/*
* This file contains code from zlib library v.1.2.3 with modifications
* by aCaB <acab@clamav.net> to allow decompression of deflate64 stereams
* (aka zip method 9). The implementation is heavily inspired by InfoZip
* and zlib's inf9back.c
*
* Full copy of the original zlib license follows:
*/
/* zlib.h -- interface of the 'zlib' general purpose compression library
version 1.2.3, July 18th, 2005
Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
Jean-loup Gailly Mark Adler
jloup@gzip.org madler@alumni.caltech.edu
The data format used by the zlib library is described by RFCs (Request for
Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt
(zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
*/
const char inflate64_copyright[] =
" inflate 1.2.3 Copyright 1995-2005 Mark Adler ";
/*
If you use the zlib library in a product, an acknowledgment is welcome
in the documentation of your product. If for some reason you cannot
include such an acknowledgment, I would appreciate that you keep this
copyright string in the executable of your product.
*/
#include "inflate64_priv.h"
#include <stdlib.h> /* calloc/free */
#include <string.h> /* memcpy */
#include "others.h"
/* function prototypes */
local void fixedtables OF((struct inflate_state FAR *state));
local int updatewindow OF((z_stream64p strm, unsigned out));
local int inflate_table OF((codetype type, unsigned short FAR *lens,
unsigned codes, code FAR * FAR *table,
unsigned FAR *bits, unsigned short FAR *work));
int ZEXPORT inflate64Init2(strm, windowBits)
z_stream64p strm;
int windowBits;
{
struct inflate_state FAR *state;
if (strm == Z_NULL) return Z_STREAM_ERROR;
state = (struct inflate_state FAR *)cli_calloc(1, sizeof(struct inflate_state));
if (state == Z_NULL) return Z_MEM_ERROR;
Tracev((stderr, "inflate: allocated\n"));
strm->state = (struct internal_state FAR *)state;
if (windowBits < 0) {
state->wrap = 0;
windowBits = -windowBits;
}
else {
state->wrap = (windowBits >> 4) + 1;
}
if (windowBits < 8 || windowBits > MAX_WBITS64) {
free(state);
strm->state = Z_NULL;
return Z_STREAM_ERROR;
}
state->wbits = (unsigned)windowBits;
state->window = Z_NULL;
strm->total_in = strm->total_out = state->total = 0;
strm->adler = 1; /* to support ill-conceived Java test suite */
state->mode = HEAD;
state->last = 0;
state->havedict = 0;
state->dmax = 32768U;
state->wsize = 0;
state->whave = 0;
state->write = 0;
state->hold = 0;
state->bits = 0;
state->lencode = state->distcode = state->next = state->codes;
Tracev((stderr, "inflate: reset\n"));
return Z_OK;
}
/*
Return state with length and distance decoding tables and index sizes set to
fixed code decoding. Normally this returns fixed tables from inffixed.h.
If BUILDFIXED is defined, then instead this routine builds the tables the
first time it's called, and returns those tables the first time and
thereafter. This reduces the size of the code by about 2K bytes, in
exchange for a little execution time. However, BUILDFIXED should not be
used for threaded applications, since the rewriting of the tables and virgin
may not be thread-safe.
*/
local void fixedtables(state)
struct inflate_state FAR *state;
{
#ifdef BUILDFIXED
static int virgin = 1;
static code *lenfix, *distfix;
static code fixed[544];
/* build fixed huffman tables if first call (may not be thread safe) */
if (virgin) {
unsigned sym, bits;
static code *next;
/* literal/length table */
sym = 0;
while (sym < 144) state->lens[sym++] = 8;
while (sym < 256) state->lens[sym++] = 9;
while (sym < 280) state->lens[sym++] = 7;
while (sym < 288) state->lens[sym++] = 8;
next = fixed;
lenfix = next;
bits = 9;
inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
/* distance table */
sym = 0;
while (sym < 32) state->lens[sym++] = 5;
distfix = next;
bits = 5;
inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
/* do this just once */
virgin = 0;
}
#else /* !BUILDFIXED */
# include "inffixed64.h"
#endif /* BUILDFIXED */
state->lencode = lenfix;
state->lenbits = 9;
state->distcode = distfix;
state->distbits = 5;
}
/*
Update the window with the last wsize (normally 32K) bytes written before
returning. If window does not exist yet, create it. This is only called
when a window is already in use, or when output has been written during this
inflate call, but the end of the deflate stream has not been reached yet.
It is also called to create a window for dictionary data when a dictionary
is loaded.
Providing output buffers larger than 32K to inflate() should provide a speed
advantage, since only the last 32K of output is copied to the sliding window
upon return from inflate(), and since all distances after the first 32K of
output will fall in the output data, making match copies simpler and faster.
The advantage may be dependent on the size of the processor's data caches.
*/
local int updatewindow(strm, out)
z_stream64p strm;
unsigned out;
{
struct inflate_state FAR *state;
unsigned copy, dist;
state = (struct inflate_state FAR *)strm->state;
/* if it hasn't been done already, allocate space for the window */
if (state->window == Z_NULL) {
state->window = (unsigned char FAR *)cli_calloc(1U << state->wbits, sizeof(unsigned char));
if (state->window == Z_NULL) return 1;
}
/* if window not in use yet, initialize */
if (state->wsize == 0) {
state->wsize = 1U << state->wbits;
state->write = 0;
state->whave = 0;
}
/* copy state->wsize or less output bytes into the circular window */
copy = out - strm->avail_out;
if (copy >= state->wsize) {
memcpy(state->window, strm->next_out - state->wsize, state->wsize);
state->write = 0;
state->whave = state->wsize;
}
else {
dist = state->wsize - state->write;
if (dist > copy) dist = copy;
memcpy(state->window + state->write, strm->next_out - copy, dist);
copy -= dist;
if (copy) {
memcpy(state->window, strm->next_out - copy, copy);
state->write = copy;
state->whave = state->wsize;
}
else {
state->write += dist;
if (state->write == state->wsize) state->write = 0;
if (state->whave < state->wsize) state->whave += dist;
}
}
return 0;
}
/* Macros for inflate(): */
/* check function to use adler32() for zlib or crc32() for gzip */
# define UPDATE(check, buf, len) adler32(check, buf, len)
/* Load registers with state in inflate() for speed */
#define LOAD() \
do { \
put = strm->next_out; \
left = strm->avail_out; \
next = strm->next_in; \
have = strm->avail_in; \
hold = state->hold; \
bits = state->bits; \
} while (0)
/* Restore state from registers in inflate() */
#define RESTORE() \
do { \
strm->next_out = put; \
strm->avail_out = left; \
strm->next_in = next; \
strm->avail_in = have; \
state->hold = hold; \
state->bits = bits; \
} while (0)
/* Clear the input bit accumulator */
#define INITBITS() \
do { \
hold = 0; \
bits = 0; \
} while (0)
/* Get a byte of input into the bit accumulator, or return from inflate()
if there is no input available. */
#define PULLBYTE() \
do { \
if (have == 0) goto inf_leave; \
have--; \
hold += (unsigned long)(*next++) << bits; \
bits += 8; \
} while (0)
/* Assure that there are at least n bits in the bit accumulator. If there is
not enough available input to do that, then return from inflate(). */
#define NEEDBITS(n) \
do { \
while (bits < (unsigned)(n)) \
PULLBYTE(); \
} while (0)
/* Return the low n bits of the bit accumulator (n < 16) */
#define BITS(n) \
((unsigned)hold & ((1U << (n)) - 1))
/* Remove n bits from the bit accumulator */
#define DROPBITS(n) \
do { \
hold >>= (n); \
bits -= (unsigned)(n); \
} while (0)
/* Remove zero to seven bits as needed to go to a byte boundary */
#define BYTEBITS() \
do { \
hold >>= bits & 7; \
bits -= bits & 7; \
} while (0)
/* Reverse the bytes in a 32-bit value */
#define REVERSE(q) \
((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + \
(((q) & 0xff00) << 8) + (((q) & 0xff) << 24))
/*
inflate() uses a state machine to process as much input data and generate as
much output data as possible before returning. The state machine is
structured roughly as follows:
for (;;) switch (state) {
...
case STATEn:
if (not enough input data or output space to make progress)
return;
... make progress ...
state = STATEm;
break;
...
}
so when inflate() is called again, the same case is attempted again, and
if the appropriate resources are provided, the machine proceeds to the
next state. The NEEDBITS() macro is usually the way the state evaluates
whether it can proceed or should return. NEEDBITS() does the return if
the requested bits are not available. The typical use of the BITS macros
is:
NEEDBITS(n);
... do something with BITS(n) ...
DROPBITS(n);
where NEEDBITS(n) either returns from inflate() if there isn't enough
input left to load n bits into the accumulator, or it continues. BITS(n)
gives the low n bits in the accumulator. When done, DROPBITS(n) drops
the low n bits off the accumulator. INITBITS() clears the accumulator
and sets the number of available bits to zero. BYTEBITS() discards just
enough bits to put the accumulator on a byte boundary. After BYTEBITS()
and a NEEDBITS(8), then BITS(8) would return the next byte in the stream.
NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return
if there is no input available. The decoding of variable length codes uses
PULLBYTE() directly in order to pull just enough bytes to decode the next
code, and no more.
Some states loop until they get enough input, making sure that enough
state information is maintained to continue the loop where it left off
if NEEDBITS() returns in the loop. For example, want, need, and keep
would all have to actually be part of the saved state in case NEEDBITS()
returns:
case STATEw:
while (want < need) {
NEEDBITS(n);
keep[want++] = BITS(n);
DROPBITS(n);
}
state = STATEx;
case STATEx:
As shown above, if the next state is also the next case, then the break
is omitted.
A state may also return if there is not enough output space available to
complete that state. Those states are copying stored data, writing a
literal byte, and copying a matching string.
When returning, a "goto inf_leave" is used to update the total counters,
update the check value, and determine whether any progress has been made
during that inflate() call in order to return the proper return code.
Progress is defined as a change in either strm->avail_in or strm->avail_out.
When there is a window, goto inf_leave will update the window with the last
output written. If a goto inf_leave occurs in the middle of decompression
and there is no window currently, goto inf_leave will create one and copy
output to the window for the next call of inflate().
In this implementation, the flush parameter of inflate() only affects the
return code (per zlib.h). inflate() always writes as much as possible to
strm->next_out, given the space available and the provided input--the effect
documented in zlib.h of Z_SYNC_FLUSH. Furthermore, inflate() always defers
the allocation of and copying into a sliding window until necessary, which
provides the effect documented in zlib.h for Z_FINISH when the entire input
stream available. So the only thing the flush parameter actually does is:
when flush is set to Z_FINISH, inflate() cannot return Z_OK. Instead it
will return Z_BUF_ERROR if it has not reached the end of the stream.
*/
int ZEXPORT inflate64(strm, flush)
z_stream64p strm;
int flush;
{
struct inflate_state FAR *state;
unsigned char FAR *next; /* next input */
unsigned char FAR *put; /* next output */
unsigned have, left; /* available input and output */
unsigned long hold; /* bit buffer */
unsigned bits; /* bits in bit buffer */
unsigned in, out; /* save starting available input and output */
unsigned copy; /* number of stored or match bytes to copy */
unsigned char FAR *from; /* where to copy match bytes from */
code this; /* current decoding table entry */
code last; /* parent table entry */
unsigned len; /* length to copy for repeats, bits to drop */
int ret; /* return code */
static const unsigned short order[19] = /* permutation of code lengths */
{16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
if (strm == Z_NULL || strm->state == Z_NULL || strm->next_out == Z_NULL ||
(strm->next_in == Z_NULL && strm->avail_in != 0))
return Z_STREAM_ERROR;
state = (struct inflate_state FAR *)strm->state;
if (state->mode == TYPE) state->mode = TYPEDO; /* skip check */
LOAD();
in = have;
out = left;
ret = Z_OK;
for (;;)
switch (state->mode) {
case HEAD:
if (state->wrap == 0) {
state->mode = TYPEDO;
break;
}
NEEDBITS(16);
if (
((BITS(8) << 8) + (hold >> 8)) % 31) {
state->mode = ACAB_BAD;
break;
}
if (BITS(4) != Z_DEFLATED) {
state->mode = ACAB_BAD;
break;
}
DROPBITS(4);
len = BITS(4) + 8;
if (len > state->wbits) {
state->mode = ACAB_BAD;
break;
}
state->dmax = 1U << len;
Tracev((stderr, "inflate: zlib header ok\n"));
strm->adler = state->check = adler32(0L, Z_NULL, 0);
state->mode = hold & 0x200 ? DICTID : TYPE;
INITBITS();
break;
case DICTID:
NEEDBITS(32);
strm->adler = state->check = REVERSE(hold);
INITBITS();
state->mode = DICT;
case DICT:
RESTORE();
return Z_NEED_DICT;
case TYPE:
if (flush == Z_BLOCK) goto inf_leave;
case TYPEDO:
if (state->last) {
BYTEBITS();
state->mode = CHECK;
break;
}
NEEDBITS(3);
state->last = BITS(1);
DROPBITS(1);
switch (BITS(2)) {
case 0: /* stored block */
Tracev((stderr, "inflate: stored block%s\n",
state->last ? " (last)" : ""));
state->mode = STORED;
break;
case 1: /* fixed block */
fixedtables(state);
Tracev((stderr, "inflate: fixed codes block%s\n",
state->last ? " (last)" : ""));
state->mode = LEN; /* decode codes */
break;
case 2: /* dynamic block */
Tracev((stderr, "inflate: dynamic codes block%s\n",
state->last ? " (last)" : ""));
state->mode = TABLE;
break;
case 3:
state->mode = ACAB_BAD;
}
DROPBITS(2);
break;
case STORED:
BYTEBITS(); /* go to byte boundary */
NEEDBITS(32);
if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
state->mode = ACAB_BAD;
break;
}
state->length = (unsigned)hold & 0xffff;
Tracev((stderr, "inflate: stored length %u\n",
state->length));
INITBITS();
state->mode = COPY;
case COPY:
copy = state->length;
if (copy) {
if (copy > have) copy = have;
if (copy > left) copy = left;
if (copy == 0) goto inf_leave;
memcpy(put, next, copy);
have -= copy;
next += copy;
left -= copy;
put += copy;
state->length -= copy;
break;
}
Tracev((stderr, "inflate: stored end\n"));
state->mode = TYPE;
break;
case TABLE:
NEEDBITS(14);
state->nlen = BITS(5) + 257;
DROPBITS(5);
state->ndist = BITS(5) + 1;
DROPBITS(5);
state->ncode = BITS(4) + 4;
DROPBITS(4);
#ifndef PKZIP_BUG_WORKAROUND
if (state->nlen > 286 || state->ndist > 30) {
state->mode = ACAB_BAD;
break;
}
#endif
Tracev((stderr, "inflate: table sizes ok\n"));
state->have = 0;
state->mode = LENLENS;
case LENLENS:
while (state->have < state->ncode) {
NEEDBITS(3);
state->lens[order[state->have++]] = (unsigned short)BITS(3);
DROPBITS(3);
}
while (state->have < 19)
state->lens[order[state->have++]] = 0;
state->next = state->codes;
state->lencode = (code const FAR *)(state->next);
state->lenbits = 7;
ret = inflate_table(CODES, state->lens, 19, &(state->next),
&(state->lenbits), state->work);
if (ret) {
state->mode = ACAB_BAD;
break;
}
Tracev((stderr, "inflate: code lengths ok\n"));
state->have = 0;
state->mode = CODELENS;
case CODELENS:
while (state->have < state->nlen + state->ndist) {
for (;;) {
this = state->lencode[BITS(state->lenbits)];
if ((unsigned)(this.bits) <= bits) break;
PULLBYTE();
}
if (this.val < 16) {
NEEDBITS(this.bits);
DROPBITS(this.bits);
state->lens[state->have++] = this.val;
}
else {
if (this.val == 16) {
NEEDBITS(this.bits + 2);
DROPBITS(this.bits);
if (state->have == 0) {
state->mode = ACAB_BAD;
break;
}
len = state->lens[state->have - 1];
copy = 3 + BITS(2);
DROPBITS(2);
}
else if (this.val == 17) {
NEEDBITS(this.bits + 3);
DROPBITS(this.bits);
len = 0;
copy = 3 + BITS(3);
DROPBITS(3);
}
else {
NEEDBITS(this.bits + 7);
DROPBITS(this.bits);
len = 0;
copy = 11 + BITS(7);
DROPBITS(7);
}
if (state->have + copy > state->nlen + state->ndist) {
state->mode = ACAB_BAD;
break;
}
while (copy--)
state->lens[state->have++] = (unsigned short)len;
}
}
/* handle error breaks in while */
if (state->mode == ACAB_BAD) break;
/* build code tables */
state->next = state->codes;
state->lencode = (code const FAR *)(state->next);
state->lenbits = 9;
ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
&(state->lenbits), state->work);
if (ret) {
state->mode = ACAB_BAD;
break;
}
state->distcode = (code const FAR *)(state->next);
state->distbits = 6;
ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
&(state->next), &(state->distbits), state->work);
if (ret) {
state->mode = ACAB_BAD;
break;
}
Tracev((stderr, "inflate: codes ok\n"));
state->mode = LEN;
case LEN:
/* if (have >= 6 && left >= 258) {
RESTORE();
inflate_fast(strm, out);
LOAD();
break;
}*/
for (;;) {
this = state->lencode[BITS(state->lenbits)];
if ((unsigned)(this.bits) <= bits) break;
PULLBYTE();
}
if (this.op && (this.op & 0xf0) == 0) {
last = this;
for (;;) {
this = state->lencode[last.val +
(BITS(last.bits + last.op) >> last.bits)];
if ((unsigned)(last.bits + this.bits) <= bits) break;
PULLBYTE();
}
DROPBITS(last.bits);
}
DROPBITS(this.bits);
state->length = (unsigned)this.val;
if ((int)(this.op) == 0) {
Tracevv((stderr, this.val >= 0x20 && this.val < 0x7f ?
"inflate: literal '%c'\n" :
"inflate: literal 0x%02x\n", this.val));
state->mode = LIT;
break;
}
Tracevv((stderr, "inflate: op %u\n", this.op));
if (this.op & 32) {
Tracevv((stderr, "inflate: end of block\n"));
state->mode = TYPE;
break;
}
if (this.op & 64) {
state->mode = ACAB_BAD;
break;
}
state->extra = (unsigned)(this.op) & 31;
state->mode = LENEXT;
case LENEXT:
if (state->extra) {
NEEDBITS(state->extra);
state->length += BITS(state->extra);
DROPBITS(state->extra);
}
Tracevv((stderr, "inflate: length %u\n", state->length));
state->mode = DIST;
case DIST:
for (;;) {
this = state->distcode[BITS(state->distbits)];
if ((unsigned)(this.bits) <= bits) break;
PULLBYTE();
}
if ((this.op & 0xf0) == 0) {
last = this;
for (;;) {
this = state->distcode[last.val +
(BITS(last.bits + last.op) >> last.bits)];
if ((unsigned)(last.bits + this.bits) <= bits) break;
PULLBYTE();
}
DROPBITS(last.bits);
}
DROPBITS(this.bits);
if (this.op & 64) {
state->mode = ACAB_BAD;
break;
}
Tracevv((stderr, "inflate: val %u\n", state->offset));
state->offset = (unsigned)this.val;
state->extra = (unsigned)(this.op) & 15;
state->mode = DISTEXT;
case DISTEXT:
if (state->extra) {
NEEDBITS(state->extra);
state->offset += BITS(state->extra);
DROPBITS(state->extra);
}
#ifdef INFLATE_STRICT
if (state->offset > state->dmax) {
state->mode = ACAB_BAD;
break;
}
#endif
if (state->offset > state->whave + out - left) {
state->mode = ACAB_BAD;
break;
}
Tracevv((stderr, "inflate: distance %u\n", state->offset));
state->mode = MATCH;
case MATCH:
if (left == 0) goto inf_leave;
copy = out - left;
if (state->offset > copy) { /* copy from window */
copy = state->offset - copy;
if (copy > state->write) {
copy -= state->write;
from = state->window + (state->wsize - copy);
}
else
from = state->window + (state->write - copy);
if (copy > state->length) copy = state->length;
}
else { /* copy from output */
from = put - state->offset;
copy = state->length;
}
if (copy > left) copy = left;
left -= copy;
state->length -= copy;
do {
*put++ = *from++;
} while (--copy);
if (state->length == 0) state->mode = LEN;
break;
case LIT:
if (left == 0) goto inf_leave;
*put++ = (unsigned char)(state->length);
left--;
state->mode = LEN;
break;
case CHECK:
if (state->wrap) {
NEEDBITS(32);
out -= left;
strm->total_out += out;
state->total += out;
if (out)
strm->adler = state->check =
UPDATE(state->check, put - out, out);
out = left;
if ((
REVERSE(hold)) != state->check) {
state->mode = ACAB_BAD;
break;
}
INITBITS();
Tracev((stderr, "inflate: check matches trailer\n"));
}
state->mode = DONE;
case DONE:
ret = Z_STREAM_END;
goto inf_leave;
case ACAB_BAD:
ret = Z_DATA_ERROR;
goto inf_leave;
case MEM:
return Z_MEM_ERROR;
case SYNC:
default:
return Z_STREAM_ERROR;
}
/*
Return from inflate(), updating the total counts and the check value.
If there was no progress during the inflate() call, return a buffer
error. Call updatewindow() to create and/or update the window state.
Note: a memory error from inflate() is non-recoverable.
*/
inf_leave:
RESTORE();
if (state->wsize || (state->mode < CHECK && out != strm->avail_out))
if (updatewindow(strm, out)) {
state->mode = MEM;
return Z_MEM_ERROR;
}
in -= strm->avail_in;
out -= strm->avail_out;
strm->total_in += in;
strm->total_out += out;
state->total += out;
if (state->wrap && out)
strm->adler = state->check =
UPDATE(state->check, strm->next_out - out, out);
strm->data_type = state->bits + (state->last ? 64 : 0) +
(state->mode == TYPE ? 128 : 0);
if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
ret = Z_BUF_ERROR;
return ret;
}
int ZEXPORT inflate64End(strm)
z_stream64p strm;
{
struct inflate_state FAR *state;
if (strm == Z_NULL || strm->state == Z_NULL)
return Z_STREAM_ERROR;
state = (struct inflate_state FAR *)strm->state;
if (state->window != Z_NULL) free(state->window);
free(strm->state);
strm->state = Z_NULL;
Tracev((stderr, "inflate: end\n"));
return Z_OK;
}
/*
Build a set of tables to decode the provided canonical Huffman code.
The code lengths are lens[0..codes-1]. The result starts at *table,
whose indices are 0..2^bits-1. work is a writable array of at least
lens shorts, which is used as a work area. type is the type of code
to be generated, CODES, LENS, or DISTS. On return, zero is success,
-1 is an invalid code, and +1 means that ENOUGH isn't enough. table
on return points to the next available entry's address. bits is the
requested root table index bits, and on return it is the actual root
table index bits. It will differ if the request is greater than the
longest code or if it is less than the shortest code.
*/
local int inflate_table(type, lens, codes, table, bits, work)
codetype type;
unsigned short FAR *lens;
unsigned codes;
code FAR * FAR *table;
unsigned FAR *bits;
unsigned short FAR *work;
{
unsigned len; /* a code's length in bits */
unsigned sym; /* index of code symbols */
unsigned min, max; /* minimum and maximum code lengths */
unsigned root; /* number of index bits for root table */
unsigned curr; /* number of index bits for current table */
unsigned drop; /* code bits to drop for sub-table */
int left; /* number of prefix codes available */
unsigned used; /* code entries in table used */
unsigned huff; /* Huffman code */
unsigned incr; /* for incrementing code, index */
unsigned fill; /* index for replicating entries */
unsigned low; /* low bits for current root entry */
unsigned mask; /* mask for low root bits */
code this; /* table entry for duplication */
code FAR *next; /* next available space in table */
const unsigned short FAR *base; /* base value table to use */
const unsigned short FAR *extra; /* extra bits table to use */
int end; /* use base and extra for symbol > end */
unsigned short count[MAXBITS+1]; /* number of codes of each length */
unsigned short offs[MAXBITS+1]; /* offsets in table for each length */
static const unsigned short lbase[31] = { /* Length codes 257..285 base */
3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, /* 258 */ 3, 0, 0};
static const unsigned short lext[31] = { /* Length codes 257..285 extra */
/* 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, */
/* 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 31, 201, 196}; */
128, 128, 128, 128, 128, 128, 128, 128, 129, 129, 129, 129, 130, 130, 130, 130,
131, 131, 131, 131, 132, 132, 132, 132, 133, 133, 133, 133, 144, 201, 196};
static const unsigned short dbase[32] = { /* Distance codes 0..29 base */
1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
8193, 12289, 16385, 24577, 32769, 49153};
static const unsigned short dext[32] = { /* Distance codes 0..29 extra */
16, 16, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22,
23, 23, 24, 24, 25, 25, 26, 26, 27, 27,
28, 28, 29, 29, 30, 30};
/*
Process a set of code lengths to create a canonical Huffman code. The
code lengths are lens[0..codes-1]. Each length corresponds to the
symbols 0..codes-1. The Huffman code is generated by first sorting the
symbols by length from short to long, and retaining the symbol order
for codes with equal lengths. Then the code starts with all zero bits
for the first code of the shortest length, and the codes are integer
increments for the same length, and zeros are appended as the length
increases. For the deflate format, these bits are stored backwards
from their more natural integer increment ordering, and so when the
decoding tables are built in the large loop below, the integer codes
are incremented backwards.
This routine assumes, but does not check, that all of the entries in
lens[] are in the range 0..MAXBITS. The caller must assure this.
1..MAXBITS is interpreted as that code length. zero means that that
symbol does not occur in this code.
The codes are sorted by computing a count of codes for each length,
creating from that a table of starting indices for each length in the
sorted table, and then entering the symbols in order in the sorted
table. The sorted table is work[], with that space being provided by
the caller.
The length counts are used for other purposes as well, i.e. finding
the minimum and maximum length codes, determining if there are any
codes at all, checking for a valid set of lengths, and looking ahead
at length counts to determine sub-table sizes when building the
decoding tables.
*/
/* accumulate lengths for codes (assumes lens[] all in 0..MAXBITS) */
for (len = 0; len <= MAXBITS; len++)
count[len] = 0;
for (sym = 0; sym < codes; sym++)
count[lens[sym]]++;
/* bound code lengths, force root to be within code lengths */
root = *bits;
for (max = MAXBITS; max >= 1; max--)
if (count[max] != 0) break;
if (root > max) root = max;
if (max == 0) { /* no symbols to code at all */
this.op = (unsigned char)64; /* invalid code marker */
this.bits = (unsigned char)1;
this.val = (unsigned short)0;
*(*table)++ = this; /* make a table to force an error */
*(*table)++ = this;
*bits = 1;
return 0; /* no symbols, but wait for decoding to report error */
}
for (min = 1; min <= MAXBITS; min++)
if (count[min] != 0) break;
if (root < min) root = min;
/* check for an over-subscribed or incomplete set of lengths */
left = 1;
for (len = 1; len <= MAXBITS; len++) {
left <<= 1;
left -= count[len];
if (left < 0) return -1; /* over-subscribed */
}
if (left > 0 && (type == CODES || max != 1))
return -1; /* incomplete set */
/* generate offsets into symbol table for each length for sorting */
offs[1] = 0;
for (len = 1; len < MAXBITS; len++)
offs[len + 1] = offs[len] + count[len];
/* sort symbols by length, by symbol order within each length */
for (sym = 0; sym < codes; sym++)
if (lens[sym] != 0) work[offs[lens[sym]]++] = (unsigned short)sym;
/*
Create and fill in decoding tables. In this loop, the table being
filled is at next and has curr index bits. The code being used is huff
with length len. That code is converted to an index by dropping drop
bits off of the bottom. For codes where len is less than drop + curr,
those top drop + curr - len bits are incremented through all values to
fill the table with replicated entries.
root is the number of index bits for the root table. When len exceeds
root, sub-tables are created pointed to by the root entry with an index
of the low root bits of huff. This is saved in low to check for when a
new sub-table should be started. drop is zero when the root table is
being filled, and drop is root when sub-tables are being filled.
When a new sub-table is needed, it is necessary to look ahead in the
code lengths to determine what size sub-table is needed. The length
counts are used for this, and so count[] is decremented as codes are
entered in the tables.
used keeps track of how many table entries have been allocated from the
provided *table space. It is checked when a LENS table is being made
against the space in *table, ENOUGH, minus the maximum space needed by
the worst case distance code, MAXD. This should never happen, but the
sufficiency of ENOUGH has not been proven exhaustively, hence the check.
This assumes that when type == LENS, bits == 9.
sym increments through all symbols, and the loop terminates when
all codes of length max, i.e. all codes, have been processed. This
routine permits incomplete codes, so another loop after this one fills
in the rest of the decoding tables with invalid code markers.
*/
/* set up for code type */
switch (type) {
case CODES:
base = extra = work; /* dummy value--not used */
end = 19;
break;
case LENS:
base = lbase;
base -= 257;
extra = lext;
extra -= 257;
end = 256;
break;
default: /* DISTS */
base = dbase;
extra = dext;
end = -1;
}
/* initialize state for loop */
huff = 0; /* starting code */
sym = 0; /* starting code symbol */
len = min; /* starting code length */
next = *table; /* current table to fill in */
curr = root; /* current table index bits */
drop = 0; /* current bits to drop from code for index */
low = (unsigned)(-1); /* trigger new sub-table when len > root */
used = 1U << root; /* use root table entries */
mask = used - 1; /* mask for comparing low */
/* check available table space */
if (type == LENS && used >= ENOUGH - MAXD)
return 1;
/* process all codes and make table entries */
for (;;) {
/* create table entry */
this.bits = (unsigned char)(len - drop);
if ((int)(work[sym]) < end) {
this.op = (unsigned char)0;
this.val = work[sym];
}
else if ((int)(work[sym]) > end) {
this.op = (unsigned char)(extra[work[sym]]);
this.val = base[work[sym]];
}
else {
this.op = (unsigned char)(32 + 64); /* end of block */
this.val = 0;
}
/* replicate for those indices with low len bits equal to huff */
incr = 1U << (len - drop);
fill = 1U << curr;
min = fill; /* save offset to next table */
do {
fill -= incr;
next[(huff >> drop) + fill] = this;
} while (fill != 0);
/* backwards increment the len-bit code huff */
incr = 1U << (len - 1);
while (huff & incr)
incr >>= 1;
if (incr != 0) {
huff &= incr - 1;
huff += incr;
}
else
huff = 0;
/* go to next symbol, update count, len */
sym++;
if (--(count[len]) == 0) {
if (len == max) break;
len = lens[work[sym]];
}
/* create new sub-table if needed */
if (len > root && (huff & mask) != low) {
/* if first time, transition to sub-tables */
if (drop == 0)
drop = root;
/* increment past last table */
next += min; /* here min is 1 << curr */
/* determine length of next table */
curr = len - drop;
left = (int)(1 << curr);
while (curr + drop < max) {
left -= count[curr + drop];
if (left <= 0) break;
curr++;
left <<= 1;
}
/* check for enough space */
used += 1U << curr;
if (type == LENS && used >= ENOUGH - MAXD)
return 1;
/* point entry in root table to sub-table */
low = huff & mask;
(*table)[low].op = (unsigned char)curr;
(*table)[low].bits = (unsigned char)root;
(*table)[low].val = (unsigned short)(next - *table);
}
}
/*
Fill in rest of table for incomplete codes. This loop is similar to the
loop above in incrementing huff for table indices. It is assumed that
len is equal to curr + drop, so there is no loop needed to increment
through high index bits. When the current sub-table is filled, the loop
drops back to the root table to fill in any remaining entries there.
*/
this.op = (unsigned char)64; /* invalid code marker */
this.bits = (unsigned char)(len - drop);
this.val = (unsigned short)0;
while (huff != 0) {
/* when done with sub-table, drop back to root table */
if (drop != 0 && (huff & mask) != low) {
drop = 0;
len = root;
next = *table;
this.bits = (unsigned char)len;
}
/* put invalid code marker in table */
next[huff >> drop] = this;
/* backwards increment the len-bit code huff */
incr = 1U << (len - 1);
while (huff & incr)
incr >>= 1;
if (incr != 0) {
huff &= incr - 1;
huff += incr;
}
else
huff = 0;
}
/* set return parameters */
*table += used;
*bits = root;
return 0;
}