[sql] Import reference version of SQLite 3.8.7.4.

third_party/sqlite/sqlite-src-3080704/tool/showstat4.c

+/*
+** This utility program decodes and displays the content of the
+** sqlite_stat4 table in the database file named on the command
+** line.
+*/
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include "sqlite3.h"
+
+typedef sqlite3_int64 i64;   /* 64-bit signed integer type */
+
+
+/*
+** Convert the var-int format into i64.  Return the number of bytes
+** in the var-int.  Write the var-int value into *pVal.
+*/
+static int decodeVarint(const unsigned char *z, i64 *pVal){
+  i64 v = 0;
+  int i;
+  for(i=0; i<8; i++){
+    v = (v<<7) + (z[i]&0x7f);
+    if( (z[i]&0x80)==0 ){ *pVal = v; return i+1; }
+  }
+  v = (v<<8) + (z[i]&0xff);
+  *pVal = v;
+  return 9;
+}
+
+
+
+int main(int argc, char **argv){
+  sqlite3 *db;
+  sqlite3_stmt *pStmt;
+  char *zIdx = 0;
+  int rc, j, x, y, mxHdr;
+  const unsigned char *aSample;
+  int nSample;
+  i64 iVal;
+  const char *zSep;
+
+  if( argc!=2 ){
+    fprintf(stderr, "Usage: %s DATABASE-FILE\n", argv[0]);
+    exit(1);
+  }
+  rc = sqlite3_open(argv[1], &db);
+  if( rc!=SQLITE_OK || db==0 ){
+    fprintf(stderr, "Cannot open database file [%s]\n", argv[1]);
+    exit(1);
+  }
+  rc = sqlite3_prepare_v2(db,
+        "SELECT tbl||'.'||idx, nEq, nLT, nDLt, sample "
+        "FROM sqlite_stat4 ORDER BY 1", -1,
+        &pStmt, 0);
+  if( rc!=SQLITE_OK || pStmt==0 ){
+    fprintf(stderr, "%s\n", sqlite3_errmsg(db));
+    sqlite3_close(db);
+    exit(1);
+  }
+  while( SQLITE_ROW==sqlite3_step(pStmt) ){
+    if( zIdx==0 || strcmp(zIdx, (const char*)sqlite3_column_text(pStmt,0))!=0 ){
+      if( zIdx ) printf("\n");
+      sqlite3_free(zIdx);
+      zIdx = sqlite3_mprintf("%s", sqlite3_column_text(pStmt,0));
+      printf("%s:\n", zIdx);
+    }else{
+      printf("  -----------------------------------------------------------\n");
+    }
+    printf("  nEq    = %s\n", sqlite3_column_text(pStmt,1));
+    printf("  nLt    = %s\n", sqlite3_column_text(pStmt,2));
+    printf("  nDLt   = %s\n", sqlite3_column_text(pStmt,3));
+    printf("  sample = x'");
+    aSample = sqlite3_column_blob(pStmt,4);
+    nSample = sqlite3_column_bytes(pStmt,4);
+    for(j=0; j<nSample; j++) printf("%02x", aSample[j]);
+    printf("'\n          ");
+    zSep = " ";
+    x = decodeVarint(aSample, &iVal);
+    if( iVal<x || iVal>nSample ){
+      printf(" <error>\n");
+      continue;
+    }
+    y = mxHdr = (int)iVal;
+    while( x<mxHdr ){
+      int sz;
+      i64 v;
+      x += decodeVarint(aSample+x, &iVal);
+      if( x>mxHdr ) break;
+      if( iVal<0 ) break;
+      switch( iVal ){
+        case 0:  sz = 0;  break;
+        case 1:  sz = 1;  break;
+        case 2:  sz = 2;  break;
+        case 3:  sz = 3;  break;
+        case 4:  sz = 4;  break;
+        case 5:  sz = 6;  break;
+        case 6:  sz = 8;  break;
+        case 7:  sz = 8;  break;
+        case 8:  sz = 0;  break;
+        case 9:  sz = 0;  break;
+        case 10:
+        case 11: sz = 0;  break;
+        default: sz = (int)(iVal-12)/2;  break;
+      }
+      if( y+sz>nSample ) break;
+      if( iVal==0 ){
+        printf("%sNULL", zSep);
+      }else if( iVal==8 || iVal==9 ){
+        printf("%s%d", zSep, ((int)iVal)-8);
+      }else if( iVal<=7 ){
+        v = (signed char)aSample[y];
+        for(j=1; j<sz; j++){
+          v = (v<<8) + aSample[y+j];
+        }
+        if( iVal==7 ){
+          double r;
+          memcpy(&r, &v, sizeof(r));
+          printf("%s%#g", zSep, r);
+        }else{
+          printf("%s%lld", zSep, v);
+        }
+      }else if( (iVal&1)==0 ){
+        printf("%sx'", zSep);
+        for(j=0; j<sz; j++){
+          printf("%02x", aSample[y+j]);
+        }
+        printf("'");
+      }else{
+        printf("%s\"", zSep);
+        for(j=0; j<sz; j++){
+          char c = (char)aSample[y+j];
+          if( isprint(c) ){
+            if( c=='"' || c=='\\' ) putchar('\\');
+            putchar(c);
+          }else if( c=='\n' ){
+            printf("\\n");
+          }else if( c=='\t' ){
+            printf("\\t");
+          }else if( c=='\r' ){
+            printf("\\r");
+          }else{
+            printf("\\%03o", c);
+          }
+        }
+        printf("\"");
+      }
+      zSep = ",";
+      y += sz;
+    }
+    printf("\n");
+  }
+  sqlite3_free(zIdx);
+  sqlite3_finalize(pStmt);
+  sqlite3_close(db);
+  return 0;
+}