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token.c

Go to the documentation of this file.

/* 
   Copyright (C) Andrew Tridgell 1996
   Copyright (C) Paul Mackerras 1996
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "rsync.h"
#include "zlib/zlib.h"

extern int do_compression;
static int compression_level = Z_DEFAULT_COMPRESSION;

/* determine the compression level based on a wildcard filename list */
void set_compression(char *fname)
{
        extern int module_id;
        char *dont;
        char *tok;

        if (!do_compression) return;

        compression_level = Z_DEFAULT_COMPRESSION;
        dont = lp_dont_compress(module_id);

        if (!dont || !*dont) return;

        if ((dont[0] == '*') && (!dont[1])) {
                /* an optimization to skip the rest of this routine */
                compression_level = 0;
                return;
        }

        dont = strdup(dont);
        fname = strdup(fname);
        if (!dont || !fname) return;

        strlower(dont);
        strlower(fname);

        for (tok=strtok(dont," ");tok;tok=strtok(NULL," ")) {
                if (fnmatch(tok, fname, 0) == 0) {
                        compression_level = 0;
                        break;
                }
        }
        free(dont);
        free(fname);
}

/* non-compressing recv token */
static int simple_recv_token(int f,char **data)
{
        static int residue;
        static char *buf;
        int n;

        if (!buf) {
                buf = (char *)malloc(CHUNK_SIZE);
                if (!buf) out_of_memory("simple_recv_token");
        }

        if (residue == 0) {
                int i = read_int(f);
                if (i <= 0) return i;
                residue = i;
        }

        *data = buf;
        n = MIN(CHUNK_SIZE,residue);
        residue -= n;
        read_buf(f,buf,n);
        return n;
}


/* non-compressing send token */
static void simple_send_token(int f,int token,
                              struct map_struct *buf,OFF_T offset,int n)
{
        extern int write_batch; /* dw */
        int hold_int; /* dw */

        if (n > 0) {
                int l = 0;
                while (l < n) {
                        int n1 = MIN(CHUNK_SIZE,n-l);
                        write_int(f,n1);
                        write_buf(f,map_ptr(buf,offset+l,n1),n1);
                        if (write_batch) {
                            write_batch_delta_file( (char *) &n1, sizeof(int) );
                            write_batch_delta_file(map_ptr(buf,offset+l,n1),n1);
                        }
                        l += n1;
                }
        }
        /* a -2 token means to send data only and no token */
        if (token != -2) {
                write_int(f,-(token+1));
                if (write_batch) {
                    hold_int = -(token+1);
                    write_batch_delta_file( (char *) &hold_int, sizeof(int) );
                }
        }
}


/* Flag bytes in compressed stream are encoded as follows: */
#define END_FLAG        0       /* that's all folks */
#define TOKEN_LONG      0x20    /* followed by 32-bit token number */
#define TOKENRUN_LONG   0x21    /* ditto with 16-bit run count */
#define DEFLATED_DATA   0x40    /* + 6-bit high len, then low len byte */
#define TOKEN_REL       0x80    /* + 6-bit relative token number */
#define TOKENRUN_REL    0xc0    /* ditto with 16-bit run count */

#define MAX_DATA_COUNT  16383   /* fit 14 bit count into 2 bytes with flags */

/* For coding runs of tokens */
static int last_token = -1;
static int run_start;
static int last_run_end;

/* Deflation state */
static z_stream tx_strm;

/* Output buffer */
static char *obuf;

/* Send a deflated token */
static void
send_deflated_token(int f, int token,
                    struct map_struct *buf, OFF_T offset, int nb, int toklen)
{
        int n, r;
        static int init_done, flush_pending;
        extern int write_batch;  /* dw */
        char temp_byte;   /* dw */

        if (last_token == -1) {
                /* initialization */
                if (!init_done) {
                        tx_strm.next_in = NULL;
                        tx_strm.zalloc = NULL;
                        tx_strm.zfree = NULL;
                        if (deflateInit2(&tx_strm, compression_level,
                                         Z_DEFLATED, -15, 8,
                                         Z_DEFAULT_STRATEGY) != Z_OK) {
                                rprintf(FERROR, "compression init failed\n");
                                exit_cleanup(RERR_STREAMIO);
                        }
                        if ((obuf = malloc(MAX_DATA_COUNT+2)) == NULL)
                                out_of_memory("send_deflated_token");
                        init_done = 1;
                } else
                        deflateReset(&tx_strm);
                last_run_end = 0;
                run_start = token;
                flush_pending = 0;

        } else if (last_token == -2) {
                run_start = token;

        } else if (nb != 0 || token != last_token + 1
                   || token >= run_start + 65536) {
                /* output previous run */
                r = run_start - last_run_end;
                n = last_token - run_start;
                if (r >= 0 && r <= 63) {
                        write_byte(f, (n==0? TOKEN_REL: TOKENRUN_REL) + r);
                        if (write_batch) { /* dw */
                            temp_byte = (char)( (n==0? TOKEN_REL: TOKENRUN_REL) + r);
                            write_batch_delta_file(&temp_byte,sizeof(char));
                        }
                } else {
                        write_byte(f, (n==0? TOKEN_LONG: TOKENRUN_LONG));
                        write_int(f, run_start);
                        if (write_batch) { /* dw */
                            temp_byte = (char)(n==0? TOKEN_LONG: TOKENRUN_LONG);
                            write_batch_delta_file(&temp_byte,sizeof(temp_byte));
                            write_batch_delta_file((char *)&run_start,sizeof(run_start));
                        }
                }
                if (n != 0) {
                        write_byte(f, n);
                        write_byte(f, n >> 8);
                        if (write_batch) { /* dw */
                            write_batch_delta_file((char *)&n,sizeof(char));
                            temp_byte = (char) n >> 8;
                            write_batch_delta_file(&temp_byte,sizeof(temp_byte));
                        }
                }
                last_run_end = last_token;
                run_start = token;
        }

        last_token = token;

        if (nb != 0 || flush_pending) {
                /* deflate the data starting at offset */
                int flush = Z_NO_FLUSH;
                tx_strm.avail_in = 0;
                tx_strm.avail_out = 0;
                do {
                        if (tx_strm.avail_in == 0 && nb != 0) {
                                /* give it some more input */
                                n = MIN(nb, CHUNK_SIZE);
                                tx_strm.next_in = (Bytef *)
                                        map_ptr(buf, offset, n);
                                tx_strm.avail_in = n;
                                nb -= n;
                                offset += n;
                        }
                        if (tx_strm.avail_out == 0) {
                                tx_strm.next_out = (Bytef *)(obuf + 2);
                                tx_strm.avail_out = MAX_DATA_COUNT;
                                if (flush != Z_NO_FLUSH) {
                                        /*
                                         * We left the last 4 bytes in the
                                         * buffer, in case they are the
                                         * last 4.  Move them to the front.
                                         */
                                        memcpy(tx_strm.next_out,
                                               obuf+MAX_DATA_COUNT-2, 4);
                                        tx_strm.next_out += 4;
                                        tx_strm.avail_out -= 4;
                                }
                        }
                        if (nb == 0 && token != -2)
                                flush = Z_SYNC_FLUSH;
                        r = deflate(&tx_strm, flush);
                        if (r != Z_OK) {
                                rprintf(FERROR, "deflate returned %d\n", r);
                                exit_cleanup(RERR_STREAMIO);
                        }
                        if (nb == 0 || tx_strm.avail_out == 0) {
                                n = MAX_DATA_COUNT - tx_strm.avail_out;
                                if (flush != Z_NO_FLUSH) {
                                        /*
                                         * We have to trim off the last 4
                                         * bytes of output when flushing
                                         * (they are just 0, 0, ff, ff).
                                         */
                                        n -= 4;
                                }
                                if (n > 0) {
                                        obuf[0] = DEFLATED_DATA + (n >> 8);
                                        obuf[1] = n;
                                        write_buf(f, obuf, n+2);
                                        if (write_batch) /* dw */
                                            write_batch_delta_file(obuf,n+2);
                                }
                        }
                } while (nb != 0 || tx_strm.avail_out == 0);
                flush_pending = token == -2;
        }

        if (token == -1) {
                /* end of file - clean up */
                write_byte(f, END_FLAG);
                if (write_batch) { /* dw */
                    temp_byte = END_FLAG;
                    write_batch_delta_file((char *)&temp_byte,sizeof(temp_byte));
                }

        } else if (token != -2) {
                /* add the data in the current block to the compressor's
                   history and hash table */
                tx_strm.next_in = (Bytef *) map_ptr(buf, offset, toklen);
                tx_strm.avail_in = toklen;
                tx_strm.next_out = (Bytef *) obuf;
                tx_strm.avail_out = MAX_DATA_COUNT;
                r = deflate(&tx_strm, Z_INSERT_ONLY);
                if (r != Z_OK || tx_strm.avail_in != 0) {
                        rprintf(FERROR, "deflate on token returned %d (%d bytes left)\n",
                                r, tx_strm.avail_in);
                        exit_cleanup(RERR_STREAMIO);
                }
        }
}


/* tells us what the receiver is in the middle of doing */
static enum { r_init, r_idle, r_running, r_inflating, r_inflated } recv_state;

/* for inflating stuff */
static z_stream rx_strm;
static char *cbuf;
static char *dbuf;

/* for decoding runs of tokens */
static int rx_token;
static int rx_run;

/* Receive a deflated token and inflate it */
static int
recv_deflated_token(int f, char **data)
{
        int n, r, flag;
        static int init_done;
        static int saved_flag;

        for (;;) {
                switch (recv_state) {
                case r_init:
                        if (!init_done) {
                                rx_strm.next_out = NULL;
                                rx_strm.zalloc = NULL;
                                rx_strm.zfree = NULL;
                                if (inflateInit2(&rx_strm, -15) != Z_OK) {
                                        rprintf(FERROR, "inflate init failed\n");
                                        exit_cleanup(RERR_STREAMIO);
                                }
                                if ((cbuf = malloc(MAX_DATA_COUNT)) == NULL
                                    || (dbuf = malloc(CHUNK_SIZE)) == NULL)
                                        out_of_memory("recv_deflated_token");
                                init_done = 1;
                        } else {
                                inflateReset(&rx_strm);
                        }
                        recv_state = r_idle;
                        rx_token = 0;
                        break;

                case r_idle:
                case r_inflated:
                        if (saved_flag) {
                                flag = saved_flag & 0xff;
                                saved_flag = 0;
                        } else
                                flag = read_byte(f);
                        if ((flag & 0xC0) == DEFLATED_DATA) {
                                n = ((flag & 0x3f) << 8) + read_byte(f);
                                read_buf(f, cbuf, n);
                                rx_strm.next_in = (Bytef *)cbuf;
                                rx_strm.avail_in = n;
                                recv_state = r_inflating;
                                break;
                        }
                        if (recv_state == r_inflated) {
                                /* check previous inflated stuff ended correctly */
                                rx_strm.avail_in = 0;
                                rx_strm.next_out = (Bytef *)dbuf;
                                rx_strm.avail_out = CHUNK_SIZE;
                                r = inflate(&rx_strm, Z_SYNC_FLUSH);
                                n = CHUNK_SIZE - rx_strm.avail_out;
                                /*
                                 * Z_BUF_ERROR just means no progress was
                                 * made, i.e. the decompressor didn't have
                                 * any pending output for us.
                                 */
                                if (r != Z_OK && r != Z_BUF_ERROR) {
                                        rprintf(FERROR, "inflate flush returned %d (%d bytes)\n",
                                                r, n);
                                        exit_cleanup(RERR_STREAMIO);
                                }
                                if (n != 0 && r != Z_BUF_ERROR) {
                                        /* have to return some more data and
                                           save the flag for later. */
                                        saved_flag = flag + 0x10000;
                                        *data = dbuf;
                                        return n;
                                }
                                /*
                                 * At this point the decompressor should
                                 * be expecting to see the 0, 0, ff, ff bytes.
                                 */
                                if (!inflateSyncPoint(&rx_strm)) {
                                        rprintf(FERROR, "decompressor lost sync!\n");
                                        exit_cleanup(RERR_STREAMIO);
                                }
                                rx_strm.avail_in = 4;
                                rx_strm.next_in = (Bytef *)cbuf;
                                cbuf[0] = cbuf[1] = 0;
                                cbuf[2] = cbuf[3] = 0xff;
                                inflate(&rx_strm, Z_SYNC_FLUSH);
                                recv_state = r_idle;
                        }
                        if (flag == END_FLAG) {
                                /* that's all folks */
                                recv_state = r_init;
                                return 0;
                        }

                        /* here we have a token of some kind */
                        if (flag & TOKEN_REL) {
                                rx_token += flag & 0x3f;
                                flag >>= 6;
                        } else
                                rx_token = read_int(f);
                        if (flag & 1) {
                                rx_run = read_byte(f);
                                rx_run += read_byte(f) << 8;
                                recv_state = r_running;
                        }
                        return -1 - rx_token;

                case r_inflating:
                        rx_strm.next_out = (Bytef *)dbuf;
                        rx_strm.avail_out = CHUNK_SIZE;
                        r = inflate(&rx_strm, Z_NO_FLUSH);
                        n = CHUNK_SIZE - rx_strm.avail_out;
                        if (r != Z_OK) {
                                rprintf(FERROR, "inflate returned %d (%d bytes)\n", r, n);
                                exit_cleanup(RERR_STREAMIO);
                        }
                        if (rx_strm.avail_in == 0)
                                recv_state = r_inflated;
                        if (n != 0) {
                                *data = dbuf;
                                return n;
                        }
                        break;

                case r_running:
                        ++rx_token;
                        if (--rx_run == 0)
                                recv_state = r_idle;
                        return -1 - rx_token;
                }
        }
}

/*
 * put the data corresponding to a token that we've just returned
 * from recv_deflated_token into the decompressor's history buffer.
 */
static void see_deflate_token(char *buf, int len)
{
        int r, blklen;
        unsigned char hdr[5];

        rx_strm.avail_in = 0;
        blklen = 0;
        hdr[0] = 0;
        do {
                if (rx_strm.avail_in == 0 && len != 0) {
                        if (blklen == 0) {
                                /* Give it a fake stored-block header. */
                                rx_strm.next_in = (Bytef *)hdr;
                                rx_strm.avail_in = 5;
                                blklen = len;
                                if (blklen > 0xffff)
                                        blklen = 0xffff;
                                hdr[1] = blklen;
                                hdr[2] = blklen >> 8;
                                hdr[3] = ~hdr[1];
                                hdr[4] = ~hdr[2];
                        } else {
                                rx_strm.next_in = (Bytef *)buf;
                                rx_strm.avail_in = blklen;
                                len -= blklen;
                                blklen = 0;
                        }
                }
                rx_strm.next_out = (Bytef *)dbuf;
                rx_strm.avail_out = CHUNK_SIZE;
                r = inflate(&rx_strm, Z_SYNC_FLUSH);
                if (r != Z_OK) {
                        rprintf(FERROR, "inflate (token) returned %d\n", r);
                        exit_cleanup(RERR_STREAMIO);
                }
        } while (len || rx_strm.avail_out == 0);
}

/**
 * Transmit a verbatim buffer of length @p n followed by a token.
 * If token == -1 then we have reached EOF 
 * If n == 0 then don't send a buffer
 */
void send_token(int f,int token,struct map_struct *buf,OFF_T offset,
                int n,int toklen)
{
        if (!do_compression) {
                simple_send_token(f,token,buf,offset,n);
        } else {
                send_deflated_token(f, token, buf, offset, n, toklen);
        }
}


/*
 * receive a token or buffer from the other end. If the reurn value is >0 then
 * it is a data buffer of that length, and *data will point at the data.
 * if the return value is -i then it represents token i-1
 * if the return value is 0 then the end has been reached
 */
int recv_token(int f,char **data)
{
        int tok;

        if (!do_compression) {
                tok = simple_recv_token(f,data);
        } else {
                tok = recv_deflated_token(f, data);
        }
        return tok;
}

/*
 * look at the data corresponding to a token, if necessary
 */
void see_token(char *data, int toklen)
{
        if (do_compression)
                see_deflate_token(data, toklen);
}

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