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Replace static bufs with a StringInfo in cash_words()

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For clarity. The code was correct, and the buffer was large enough,
but string manipulation with no bounds checking is scary.

This incurs an extra palloc+pfree to every call, but in quick
performance testing, it doesn't seem to be significant.

Reviewed-by: Robert Haas
Discussion: https://www.postgresql.org/message-id/7f86e06a-98c5-4ce3-8ec9-3885c8de0358@iki.fi
This commit is contained in:
Heikki Linnakangas 2024-07-30 22:02:58 +03:00
parent 47c98035c6
commit 5bf948d564
1 changed files with 44 additions and 41 deletions
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85
src/backend/utils/adt/cash.c
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@ -35,10 +35,9 @@
* Private routines
************************************************************************/
static const char *
num_word(Cash value)
static void
append_num_word(StringInfo buf, Cash value)
{
static char buf[128];
static const char *const small[] = {
"zero", "one", "two", "three", "four", "five", "six", "seven",
"eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen",
@ -50,13 +49,16 @@ num_word(Cash value)
/* deal with the simple cases first */
if (value <= 20)
return small[value];
{
appendStringInfoString(buf, small[value]);
return;
}
/* is it an even multiple of 100? */
if (!tu)
{
sprintf(buf, "%s hundred", small[value / 100]);
return buf;
appendStringInfo(buf, "%s hundred", small[value / 100]);
return;
}
/* more than 99? */
@ -64,27 +66,25 @@ num_word(Cash value)
{
/* is it an even multiple of 10 other than 10? */
if (value % 10 == 0 && tu > 10)
sprintf(buf, "%s hundred %s",
small[value / 100], big[tu / 10]);
appendStringInfo(buf, "%s hundred %s",
small[value / 100], big[tu / 10]);
else if (tu < 20)
sprintf(buf, "%s hundred and %s",
small[value / 100], small[tu]);
appendStringInfo(buf, "%s hundred and %s",
small[value / 100], small[tu]);
else
sprintf(buf, "%s hundred %s %s",
small[value / 100], big[tu / 10], small[tu % 10]);
appendStringInfo(buf, "%s hundred %s %s",
small[value / 100], big[tu / 10], small[tu % 10]);
}
else
{
/* is it an even multiple of 10 other than 10? */
if (value % 10 == 0 && tu > 10)
sprintf(buf, "%s", big[tu / 10]);
appendStringInfoString(buf, big[tu / 10]);
else if (tu < 20)
sprintf(buf, "%s", small[tu]);
appendStringInfoString(buf, small[tu]);
else
sprintf(buf, "%s %s", big[tu / 10], small[tu % 10]);
appendStringInfo(buf, "%s %s", big[tu / 10], small[tu % 10]);
}
return buf;
} /* num_word() */
static inline Cash
@ -960,8 +960,9 @@ cash_words(PG_FUNCTION_ARGS)
{
Cash value = PG_GETARG_CASH(0);
uint64 val;
char buf[256];
char *p = buf;
StringInfoData buf;
text *res;
Cash dollars;
Cash m0;
Cash m1;
Cash m2;
@ -970,19 +971,19 @@ cash_words(PG_FUNCTION_ARGS)
Cash m5;
Cash m6;
initStringInfo(&buf);
/* work with positive numbers */
if (value < 0)
{
value = -value;
strcpy(buf, "minus ");
p += 6;
appendStringInfoString(&buf, "minus ");
}
else
buf[0] = '\0';
/* Now treat as unsigned, to avoid trouble at INT_MIN */
val = (uint64) value;
dollars = val / INT64CONST(100);
m0 = val % INT64CONST(100); /* cents */
m1 = (val / INT64CONST(100)) % 1000; /* hundreds */
m2 = (val / INT64CONST(100000)) % 1000; /* thousands */
@ -993,49 +994,51 @@ cash_words(PG_FUNCTION_ARGS)
if (m6)
{
strcat(buf, num_word(m6));
strcat(buf, " quadrillion ");
append_num_word(&buf, m6);
appendStringInfoString(&buf, " quadrillion ");
}
if (m5)
{
strcat(buf, num_word(m5));
strcat(buf, " trillion ");
append_num_word(&buf, m5);
appendStringInfoString(&buf, " trillion ");
}
if (m4)
{
strcat(buf, num_word(m4));
strcat(buf, " billion ");
append_num_word(&buf, m4);
appendStringInfoString(&buf, " billion ");
}
if (m3)
{
strcat(buf, num_word(m3));
strcat(buf, " million ");
append_num_word(&buf, m3);
appendStringInfoString(&buf, " million ");
}
if (m2)
{
strcat(buf, num_word(m2));
strcat(buf, " thousand ");
append_num_word(&buf, m2);
appendStringInfoString(&buf, " thousand ");
}
if (m1)
strcat(buf, num_word(m1));
append_num_word(&buf, m1);
if (!*p)
strcat(buf, "zero");
if (dollars == 0)
appendStringInfoString(&buf, "zero");
strcat(buf, (val / 100) == 1 ? " dollar and " : " dollars and ");
strcat(buf, num_word(m0));
strcat(buf, m0 == 1 ? " cent" : " cents");
appendStringInfoString(&buf, dollars == 1 ? " dollar and " : " dollars and ");
append_num_word(&buf, m0);
appendStringInfoString(&buf, m0 == 1 ? " cent" : " cents");
/* capitalize output */
buf[0] = pg_toupper((unsigned char) buf[0]);
buf.data[0] = pg_toupper((unsigned char) buf.data[0]);
/* return as text datum */
PG_RETURN_TEXT_P(cstring_to_text(buf));
res = cstring_to_text_with_len(buf.data, buf.len);
pfree(buf.data);
PG_RETURN_TEXT_P(res);
}