gz_statep)file;
if (state->mode != GZ_READ && state->mode != GZ_WRITE)
return;
/* clear error and end-of-file */
if (state->mode == GZ_READ)
state->eof = 0;
gz_error(state, Z_OK, NULL);
}
/* Create an error message in allocated memory and set state->err and
state->msg accordingly. Free any previous error message already there. Do
not try to free or allocate space if the error is Z_MEM_ERROR (out of
memory). Simply save the error message as a static string. If there is an
allocation failure constructing the error message, then convert the error to
out of memory. */
void ZEXPORT gz_error(state, err, msg)
gz_statep state;
int err;
const char *msg;
{
/* free previously allocated message and clear */
if (state->msg != NULL) {
if (state->err != Z_MEM_ERROR)
free(state->msg);
state->msg = NULL;
}
/* set error code, and if no message, then done */
state->err = err;
if (msg == NULL)
return;
/* for an out of memory error, save as static string */
if (err == Z_MEM_ERROR) {
state->msg = (char *)msg;
return;
}
/* construct error message with path */
if ((state->msg = malloc(strlen(state->path) + strlen(msg) + 3)) == NULL) {
state->err = Z_MEM_ERROR;
state->msg = (char *)"out of memory";
return;
}
strcpy(state->msg, state->path);
strcat(state->msg, ": ");
strcat(state->msg, msg);
return;
}
#ifndef INT_MAX
/* portably return maximum value for an int (when limits.h presumed not
available) -- we need to do this to cover cases where 2's complement not
used, since C standard permits 1's complement and sign-bit representations,
otherwise we could just use ((unsigned)-1) >> 1 */
unsigned ZEXPORT gz_intmax()
{
unsigned p, q;
p = 1;
do {
q = p;
p <<= 1;
p++;
} while (p > q);
return q >> 1;
}
#endif

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/* gzread.c -- zlib functions for reading gzip files
* Copyright (C) 2004, 2005, 2010 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include "gzguts.h"
/* Local functions */
local int gz_load OF((gz_statep, unsigned char *, unsigned, unsigned *));
local int gz_avail OF((gz_statep));
local int gz_next4 OF((gz_statep, unsigned long *));
local int gz_head OF((gz_statep));
local int gz_decomp OF((gz_statep));
local int gz_make OF((gz_statep));
local int gz_skip OF((gz_statep, z_off64_t));
/* Use read() to load a buffer -- return -1 on error, otherwise 0. Read from
state->fd, and update state->eof, state->err, and state->msg as appropriate.
This function needs to loop on read(), since read() is not guaranteed to
read the number of bytes requested, depending on the type of descriptor. */
local int gz_load(state, buf, len, have)
gz_statep state;
unsigned char *buf;
unsigned len;
unsigned *have;
{
int ret;
*have = 0;
do {
ret = read(state->fd, buf + *have, len - *have);
if (ret <= 0)
break;
*have += ret;
} while (*have < len);
if (ret < 0) {
gz_error(state, Z_ERRNO, zstrerror());
return -1;
}
if (ret == 0)
state->eof = 1;
return 0;
}
/* Load up input buffer and set eof flag if last data loaded -- return -1 on
error, 0 otherwise. Note that the eof flag is set when the end of the input
file is reached, even though there may be unused data in the buffer. Once
that data has been used, no more attempts will be made to read the file.
gz_avail() assumes that strm->avail_in == 0. */
local int gz_avail(state)
gz_statep state;
{
z_streamp strm = &(state->strm);
if (state->err != Z_OK)
return -1;
if (state->eof == 0) {
if (gz_load(state, state->in, state->size, &(strm->avail_in)) == -1)
return -1;
strm->next_in = state->in;
}
return 0;
}
/* Get next byte from input, or -1 if end or error. */
#define NEXT() ((strm->avail_in == 0 && gz_avail(state) == -1) ? -1 : \
(strm->avail_in == 0 ? -1 : \
(strm->avail_in--, *(strm->next_in)++)))
/* Get a four-byte little-endian integer and return 0 on success and the value
in *ret. Otherwise -1 is returned and *ret is not modified. */
local int gz_next4(state, ret)
gz_statep state;
unsigned long *ret;
{
int ch;
unsigned long val;
z_streamp strm = &(state->strm);
val = NEXT();
val += (unsigned)NEXT() << 8;
val += (unsigned long)NEXT() << 16;
ch = NEXT();
if (ch == -1)
return -1;
val += (unsigned long)ch << 24;
*ret = val;
return 0;
}
/* Look for gzip header, set up for inflate or copy. state->have must be zero.
If this is the first time in, allocate required memory. state->how will be
left unchanged if there is no more input data available, will be set to COPY
if there is no gzip header and direct copying will be performed, or it will
be set to GZIP for decompression, and the gzip header will be skipped so
that the next available input data is the raw deflate stream. If direct
copying, then leftover input data from the input buffer will be copied to
the output buffer. In that case, all further file reads will be directly to
either the output buffer or a user buffer. If decompressing, the inflate
state and the check value will be initialized. gz_head() will return 0 on
success or -1 on failure. Failures may include read errors or gzip header
errors. */
local int gz_head(state)
gz_statep state;
{
z_streamp strm = &(state->strm);
int flags;
unsigned len;
/* allocate read buffers and inflate memory */
if (state->size == 0) {
/* allocate buffers */
state->in = malloc(state->want);
state->out = malloc(state->want << 1);
if (state->in == NULL || state->out == NULL) {
if (state->out != NULL)
free(state->out);
if (state->in != NULL)
free(state->in);
gz_error(state, Z_MEM_ERROR, "out of memory");
return -1;
}
state->size = state->want;
/* allocate inflate memory */
state->strm.zalloc = Z_NULL;
state->strm.zfree = Z_NULL;
state->strm.opaque = Z_NULL;
state->strm.avail_in = 0;
state->strm.next_in = Z_NULL;
if (inflateInit2(&(state->strm), -15) != Z_OK) { /* raw inflate */
free(state->out);
free(state->in);
state->size = 0;
gz_error(state, Z_MEM_ERROR, "out of memory");
return -1;
}
}
/* get some data in the input buffer */
if (strm->avail_in == 0) {
if (gz_avail(state) == -1)
return -1;
if (strm->avail_in == 0)
return 0;
}
/* look for the gzip magic header bytes 31 and 139 */
if (strm->next_in[0] == 31) {
strm->avail_in--;
strm->next_in++;
if (strm->avail_in == 0 && gz_avail(state) == -1)
return -1;
if (strm->avail_in && strm->next_in[0] == 139) {
/* we have a gzip header, woo hoo! */
strm->avail_in--;
strm->next_in++;
/* skip rest of header */
if (NEXT() != 8) { /* compression method */
gz_error(state, Z_DATA_ERROR, "unknown compression method");
return -1;
}
flags = NEXT();
if (flags & 0xe0) { /* reserved flag bits */
gz_error(state, Z_DATA_ERROR, "unknown header flags set");
return -1;
}
NEXT(); /* modification time */
NEXT();
NEXT();
NEXT();
NEXT(); /* extra flags */
NEXT(); /* operating system */
if (flags & 4) { /* extra field */
len = (unsigned)NEXT();
len += (unsigned)NEXT() << 8;
while (len--)
if (NEXT() < 0)
break;
}
if (flags & 8) /* file name */
while (NEXT() > 0)
;
if (flags & 16) /* comment */
while (NEXT() > 0)
;
if (flags & 2) { /* header crc */
NEXT();
NEXT();
}
/* an unexpected end of file is not checked for here -- it will be
noticed on the first request for uncompressed data */
/* set up for decompression */
inflateReset(strm);
strm->adler = crc32(0L, Z_NULL, 0);
state->how = GZIP;
state->direct = 0;
return 0;
}
else {
/* not a gzip file -- save first byte (31) and fall to raw i/o */
state->out[0] = 31;
state->have = 1;
}
}
/* doing raw i/o, save start of raw data for seeking, copy any leftover
input to output -- this assumes that the output buffer is larger than
the input buffer, which also assures space for gzungetc() */
state->raw = state->pos;
state->next = state->out;
if (strm->avail_in) {
memcpy(state->next + state->have, strm->next_in, strm->avail_in);
state->have += strm->avail_in;
strm->avail_in = 0;
}
state->how = COPY;
state->direct = 1;
return 0;
}
/* Decompress from input to the provided next_out and avail_out in the state.
If the end of the compressed data is reached, then verify the gzip trailer
check value and length (modulo 2^32). state->have and state->next are set
to point to the just decompressed data, and the crc is updated. If the
trailer is verified, state->how is reset to LOOK to look for the next gzip
stream or raw data, once state->have is depleted. Returns 0 on success, -1
on failure. Failures may include invalid compressed data or a failed gzip
trailer verification. */
local int gz_decomp(state)
gz_statep state;
{
int ret;
unsigned had;
unsigned long crc, len;
z_streamp strm = &(state->strm);
/* fill output buffer up to end of deflate stream */
had = strm->avail_out;
do {
/* get more input for inflate() */
if (strm->avail_in == 0 && gz_avail(state) == -1)
return -1;
if (strm->avail_in == 0) {
gz_error(state, Z_DATA_ERROR, "unexpected end of file");
return -1;
}
/* decompress and handle errors */
ret = inflate(strm, Z_NO_FLUSH);
if (ret == Z_STREAM_ERROR || ret == Z_NEED_DICT) {
gz_error(state, Z_STREAM_ERROR,
"internal error: inflate stream corrupt");
return -1;
}
if (ret == Z_MEM_ERROR) {
gz_error(state, Z_MEM_ERROR, "out of memory");
return -1;
}
if (ret == Z_DATA_ERROR) { /* deflate stream invalid */
gz_error(state, Z_DATA_ERROR,
strm->msg == NULL ? "compressed data error" : strm->msg);
return -1;
}
} while (strm->avail_out && ret != Z_STREAM_END);
/* update available output and crc check value */
state->have = had - strm->avail_out;
state->next = strm->next_out - state->have;
strm->adler = crc32(strm->adler, state->next, state->have);
/* check gzip trailer if at end of deflate stream */
if (ret == Z_STREAM_END) {
if (gz_next4(state, &crc) == -1 || gz_next4(state, &len) == -1) {
gz_error(state, Z_DATA_ERROR, "unexpected end of file");
return -1;
}
if (crc != strm->adler) {
gz_error(state, Z_DATA_ERROR, "incorrect data check");
return -1;
}
if (len != (strm->total_out & 0xffffffffL)) {
gz_error(state, Z_DATA_ERROR, "incorrect length check");
return -1;
}
state->how = LOOK; /* ready for next stream, once have is 0 (leave
state->direct unchanged to remember how) */
}
/* good decompression */
return 0;
}
/* Make data and put in the output buffer. Assumes that state->have == 0.
Data is either copied from the input file or decompressed from the input
file depending on state->how. If state->how is LOOK, then a gzip header is
looked for (and skipped if found) to determine wither to copy or decompress.
Returns -1 on error, otherwise 0. gz_make() will leave state->have as COPY
or GZIP unless the end of the input file has been reached and all data has
been processed. */
local int gz_make(state)
gz_statep state;
{
z_streamp strm = &(state->strm);
if (state->how == LOOK) { /* look for gzip header */
if (gz_head(state) == -1)
return -1;
if (state->have) /* got some data from gz_head() */
return 0;
}
if (state->how == COPY) { /* straight copy */
if (gz_load(state, state->out, state->size << 1, &(state->have)) == -1)
return -1;
state->next = state->out;
}
else if (state->how == GZIP) { /* decompress */
strm->avail_out = state->size << 1;
strm->next_out = state->out;
if (gz_decomp(state) == -1)
return -1;
}
return 0;
}
/* Skip len uncompressed bytes of output. Return -1 on error, 0 on success. */
local int gz_skip(state, len)
gz_statep state;
z_off64_t len;
{
unsigned n;
/* skip over len bytes or reach end-of-file, whichever comes first */
while (len)
/* skip over whatever is in output buffer */
if (state->have) {
n = GT_OFF(state->have) || (z_off64_t)state->have > len ?
(unsigned)len : state->have;
state->have -= n;
state->next += n;
state->pos += n;
len -= n;
}
/* output buffer empty -- return if we're at the end of the input */
else if (state->eof && state->strm.avail_in == 0)
break;
/* need more data to skip -- load up output buffer */
else {
/* get more output, looking for header if required */
if (gz_make(state) == -1)
return -1;
}
return 0;
}
/* -- see zlib.h -- */
int ZEXPORT gzread(file, buf, len)
gzFile file;
voidp buf;
unsigned len;
{
unsigned got, n;
gz_statep state;
z_streamp strm;
/* get internal structure */
if (file == NULL)
return -1;
state = (gz_statep)file;
strm = &(state->strm);
/* check that we're reading and that there's no error */
if (state->mode != GZ_READ || state->err != Z_OK)
return -1;
/* since an int is returned, make sure len fits in one, otherwise return
with an error (this avoids the flaw in the interface) */
if ((int)len < 0) {
gz_error(state, Z_BUF_ERROR, "requested length does not fit in int");
return -1;
}
/* if len is zero, avoid unnecessary operations */
if (len == 0)
return 0;
/* process a skip request */
if (state->seek) {
state->seek = 0;
if (gz_skip(state, state->skip) == -1)
return -1;
}
/* get len bytes to buf, or less than len if at the end */
got = 0;
do {
/* first just try copying data from the output buffer */
if (state->have) {
n = state->have > len ? len : state->have;
memcpy(buf, state->next, n);
state->next += n;
state->have -= n;
}
/* output buffer empty -- return if we're at the end of the input */
else if (state->eof && strm->avail_in == 0)
break;
/* need output data -- for small len or new stream load up our output
buffer */
else if (state->how == LOOK || len < (state->size << 1)) {
/* get more output, looking for header if required */
if (gz_make(state) == -1)
return -1;
continue; /* no progress yet -- go back to memcpy() above */
/* the copy above assures that we will leave with space in the
output buffer, allowing at least one gzungetc() to succeed */
}
/* large len -- read directly into user buffer */
else if (state->how == COPY) { /* read directly */
if (gz_load(state, buf, len, &n) == -1)
return -1;
}
/* large len -- decompress directly into user buffer */
else { /* state->how == GZIP */
strm->avail_out = len;
strm->next_out = buf;
if (gz_decomp(state) == -1)
return -1;
n = state->have;
state->have = 0;
}
/* update progress */
len -= n;
buf = (char *)buf + n;
got += n;
state->pos += n;
} while (len);
/* return number of bytes read into user buffer (will fit in int) */
return (int)got;
}
/* -- see zlib.h -- */
int ZEXPORT gzgetc(file)
gzFile file;
{
int ret;
unsigned char buf[1];
gz_statep state;
/* get internal structure */
if (file == NULL)
return -1;
state = (gz_statep)file;
/* check that we're reading and that there's no error */
if (state->mode != GZ_READ || state->err != Z_OK)
return -1;
/* try output buffer (no need to check for skip request) */
if (state->have) {
state->have--;
state->pos++;
return *(state->next)++;
}
/* nothing there -- try gzread() */
ret = gzread(file, buf, 1);
return ret < 1 ? -1 : buf[0];
}
/* -- see zlib.h -- */
int ZEXPORT gzungetc(c, file)
int c;
gzFile file;
{
gz_statep state;
/* get internal structure */
if (file == NULL)
return -1;
state = (gz_statep)file;
/* check that we're reading and that there's no error */
if (state->mode != GZ_READ || state->err != Z_OK)
return -1;
/* process a skip request */
if (state->seek) {
state->seek = 0;
if (gz_skip(state, state->skip) == -1)
return -1;
}
/* can't push EOF */
if (c < 0)
return -1;
/* if output buffer empty, put byte at end (allows more pushing) */
if (state->have == 0) {
state->have = 1;
state->next = state->out + (state->size << 1) - 1;
state->next[0] = c;
state->pos--;
return c;
}
/* if no room, give up (must have already done a gzungetc()) */
if (state->have == (state->size << 1)) {
gz_error(state, Z_BUF_ERROR, "out of room to push characters");
return -1;
}
/* slide output data if needed and insert byte before existing data */
if (state->next == state->out) {
unsigned char *src = state->out + state->have;
unsigned char *dest = state->out + (state->size << 1);
while (src > state->out)
*--dest = *--src;
state->next = dest;
}
state->have++;
state->next--;
state->next[0] = c;
state->pos--;
return c;
}
/* -- see zlib.h -- */
char * ZEXPORT gzgets(file, buf, len)
gzFile file;
char *buf;
int len;
{
unsigned left, n;
char *str;
unsigned char *eol;
gz_statep state;
/* check parameters and get internal structure */
if (file == NULL || buf == NULL || len < 1)
return NULL;
state = (gz_statep)file;
/* check that we're reading and that there's no error */
if (state->mode != GZ_READ || state->err != Z_OK)
return NULL;
/* process a skip request */
if (state->seek) {
state->seek = 0;
if (gz_skip(state, state->skip) == -1)
return NULL;
}
/* copy output bytes up to new line or len - 1, whichever comes first --
append a terminating zero to the string (we don't check for a zero in
the contents, let the user worry about that) */
str = buf;
left = (unsigned)len - 1;
if (left) do {
/* assure that something is in the output buffer */
if (state->have == 0) {
if (gz_make(state) == -1)
return NULL; /* error */
if (state->have == 0) { /* end of file */
if (buf == str) /* got bupkus */
return NULL;
break; /* got something -- return it */
}
}
/* look for end-of-line in current output buffer */
n = state->have > left ? left : state->have;
eol = memchr(state->next, '\n', n);
if (eol != NULL)
n = (unsigned)(eol - state->next) + 1;
/* copy through end-of-line, or remainder if not found */
memcpy(buf, state->next, n);
state->have -= n;
state->next += n;
state->pos += n;
left -= n;
buf += n;
} while (left && eol == NULL);
/* found end-of-line or out of space -- terminate string and return it */
buf[0] = 0;
return str;
}
/* -- see zlib.h -- */
int ZEXPORT gzdirect(file)
gzFile file;
{
gz_statep state;
/* get internal structure */
if (file == NULL)
return 0;
state = (gz_statep)file;
/* check that we're reading */
if (state->mode != GZ_READ)
return 0;
/* if the state is not known, but we can find out, then do so (this is
mainly for right after a gzopen() or gzdopen()) */
if (state->how == LOOK && state->have == 0)
(void)gz_head(state);
/* return 1 if reading direct, 0 if decompressing a gzip stream */
return state->direct;
}
/* -- see zlib.h -- */
int ZEXPORT gzclose_r(file)
gzFile file;
{
int ret;
gz_statep state;
/* get internal structure */
if (file == NULL)
return Z_STREAM_ERROR;
state = (gz_statep)file;
/* check that we're reading */
if (state->mode != GZ_READ)
return Z_STREAM_ERROR;
/* free memory and close file */
if (state->size) {
inflateEnd(&(state->strm));
free(state->out);
free(state->in);
}
gz_error(state, Z_OK, NULL);
free(state->path);
ret = close(state->fd);
free(state);
return ret ? Z_ERRNO : Z_OK;
}

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/* gzwrite.c -- zlib functions for writing gzip files
* Copyright (C) 2004, 2005, 2010 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include "gzguts.h"
/* Local functions */
local int gz_init OF((gz_statep));
local int gz_comp OF((gz_statep, int));
local int gz_zero OF((gz_statep, z_off64_t));
/* Initialize state for writing a gzip file. Mark initialization by setting
state->size to non-zero. Return -1 on failure or 0 on success. */
local int gz_init(state)
gz_statep state;
{
int ret;
z_streamp strm = &(state->strm);
/* allocate input and output buffers */
state->in = malloc(state->want);
state->out = malloc(state->want);
if (state->in == NULL || state->out == NULL) {
if (state->out != NULL)
free(state->out);
if (state->in != NULL)
free(state->in);
gz_error(state, Z_MEM_ERROR, "out of memory");
return -1;
}
/* allocate deflate memory, set up for gzip compression */
strm->zalloc = Z_NULL;
strm->zfree = Z_NULL;
strm->opaque = Z_NULL;
ret = deflateInit2(strm, state->level, Z_DEFLATED,
15 + 16, 8, state->strategy);
if (ret != Z_OK) {
free(state->in);
gz_error(state, Z_MEM_ERROR, "out of memory");
return -1;
}
/* mark state as initialized */
state->size = state->want;
/* initialize write buffer */
strm->avail_out = state->size;
strm->next_out = state->out;
state->next = strm->next_out;
return 0;
}
/* Compress whatever is at avail_in and next_in and write to the output file.
Return -1 if there is an error writing to the output file, otherwise 0.
flush is assumed to be a valid deflate() flush value. If flush is Z_FINISH,
then the deflate() state is reset to start a new gzip stream. */
local int gz_comp(state, flush)
gz_statep state;
int flush;
{
int ret, got;
unsigned have;
z_streamp strm = &(state->strm);
/* allocate memory if this is the first time through */
if (state->size == 0 && gz_init(state) == -1)
return -1;
/* run deflate() on provided input until it produces no more output */
ret = Z_OK;
do {
/* write out current buffer contents if full, or if flushing, but if
doing Z_FINISH then don't write until we get to Z_STREAM_END */
if (strm->avail_out == 0 || (flush != Z_NO_FLUSH &&
(flush != Z_FINISH || ret == Z_STREAM_END))) {
have = (unsigned)(strm->next_out - state->next);
if (have && ((got = write(state->fd, state->next, have)) < 0 ||
(unsigned)got != have)) {
gz_error(state, Z_ERRNO, zstrerror());
return -1;
}
if (strm->avail_out == 0) {
strm->avail_out = state->size;
strm->next_out = state->out;
}
state->next = strm->next_out;
}
/* compress */
have = strm->avail_out;
ret = deflate(strm, flush);
if (ret == Z_STREAM_ERROR) {
gz_error(state, Z_STREAM_ERROR,
"internal error: deflate stream corrupt");
return -1;
}
have -= strm->avail_out;
} while (have);
/* if that completed a deflate stream, allow another to start */
if (flush == Z_FINISH)
deflateReset(strm);
/* all done, no errors */
return 0;
}
/* Compress len zeros to output. Return -1 on error, 0 on success. */
local int gz_zero(state, len)
gz_statep state;
z_off64_t len;
{
int first;
unsigned n;
z_streamp strm = &(state->strm);
/* consume whatever's left in the input buffer */
if (strm->avail_in && gz_comp(state, Z_NO_FLUSH) == -1)
return -1;
/* compress len zeros (len guaranteed > 0) */
first = 1;
while (len) {
n = GT_OFF(state->size) || (z_off64_t)state->size > len ?
(unsigned)len : state->size;
if (first) {
memset(state->in, 0, n);
first = 0;
}
strm->avail_in = n;
strm->next_in = state->in;
state->pos += n;
if (gz_comp(state, Z_NO_FLUSH) == -1)
return -1;
len -= n;
}
return 0;
}
/* -- see zlib.h -- */
int ZEXPORT gzwrite(file, buf, len)
gzFile file;
voidpc buf;
unsigned len;
{
unsigned put = len;
unsigned n;
gz_statep state;
z_streamp strm;
/* get internal structure */
if (file == NULL)
return 0;
state = (gz_statep)file;
strm = &(state->strm);
/* check that we're writing and that there's no error */
if (state->mode != GZ_WRITE || state->err != Z_OK)
return 0;
/* since an int is returned, make sure len fits in one, otherwise return
with an error (this avoids the flaw in the interface) */
if ((int)len < 0) {
gz_error(state, Z_BUF_ERROR, "requested length does not fit in int");
return 0;
}
/* if len is zero, avoid unnecessary operations */
if (len == 0)
return 0;
/* allocate memory if this is the first time through */
if (state->size == 0 && gz_init(state) == -1)
return 0;
/* check for seek request */
if (state->seek) {
state->seek = 0;
if (gz_zero(state, state->skip) == -1)
return 0;
}
/* for small len, copy to input buffer, otherwise compress directly */
if (len < state->size) {
/* copy to input buffer, compress when full */
do {
if (strm->avail_in == 0)
strm->next_in = state->in;
n = state->size - strm->avail_in;
if (n > len)
n = len;
memcpy(strm->next_in + strm->avail_in, buf, n);
strm->avail_in += n;
state->pos += n;
buf = (char *)buf + n;
len -= n;
if (len && gz_comp(state, Z_NO_FLUSH) == -1)
return 0;
} while (len);
}
else {
/* consume whatever's left in the input buffer */
if (strm->avail_in && gz_comp(state, Z_NO_FLUSH) == -1)
return 0;
/* directly compress user buffer to file */
strm->avail_in = len;
strm->next_in = (voidp)buf;
state->pos += len;
if (gz_comp(state, Z_NO_FLUSH) == -1)
return 0;
}
/* input was all buffered or compressed (put will fit in int) */
return (int)put;
}
/* -- see zlib.h -- */
int ZEXPORT gzputc(file, c)
gzFile file;
int c;
{
unsigned char buf[1];
gz_statep state;
z_streamp strm;
/* get internal structure */
if (file == NULL)
return -1;
state = (gz_statep)file;
strm = &(state->strm);
/* check that we're writing and that there's no error */
if (state->mode != GZ_WRITE || state->err != Z_OK)
return -1;
/* check for seek request */
if (state->seek) {
state->seek = 0;
if (gz_zero(state, state->skip) == -1)
return -1;
}
/* try writing to input buffer for speed (state->size == 0 if buffer not
initialized) */
if (strm->avail_in < state->size) {
if (strm->avail_in == 0)
strm->next_in = state->in;
strm->next_in[strm->avail_in++] = c;
state->pos++;
return c;
}
/* no room in buffer or not initialized, use gz_write() */
buf[0] = c;
if (gzwrite(file, buf, 1) != 1)
return -1;
return c;
}
/* -- see zlib.h -- */
int ZEXPORT gzputs(file, str)
gzFile file;
const char *str;
{
int ret;
unsigned len;
/* write string */
len = (unsigned)strlen(str);
ret = gzwrite(file, str, len);
return ret == 0 && len != 0 ? -1 : ret;
}
#ifdef STDC
#include <stdarg.h>
/* -- see zlib.h -- */
int ZEXPORTVA gzprintf (gzFile file, const char *format, ...)
{
int size, len;
gz_statep state;
z_streamp strm;
va_list va;
/* get internal structure */
if (file == NULL)
return -1;
state = (gz_statep)file;
strm = &(state->strm);
/* check that we're writing and that there's no error */
if (state->mode != GZ_WRITE || state->err != Z_OK)
return 0;
/* make sure we have some buffer space */
if (state->size == 0 && gz_init(state) == -1)
return 0;
/* check for seek request */
if (state->seek) {
state->seek = 0;
if (gz_zero(state, state->skip) == -1)
return 0;
}
/* consume whatever's left in the input buffer */
if (strm->avail_in && gz_comp(state, Z_NO_FLUSH) == -1)
return 0;
/* do the printf() into the input buffer, put length in len */
size = (int)(state->size);
state->in[size - 1] = 0;
va_start(va, format);
#ifdef NO_vsnprintf
# ifdef HAS_vsprintf_void
(void)vsprintf(state->in, format, va);
va_end(va);
for (len = 0; len < size; len++)
if (state->in[len] == 0) break;
# else
len = vsprintf(state->in, format, va);
va_end(va);
# endif
#else
# ifdef HAS_vsnprintf_void
(void)vsnprintf(state->in, size, format, va);
va_end(va);
len = strlen(state->in);
# else
len = vsnprintf((char *)(state->in), size, format, va);
va_end(va);
# endif
#endif
/* check that printf() results fit in buffer */
if (len <= 0 || len >= (int)size || state->in[size - 1] != 0)
return 0;
/* update buffer and position, defer compression until needed */
strm->avail_in = (unsigned)len;
strm->next_in = state->in;
state->pos += len;
return len;
}
#else /* !STDC */
/* -- see zlib.h -- */
int ZEXPORTVA gzprintf (file, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
a11, a12, a13, a14, a15, a16, a17, a18, a19, a20)
gzFile file;
const char *format;
int a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
a11, a12, a13, a14, a15, a16, a17, a18, a19, a20;
{
int size, len;
gz_statep state;
z_streamp strm;
/* get internal structure */
if (file == NULL)
return -1;
state = (gz_statep)file;
strm = &(state->strm);
/* check that we're writing and that there's no error */
if (state->mode != GZ_WRITE || state->err != Z_OK)
return 0;
/* make sure we have some buffer space */
if (state->size == 0 && gz_init(state) == -1)
return 0;
/* check for seek request */
if (state->seek) {
state->seek = 0;
if (gz_zero(state, state->skip) == -1)
return 0;
}
/* consume whatever's left in the input buffer */
if (strm->avail_in && gz_comp(state, Z_NO_FLUSH) == -1)
return 0;
/* do the printf() into the input buffer, put length in len */
size = (int)(state->size);
state->in[size - 1] = 0;
#ifdef NO_snprintf
# ifdef HAS_sprintf_void
sprintf(state->in, format, a1, a2, a3, a4, a5, a6, a7, a8,
a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
for (len = 0; len < size; len++)
if (state->in[len] == 0) break;
# else
len = sprintf(state->in, format, a1, a2, a3, a4, a5, a6, a7, a8,
a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
# endif
#else
# ifdef HAS_snprintf_void
snprintf(state->in, size, format, a1, a2, a3, a4, a5, a6, a7, a8,
a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
len = strlen(state->in);
# else
len = snprintf(state->in, size, format, a1, a2, a3, a4, a5, a6, a7, a8,
a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
# endif
#endif
/* check that printf() results fit in buffer */
if (len <= 0 || len >= (int)size || state->in[size - 1] != 0)
return 0;
/* update buffer and position, defer compression until needed */
strm->avail_in = (unsigned)len;
strm->next_in = state->in;
state->pos += len;
return len;
}
#endif
/* -- see zlib.h -- */
int ZEXPORT gzflush(file, flush)
gzFile file;
int flush;
{
gz_statep state;
/* get internal structure */
if (file == NULL)
return -1;
state = (gz_statep)file;
/* check that we're writing and that there's no error */
if (state->mode != GZ_WRITE || state->err != Z_OK)
return Z_STREAM_ERROR;
/* check flush parameter */
if (flush < 0 || flush > Z_FINISH)
return Z_STREAM_ERROR;
/* check for seek request */
if (state->seek) {
state->seek = 0;
if (gz_zero(state, state->skip) == -1)
return -1;
}
/* compress remaining data with requested flush */
gz_comp(state, flush);
return state->err;
}
/* -- see zlib.h -- */
int ZEXPORT gzsetparams(file, level, strategy)
gzFile file;
int level;
int strategy;
{
gz_statep state;
z_streamp strm;
/* get internal structure */
if (file == NULL)
return Z_STREAM_ERROR;
state = (gz_statep)file;
strm = &(state->strm);
/* check that we're writing and that there's no error */
if (state->mode != GZ_WRITE || state->err != Z_OK)
return Z_STREAM_ERROR;
/* if no change is requested, then do nothing */
if (level == state->level && strategy == state->strategy)
return Z_OK;
/* check for seek request */
if (state->seek) {
state->seek = 0;
if (gz_zero(state, state->skip) == -1)
return -1;
}
/* change compression parameters for subsequent input */
if (state->size) {
/* flush previous input with previous parameters before changing */
if (strm->avail_in && gz_comp(state, Z_PARTIAL_FLUSH) == -1)
return state->err;
deflateParams(strm, level, strategy);
}
state->level = level;
state->strategy = strategy;
return Z_OK;
}
/* -- see zlib.h -- */
int ZEXPORT gzclose_w(file)
gzFile file;
{
int ret = 0;
gz_statep state;
/* get internal structure */
if (file == NULL)
return Z_STREAM_ERROR;
state = (gz_statep)file;
/* check that we're writing */
if (state->mode != GZ_WRITE)
return Z_STREAM_ERROR;
/* check for seek request */
if (state->seek) {
state->seek = 0;
ret += gz_zero(state, state->skip);
}
/* flush, free memory, and close file */
ret += gz_comp(state, Z_FINISH);
(void)deflateEnd(&(state->strm));
free(state->out);
free(state->in);
gz_error(state, Z_OK, NULL);
free(state->path);
ret += close(state->fd);
free(state);
return ret ? Z_ERRNO : Z_OK;
}