Index: third_party/sqlite/sqlite-src-3080704/ext/misc/percentile.c |
diff --git a/third_party/sqlite/sqlite-src-3080704/ext/misc/percentile.c b/third_party/sqlite/sqlite-src-3080704/ext/misc/percentile.c |
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index 0000000000000000000000000000000000000000..74a4c9d12b45a12477cde8c131698760d469819c |
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+++ b/third_party/sqlite/sqlite-src-3080704/ext/misc/percentile.c |
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+/* |
+** 2013-05-28 |
+** |
+** 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 file contains code to implement the percentile(Y,P) SQL function |
+** as described below: |
+** |
+** (1) The percentile(Y,P) function is an aggregate function taking |
+** exactly two arguments. |
+** |
+** (2) If the P argument to percentile(Y,P) is not the same for every |
+** row in the aggregate then an error is thrown. The word "same" |
+** in the previous sentence means that the value differ by less |
+** than 0.001. |
+** |
+** (3) If the P argument to percentile(Y,P) evaluates to anything other |
+** than a number in the range of 0.0 to 100.0 inclusive then an |
+** error is thrown. |
+** |
+** (4) If any Y argument to percentile(Y,P) evaluates to a value that |
+** is not NULL and is not numeric then an error is thrown. |
+** |
+** (5) If any Y argument to percentile(Y,P) evaluates to plus or minus |
+** infinity then an error is thrown. (SQLite always interprets NaN |
+** values as NULL.) |
+** |
+** (6) Both Y and P in percentile(Y,P) can be arbitrary expressions, |
+** including CASE WHEN expressions. |
+** |
+** (7) The percentile(Y,P) aggregate is able to handle inputs of at least |
+** one million (1,000,000) rows. |
+** |
+** (8) If there are no non-NULL values for Y, then percentile(Y,P) |
+** returns NULL. |
+** |
+** (9) If there is exactly one non-NULL value for Y, the percentile(Y,P) |
+** returns the one Y value. |
+** |
+** (10) If there N non-NULL values of Y where N is two or more and |
+** the Y values are ordered from least to greatest and a graph is |
+** drawn from 0 to N-1 such that the height of the graph at J is |
+** the J-th Y value and such that straight lines are drawn between |
+** adjacent Y values, then the percentile(Y,P) function returns |
+** the height of the graph at P*(N-1)/100. |
+** |
+** (11) The percentile(Y,P) function always returns either a floating |
+** point number or NULL. |
+** |
+** (12) The percentile(Y,P) is implemented as a single C99 source-code |
+** file that compiles into a shared-library or DLL that can be loaded |
+** into SQLite using the sqlite3_load_extension() interface. |
+*/ |
+#include "sqlite3ext.h" |
+SQLITE_EXTENSION_INIT1 |
+#include <assert.h> |
+#include <string.h> |
+#include <stdlib.h> |
+ |
+/* The following object is the session context for a single percentile() |
+** function. We have to remember all input Y values until the very end. |
+** Those values are accumulated in the Percentile.a[] array. |
+*/ |
+typedef struct Percentile Percentile; |
+struct Percentile { |
+ unsigned nAlloc; /* Number of slots allocated for a[] */ |
+ unsigned nUsed; /* Number of slots actually used in a[] */ |
+ double rPct; /* 1.0 more than the value for P */ |
+ double *a; /* Array of Y values */ |
+}; |
+ |
+/* |
+** Return TRUE if the input floating-point number is an infinity. |
+*/ |
+static int isInfinity(double r){ |
+ sqlite3_uint64 u; |
+ assert( sizeof(u)==sizeof(r) ); |
+ memcpy(&u, &r, sizeof(u)); |
+ return ((u>>52)&0x7ff)==0x7ff; |
+} |
+ |
+/* |
+** Return TRUE if two doubles differ by 0.001 or less |
+*/ |
+static int sameValue(double a, double b){ |
+ a -= b; |
+ return a>=-0.001 && a<=0.001; |
+} |
+ |
+/* |
+** The "step" function for percentile(Y,P) is called once for each |
+** input row. |
+*/ |
+static void percentStep(sqlite3_context *pCtx, int argc, sqlite3_value **argv){ |
+ Percentile *p; |
+ double rPct; |
+ int eType; |
+ double y; |
+ assert( argc==2 ); |
+ |
+ /* Requirement 3: P must be a number between 0 and 100 */ |
+ eType = sqlite3_value_numeric_type(argv[1]); |
+ rPct = sqlite3_value_double(argv[1]); |
+ if( (eType!=SQLITE_INTEGER && eType!=SQLITE_FLOAT) || |
+ ((rPct = sqlite3_value_double(argv[1]))<0.0 || rPct>100.0) ){ |
+ sqlite3_result_error(pCtx, "2nd argument to percentile() is not " |
+ "a number between 0.0 and 100.0", -1); |
+ return; |
+ } |
+ |
+ /* Allocate the session context. */ |
+ p = (Percentile*)sqlite3_aggregate_context(pCtx, sizeof(*p)); |
+ if( p==0 ) return; |
+ |
+ /* Remember the P value. Throw an error if the P value is different |
+ ** from any prior row, per Requirement (2). */ |
+ if( p->rPct==0.0 ){ |
+ p->rPct = rPct+1.0; |
+ }else if( !sameValue(p->rPct,rPct+1.0) ){ |
+ sqlite3_result_error(pCtx, "2nd argument to percentile() is not the " |
+ "same for all input rows", -1); |
+ return; |
+ } |
+ |
+ /* Ignore rows for which Y is NULL */ |
+ eType = sqlite3_value_type(argv[0]); |
+ if( eType==SQLITE_NULL ) return; |
+ |
+ /* If not NULL, then Y must be numeric. Otherwise throw an error. |
+ ** Requirement 4 */ |
+ if( eType!=SQLITE_INTEGER && eType!=SQLITE_FLOAT ){ |
+ sqlite3_result_error(pCtx, "1st argument to percentile() is not " |
+ "numeric", -1); |
+ return; |
+ } |
+ |
+ /* Throw an error if the Y value is infinity or NaN */ |
+ y = sqlite3_value_double(argv[0]); |
+ if( isInfinity(y) ){ |
+ sqlite3_result_error(pCtx, "Inf input to percentile()", -1); |
+ return; |
+ } |
+ |
+ /* Allocate and store the Y */ |
+ if( p->nUsed>=p->nAlloc ){ |
+ unsigned n = p->nAlloc*2 + 250; |
+ double *a = sqlite3_realloc(p->a, sizeof(double)*n); |
+ if( a==0 ){ |
+ sqlite3_free(p->a); |
+ memset(p, 0, sizeof(*p)); |
+ sqlite3_result_error_nomem(pCtx); |
+ return; |
+ } |
+ p->nAlloc = n; |
+ p->a = a; |
+ } |
+ p->a[p->nUsed++] = y; |
+} |
+ |
+/* |
+** Compare to doubles for sorting using qsort() |
+*/ |
+static int doubleCmp(const void *pA, const void *pB){ |
+ double a = *(double*)pA; |
+ double b = *(double*)pB; |
+ if( a==b ) return 0; |
+ if( a<b ) return -1; |
+ return +1; |
+} |
+ |
+/* |
+** Called to compute the final output of percentile() and to clean |
+** up all allocated memory. |
+*/ |
+static void percentFinal(sqlite3_context *pCtx){ |
+ Percentile *p; |
+ unsigned i1, i2; |
+ double v1, v2; |
+ double ix, vx; |
+ p = (Percentile*)sqlite3_aggregate_context(pCtx, 0); |
+ if( p==0 ) return; |
+ if( p->a==0 ) return; |
+ if( p->nUsed ){ |
+ qsort(p->a, p->nUsed, sizeof(double), doubleCmp); |
+ ix = (p->rPct-1.0)*(p->nUsed-1)*0.01; |
+ i1 = (unsigned)ix; |
+ i2 = ix==(double)i1 || i1==p->nUsed-1 ? i1 : i1+1; |
+ v1 = p->a[i1]; |
+ v2 = p->a[i2]; |
+ vx = v1 + (v2-v1)*(ix-i1); |
+ sqlite3_result_double(pCtx, vx); |
+ } |
+ sqlite3_free(p->a); |
+ memset(p, 0, sizeof(*p)); |
+} |
+ |
+ |
+#ifdef _WIN32 |
+__declspec(dllexport) |
+#endif |
+int sqlite3_percentile_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, "percentile", 2, SQLITE_UTF8, 0, |
+ 0, percentStep, percentFinal); |
+ return rc; |
+} |