librsync  2.3.2
emit.c
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1 /*= -*- c-basic-offset: 4; indent-tabs-mode: nil; -*-
2  *
3  * librsync -- dynamic caching and delta update in HTTP
4  *
5  * Copyright (C) 2000, 2001, 2004 by Martin Pool <mbp@sourcefrog.net>
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public License
9  * as published by the Free Software Foundation; either version 2.1 of
10  * the License, or (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful, but
13  * WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with this program; if not, write to the Free Software
19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20  */
21 
22 /** \file emit.c
23  * encoding output routines.
24  *
25  * \todo Pluggable encoding formats: gdiff-style, rsync 24, ed (text), Delta
26  * HTTP. */
27 
28 #include "config.h"
29 #include <assert.h>
30 #include <stdlib.h>
31 #include "librsync.h"
32 #include "emit.h"
33 #include "job.h"
34 #include "netint.h"
35 #include "command.h"
36 #include "prototab.h"
37 #include "trace.h"
38 
39 /** Write the magic for the start of a delta. */
41 {
42  rs_trace("emit DELTA magic");
43  rs_squirt_n4(job, RS_DELTA_MAGIC);
44 }
45 
46 /** Write a LITERAL command. */
47 void rs_emit_literal_cmd(rs_job_t *job, int len)
48 {
49  int cmd;
50  int param_len = len <= 64 ? 0 : rs_int_len(len);
51 
52  if (param_len == 0) {
53  cmd = len;
54  rs_trace("emit LITERAL_%d, cmd_byte=%#04x", len, cmd);
55  } else if (param_len == 1) {
56  cmd = RS_OP_LITERAL_N1;
57  rs_trace("emit LITERAL_N1(len=%d), cmd_byte=%#04x", len, cmd);
58  } else if (param_len == 2) {
59  cmd = RS_OP_LITERAL_N2;
60  rs_trace("emit LITERAL_N2(len=%d), cmd_byte=%#04x", len, cmd);
61  } else {
62  assert(param_len == 4);
63  cmd = RS_OP_LITERAL_N4;
64  rs_trace("emit LITERAL_N4(len=%d), cmd_byte=%#04x", len, cmd);
65  }
66 
67  rs_squirt_byte(job, (rs_byte_t)cmd);
68  if (param_len)
69  rs_squirt_netint(job, len, param_len);
70 
71  job->stats.lit_cmds++;
72  job->stats.lit_bytes += len;
73  job->stats.lit_cmdbytes += 1 + param_len;
74 }
75 
76 /** Write a COPY command for given offset and length.
77  *
78  * There is a choice of variable-length encodings, depending on the size of
79  * representation for the parameters. */
80 void rs_emit_copy_cmd(rs_job_t *job, rs_long_t where, rs_long_t len)
81 {
82  int cmd;
83  rs_stats_t *stats = &job->stats;
84  const int where_bytes = rs_int_len(where);
85  const int len_bytes = rs_int_len(len);
86 
87  /* Commands ascend (1,1), (1,2), ... (8, 8) */
88  if (where_bytes == 8)
89  cmd = RS_OP_COPY_N8_N1;
90  else if (where_bytes == 4)
91  cmd = RS_OP_COPY_N4_N1;
92  else if (where_bytes == 2)
93  cmd = RS_OP_COPY_N2_N1;
94  else {
95  assert(where_bytes == 1);
96  cmd = RS_OP_COPY_N1_N1;
97  }
98  if (len_bytes == 1) ;
99  else if (len_bytes == 2)
100  cmd += 1;
101  else if (len_bytes == 4)
102  cmd += 2;
103  else {
104  assert(len_bytes == 8);
105  cmd += 3;
106  }
107 
108  rs_trace("emit COPY_N%d_N%d(where=" FMT_LONG ", len=" FMT_LONG
109  "), cmd_byte=%#04x", where_bytes, len_bytes, where, len, cmd);
110  rs_squirt_byte(job, (rs_byte_t)cmd);
111  rs_squirt_netint(job, where, where_bytes);
112  rs_squirt_netint(job, len, len_bytes);
113 
114  stats->copy_cmds++;
115  stats->copy_bytes += len;
116  stats->copy_cmdbytes += 1 + where_bytes + len_bytes;
117 }
118 
119 /** Write an END command. */
121 {
122  int cmd = RS_OP_END;
123 
124  rs_trace("emit END, cmd_byte=%#04x", cmd);
125  rs_squirt_byte(job, (rs_byte_t)cmd);
126 }
logging functions.
rs_long_t lit_cmdbytes
Number of bytes used in literal command headers.
Definition: librsync.h:215
void rs_emit_delta_header(rs_job_t *job)
Write the magic for the start of a delta.
Definition: emit.c:40
Types of commands present in the encoding stream.
rs_result rs_squirt_byte(rs_job_t *job, rs_byte_t val)
Write a single byte to a stream output.
Definition: netint.c:51
A delta file.
Definition: librsync.h:71
void rs_emit_end_cmd(rs_job_t *job)
Write an END command.
Definition: emit.c:120
rs_stats_t stats
Encoding statistics.
Definition: job.h:72
Public header for librsync.
int lit_cmds
Number of literal commands.
Definition: librsync.h:213
rs_long_t lit_bytes
Number of literal bytes.
Definition: librsync.h:214
Performance statistics from a librsync encoding or decoding operation.
Definition: librsync.h:210
How to emit commands to the client.
rs_result rs_squirt_netint(rs_job_t *job, rs_long_t val, int len)
Write a variable-length integer to a stream.
Definition: netint.c:64
void rs_emit_copy_cmd(rs_job_t *job, rs_long_t where, rs_long_t len)
Write a COPY command for given offset and length.
Definition: emit.c:80
Delta file commands.
void rs_emit_literal_cmd(rs_job_t *job, int len)
Write a LITERAL command.
Definition: emit.c:47
The contents of this structure are private.
Definition: job.h:26