in zlib/inflate.c [592:1203]
int ZEXPORT inflate(strm, flush)
z_streamp 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 */
#ifdef GUNZIP
unsigned char hbuf[4]; /* buffer for gzip header crc calculation */
#endif
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};
/* XXXMYSQL: To assert that put is never used uninitialized */
#ifdef DEBUG
put = NULL;
#endif /* DEBUG */
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);
#ifdef GUNZIP
if ((state->wrap & 2) && hold == 0x8b1f) { /* gzip header */
state->check = crc32(0L, Z_NULL, 0);
CRC2(state->check, hold);
INITBITS();
state->mode = FLAGS;
break;
}
state->flags = 0; /* expect zlib header */
if (state->head != Z_NULL)
state->head->done = -1;
if (!(state->wrap & 1) || /* check if zlib header allowed */
#else
if (
#endif
((BITS(8) << 8) + (hold >> 8)) % 31) {
strm->msg = (char *)"incorrect header check";
state->mode = BAD;
break;
}
if (BITS(4) != Z_DEFLATED) {
strm->msg = (char *)"unknown compression method";
state->mode = BAD;
break;
}
DROPBITS(4);
len = BITS(4) + 8;
if (len > state->wbits) {
strm->msg = (char *)"invalid window size";
state->mode = 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;
#ifdef GUNZIP
case FLAGS:
NEEDBITS(16);
state->flags = (int)(hold);
if ((state->flags & 0xff) != Z_DEFLATED) {
strm->msg = (char *)"unknown compression method";
state->mode = BAD;
break;
}
if (state->flags & 0xe000) {
strm->msg = (char *)"unknown header flags set";
state->mode = BAD;
break;
}
if (state->head != Z_NULL)
state->head->text = (int)((hold >> 8) & 1);
if (state->flags & 0x0200) CRC2(state->check, hold);
INITBITS();
state->mode = TIME;
case TIME:
NEEDBITS(32);
if (state->head != Z_NULL)
state->head->time = hold;
if (state->flags & 0x0200) CRC4(state->check, hold);
INITBITS();
state->mode = OS;
case OS:
NEEDBITS(16);
if (state->head != Z_NULL) {
state->head->xflags = (int)(hold & 0xff);
state->head->os = (int)(hold >> 8);
}
if (state->flags & 0x0200) CRC2(state->check, hold);
INITBITS();
state->mode = EXLEN;
case EXLEN:
if (state->flags & 0x0400) {
NEEDBITS(16);
state->length = (unsigned)(hold);
if (state->head != Z_NULL)
state->head->extra_len = (unsigned)hold;
if (state->flags & 0x0200) CRC2(state->check, hold);
INITBITS();
}
else if (state->head != Z_NULL)
state->head->extra = Z_NULL;
state->mode = EXTRA;
case EXTRA:
if (state->flags & 0x0400) {
copy = state->length;
if (copy > have) copy = have;
if (copy) {
if (state->head != Z_NULL &&
state->head->extra != Z_NULL) {
len = state->head->extra_len - state->length;
zmemcpy(state->head->extra + len, next,
len + copy > state->head->extra_max ?
state->head->extra_max - len : copy);
}
if (state->flags & 0x0200)
state->check = crc32(state->check, next, copy);
have -= copy;
next += copy;
state->length -= copy;
}
if (state->length) goto inf_leave;
}
state->length = 0;
state->mode = NAME;
case NAME:
if (state->flags & 0x0800) {
if (have == 0) goto inf_leave;
copy = 0;
do {
len = (unsigned)(next[copy++]);
if (state->head != Z_NULL &&
state->head->name != Z_NULL &&
state->length < state->head->name_max)
state->head->name[state->length++] = len;
} while (len && copy < have);
if (state->flags & 0x0200)
state->check = crc32(state->check, next, copy);
have -= copy;
next += copy;
if (len) goto inf_leave;
}
else if (state->head != Z_NULL)
state->head->name = Z_NULL;
state->length = 0;
state->mode = COMMENT;
case COMMENT:
if (state->flags & 0x1000) {
if (have == 0) goto inf_leave;
copy = 0;
do {
len = (unsigned)(next[copy++]);
if (state->head != Z_NULL &&
state->head->comment != Z_NULL &&
state->length < state->head->comm_max)
state->head->comment[state->length++] = len;
} while (len && copy < have);
if (state->flags & 0x0200)
state->check = crc32(state->check, next, copy);
have -= copy;
next += copy;
if (len) goto inf_leave;
}
else if (state->head != Z_NULL)
state->head->comment = Z_NULL;
state->mode = HCRC;
case HCRC:
if (state->flags & 0x0200) {
NEEDBITS(16);
if (hold != (state->check & 0xffff)) {
strm->msg = (char *)"header crc mismatch";
state->mode = BAD;
break;
}
INITBITS();
}
if (state->head != Z_NULL) {
state->head->hcrc = (int)((state->flags >> 9) & 1);
state->head->done = 1;
}
strm->adler = state->check = crc32(0L, Z_NULL, 0);
state->mode = TYPE;
break;
#endif
case DICTID:
NEEDBITS(32);
strm->adler = state->check = REVERSE(hold);
INITBITS();
state->mode = DICT;
case DICT:
if (state->havedict == 0) {
RESTORE();
return Z_NEED_DICT;
}
strm->adler = state->check = adler32(0L, Z_NULL, 0);
state->mode = TYPE;
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:
strm->msg = (char *)"invalid block type";
state->mode = BAD;
}
DROPBITS(2);
break;
case STORED:
BYTEBITS(); /* go to byte boundary */
NEEDBITS(32);
if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
strm->msg = (char *)"invalid stored block lengths";
state->mode = 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;
/* XXXMYSQL: Assert that put is not uninitialized */
Assert ( put != NULL, "put is uninitialized" );
zmemcpy(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) {
strm->msg = (char *)"too many length or distance symbols";
state->mode = 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) {
strm->msg = (char *)"invalid code lengths set";
state->mode = 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) {
strm->msg = (char *)"invalid bit length repeat";
state->mode = 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) {
strm->msg = (char *)"invalid bit length repeat";
state->mode = BAD;
break;
}
while (copy--)
state->lens[state->have++] = (unsigned short)len;
}
}
/* handle error breaks in while */
if (state->mode == 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) {
strm->msg = (char *)"invalid literal/lengths set";
state->mode = 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) {
strm->msg = (char *)"invalid distances set";
state->mode = 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;
}
if (this.op & 32) {
Tracevv((stderr, "inflate: end of block\n"));
state->mode = TYPE;
break;
}
if (this.op & 64) {
strm->msg = (char *)"invalid literal/length code";
state->mode = BAD;
break;
}
state->extra = (unsigned)(this.op) & 15;
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) {
strm->msg = (char *)"invalid distance code";
state->mode = BAD;
break;
}
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) {
strm->msg = (char *)"invalid distance too far back";
state->mode = BAD;
break;
}
#endif
if (state->offset > state->whave + out - left) {
strm->msg = (char *)"invalid distance too far back";
state->mode = 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 */
/* XXXMYSQL: Assert that put is not uninitialized */
Assert ( put != NULL, "put is uninitialized" );
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) {
/* XXXMYSQL: Assert that put is not uninitialized */
Assert ( put != NULL, "put is uninitialized" );
strm->adler = state->check =
UPDATE(state->check, put - out, out);
}
out = left;
if ((
#ifdef GUNZIP
state->flags ? hold :
#endif
REVERSE(hold)) != state->check) {
strm->msg = (char *)"incorrect data check";
state->mode = BAD;
break;
}
INITBITS();
Tracev((stderr, "inflate: check matches trailer\n"));
}
#ifdef GUNZIP
state->mode = LENGTH;
case LENGTH:
if (state->wrap && state->flags) {
NEEDBITS(32);
if (hold != (state->total & 0xffffffffUL)) {
strm->msg = (char *)"incorrect length check";
state->mode = BAD;
break;
}
INITBITS();
Tracev((stderr, "inflate: length matches trailer\n"));
}
#endif
state->mode = DONE;
case DONE:
ret = Z_STREAM_END;
goto inf_leave;
case 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;
}