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mppc_enc: add hash tables to speed up mppc encoder

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This commit is contained in:
Jay Sorg
2012-03-27 00:43:53 -07:00
parent 82542fdb21
commit 3996620064
3 changed files with 429 additions and 302 deletions
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8
cunit/test_mppc_enc.c
View File

@@ -527,13 +527,13 @@ void test_mppc_enc(void)
block_num++;
total += bytes_read;
DLOG(("block_num=%d\n", block_num));
CU_ASSERT(compress_rdp(enc, (uint8*) buf, bytes_read) == true);
CU_ASSERT(compress_rdp(enc, (uint8*) buf, bytes_read) != false);
if (enc->flags & PACKET_COMPRESSED)
{
DLOG(("%d bytes compressed to %d\n", bytes_read, enc->bytes_in_opb));
clen += enc->bytes_in_opb;
CU_ASSERT(decompress_rdp_5(&rdp, (uint8 *) enc->outputBuffer,
enc->bytes_in_opb, enc->flags, &roff, &rlen) == true);
enc->bytes_in_opb, enc->flags, &roff, &rlen) != false);
CU_ASSERT(bytes_read == rlen);
CU_ASSERT(memcmp(buf, &rdp.mppc->history_buf[roff], rlen) == 0);
}
@@ -563,11 +563,11 @@ void test_mppc_enc(void)
/* save starting time */
gettimeofday(&start_time, NULL);
CU_ASSERT(compress_rdp(enc, (uint8*) decompressed_rd5_data, data_len) == true);
CU_ASSERT(compress_rdp(enc, (uint8*) decompressed_rd5_data, data_len) != false);
if (enc->flags & PACKET_COMPRESSED)
{
CU_ASSERT(decompress_rdp_5(&rdp, (uint8 *) enc->outputBuffer,
enc->bytes_in_opb, enc->flags, &roff, &rlen) == true);
enc->bytes_in_opb, enc->flags, &roff, &rlen) != false);
CU_ASSERT(data_len == rlen);
CU_ASSERT(memcmp(decompressed_rd5_data, &rdp.mppc->history_buf[roff], rlen) == 0);
}

722
libfreerdp-core/mppc_enc.c
View File

@@ -29,6 +29,46 @@
#define RDP_40_HIST_BUF_LEN (1024 * 8) /* RDP 4.0 uses 8K history buf */
#define RDP_50_HIST_BUF_LEN (1024 * 64) /* RDP 5.0 uses 64K history buf */
#define CRC_INIT 0xFFFF
#define CRC(crcval, newchar) crcval = (crcval >> 8) ^ crc_table[(crcval ^ newchar) & 0x00ff]
/* CRC16 defs */
static const uint16 crc_table[256] =
{
0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};
/*****************************************************************************
insert 2 bits into outputBuffer
******************************************************************************/
@@ -406,14 +446,22 @@ struct rdp_mppc_enc* mppc_enc_new(int protocol_type)
xfree(enc);
return NULL;
}
enc->outputBufferPlus = (char*) xzalloc(enc->buf_len + 32);
enc->outputBufferPlus = (char*) xzalloc(enc->buf_len + 64);
if (enc->outputBufferPlus == NULL)
{
xfree(enc->historyBuffer);
xfree(enc);
return NULL;
}
enc->outputBuffer = enc->outputBufferPlus + 32;
enc->outputBuffer = enc->outputBufferPlus + 64;
enc->hash_table = (uint16*) xzalloc(enc->buf_len * 2);
if (enc->hash_table == NULL)
{
xfree(enc->historyBuffer);
xfree(enc->outputBufferPlus);
xfree(enc);
return NULL;
}
return enc;
}
@@ -429,6 +477,7 @@ void mppc_enc_free(struct rdp_mppc_enc* enc)
return;
xfree(enc->historyBuffer);
xfree(enc->outputBufferPlus);
xfree(enc->hash_table);
xfree(enc);
}
@@ -475,7 +524,7 @@ boolean compress_rdp_4(struct rdp_mppc_enc* enc, uint8* srcData, int len)
}
/**
* encode (compress) data using RDP 5.0 protocol
* encode (compress) data using RDP 5.0 protocol using hash table
*
* @param enc encoder state info
* @param srcData uncompressed data
@@ -492,25 +541,31 @@ boolean compress_rdp_5(struct rdp_mppc_enc* enc, uint8* srcData, int len)
char* hbuf_start; /* points to start of history buffer */
char* cptr1;
char* cptr2;
char* cptr3;
char* index_ptr;
int opb_index; /* index into outputBuffer */
int bits_left; /* unused bits in current byte in outputBuffer */
uint32 copy_offset; /* pattern match starts here... */
uint32 lom; /* ...and matches this many bytes */
int last_crc_index; /* don't compute CRC beyond this index */
uint16 *hash_table; /* hash table for pattern matching */
uint32 copy_offset; /* pattern match starts here... */
uint32 lom; /* ...and matches this many bytes */
uint32 saved_lom;
uint32 i;
uint32 j;
uint32 k;
uint32 x;
uint8 data;
uint8 data;
uint16 data16;
uint32 historyOffset;
uint16 crc;
uint ctr;
uint saved_ctr;
uint data_end;
uint8 byte_val;
crc = 0;
opb_index = 0;
bits_left = 8;
copy_offset = 0;
hash_table = enc->hash_table;
hbuf_start = enc->historyBuffer;
outputBuffer = enc->outputBuffer;
memset(outputBuffer, 0, len);
@@ -526,21 +581,28 @@ boolean compress_rdp_5(struct rdp_mppc_enc* enc, uint8* srcData, int len)
/* historyBuffer cannot hold srcData - rewind it */
enc->historyOffset = 0;
enc->flagsHold |= PACKET_AT_FRONT;
memset(hash_table, 0, enc->buf_len * 2);
}
/* point to next free byte in historyBuffer */
historyOffset = enc->historyOffset;
/* add / append new data to historyBuffer */
memcpy(&(enc->historyBuffer[enc->historyOffset]), srcData, len);
historyPointer = &(enc->historyBuffer[enc->historyOffset]);
memcpy(&(enc->historyBuffer[historyOffset]), srcData, len);
/* point to start of data to be compressed */
historyPointer = &(enc->historyBuffer[historyOffset]);
ctr = copy_offset = lom = 0;
/* if we are at start of history buffer, do not attempt to compress */
/* first 2 bytes,because minimum LoM is 3 */
if (enc->historyOffset == 0)
if (historyOffset == 0)
{
/* encode first two bytes are literals */
for (x = 0; x < 2; x++)
{
data = *(historyPointer++);
data = *(historyPointer + x);
DLOG(("%.2x ", (unsigned char) data));
if (data & 0x80)
{
@@ -555,312 +617,373 @@ boolean compress_rdp_5(struct rdp_mppc_enc* enc, uint8* srcData, int len)
insert_8_bits(data);
}
}
/* store hash for first two entries in historyBuffer */
crc = CRC_INIT;
byte_val = enc->historyBuffer[0];
CRC(crc, byte_val);
byte_val = enc->historyBuffer[1];
CRC(crc, byte_val);
byte_val = enc->historyBuffer[2];
CRC(crc, byte_val);
hash_table[crc] = 0;
crc = CRC_INIT;
byte_val = enc->historyBuffer[1];
CRC(crc, byte_val);
byte_val = enc->historyBuffer[2];
CRC(crc, byte_val);
byte_val = enc->historyBuffer[3];
CRC(crc, byte_val);
hash_table[crc] = 1;
/* first two bytes have already been processed */
ctr = 2;
}
enc->historyOffset += len;
/* point to last byte in new data */
hptr_end = &(enc->historyBuffer[enc->historyOffset - 1]);
while (historyPointer <= hptr_end)
/* do not compute CRC beyond this */
last_crc_index = enc->historyOffset - 3;
/* do not search for pattern match beyond this */
data_end = len - 2;
/* start compressing data */
while (ctr < data_end)
{
/* do not search beyond index_ptr */
index_ptr = (historyPointer == hptr_end) ? historyPointer - 2 : historyPointer - 1;
cptr1 = historyPointer + ctr;
cptr1 = hbuf_start;
lom = 0;
saved_lom = 0;
crc = CRC_INIT;
byte_val = *cptr1;
CRC(crc, byte_val);
byte_val = *(cptr1 + 1);
CRC(crc, byte_val);
byte_val = *(cptr1 + 2);
CRC(crc, byte_val);
while (1)
/* cptr2 points to start of pattern match */
cptr2 = hbuf_start + hash_table[crc];
copy_offset = cptr1 - cptr2;
/* save current entry */
hash_table[crc] = cptr1 - hbuf_start;
/* double check that we have a pattern match */
if ((*cptr1 != *cptr2) ||
(*(cptr1 + 1) != *(cptr2 + 1)) ||
(*(cptr1 + 2) != *(cptr2 + 2)))
{
/* look for first byte match */
while ((cptr1 <= index_ptr) && (*cptr1 != *historyPointer))
{
cptr1++;
}
/* no match found; encode literal byte */
data = *cptr1;
if (cptr1 > index_ptr)
{
break;
}
/* got a one byte match - continue looking */
lom = 1;
cptr1++;
cptr2 = cptr1;
cptr3 = historyPointer + 1;
while (*(cptr2++) == *(cptr3++))
{
lom++;
if (cptr3 > hptr_end)
{
break;
}
}
if (lom < 3)
{
/* false alarm, keep looking */
lom = 0;
}
else
{
if (lom >= saved_lom)
{
/* this is a longer match, or a match closer to historyPointer */
saved_lom = lom;
copy_offset = (historyPointer - cptr1) + 1;
}
}
}
if (saved_lom)
{
/* insert_tuple */
DLOG(("<%d: %ld,%d> ", (int) (historyPointer - enc->historyBuffer),
(long) copy_offset, saved_lom));
lom = saved_lom;
historyPointer += lom;
/*
** encode copy_offset and insert into output buffer
*/
if ((copy_offset >= 0) && (copy_offset <= 63))
{
/* insert binary header */
data = 0x1f;
insert_5_bits(data);
/* insert 6 bits of copy_offset */
data = (char) (copy_offset & 0x3f);
insert_6_bits(data);
}
else if ((copy_offset >= 64) && (copy_offset <= 319))
{
/* insert binary header */
data = 0x1e;
insert_5_bits(data);
/* insert 8 bits of copy offset */
data = (char) (copy_offset - 64);
insert_8_bits(data);
}
else if ((copy_offset >= 320) && (copy_offset <= 2367))
{
/* insert binary header */
data = 0x0e;
insert_4_bits(data);
/* insert 11 bits of copy offset */
data16 = copy_offset - 320;;
insert_11_bits(data16);
}
else
{
/* copy_offset is 2368+ */
/* insert binary header */
data = 0x06;
insert_3_bits(data);
/* insert 16 bits of copy offset */
data16 = copy_offset - 2368;;
insert_16_bits(data16);
}
/*
** encode length of match and insert into output buffer
*/
if (lom == 3)
{
/* binary header is 'zero'; since outputBuffer is zero */
/* filled, all we have to do is update bits_left */
bits_left--;
if (bits_left == 0)
{
opb_index++;
bits_left = 8;
}
}
else if ((lom >= 4) && (lom <= 7))
{
/* insert binary header */
data = 0x02;
insert_2_bits(data);
/* insert lower 2 bits of LoM */
data = (char) (lom - 4);
insert_2_bits(data);
}
else if ((lom >= 8) && (lom <= 15))
{
/* insert binary header */
data = 0x06;
insert_3_bits(data);
/* insert lower 3 bits of LoM */
data = (char) (lom - 8);
insert_3_bits(data);
}
else if ((lom >= 16) && (lom <= 31))
{
/* insert binary header */
data = 0x0e;
insert_4_bits(data);
/* insert lower 4 bits of LoM */
data = (char) (lom - 16);
insert_4_bits(data);
}
else if ((lom >= 32) && (lom <= 63))
{
/* insert binary header */
data = 0x1e;
insert_5_bits(data);
/* insert lower 5 bits of LoM */
data = (char) (lom - 32);
insert_5_bits(data);
}
else if ((lom >= 64) && (lom <= 127))
{
/* insert binary header */
data = 0x3e;
insert_6_bits(data);
/* insert lower 6 bits of LoM */
data = (char) (lom - 64);
insert_6_bits(data);
}
else if ((lom >= 128) && (lom <= 255))
{
/* insert binary header */
data = 0x7e;
insert_7_bits(data);
/* insert lower 7 bits of LoM */
data = (char) (lom - 128);
insert_7_bits(data);
}
else if ((lom >= 256) && (lom <= 511))
{
/* insert binary header */
data = 0xfe;
insert_8_bits(data);
/* insert lower 8 bits of LoM */
data = (char) (lom - 256);
insert_8_bits(data);
}
else if ((lom >= 512) && (lom <= 1023))
{
/* insert binary header */
data16 = 0x1fe;
insert_9_bits(data16);
/* insert lower 9 bits of LoM */
data16 = lom - 512;
insert_9_bits(data16);
}
else if ((lom >= 1024) && (lom <= 2047))
{
/* insert binary header */
data16 = 0x3fe;
insert_10_bits(data16);
/* insert 10 lower bits of LoM */
data16 = lom - 1024;
insert_10_bits(data16);
}
else if ((lom >= 2048) && (lom <= 4095))
{
/* insert binary header */
data16 = 0x7fe;
insert_11_bits(data16);
/* insert 11 lower bits of LoM */
data16 = lom - 2048;
insert_11_bits(data16);
}
else if ((lom >= 4096) && (lom <= 8191))
{
/* insert binary header */
data16 = 0xffe;
insert_12_bits(data16);
/* insert 12 lower bits of LoM */
data16 = lom - 4096;
insert_12_bits(data16);
}
else if ((lom >= 8192) && (lom <= 16383))
{
/* insert binary header */
data16 = 0x1ffe;
insert_13_bits(data16);
/* insert 13 lower bits of LoM */
data16 = lom - 8192;
insert_13_bits(data16);
}
else if ((lom >= 16384) && (lom <= 32767))
{
/* insert binary header */
data16 = 0x3ffe;
insert_14_bits(data16);
/* insert 14 lower bits of LoM */
data16 = lom - 16384;
insert_14_bits(data16);
}
else if ((lom >= 32768) && (lom <= 65535))
{
/* insert binary header */
data16 = 0x7ffe;
insert_15_bits(data16);
/* insert 15 lower bits of LoM */
data16 = lom - 32768;
insert_15_bits(data16);
}
}
else
{
/* insert_literal */
/* data not found in historyBuffer; encode and place data in output buffer */
data = *(historyPointer++);
DLOG(("%.2x ", (unsigned char) data));
if (data & 0x80)
if (data < 0x80)
{
/* insert encoded literal */
/* literal byte < 0x80 */
insert_8_bits(data);
}
else
{
/* literal byte >= 0x80 */
insert_2_bits(0x02);
data &= 0x7f;
insert_7_bits(data);
}
else
{
/* insert literal */
insert_8_bits(data);
}
ctr++;
continue;
}
/* if bits_left == 8, opb_index has already been incremented */
if ((bits_left == 8) && (opb_index > len))
/* we have a match - compute Length of Match */
cptr1 += 3;
cptr2 += 3;
lom = 3;
while ((cptr1 <= hptr_end) && (*(cptr1++) == *(cptr2++)))
{
/* compressed data longer than uncompressed data */
/* give up */
enc->historyOffset = historyOffset;
return true;
lom++;
}
else if (opb_index + 1 > len)
saved_ctr = ctr + lom;
DLOG(("<%d: %ld,%d> ", (historyPointer + ctr) - hbuf_start, copy_offset, lom));
/* compute CRC for matching segment and store in hash table */
cptr1 = historyPointer + ctr;
if (cptr1 + lom > hbuf_start + last_crc_index)
{
/* compressed data longer than uncompressed data */
/* give up */
enc->historyOffset = historyOffset;
return true;
/* we have gone beyond last_crc_index - go back */
j = last_crc_index - (cptr1 - hbuf_start);
}
} /* end while (historyPointer < hptr_end) */
else
{
j = lom - 1;
}
ctr++;
for (i = 0; i < j; i++)
{
cptr1 = historyPointer + ctr;
/* compute CRC on triplet */
crc = CRC_INIT;
byte_val = *(cptr1++);
CRC(crc, byte_val);
byte_val = *(cptr1++);
CRC(crc, byte_val);
byte_val = *(cptr1++);
CRC(crc, byte_val);
/* save current entry */
hash_table[crc] = (cptr1 - 3) - hbuf_start;
/* point to next triplet */
ctr++;
}
ctr = saved_ctr;
/* encode copy_offset and insert into output buffer */
if ((copy_offset >= 0) && (copy_offset <= 63))
{
/* insert binary header */
data = 0x1f;
insert_5_bits(data);
/* insert 6 bits of copy_offset */
data = (char) (copy_offset & 0x3f);
insert_6_bits(data);
}
else if ((copy_offset >= 64) && (copy_offset <= 319))
{
/* insert binary header */
data = 0x1e;
insert_5_bits(data);
/* insert 8 bits of copy offset */
data = (char) (copy_offset - 64);
insert_8_bits(data);
}
else if ((copy_offset >= 320) && (copy_offset <= 2367))
{
/* insert binary header */
data = 0x0e;
insert_4_bits(data);
/* insert 11 bits of copy offset */
data16 = copy_offset - 320;;
insert_11_bits(data16);
}
else
{
/* copy_offset is 2368+ */
/* insert binary header */
data = 0x06;
insert_3_bits(data);
/* insert 16 bits of copy offset */
data16 = copy_offset - 2368;;
insert_16_bits(data16);
}
/* encode length of match and insert into output buffer */
if (lom == 3)
{
/* binary header is 'zero'; since outputBuffer is zero */
/* filled, all we have to do is update bits_left */
bits_left--;
if (bits_left == 0)
{
opb_index++;
bits_left = 8;
}
}
else if ((lom >= 4) && (lom <= 7))
{
/* insert binary header */
data = 0x02;
insert_2_bits(data);
/* insert lower 2 bits of LoM */
data = (char) (lom - 4);
insert_2_bits(data);
}
else if ((lom >= 8) && (lom <= 15))
{
/* insert binary header */
data = 0x06;
insert_3_bits(data);
/* insert lower 3 bits of LoM */
data = (char) (lom - 8);
insert_3_bits(data);
}
else if ((lom >= 16) && (lom <= 31))
{
/* insert binary header */
data = 0x0e;
insert_4_bits(data);
/* insert lower 4 bits of LoM */
data = (char) (lom - 16);
insert_4_bits(data);
}
else if ((lom >= 32) && (lom <= 63))
{
/* insert binary header */
data = 0x1e;
insert_5_bits(data);
/* insert lower 5 bits of LoM */
data = (char) (lom - 32);
insert_5_bits(data);
}
else if ((lom >= 64) && (lom <= 127))
{
/* insert binary header */
data = 0x3e;
insert_6_bits(data);
/* insert lower 6 bits of LoM */
data = (char) (lom - 64);
insert_6_bits(data);
}
else if ((lom >= 128) && (lom <= 255))
{
/* insert binary header */
data = 0x7e;
insert_7_bits(data);
/* insert lower 7 bits of LoM */
data = (char) (lom - 128);
insert_7_bits(data);
}
else if ((lom >= 256) && (lom <= 511))
{
/* insert binary header */
data = 0xfe;
insert_8_bits(data);
/* insert lower 8 bits of LoM */
data = (char) (lom - 256);
insert_8_bits(data);
}
else if ((lom >= 512) && (lom <= 1023))
{
/* insert binary header */
data16 = 0x1fe;
insert_9_bits(data16);
/* insert lower 9 bits of LoM */
data16 = lom - 512;
insert_9_bits(data16);
}
else if ((lom >= 1024) && (lom <= 2047))
{
/* insert binary header */
data16 = 0x3fe;
insert_10_bits(data16);
/* insert 10 lower bits of LoM */
data16 = lom - 1024;
insert_10_bits(data16);
}
else if ((lom >= 2048) && (lom <= 4095))
{
/* insert binary header */
data16 = 0x7fe;
insert_11_bits(data16);
/* insert 11 lower bits of LoM */
data16 = lom - 2048;
insert_11_bits(data16);
}
else if ((lom >= 4096) && (lom <= 8191))
{
/* insert binary header */
data16 = 0xffe;
insert_12_bits(data16);
/* insert 12 lower bits of LoM */
data16 = lom - 4096;
insert_12_bits(data16);
}
else if ((lom >= 8192) && (lom <= 16383))
{
/* insert binary header */
data16 = 0x1ffe;
insert_13_bits(data16);
/* insert 13 lower bits of LoM */
data16 = lom - 8192;
insert_13_bits(data16);
}
else if ((lom >= 16384) && (lom <= 32767))
{
/* insert binary header */
data16 = 0x3ffe;
insert_14_bits(data16);
/* insert 14 lower bits of LoM */
data16 = lom - 16384;
insert_14_bits(data16);
}
else if ((lom >= 32768) && (lom <= 65535))
{
/* insert binary header */
data16 = 0x7ffe;
insert_15_bits(data16);
/* insert 15 lower bits of LoM */
data16 = lom - 32768;
insert_15_bits(data16);
}
} /* end while (ctr < data_end) */
/* add remaining data to the output */
while (len - ctr > 0)
{
data = srcData[ctr];
DLOG(("%.2x ", (unsigned char) data));
if (data < 0x80)
{
/* literal byte < 0x80 */
insert_8_bits(data);
}
else
{
/* literal byte >= 0x80 */
insert_2_bits(0x02);
data &= 0x7f;
insert_7_bits(data);
}
ctr++;
}
/* if bits_left == 8, opb_index has already been incremented */
if ((bits_left == 8) && (opb_index > len))
{
/* compressed data longer than uncompressed data */
/* give up */
enc->historyOffset = 0;
memset(hash_table, 0, enc->buf_len * 2);
enc->flagsHold |= PACKET_FLUSHED;
enc->first_pkt = 1;
return true;
}
else if (opb_index + 1 > len)
{
/* compressed data longer than uncompressed data */
/* give up */
enc->historyOffset = 0;
memset(hash_table, 0, enc->buf_len * 2);
enc->flagsHold |= PACKET_FLUSHED;
enc->first_pkt = 1;
return true;
}
/* if bits_left != 8, increment opb_index, which is zero indexed */
if (bits_left != 8)
@@ -871,7 +994,10 @@ boolean compress_rdp_5(struct rdp_mppc_enc* enc, uint8* srcData, int len)
if (opb_index > len)
{
/* give up */
enc->historyOffset = historyOffset;
enc->historyOffset = 0;
memset(hash_table, 0, enc->buf_len * 2);
enc->flagsHold |= PACKET_FLUSHED;
enc->first_pkt = 1;
return true;
}
enc->flags |= PACKET_COMPRESSED;
@@ -881,5 +1007,5 @@ boolean compress_rdp_5(struct rdp_mppc_enc* enc, uint8* srcData, int len)
enc->flagsHold = 0;
DLOG(("\n"));
return true;
return true;
}

1
libfreerdp-core/mppc_enc.h
View File

@@ -39,6 +39,7 @@ struct rdp_mppc_enc
int flags; /* PACKET_COMPRESSED, PACKET_AT_FRONT, PACKET_FLUSHED etc */
int flagsHold;
int first_pkt; /* this is the first pkt passing through enc */
uint16* hash_table;
};
boolean compress_rdp(struct rdp_mppc_enc* enc, uint8* srcData, int len);