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Commit211ed36

Browse files
Jan WieckJan Wieck
Jan Wieck
authored and
Jan Wieck
committed
Some minor corrections to the LZ compression. In fact I wanted to
HAVE the required OID's first.Jan
1 parent79c3b71 commit211ed36

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3 files changed

+49
-13
lines changed

3 files changed

+49
-13
lines changed

‎src/backend/utils/adt/lztext.c‎

Lines changed: 15 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -1,10 +1,13 @@
11
/* ----------
22
* lztext.c -
33
*
4-
* $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/lztext.c,v 1.1 1999/11/1721:21:50 wieck Exp $
4+
* $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/lztext.c,v 1.2 1999/11/1722:18:45 wieck Exp $
55
*
66
*Text type with internal LZ compressed representation. Uses the
77
*standard PostgreSQL compression method.
8+
*
9+
*This code requires that the LZ compressor found in pg_lzcompress
10+
*codes a usable VARSIZE word at the beginning of the output buffer.
811
* ----------
912
*/
1013

@@ -42,7 +45,7 @@ lztextin(char *str)
4245
returnNULL;
4346

4447
/* ----------
45-
* Determine input size andeventually tuple size
48+
* Determine input size andmaximum output Datum size
4649
* ----------
4750
*/
4851
rawsize=strlen(str);
@@ -56,8 +59,9 @@ lztextin(char *str)
5659
pglz_compress(str,rawsize,tmp,NULL);
5760

5861
/* ----------
59-
* If we miss less than x% bytes at the end of the temp value,
60-
* so be it. Therefore we save a memcpy().
62+
* If we miss less than 25% bytes at the end of the temp value,
63+
* so be it. Therefore we save a palloc()/memcpy()/pfree()
64+
* sequence.
6165
* ----------
6266
*/
6367
if (tmp_size-tmp->varsize<256||
@@ -141,7 +145,7 @@ lztextlen(lztext *lz)
141145
* without multibyte support, it's the remembered rawsize
142146
* ----------
143147
*/
144-
returnlz->rawsize;
148+
returnPGLZ_RAW_SIZE(lz);
145149
}
146150

147151

@@ -166,7 +170,7 @@ lztextoctetlen(lztext *lz)
166170
* Return the varsize minus the VARSIZE field itself.
167171
* ----------
168172
*/
169-
returnlz->varsize-sizeof(int32);
173+
returnVARSIZE(lz)-VARHDRSZ;
170174
}
171175

172176

@@ -208,8 +212,9 @@ text_lztext(text *txt)
208212
pglz_compress(str,rawsize,tmp,NULL);
209213

210214
/* ----------
211-
* If we miss less than x% bytes at the end of the temp value,
212-
* so be it. Therefore we save a memcpy().
215+
* If we miss less than 25% bytes at the end of the temp value,
216+
* so be it. Therefore we save a palloc()/memcpy()/pfree()
217+
* sequence.
213218
* ----------
214219
*/
215220
if (tmp_size-tmp->varsize<256||
@@ -250,15 +255,15 @@ lztext_text(lztext *lz)
250255
* Allocate and initialize the text result
251256
* ----------
252257
*/
253-
result= (text*)palloc(lz->rawsize+VARHDRSZ+1);
258+
result= (text*)palloc(PGLZ_RAW_SIZE(lz)+VARHDRSZ+1);
254259
VARSIZE(result)=lz->rawsize+VARHDRSZ;
255260

256261
/* ----------
257262
* Decompress directly into the text data area.
258263
* ----------
259264
*/
260-
pglz_decompress(lz,VARDATA(result));
261265
VARDATA(result)[lz->rawsize]=0;
266+
pglz_decompress(lz,VARDATA(result));
262267

263268
returnresult;
264269
}

‎src/backend/utils/adt/pg_lzcompress.c‎

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
11
/* ----------
22
* pg_lzcompress.c -
33
*
4-
* $Header: /cvsroot/pgsql/src/backend/utils/adt/pg_lzcompress.c,v 1.1 1999/11/1721:21:50 wieck Exp $
4+
* $Header: /cvsroot/pgsql/src/backend/utils/adt/pg_lzcompress.c,v 1.2 1999/11/1722:18:45 wieck Exp $
55
*
66
*This is an implementation of LZ compression for PostgreSQL.
77
*It uses a simple history table and generates 2-3 byte tags
@@ -385,6 +385,8 @@ pglz_find_match (PGLZ_HistEntry **hstart, char *input, char *end,
385385

386386
/* ----------
387387
* pglz_compress -
388+
*
389+
*Compresses source into dest using strategy.
388390
* ----------
389391
*/
390392
int
@@ -580,6 +582,8 @@ pglz_compress (char *source, int slen, PGLZ_Header *dest, PGLZ_Strategy *strateg
580582

581583
/* ----------
582584
* pglz_decompress -
585+
*
586+
*Decompresses source into dest.
583587
* ----------
584588
*/
585589
int

‎src/include/utils/pg_lzcompress.h‎

Lines changed: 29 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
11
/* ----------
22
* pg_lzcompress.h -
33
*
4-
* $Header: /cvsroot/pgsql/src/include/utils/pg_lzcompress.h,v 1.1 1999/11/1721:21:51 wieck Exp $
4+
* $Header: /cvsroot/pgsql/src/include/utils/pg_lzcompress.h,v 1.2 1999/11/1722:18:46 wieck Exp $
55
*
66
*Definitions for the builtin LZ compressor
77
* ----------
@@ -37,9 +37,36 @@ typedef struct PGLZ_Header {
3737
*/
3838
#definePGLZ_MAX_OUTPUT(_dlen)((_dlen) + (((_dlen) | 0x07) >> 3)\
3939
+ sizeof(PGLZ_Header))
40+
41+
/* ----------
42+
* PGLZ_RAW_SIZE -
43+
*
44+
*Macro to determine the uncompressed data size contained
45+
*in the entry.
46+
* ----------
47+
*/
4048
#definePGLZ_RAW_SIZE(_lzdata)(_lzdata->rawsize)
49+
50+
/* ----------
51+
* PGLZ_IS_COMPRESSED -
52+
*
53+
*Macro to determine if the data itself is stored as raw
54+
*uncompressed data.
55+
* ----------
56+
*/
4157
#definePGLZ_IS_COMPRESSED(_lzdata)(_lzdata->varsize != \
42-
_lzdata->rawsize + sizeof(PGLZ_Header))
58+
_lzdata->rawsize + \
59+
sizeof(PGLZ_Header))
60+
61+
/* ----------
62+
* PGLZ_RAW_DATA -
63+
*
64+
*Macro to get access to the plain compressed or uncompressed
65+
*data. Useful if PGLZ_IS_COMPRESSED returns false.
66+
* ----------
67+
*/
68+
#definePGLZ_RAW_DATA(_lzdata)(((char *)(_lzdata)) + \
69+
sizeof(PGLZ_Header))
4370

4471
/* ----------
4572
* PGLZ_Strategy -

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