Fix for bugs #68114 (Build fails on OS X due to undefined symbols)

and #68657 (Reading 4 byte floats with Mysqli and libmysqlclient
has rounding errors).

The patch removes support for Decimal floating point numbers and
now defaults to using similar logic as what libmysqlclient does:
convert a 4 byte floating point number into a string, and then the
string into a double. The quirks of MySQL are maintained as seen in
Field_Float::val_str()

Author: keyurdg

ext/mysqli/mysqli_api.c

@@ -33,6 +33,7 @@
 #include "ext/standard/php_smart_str.h"
 #include "php_mysqli_structs.h"
 #include "mysqli_priv.h"
+#include "ext/standard/float_to_double.h"
 
 
 #if !defined(MYSQLI_USE_MYSQLND)
@@ -413,8 +414,18 @@ mysqli_stmt_bind_result_do_bind(MY_STMT *stmt, zval ***args, unsigned int argc,
 		col_type = (stmt->stmt->fields) ? stmt->stmt->fields[ofs].type : MYSQL_TYPE_STRING;
 
 		switch (col_type) {
-			case MYSQL_TYPE_DOUBLE:
 			case MYSQL_TYPE_FLOAT:
+				convert_to_double_ex(args[i]);
+				stmt->result.buf[ofs].type = IS_DOUBLE;
+				stmt->result.buf[ofs].buflen = sizeof(float);
+
+				stmt->result.buf[ofs].val = (char *)emalloc(sizeof(float));
+				bind[ofs].buffer_type = MYSQL_TYPE_FLOAT;
+				bind[ofs].buffer = stmt->result.buf[ofs].val;
+				bind[ofs].is_null = &stmt->result.is_null[ofs];
+				break;
+
+			case MYSQL_TYPE_DOUBLE:
 				convert_to_double_ex(args[i]);
 				stmt->result.buf[ofs].type = IS_DOUBLE;
 				stmt->result.buf[ofs].buflen = sizeof(double);
@@ -1045,8 +1056,22 @@ void mysqli_stmt_fetch_libmysql(INTERNAL_FUNCTION_PARAMETERS)
 						}
 						break;
 					case IS_DOUBLE:
-						ZVAL_DOUBLE(stmt->result.vars[i], *(double *)stmt->result.buf[i].val);
+					{
+						double dval;
+						if (stmt->stmt->bind[i].buffer_type == MYSQL_TYPE_FLOAT) {
+#ifndef NOT_FIXED_DEC
+# define NOT_FIXED_DEC 31
+#endif
+							dval = float_to_double(*(float *)stmt->result.buf[i].val,
+										(stmt->stmt->fields[i].decimals >= NOT_FIXED_DEC) ? -1 :
+										stmt->stmt->fields[i].decimals);
+						} else {
+							dval = *((double *)stmt->result.buf[i].val);
+						}
+
+						ZVAL_DOUBLE(stmt->result.vars[i], dval);
 						break;
+					}
 					case IS_STRING:
 						if (stmt->stmt->bind[i].buffer_type == MYSQL_TYPE_LONGLONG
 #if MYSQL_VERSION_ID > 50002

ext/mysqli/tests/010.phpt

@@ -62,18 +62,18 @@ mysqli_close($link);
 --EXPECT--
 array(7) {
   [0]=>
-  float(3.141593)
+  float(3.14159)
   [1]=>
   float(-1.0E-6)
   [2]=>
   float(0)
   [3]=>
   float(1.0E+12)
   [4]=>
-  float(0.5646425)
+  float(0.564642)
   [5]=>
   float(1)
   [6]=>
-  float(8.888889E+14)
+  float(8.88889E+14)
 }
 done!

ext/mysqli/tests/bug67839.phpt

@@ -36,19 +36,27 @@ mysqli_float_handling - ensure 4 byte float is handled correctly
 		die();
 	}
 
-	if (!mysqli_stmt_execute($stmt)) {
+	$id = null;
+	$fp4 = null;
+	$fp8 = null;
+
+	if (!mysqli_stmt_bind_result($stmt, $id, $fp4, $fp8)) {
 		printf("[006] [%d] %s\n", mysqli_errno($link), mysqli_error($link));
 		die();
 	}
 
-
-	if (!($result = mysqli_stmt_get_result($stmt))) {
+	if (!mysqli_stmt_execute($stmt)) {
 		printf("[007] [%d] %s\n", mysqli_errno($link), mysqli_error($link));
 		die();
 	}
 
-	$data = mysqli_fetch_assoc($result);
-	print $data['id'] . ": " . $data['fp4'] . ": " . $data['fp8'] . "\n";
+
+	if (!(mysqli_stmt_fetch($stmt))) {
+		printf("[008] [%d] %s\n", mysqli_errno($link), mysqli_error($link));
+		die();
+	}
+
+	print $id . ": " . $fp4 . ": " . $fp8 . "\n";
 ?>
 --CLEAN--
 <?php

ext/mysqlnd/config9.m4

@@ -61,34 +61,3 @@ if test "$PHP_MYSQLND" != "no" || test "$PHP_MYSQLND_ENABLED" = "yes" || test "$
 #endif
   ])
 fi
-
-dnl
-dnl Check if the compiler supports Decimal32/64/128 types from the IEEE-754 2008 version
-dnl References: http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1657.pdf
-dnl http://speleotrove.com/decimal/
-dnl
-AC_CACHE_CHECK([whether whether compiler supports Decimal32/64/128 types], ac_cv_decimal_fp_supported,[
-AC_TRY_RUN( [
-#include <stdio.h>
-#include <string.h>
-
-int main(int argc, char **argv) {
-	typedef float dec32 __attribute__((mode(SD)));
-	dec32 k = 99.49f;
-	double d2 = (double)k;
-	const char *check_str = "99.49";
-	char print_str[32];
-
-	snprintf(print_str, 32, "%f", d2);
-	return memcmp(print_str, check_str, 5);
-}
-],[
-  ac_cv_decimal_fp_supported=yes
-],[
-  ac_cv_decimal_fp_supported=no
-],[
-  ac_cv_decimal_fp_supported=no
-])])
-if test "$ac_cv_decimal_fp_supported" = "yes"; then
-  AC_DEFINE(HAVE_DECIMAL_FP_SUPPORT, 1, [Define if the compiler supports Decimal32/64/128 types.])
-fi

ext/mysqlnd/mysqlnd_ps_codec.c

@@ -24,6 +24,7 @@
 #include "mysqlnd_wireprotocol.h"
 #include "mysqlnd_priv.h"
 #include "mysqlnd_debug.h"
+#include "ext/standard/float_to_double.h"
 
 #define MYSQLND_SILENT
 
@@ -181,56 +182,12 @@ ps_fetch_float(zval * zv, const MYSQLND_FIELD * const field, unsigned int pack_l
 	(*row)+= 4;
 	DBG_INF_FMT("value=%f", fval);
 
-	/*
-	 * The following is needed to correctly support 4-byte floats.
-	 * Otherwise, a value of 9.99 in a FLOAT column comes out of mysqli
-	 * as 9.9998998641968.
-	 *
-	 * For GCC, we use the built-in decimal support to "up-convert" a
-	 * 4-byte float to a 8-byte double.
-	 * When that is not available, we fall back to converting the float
-	 * to a string and then converting the string to a double. This mimics
-	 * what MySQL does.
-	 */
-#ifdef HAVE_DECIMAL_FP_SUPPORT
-	{
-		typedef float dec32 __attribute__((mode(SD)));
-		/* volatile so the compiler will not optimize away the conversion */
-		volatile dec32 d32val = fval;
-
-		/* The following cast is guaranteed to do the right thing */
-		dval = (double) d32val;
-	}
-#elif defined(PHP_WIN32)
-	{
-		/* float datatype on Winows is already 4 byte but has a precision of 7 digits */
-		char num_buf[2048];
-		(void)_gcvt_s(num_buf, 2048, fval, field->decimals >= 31 ? 7 : field->decimals);
-		dval = zend_strtod(num_buf, NULL);
-	}
-#else
-	{
-		char num_buf[2048]; /* Over allocated */
-		char *s;
-
-#ifndef FLT_DIG
-# define FLT_DIG 6
-#endif
-		/* Convert to string. Ignoring localization, etc.
-		 * Following MySQL's rules. If precision is undefined (NOT_FIXED_DEC i.e. 31)
-		 * or larger than 31, the value is limited to 6 (FLT_DIG).
-		 */
-		s = php_gcvt(fval,
-			     field->decimals >= 31 ? FLT_DIG : field->decimals,
-			     '.',
-			     'e',
-			     num_buf);
-
-		/* And now convert back to double */
-		dval = zend_strtod(s, NULL);
-	}
+#ifndef NOT_FIXED_DEC
+# define NOT_FIXED_DEC 31
 #endif
 
+	dval = float_to_double(fval, (field->decimals >= NOT_FIXED_DEC) ? -1 : field->decimals);
+
 	ZVAL_DOUBLE(zv, dval);
 	DBG_VOID_RETURN;
 }

ext/standard/config.m4

@@ -603,7 +603,8 @@ PHP_NEW_EXTENSION(standard, array.c base64.c basic_functions.c browscap.c crc32.
                             incomplete_class.c url_scanner_ex.c ftp_fopen_wrapper.c \
                             http_fopen_wrapper.c php_fopen_wrapper.c credits.c css.c \
                             var_unserializer.c ftok.c sha1.c user_filters.c uuencode.c \
-                            filters.c proc_open.c streamsfuncs.c http.c password.c)
+                            filters.c proc_open.c streamsfuncs.c http.c password.c \
+                            float_to_double.c)
 
 PHP_ADD_MAKEFILE_FRAGMENT
 PHP_INSTALL_HEADERS([ext/standard/])

ext/standard/config.w32

@@ -20,7 +20,7 @@ EXTENSION("standard", "array.c base64.c basic_functions.c browscap.c \
 	url_scanner_ex.c ftp_fopen_wrapper.c http_fopen_wrapper.c \
 	php_fopen_wrapper.c credits.c css.c var_unserializer.c ftok.c sha1.c \
 	user_filters.c uuencode.c filters.c proc_open.c password.c \
-	streamsfuncs.c http.c flock_compat.c", false /* never shared */);
+	streamsfuncs.c http.c flock_compat.c float_to_double.c", false /* never shared */);
 	PHP_INSTALL_HEADERS("", "ext/standard");
 if (PHP_MBREGEX != "no") {
 	CHECK_HEADER_ADD_INCLUDE("oniguruma.h", "CFLAGS_STANDARD", PHP_MBREGEX + ";ext\\mbstring\\oniguruma")   

ext/standard/float_to_double.c

@@ -0,0 +1,55 @@
+/*
+  +----------------------------------------------------------------------+
+  | PHP Version 5                                                        |
+  +----------------------------------------------------------------------+
+  | Copyright (c) 2006-2014 The PHP Group                                |
+  +----------------------------------------------------------------------+
+  | This source file is subject to version 3.01 of the PHP license,      |
+  | that is bundled with this package in the file LICENSE, and is        |
+  | available through the world-wide-web at the following url:           |
+  | http://www.php.net/license/3_01.txt                                  |
+  | If you did not receive a copy of the PHP license and are unable to   |
+  | obtain it through the world-wide-web, please send a note to          |
+  | license@php.net so we can mail you a copy immediately.               |
+  +----------------------------------------------------------------------+
+  | Authors: Keyur Govande <kgovande@gmail.com>                          |
+  +----------------------------------------------------------------------+
+*/
+
+#include <float.h>
+#include "float_to_double.h"
+#include "main/snprintf.h"
+
+#define MAX_BUF_LEN 255
+
+#ifndef FLT_DIG
+# define FLT_DIG 6
+#endif
+
+/*
+ * Convert from a 4-byte float to a 8-byte decimal by first converting
+ * the float to a string, and then the string to a double.
+ * The decimals argument specifies the precision of the output. If decimals
+ * is less than zero, then a gcvt(3) like logic is used with the significant
+ * digits set to FLT_DIG i.e. 6.
+ */
+double float_to_double(float fp4, int decimals) {
+	char num_buf[MAX_BUF_LEN]; /* Over allocated */
+
+	if (decimals < 0) {
+		php_gcvt(fp4, FLT_DIG, '.', 'e', num_buf);
+	} else {
+		php_sprintf(num_buf, "%.*f", decimals, fp4);
+	}
+
+	return zend_strtod(num_buf, NULL);
+}
+
+/*
+ * Local variables:
+ * tab-width: 4
+ * c-basic-offset: 4
+ * End:
+ * vim600: noet sw=4 ts=4 fdm=marker
+ * vim<600: noet sw=4 ts=4
+ */

ext/standard/float_to_double.h

@@ -0,0 +1,35 @@
+/*
+  +----------------------------------------------------------------------+
+  | PHP Version 5                                                        |
+  +----------------------------------------------------------------------+
+  | Copyright (c) 2006-2014 The PHP Group                                |
+  +----------------------------------------------------------------------+
+  | This source file is subject to version 3.01 of the PHP license,      |
+  | that is bundled with this package in the file LICENSE, and is        |
+  | available through the world-wide-web at the following url:           |
+  | http://www.php.net/license/3_01.txt                                  |
+  | If you did not receive a copy of the PHP license and are unable to   |
+  | obtain it through the world-wide-web, please send a note to          |
+  | license@php.net so we can mail you a copy immediately.               |
+  +----------------------------------------------------------------------+
+  | Authors: Keyur Govande <kgovande@gmail.com>                          |
+  +----------------------------------------------------------------------+
+*/
+
+#ifndef FLOAT_TO_DOUBLE_H
+#define FLOAT_TO_DOUBLE_H
+
+#include "main/php.h"
+
+PHPAPI double float_to_double(float fp4, int decimals);
+
+#endif /* FLOAT_TO_DOUBLE_H */
+
+/*
+ * Local variables:
+ * tab-width: 4
+ * c-basic-offset: 4
+ * End:
+ * vim600: noet sw=4 ts=4 fdm=marker
+ * vim<600: noet sw=4 ts=4
+ */