Autoconf'd test for int64

Attached is a patch that uses autoconf to determine whether there is
a working 64-bit-int type available.

In playing around with it on my machine, I found that gcc provides
perfectly fine support for "long long" arithmetic ... but sprintf()
and sscanf(), which are system-supplied, don't work :-(. So the
autoconf test program does a cursory test on them too.

If we find that a lot of systems are like this, it might be worth
the trouble to implement binary<->ASCII conversion of int64 ourselves
rather than relying on sprintf/sscanf to handle the data type.

regards, tom lane

*** src/configure.in.orig Sat Aug 15 11:52:03 1998
--- src/configure.in Sun Aug 16 16:41:24 1998
***************
*** 522,528 ****
#endif
main() { double d = DBL_MIN; if (d != DBL_MIN) exit(-1); else exit(0); }],
AC_MSG_RESULT(yes),
! [AC_MSG_RESULT(no) AC_DEFINE(HAVE_DBL_MIN_PROBLEM)])

dnl Checks for library functions.
AC_PROG_GCC_TRADITIONAL
--- 522,604 ----
#endif
main() { double d = DBL_MIN; if (d != DBL_MIN) exit(-1); else exit(0); }],
AC_MSG_RESULT(yes),
! [AC_MSG_RESULT(no) AC_DEFINE(HAVE_DBL_MIN_PROBLEM)],
! AC_MSG_RESULT(assuming ok on target machine))
!
! dnl Check to see if we have a working 64-bit integer type.
! AC_MSG_CHECKING(whether 'long int' is 64 bits)
! AC_TRY_RUN([#include <stdio.h>
! typedef long int int64;
! #define INT64_FORMAT "%ld"
!
! int64 a = 20000001;
! int64 b = 40000005;
!
! int does_int64_work()
! {
! int64 c,d,e;
! char buf[100];
!
! if (sizeof(int64) != 8)
! return 0; /* doesn't look like the right size */
!
! /* we do perfunctory checks on multiply, divide, sprintf, sscanf */
! c = a * b;
! sprintf(buf, INT64_FORMAT, c);
! if (strcmp(buf, "800000140000005") != 0)
! return 0; /* either multiply or sprintf is busted */
! if (sscanf(buf, INT64_FORMAT, &d) != 1)
! return 0;
! if (d != c)
! return 0;
! e = d / b;
! if (e != a)
! return 0;
! return 1;
! }
! main() {
! exit(! does_int64_work());
! }],
! [AC_MSG_RESULT(yes) AC_DEFINE(HAVE_LONG_INT_64)],
! AC_MSG_RESULT(no),
! AC_MSG_RESULT(assuming not on target machine))
!
! AC_MSG_CHECKING(whether 'long long int' is 64 bits)
! AC_TRY_RUN([#include <stdio.h>
! typedef long long int int64;
! #define INT64_FORMAT "%Ld"
!
! int64 a = 20000001;
! int64 b = 40000005;
!
! int does_int64_work()
! {
! int64 c,d,e;
! char buf[100];
!
! if (sizeof(int64) != 8)
! return 0; /* doesn't look like the right size */
!
! /* we do perfunctory checks on multiply, divide, sprintf, sscanf */
! c = a * b;
! sprintf(buf, INT64_FORMAT, c);
! if (strcmp(buf, "800000140000005") != 0)
! return 0; /* either multiply or sprintf is busted */
! if (sscanf(buf, INT64_FORMAT, &d) != 1)
! return 0;
! if (d != c)
! return 0;
! e = d / b;
! if (e != a)
! return 0;
! return 1;
! }
! main() {
! exit(! does_int64_work());
! }],
! [AC_MSG_RESULT(yes) AC_DEFINE(HAVE_LONG_LONG_INT_64)],
! AC_MSG_RESULT(no),
! AC_MSG_RESULT(assuming not on target machine))

dnl Checks for library functions.
AC_PROG_GCC_TRADITIONAL
*** src/include/config.h.in.orig Sat Aug 15 11:54:54 1998
--- src/include/config.h.in Sun Aug 16 16:33:22 1998
***************
*** 219,224 ****
--- 219,230 ----
/* Set to 1 if your DBL_MIN is problematic */
#undef HAVE_DBL_MIN_PROBLEM

+ /* Set to 1 if type "long int" works and is 64 bits */
+ #undef HAVE_LONG_INT_64
+
+ /* Set to 1 if type "long long int" works and is 64 bits */
+ #undef HAVE_LONG_LONG_INT_64
+
/*
* Code below this point should not require changes
*/
*** src/include/utils/int8.h.orig Wed Jul 8 10:10:30 1998
--- src/include/utils/int8.h Sun Aug 16 16:37:51 1998
***************
*** 23,51 ****
#ifndef INT8_H
#define INT8_H

! #if defined(__alpha) || defined(PPC)
typedef long int int64;
-
#define INT64_FORMAT "%ld"
!
! #elif defined(__GNUC__) && defined(i386)
typedef long long int int64;
-
#define INT64_FORMAT "%Ld"
-
#else
typedef long int int64;
-
#define INT64_FORMAT "%ld"
#endif
-
-
- /*
- #if sizeof(int64) == 8
- #define HAVE_64BIT_INTS 1
#endif
- */
-

extern int64 *int8in(char *str);
extern char *int8out(int64 * val);
--- 23,44 ----
#ifndef INT8_H
#define INT8_H

! #ifdef HAVE_LONG_INT_64
! /* Plain "long int" fits, use it */
typedef long int int64;
#define INT64_FORMAT "%ld"
! #else
! #ifdef HAVE_LONG_LONG_INT_64
! /* We have working support for "long long int", use that */
typedef long long int int64;
#define INT64_FORMAT "%Ld"
#else
+ /* Won't actually work, but fall back to long int so that int8.c compiles */
typedef long int int64;
#define INT64_FORMAT "%ld"
+ #define INT64_IS_BUSTED
#endif
#endif

extern int64 *int8in(char *str);
extern char *int8out(int64 * val);