inflate.c

Lib files of linux kernel

                DROPBITS(state->extra);
            }
            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;
            }
            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) {
                    strm->msg = (char *)"incorrect data check";
                    state->mode = BAD;
                    break;
                }
                INITBITS();
            }
            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 zlib_updatewindow() to create and/or update the window state.
     */
  inf_leave:
    RESTORE();
    if (state->wsize || (state->mode < CHECK && out != strm->avail_out))
        zlib_updatewindow(strm, out);

    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 (flush == Z_PACKET_FLUSH && ret == Z_OK &&
            strm->avail_out != 0 && strm->avail_in == 0)
		return zlib_inflateSyncPacket(strm);

    if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
        ret = Z_BUF_ERROR;

    return ret;
}

int zlib_inflateEnd(z_streamp strm)
{
    if (strm == NULL || strm->state == NULL)
        return Z_STREAM_ERROR;
    return Z_OK;
}

#if 0
int zlib_inflateSetDictionary(z_streamp strm, const Byte *dictionary,
        uInt dictLength)
{
    struct inflate_state *state;
    unsigned long id;

    /* check state */
    if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
    state = (struct inflate_state *)strm->state;
    if (state->wrap != 0 && state->mode != DICT)
        return Z_STREAM_ERROR;

    /* check for correct dictionary id */
    if (state->mode == DICT) {
        id = zlib_adler32(0L, NULL, 0);
        id = zlib_adler32(id, dictionary, dictLength);
        if (id != state->check)
            return Z_DATA_ERROR;
    }

    /* copy dictionary to window */
    zlib_updatewindow(strm, strm->avail_out);

    if (dictLength > state->wsize) {
        memcpy(state->window, dictionary + dictLength - state->wsize,
                state->wsize);
        state->whave = state->wsize;
    }
    else {
        memcpy(state->window + state->wsize - dictLength, dictionary,
                dictLength);
        state->whave = dictLength;
    }
    state->havedict = 1;
    return Z_OK;
}
#endif

#if 0
/*
   Search buf[0..len-1] for the pattern: 0, 0, 0xff, 0xff.  Return when found
   or when out of input.  When called, *have is the number of pattern bytes
   found in order so far, in 0..3.  On return *have is updated to the new
   state.  If on return *have equals four, then the pattern was found and the
   return value is how many bytes were read including the last byte of the
   pattern.  If *have is less than four, then the pattern has not been found
   yet and the return value is len.  In the latter case, zlib_syncsearch() can be
   called again with more data and the *have state.  *have is initialized to
   zero for the first call.
 */
static unsigned zlib_syncsearch(unsigned *have, unsigned char *buf,
        unsigned len)
{
    unsigned got;
    unsigned next;

    got = *have;
    next = 0;
    while (next < len && got < 4) {
        if ((int)(buf[next]) == (got < 2 ? 0 : 0xff))
            got++;
        else if (buf[next])
            got = 0;
        else
            got = 4 - got;
        next++;
    }
    *have = got;
    return next;
}
#endif

#if 0
int zlib_inflateSync(z_streamp strm)
{
    unsigned len;               /* number of bytes to look at or looked at */
    unsigned long in, out;      /* temporary to save total_in and total_out */
    unsigned char buf[4];       /* to restore bit buffer to byte string */
    struct inflate_state *state;

    /* check parameters */
    if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
    state = (struct inflate_state *)strm->state;
    if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR;

    /* if first time, start search in bit buffer */
    if (state->mode != SYNC) {
        state->mode = SYNC;
        state->hold <<= state->bits & 7;
        state->bits -= state->bits & 7;
        len = 0;
        while (state->bits >= 8) {
            buf[len++] = (unsigned char)(state->hold);
            state->hold >>= 8;
            state->bits -= 8;
        }
        state->have = 0;
        zlib_syncsearch(&(state->have), buf, len);
    }

    /* search available input */
    len = zlib_syncsearch(&(state->have), strm->next_in, strm->avail_in);
    strm->avail_in -= len;
    strm->next_in += len;
    strm->total_in += len;

    /* return no joy or set up to restart inflate() on a new block */
    if (state->have != 4) return Z_DATA_ERROR;
    in = strm->total_in;  out = strm->total_out;
    zlib_inflateReset(strm);
    strm->total_in = in;  strm->total_out = out;
    state->mode = TYPE;
    return Z_OK;
}
#endif

/*
 * This subroutine adds the data at next_in/avail_in to the output history
 * without performing any output.  The output buffer must be "caught up";
 * i.e. no pending output but this should always be the case. The state must
 * be waiting on the start of a block (i.e. mode == TYPE or HEAD).  On exit,
 * the output will also be caught up, and the checksum will have been updated
 * if need be.
 */
int zlib_inflateIncomp(z_stream *z)
{
    struct inflate_state *state = (struct inflate_state *)z->state;
    Byte *saved_no = z->next_out;
    uInt saved_ao = z->avail_out;

    if (state->mode != TYPE && state->mode != HEAD)
	return Z_DATA_ERROR;

    /* Setup some variables to allow misuse of updateWindow */
    z->avail_out = 0;
    z->next_out = (unsigned char*)z->next_in + z->avail_in;

    zlib_updatewindow(z, z->avail_in);

    /* Restore saved variables */
    z->avail_out = saved_ao;
    z->next_out = saved_no;

    z->adler = state->check =
        UPDATE(state->check, z->next_in, z->avail_in);

    z->total_out += z->avail_in;
    z->total_in += z->avail_in;
    z->next_in += z->avail_in;
    state->total += z->avail_in;
    z->avail_in = 0;

    return Z_OK;
}