?? unzip.cpp
字號:
// copy
if (n!=0) {memcpy(p,q,n); p+=n; q+=n;}
}
// update pointers
z->next_out = p;
s->read = q;
// done
return r;
}
// simplify the use of the inflate_huft type with some defines
#define exop word.what.Exop
#define bits word.what.Bits
typedef enum { // waiting for "i:"=input, "o:"=output, "x:"=nothing
START, // x: set up for LEN
LEN, // i: get length/literal/eob next
LENEXT, // i: getting length extra (have base)
DIST, // i: get distance next
DISTEXT, // i: getting distance extra
COPY, // o: copying bytes in window, waiting for space
LIT, // o: got literal, waiting for output space
WASH, // o: got eob, possibly still output waiting
END, // x: got eob and all data flushed
BADCODE} // x: got error
inflate_codes_mode;
// inflate codes private state
struct inflate_codes_state {
// mode
inflate_codes_mode mode; // current inflate_codes mode
// mode dependent information
uInt len;
union {
struct {
const inflate_huft *tree; // pointer into tree
uInt need; // bits needed
} code; // if LEN or DIST, where in tree
uInt lit; // if LIT, literal
struct {
uInt get; // bits to get for extra
uInt dist; // distance back to copy from
} copy; // if EXT or COPY, where and how much
} sub; // submode
// mode independent information
Byte lbits; // ltree bits decoded per branch
Byte dbits; // dtree bits decoder per branch
const inflate_huft *ltree; // literal/length/eob tree
const inflate_huft *dtree; // distance tree
};
inflate_codes_statef *inflate_codes_new(
uInt bl, uInt bd,
const inflate_huft *tl,
const inflate_huft *td, // need separate declaration for Borland C++
z_streamp z)
{
inflate_codes_statef *c;
if ((c = (inflate_codes_statef *)
ZALLOC(z,1,sizeof(struct inflate_codes_state))) != Z_NULL)
{
c->mode = START;
c->lbits = (Byte)bl;
c->dbits = (Byte)bd;
c->ltree = tl;
c->dtree = td;
LuTracev((stderr, "inflate: codes new\n"));
}
return c;
}
int inflate_codes(inflate_blocks_statef *s, z_streamp z, int r)
{
uInt j; // temporary storage
const inflate_huft *t; // temporary pointer
uInt e; // extra bits or operation
uLong b; // bit buffer
uInt k; // bits in bit buffer
Byte *p; // input data pointer
uInt n; // bytes available there
Byte *q; // output window write pointer
uInt m; // bytes to end of window or read pointer
Byte *f; // pointer to copy strings from
inflate_codes_statef *c = s->sub.decode.codes; // codes state
// copy input/output information to locals (UPDATE macro restores)
LOAD
// process input and output based on current state
for(;;) switch (c->mode)
{ // waiting for "i:"=input, "o:"=output, "x:"=nothing
case START: // x: set up for LEN
#ifndef SLOW
if (m >= 258 && n >= 10)
{
UPDATE
r = inflate_fast(c->lbits, c->dbits, c->ltree, c->dtree, s, z);
LOAD
if (r != Z_OK)
{
c->mode = r == Z_STREAM_END ? WASH : BADCODE;
break;
}
}
#endif // !SLOW
c->sub.code.need = c->lbits;
c->sub.code.tree = c->ltree;
c->mode = LEN;
case LEN: // i: get length/literal/eob next
j = c->sub.code.need;
NEEDBITS(j)
t = c->sub.code.tree + ((uInt)b & inflate_mask[j]);
DUMPBITS(t->bits)
e = (uInt)(t->exop);
if (e == 0) // literal
{
c->sub.lit = t->base;
LuTracevv((stderr, t->base >= 0x20 && t->base < 0x7f ?
"inflate: literal '%c'\n" :
"inflate: literal 0x%02x\n", t->base));
c->mode = LIT;
break;
}
if (e & 16) // length
{
c->sub.copy.get = e & 15;
c->len = t->base;
c->mode = LENEXT;
break;
}
if ((e & 64) == 0) // next table
{
c->sub.code.need = e;
c->sub.code.tree = t + t->base;
break;
}
if (e & 32) // end of block
{
LuTracevv((stderr, "inflate: end of block\n"));
c->mode = WASH;
break;
}
c->mode = BADCODE; // invalid code
z->msg = (char*)"invalid literal/length code";
r = Z_DATA_ERROR;
LEAVE
case LENEXT: // i: getting length extra (have base)
j = c->sub.copy.get;
NEEDBITS(j)
c->len += (uInt)b & inflate_mask[j];
DUMPBITS(j)
c->sub.code.need = c->dbits;
c->sub.code.tree = c->dtree;
LuTracevv((stderr, "inflate: length %u\n", c->len));
c->mode = DIST;
case DIST: // i: get distance next
j = c->sub.code.need;
NEEDBITS(j)
t = c->sub.code.tree + ((uInt)b & inflate_mask[j]);
DUMPBITS(t->bits)
e = (uInt)(t->exop);
if (e & 16) // distance
{
c->sub.copy.get = e & 15;
c->sub.copy.dist = t->base;
c->mode = DISTEXT;
break;
}
if ((e & 64) == 0) // next table
{
c->sub.code.need = e;
c->sub.code.tree = t + t->base;
break;
}
c->mode = BADCODE; // invalid code
z->msg = (char*)"invalid distance code";
r = Z_DATA_ERROR;
LEAVE
case DISTEXT: // i: getting distance extra
j = c->sub.copy.get;
NEEDBITS(j)
c->sub.copy.dist += (uInt)b & inflate_mask[j];
DUMPBITS(j)
LuTracevv((stderr, "inflate: distance %u\n", c->sub.copy.dist));
c->mode = COPY;
case COPY: // o: copying bytes in window, waiting for space
f = q - c->sub.copy.dist; while (f < s->window) // modulo window size-"while" instead f += s->end - s->window; // of "if" handles invalid distances while (c->len) {
NEEDOUT
OUTBYTE(*f++)
if (f == s->end)
f = s->window;
c->len--;
}
c->mode = START;
break;
case LIT: // o: got literal, waiting for output space
NEEDOUT
OUTBYTE(c->sub.lit)
c->mode = START;
break;
case WASH: // o: got eob, possibly more output
if (k > 7) // return unused byte, if any
{
//Assert(k < 16, "inflate_codes grabbed too many bytes")
k -= 8;
n++;
p--; // can always return one
}
FLUSH
if (s->read != s->write)
LEAVE
c->mode = END;
case END:
r = Z_STREAM_END;
LEAVE
case BADCODE: // x: got error
r = Z_DATA_ERROR;
LEAVE
default:
r = Z_STREAM_ERROR;
LEAVE
}
}
void inflate_codes_free(inflate_codes_statef *c,z_streamp z)
{ ZFREE(z, c);
LuTracev((stderr, "inflate: codes free\n"));
}
// infblock.c -- interpret and process block types to last block
// Copyright (C) 1995-1998 Mark Adler
// For conditions of distribution and use, see copyright notice in zlib.h
//struct inflate_codes_state {int dummy;}; // for buggy compilers
// Table for deflate from PKZIP's appnote.txt.
const uInt border[] = { // Order of the bit length code lengths
16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
//
// Notes beyond the 1.93a appnote.txt:
//
// 1. Distance pointers never point before the beginning of the output stream.
// 2. Distance pointers can point back across blocks, up to 32k away.
// 3. There is an implied maximum of 7 bits for the bit length table and
// 15 bits for the actual data.
// 4. If only one code exists, then it is encoded using one bit. (Zero
// would be more efficient, but perhaps a little confusing.) If two
// codes exist, they are coded using one bit each (0 and 1).
// 5. There is no way of sending zero distance codes--a dummy must be
// sent if there are none. (History: a pre 2.0 version of PKZIP would
// store blocks with no distance codes, but this was discovered to be
// too harsh a criterion.) Valid only for 1.93a. 2.04c does allow
// zero distance codes, which is sent as one code of zero bits in
// length.
// 6. There are up to 286 literal/length codes. Code 256 represents the
// end-of-block. Note however that the static length tree defines
// 288 codes just to fill out the Huffman codes. Codes 286 and 287
// cannot be used though, since there is no length base or extra bits
// defined for them. Similarily, there are up to 30 distance codes.
// However, static trees define 32 codes (all 5 bits) to fill out the
// Huffman codes, but the last two had better not show up in the data.
// 7. Unzip can check dynamic Huffman blocks for complete code sets.
// The exception is that a single code would not be complete (see #4).
// 8. The five bits following the block type is really the number of
// literal codes sent minus 257.
// 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
// (1+6+6). Therefore, to output three times the length, you output
// three codes (1+1+1), whereas to output four times the same length,
// you only need two codes (1+3). Hmm.
//10. In the tree reconstruction algorithm, Code = Code + Increment
// only if BitLength(i) is not zero. (Pretty obvious.)
//11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19)
//12. Note: length code 284 can represent 227-258, but length code 285
// really is 258. The last length deserves its own, short code
// since it gets used a lot in very redundant files. The length
// 258 is special since 258 - 3 (the min match length) is 255.
//13. The literal/length and distance code bit lengths are read as a
// single stream of lengths. It is possible (and advantageous) for
// a repeat code (16, 17, or 18) to go across the boundary between
// the two sets of lengths.
void inflate_blocks_reset(inflate_blocks_statef *s, z_streamp z, uLong *c)
{
if (c != Z_NULL)
*c = s->check;
if (s->mode == IBM_BTREE || s->mode == IBM_DTREE)
ZFREE(z, s->sub.trees.blens);
if (s->mode == IBM_CODES)
inflate_codes_free(s->sub.decode.codes, z);
s->mode = IBM_TYPE;
s->bitk = 0;
s->bitb = 0;
s->read = s->write = s->window;
if (s->checkfn != Z_NULL)
z->adler = s->check = (*s->checkfn)(0L, (const Byte *)Z_NULL, 0);
LuTracev((stderr, "inflate: blocks reset\n"));
}
inflate_blocks_statef *inflate_blocks_new(z_streamp z, check_func c, uInt w)
{
inflate_blocks_statef *s;
if ((s = (inflate_blocks_statef *)ZALLOC
(z,1,sizeof(struct inflate_blocks_state))) == Z_NULL)
return s;
if ((s->hufts =
(inflate_huft *)ZALLOC(z, sizeof(inflate_huft), MANY)) == Z_NULL)
{
ZFREE(z, s);
return Z_NULL;
}
if ((s->window = (Byte *)ZALLOC(z, 1, w)) == Z_NULL)
{
ZFREE(z, s->hufts);
ZFREE(z, s);
return Z_NULL;
}
s->end = s->window + w;
s->checkfn = c;
s->mode = IBM_TYPE;
LuTracev((stderr, "inflate: blocks allocated\n"));
inflate_blocks_reset(s, z, Z_NULL);
return s;
}
int inflate_blocks(inflate_blocks_statef *s, z_streamp z, int r)
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