Index: third_party/sqlite/src/ext/misc/ieee754.c |
diff --git a/third_party/sqlite/src/ext/misc/ieee754.c b/third_party/sqlite/src/ext/misc/ieee754.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..f1438938857723b53d32b2ce14ce31c62310efd9 |
--- /dev/null |
+++ b/third_party/sqlite/src/ext/misc/ieee754.c |
@@ -0,0 +1,131 @@ |
+/* |
+** 2013-04-17 |
+** |
+** The author disclaims copyright to this source code. In place of |
+** a legal notice, here is a blessing: |
+** |
+** May you do good and not evil. |
+** May you find forgiveness for yourself and forgive others. |
+** May you share freely, never taking more than you give. |
+** |
+****************************************************************************** |
+** |
+** This SQLite extension implements functions for the exact display |
+** and input of IEEE754 Binary64 floating-point numbers. |
+** |
+** ieee754(X) |
+** ieee754(Y,Z) |
+** |
+** In the first form, the value X should be a floating-point number. |
+** The function will return a string of the form 'ieee754(Y,Z)' where |
+** Y and Z are integers such that X==Y*pow(2,Z). |
+** |
+** In the second form, Y and Z are integers which are the mantissa and |
+** base-2 exponent of a new floating point number. The function returns |
+** a floating-point value equal to Y*pow(2,Z). |
+** |
+** Examples: |
+** |
+** ieee754(2.0) -> 'ieee754(2,0)' |
+** ieee754(45.25) -> 'ieee754(181,-2)' |
+** ieee754(2, 0) -> 2.0 |
+** ieee754(181, -2) -> 45.25 |
+*/ |
+#include "sqlite3ext.h" |
+SQLITE_EXTENSION_INIT1 |
+#include <assert.h> |
+#include <string.h> |
+ |
+/* |
+** Implementation of the ieee754() function |
+*/ |
+static void ieee754func( |
+ sqlite3_context *context, |
+ int argc, |
+ sqlite3_value **argv |
+){ |
+ if( argc==1 ){ |
+ sqlite3_int64 m, a; |
+ double r; |
+ int e; |
+ int isNeg; |
+ char zResult[100]; |
+ assert( sizeof(m)==sizeof(r) ); |
+ if( sqlite3_value_type(argv[0])!=SQLITE_FLOAT ) return; |
+ r = sqlite3_value_double(argv[0]); |
+ if( r<0.0 ){ |
+ isNeg = 1; |
+ r = -r; |
+ }else{ |
+ isNeg = 0; |
+ } |
+ memcpy(&a,&r,sizeof(a)); |
+ if( a==0 ){ |
+ e = 0; |
+ m = 0; |
+ }else{ |
+ e = a>>52; |
+ m = a & ((((sqlite3_int64)1)<<52)-1); |
+ m |= ((sqlite3_int64)1)<<52; |
+ while( e<1075 && m>0 && (m&1)==0 ){ |
+ m >>= 1; |
+ e++; |
+ } |
+ if( isNeg ) m = -m; |
+ } |
+ sqlite3_snprintf(sizeof(zResult), zResult, "ieee754(%lld,%d)", |
+ m, e-1075); |
+ sqlite3_result_text(context, zResult, -1, SQLITE_TRANSIENT); |
+ }else if( argc==2 ){ |
+ sqlite3_int64 m, e, a; |
+ double r; |
+ int isNeg = 0; |
+ m = sqlite3_value_int64(argv[0]); |
+ e = sqlite3_value_int64(argv[1]); |
+ if( m<0 ){ |
+ isNeg = 1; |
+ m = -m; |
+ if( m<0 ) return; |
+ }else if( m==0 && e>1000 && e<1000 ){ |
+ sqlite3_result_double(context, 0.0); |
+ return; |
+ } |
+ while( (m>>32)&0xffe00000 ){ |
+ m >>= 1; |
+ e++; |
+ } |
+ while( ((m>>32)&0xfff00000)==0 ){ |
+ m <<= 1; |
+ e--; |
+ } |
+ e += 1075; |
+ if( e<0 ) e = m = 0; |
+ if( e>0x7ff ) m = 0; |
+ a = m & ((((sqlite3_int64)1)<<52)-1); |
+ a |= e<<52; |
+ if( isNeg ) a |= ((sqlite3_int64)1)<<63; |
+ memcpy(&r, &a, sizeof(r)); |
+ sqlite3_result_double(context, r); |
+ } |
+} |
+ |
+ |
+#ifdef _WIN32 |
+__declspec(dllexport) |
+#endif |
+int sqlite3_ieee_init( |
+ sqlite3 *db, |
+ char **pzErrMsg, |
+ const sqlite3_api_routines *pApi |
+){ |
+ int rc = SQLITE_OK; |
+ SQLITE_EXTENSION_INIT2(pApi); |
+ (void)pzErrMsg; /* Unused parameter */ |
+ rc = sqlite3_create_function(db, "ieee754", 1, SQLITE_UTF8, 0, |
+ ieee754func, 0, 0); |
+ if( rc==SQLITE_OK ){ |
+ rc = sqlite3_create_function(db, "ieee754", 2, SQLITE_UTF8, 0, |
+ ieee754func, 0, 0); |
+ } |
+ return rc; |
+} |