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Fix bogus calculation of potential output string length in translate().

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This commit is contained in:
Tom Lane 2007-09-22 05:35:52 +00:00
parent d5e6f4f828
commit a9f08b41ac
1 changed files with 20 additions and 13 deletions
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33
src/backend/utils/adt/oracle_compat.c
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@ -9,7 +9,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/oracle_compat.c,v 1.67.2.1 2007/02/08 20:33:54 momjian Exp $ * $PostgreSQL: pgsql/src/backend/utils/adt/oracle_compat.c,v 1.67.2.2 2007/09/22 05:35:52 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -1153,27 +1153,34 @@ translate(PG_FUNCTION_ARGS)
tolen, tolen,
retlen, retlen,
i; i;
int worst_len;
int str_len;
int estimate_len;
int len; int len;
int source_len; int source_len;
int from_index; int from_index;
if ((m = VARSIZE(string) - VARHDRSZ) <= 0) m = VARSIZE(string) - VARHDRSZ;
if (m <= 0)
PG_RETURN_TEXT_P(string); PG_RETURN_TEXT_P(string);
source = VARDATA(string);
fromlen = VARSIZE(from) - VARHDRSZ; fromlen = VARSIZE(from) - VARHDRSZ;
from_ptr = VARDATA(from); from_ptr = VARDATA(from);
tolen = VARSIZE(to) - VARHDRSZ; tolen = VARSIZE(to) - VARHDRSZ;
to_ptr = VARDATA(to); to_ptr = VARDATA(to);
str_len = VARSIZE(string); /*
estimate_len = (tolen * 1.0 / fromlen + 0.5) * str_len; * The worst-case expansion is to substitute a max-length character for
estimate_len = estimate_len > str_len ? estimate_len : str_len; * a single-byte character at each position of the string.
result = (text *) palloc(estimate_len); */
worst_len = pg_database_encoding_max_length() * m;
source = VARDATA(string); /* check for integer overflow */
if (worst_len / pg_database_encoding_max_length() != m)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("requested length too large")));
result = (text *) palloc(worst_len + VARHDRSZ);
target = VARDATA(result); target = VARDATA(result);
retlen = 0; retlen = 0;
@ -1226,9 +1233,9 @@ translate(PG_FUNCTION_ARGS)
VARATT_SIZEP(result) = retlen + VARHDRSZ; VARATT_SIZEP(result) = retlen + VARHDRSZ;
/* /*
* There may be some wasted space in the result if deletions occurred, but * The function result is probably much bigger than needed, if we're
* it's not worth reallocating it; the function result probably won't live * using a multibyte encoding, but it's not worth reallocating it;
* long anyway. * the result probably won't live long anyway.
*/ */
PG_RETURN_TEXT_P(result); PG_RETURN_TEXT_P(result);