Annotation of src/usr.bin/ssh/compress.c, Revision 1.2
1.1 deraadt 1: /*
2:
3: compress.c
4:
5: Author: Tatu Ylonen <ylo@cs.hut.fi>
6:
7: Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8: All rights reserved
9:
10: Created: Wed Oct 25 22:12:46 1995 ylo
11:
12: Interface to packet compression for ssh.
13:
14: */
15:
16: #include "includes.h"
1.2 ! markus 17: RCSID("$Id: compress.c,v 1.1 1999/09/26 20:53:34 deraadt Exp $");
1.1 deraadt 18:
19: #include "ssh.h"
20: #include "buffer.h"
21: #include "zlib.h"
22:
23: static z_stream incoming_stream;
24: static z_stream outgoing_stream;
25:
1.2 ! markus 26: /* Initializes compression; level is compression level from 1 to 9
! 27: (as in gzip). */
1.1 deraadt 28:
1.2 ! markus 29: void
! 30: buffer_compress_init(int level)
1.1 deraadt 31: {
1.2 ! markus 32: debug("Enabling compression at level %d.", level);
! 33: if (level < 1 || level > 9)
! 34: fatal("Bad compression level %d.", level);
! 35: inflateInit(&incoming_stream);
! 36: deflateInit(&outgoing_stream, level);
1.1 deraadt 37: }
38:
39: /* Frees any data structures allocated for compression. */
40:
1.2 ! markus 41: void
! 42: buffer_compress_uninit()
1.1 deraadt 43: {
1.2 ! markus 44: debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f",
! 45: outgoing_stream.total_in, outgoing_stream.total_out,
! 46: outgoing_stream.total_in == 0 ? 0.0 :
! 47: (double) outgoing_stream.total_out / outgoing_stream.total_in);
! 48: debug("compress incoming: raw data %lu, compressed %lu, factor %.2f",
! 49: incoming_stream.total_out, incoming_stream.total_in,
! 50: incoming_stream.total_out == 0 ? 0.0 :
! 51: (double) incoming_stream.total_in / incoming_stream.total_out);
! 52: inflateEnd(&incoming_stream);
! 53: deflateEnd(&outgoing_stream);
1.1 deraadt 54: }
55:
56: /* Compresses the contents of input_buffer into output_buffer. All
57: packets compressed using this function will form a single
58: compressed data stream; however, data will be flushed at the end of
59: every call so that each output_buffer can be decompressed
60: independently (but in the appropriate order since they together
61: form a single compression stream) by the receiver. This appends
62: the compressed data to the output buffer. */
63:
1.2 ! markus 64: void
! 65: buffer_compress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 66: {
1.2 ! markus 67: char buf[4096];
! 68: int status;
1.1 deraadt 69:
1.2 ! markus 70: /* This case is not handled below. */
! 71: if (buffer_len(input_buffer) == 0)
! 72: return;
! 73:
! 74: /* Input is the contents of the input buffer. */
! 75: outgoing_stream.next_in = buffer_ptr(input_buffer);
! 76: outgoing_stream.avail_in = buffer_len(input_buffer);
! 77:
! 78: /* Loop compressing until deflate() returns with avail_out != 0. */
! 79: do {
! 80: /* Set up fixed-size output buffer. */
! 81: outgoing_stream.next_out = buf;
! 82: outgoing_stream.avail_out = sizeof(buf);
! 83:
! 84: /* Compress as much data into the buffer as possible. */
! 85: status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
! 86: switch (status) {
! 87: case Z_OK:
! 88: /* Append compressed data to output_buffer. */
! 89: buffer_append(output_buffer, buf,
! 90: sizeof(buf) - outgoing_stream.avail_out);
! 91: break;
! 92: case Z_STREAM_END:
! 93: fatal("buffer_compress: deflate returned Z_STREAM_END");
! 94: /* NOTREACHED */
! 95: case Z_STREAM_ERROR:
! 96: fatal("buffer_compress: deflate returned Z_STREAM_ERROR");
! 97: /* NOTREACHED */
! 98: case Z_BUF_ERROR:
! 99: fatal("buffer_compress: deflate returned Z_BUF_ERROR");
! 100: /* NOTREACHED */
! 101: default:
! 102: fatal("buffer_compress: deflate returned %d", status);
! 103: /* NOTREACHED */
! 104: }
1.1 deraadt 105: }
1.2 ! markus 106: while (outgoing_stream.avail_out == 0);
1.1 deraadt 107: }
108:
109: /* Uncompresses the contents of input_buffer into output_buffer. All
110: packets uncompressed using this function will form a single
111: compressed data stream; however, data will be flushed at the end of
112: every call so that each output_buffer. This must be called for the
113: same size units that the buffer_compress was called, and in the
114: same order that buffers compressed with that. This appends the
115: uncompressed data to the output buffer. */
116:
1.2 ! markus 117: void
! 118: buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
1.1 deraadt 119: {
1.2 ! markus 120: char buf[4096];
! 121: int status;
1.1 deraadt 122:
1.2 ! markus 123: incoming_stream.next_in = buffer_ptr(input_buffer);
! 124: incoming_stream.avail_in = buffer_len(input_buffer);
1.1 deraadt 125:
1.2 ! markus 126: incoming_stream.next_out = buf;
! 127: incoming_stream.avail_out = sizeof(buf);
1.1 deraadt 128:
1.2 ! markus 129: for (;;) {
! 130: status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
! 131: switch (status) {
! 132: case Z_OK:
! 133: buffer_append(output_buffer, buf,
! 134: sizeof(buf) - incoming_stream.avail_out);
! 135: incoming_stream.next_out = buf;
! 136: incoming_stream.avail_out = sizeof(buf);
! 137: break;
! 138: case Z_STREAM_END:
! 139: fatal("buffer_uncompress: inflate returned Z_STREAM_END");
! 140: /* NOTREACHED */
! 141: case Z_DATA_ERROR:
! 142: fatal("buffer_uncompress: inflate returned Z_DATA_ERROR");
! 143: /* NOTREACHED */
! 144: case Z_STREAM_ERROR:
! 145: fatal("buffer_uncompress: inflate returned Z_STREAM_ERROR");
! 146: /* NOTREACHED */
! 147: case Z_BUF_ERROR:
! 148: /* Comments in zlib.h say that we should keep
! 149: calling inflate() until we get an error. This
! 150: appears to be the error that we get. */
! 151: return;
! 152: case Z_MEM_ERROR:
! 153: fatal("buffer_uncompress: inflate returned Z_MEM_ERROR");
! 154: /* NOTREACHED */
! 155: default:
! 156: fatal("buffer_uncompress: inflate returned %d", status);
! 157: }
1.1 deraadt 158: }
159: }
![[BACK]](/icons/back.gif){kind=icon}
Return to compress.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh