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Have pg_itoa, pg_ltoa and pg_lltoa return the length of the string

author David Rowley <drowley@postgresql.org>

2020年6月13日 00:32:00 +0000 (12:32 +1200)

committer David Rowley <drowley@postgresql.org>

2020年6月13日 00:32:00 +0000 (12:32 +1200)

Core by no means makes excessive use of these functions, but quite a large
number of those usages do require the caller to call strlen() on the
returned string. This is quite wasteful since these functions do already
have a good idea of the length of the string, so we might as well just
have them return that.

Reviewed-by: Andrew Gierth
Discussion: https://postgr.es/m/CAApHDvrm2A5x2uHYxsqriO2cUaGcFvND%2BksC9e7Tjep0t2RK_A%40mail.gmail.com

src/backend/access/common/printsimple.c patch | blob | blame | history

src/backend/utils/adt/int.c patch | blob | blame | history

src/backend/utils/adt/int8.c patch | blob | blame | history

src/backend/utils/adt/numutils.c patch | blob | blame | history

src/include/utils/builtins.h patch | blob | blame | history

diff --git a/src/backend/access/common/printsimple.c b/src/backend/access/common/printsimple.c

index 0f0b54bdae37d36a311e337a16dc88ca46211f1d..df27700df92a29e9eea975d46b52483c5f1eed9e 100644 (file)

--- a/src/backend/access/common/printsimple.c

+++ b/src/backend/access/common/printsimple.c

@@ -103,9 +103,10 @@ printsimple(TupleTableSlot *slot, DestReceiver *self)

{

int32 num = DatumGetInt32(value);

char str[12]; /* sign, 10 digits and '0円' */

+ int len;

- pg_ltoa(num, str);

- pq_sendcountedtext(&buf, str, strlen(str), false);

+ len = pg_ltoa(num, str);

+ pq_sendcountedtext(&buf, str, len, false);

}

break;

@@ -113,9 +114,10 @@ printsimple(TupleTableSlot *slot, DestReceiver *self)

{

int64 num = DatumGetInt64(value);

char str[MAXINT8LEN + 1];

+ int len;

- pg_lltoa(num, str);

- pq_sendcountedtext(&buf, str, strlen(str), false);

+ len = pg_lltoa(num, str);

+ pq_sendcountedtext(&buf, str, len, false);

}

break;

diff --git a/src/backend/utils/adt/int.c b/src/backend/utils/adt/int.c

index 63c59c56b3f9e759355e5223eb04b487bc645353..418c13e1b4cdc0beb7164a1e407f06db52f2770f 100644 (file)

--- a/src/backend/utils/adt/int.c

+++ b/src/backend/utils/adt/int.c

@@ -191,9 +191,7 @@ int2vectorout(PG_FUNCTION_ARGS)

{

if (num != 0)

*rp++ = ' ';

- pg_itoa(int2Array->values[num], rp);

- while (*++rp != '0円')

- ;

+ rp += pg_itoa(int2Array->values[num], rp);

}

*rp = '0円';

PG_RETURN_CSTRING(result);

diff --git a/src/backend/utils/adt/int8.c b/src/backend/utils/adt/int8.c

index abba8f1df04f5df50c1a5d08c71956f969cfed82..005f68d85391f4a7299307163be7da2bd5874cfe 100644 (file)

--- a/src/backend/utils/adt/int8.c

+++ b/src/backend/utils/adt/int8.c

@@ -149,9 +149,16 @@ int8out(PG_FUNCTION_ARGS)

int64 val = PG_GETARG_INT64(0);

char buf[MAXINT8LEN + 1];

char *result;

+ int len;

- pg_lltoa(val, buf);

- result = pstrdup(buf);

+ len = pg_lltoa(val, buf) + 1;

+ /*

+ * Since the length is already known, we do a manual palloc() and memcpy()

+ * to avoid the strlen() call that would otherwise be done in pstrdup().

+ */

+ result = palloc(len);

+ memcpy(result, buf, len);

PG_RETURN_CSTRING(result);

}

diff --git a/src/backend/utils/adt/numutils.c b/src/backend/utils/adt/numutils.c

index a9d3fbf758f8e1a15428baeedd24f3a59ca848e1..412ae361d2c0f665c6e835be70fa7b2f90e0a981 100644 (file)

--- a/src/backend/utils/adt/numutils.c

+++ b/src/backend/utils/adt/numutils.c

@@ -327,16 +327,17 @@ invalid_syntax:

* pg_itoa: converts a signed 16-bit integer to its string representation

+ * and returns strlen(a).

* Caller must ensure that 'a' points to enough memory to hold the result

* (at least 7 bytes, counting a leading sign and trailing NUL).

* It doesn't seem worth implementing this separately.

-void

+int

pg_itoa(int16 i, char *a)

{

- pg_ltoa((int32) i, a);

+ return pg_ltoa((int32) i, a);

}

@@ -404,25 +405,27 @@ pg_ultoa_n(uint32 value, char *a)

}

- * NUL-terminate the output of pg_ultoa_n.

+ * pg_ltoa: converts a signed 32-bit integer to its string representation and

+ * returns strlen(a).

* It is the caller's responsibility to ensure that a is at least 12 bytes long,

* which is enough room to hold a minus sign, a maximally long int32, and the

* above terminating NUL.

-void

+int

pg_ltoa(int32 value, char *a)

{

uint32 uvalue = (uint32) value;

- int len;

+ int len = 0;

if (value < 0)

{

uvalue = (uint32) 0 - uvalue;

- *a++ = '-';

+ a[len++] = '-';

}

- len = pg_ultoa_n(uvalue, a);

+ len += pg_ultoa_n(uvalue, a + len);

a[len] = '0円';

+ return len;

}

@@ -510,24 +513,27 @@ pg_ulltoa_n(uint64 value, char *a)

}

- * pg_lltoa: convert a signed 64-bit integer to its string representation

+ * pg_lltoa: converts a signed 64-bit integer to its string representation and

+ * returns strlen(a).

* Caller must ensure that 'a' points to enough memory to hold the result

* (at least MAXINT8LEN + 1 bytes, counting a leading sign and trailing NUL).

-void

+int

pg_lltoa(int64 value, char *a)

{

- int len;

uint64 uvalue = value;

+ int len = 0;

if (value < 0)

{

- *a++ = '-';

uvalue = (uint64) 0 - uvalue;

+ a[len++] = '-';

}

- len = pg_ulltoa_n(uvalue, a);

- a[len] = 0;

+ len += pg_ulltoa_n(uvalue, a + len);

+ a[len] = '0円';

+ return len;

}

diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h

index a5c8772e95fa2e237378d0b3f0fbd6fc8c8a227a..f8595642da9b7d8f5277ef63f8db62e97f397563 100644 (file)

--- a/src/include/utils/builtins.h

+++ b/src/include/utils/builtins.h

@@ -47,11 +47,11 @@ extern int namestrcmp(Name name, const char *str);

extern int32 pg_atoi(const char *s, int size, int c);

extern int16 pg_strtoint16(const char *s);

extern int32 pg_strtoint32(const char *s);

-extern void pg_itoa(int16 i, char *a);

+extern int pg_itoa(int16 i, char *a);

extern int pg_ultoa_n(uint32 l, char *a);

extern int pg_ulltoa_n(uint64 l, char *a);

-extern void pg_ltoa(int32 l, char *a);

-extern void pg_lltoa(int64 ll, char *a);

+extern int pg_ltoa(int32 l, char *a);

+extern int pg_lltoa(int64 ll, char *a);

extern char *pg_ultostr_zeropad(char *str, uint32 value, int32 minwidth);

extern char *pg_ultostr(char *str, uint32 value);

extern uint64 pg_strtouint64(const char *str, char **endptr, int base);

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