xref: /sqlite-3.40.0/src/printf.c (revision fb32c44e)
1 /*
2 ** The "printf" code that follows dates from the 1980's.  It is in
3 ** the public domain.
4 **
5 **************************************************************************
6 **
7 ** This file contains code for a set of "printf"-like routines.  These
8 ** routines format strings much like the printf() from the standard C
9 ** library, though the implementation here has enhancements to support
10 ** SQLite.
11 */
12 #include "sqliteInt.h"
13 
14 /*
15 ** Conversion types fall into various categories as defined by the
16 ** following enumeration.
17 */
18 #define etRADIX       0 /* non-decimal integer types.  %x %o */
19 #define etFLOAT       1 /* Floating point.  %f */
20 #define etEXP         2 /* Exponentional notation. %e and %E */
21 #define etGENERIC     3 /* Floating or exponential, depending on exponent. %g */
22 #define etSIZE        4 /* Return number of characters processed so far. %n */
23 #define etSTRING      5 /* Strings. %s */
24 #define etDYNSTRING   6 /* Dynamically allocated strings. %z */
25 #define etPERCENT     7 /* Percent symbol. %% */
26 #define etCHARX       8 /* Characters. %c */
27 /* The rest are extensions, not normally found in printf() */
28 #define etSQLESCAPE   9 /* Strings with '\'' doubled.  %q */
29 #define etSQLESCAPE2 10 /* Strings with '\'' doubled and enclosed in '',
30                           NULL pointers replaced by SQL NULL.  %Q */
31 #define etTOKEN      11 /* a pointer to a Token structure */
32 #define etSRCLIST    12 /* a pointer to a SrcList */
33 #define etPOINTER    13 /* The %p conversion */
34 #define etSQLESCAPE3 14 /* %w -> Strings with '\"' doubled */
35 #define etORDINAL    15 /* %r -> 1st, 2nd, 3rd, 4th, etc.  English only */
36 #define etDECIMAL    16 /* %d or %u, but not %x, %o */
37 
38 #define etINVALID    17 /* Any unrecognized conversion type */
39 
40 
41 /*
42 ** An "etByte" is an 8-bit unsigned value.
43 */
44 typedef unsigned char etByte;
45 
46 /*
47 ** Each builtin conversion character (ex: the 'd' in "%d") is described
48 ** by an instance of the following structure
49 */
50 typedef struct et_info {   /* Information about each format field */
51   char fmttype;            /* The format field code letter */
52   etByte base;             /* The base for radix conversion */
53   etByte flags;            /* One or more of FLAG_ constants below */
54   etByte type;             /* Conversion paradigm */
55   etByte charset;          /* Offset into aDigits[] of the digits string */
56   etByte prefix;           /* Offset into aPrefix[] of the prefix string */
57 } et_info;
58 
59 /*
60 ** Allowed values for et_info.flags
61 */
62 #define FLAG_SIGNED    1     /* True if the value to convert is signed */
63 #define FLAG_STRING    4     /* Allow infinite precision */
64 
65 
66 /*
67 ** The following table is searched linearly, so it is good to put the
68 ** most frequently used conversion types first.
69 */
70 static const char aDigits[] = "0123456789ABCDEF0123456789abcdef";
71 static const char aPrefix[] = "-x0\000X0";
72 static const et_info fmtinfo[] = {
73   {  'd', 10, 1, etDECIMAL,    0,  0 },
74   {  's',  0, 4, etSTRING,     0,  0 },
75   {  'g',  0, 1, etGENERIC,    30, 0 },
76   {  'z',  0, 4, etDYNSTRING,  0,  0 },
77   {  'q',  0, 4, etSQLESCAPE,  0,  0 },
78   {  'Q',  0, 4, etSQLESCAPE2, 0,  0 },
79   {  'w',  0, 4, etSQLESCAPE3, 0,  0 },
80   {  'c',  0, 0, etCHARX,      0,  0 },
81   {  'o',  8, 0, etRADIX,      0,  2 },
82   {  'u', 10, 0, etDECIMAL,    0,  0 },
83   {  'x', 16, 0, etRADIX,      16, 1 },
84   {  'X', 16, 0, etRADIX,      0,  4 },
85 #ifndef SQLITE_OMIT_FLOATING_POINT
86   {  'f',  0, 1, etFLOAT,      0,  0 },
87   {  'e',  0, 1, etEXP,        30, 0 },
88   {  'E',  0, 1, etEXP,        14, 0 },
89   {  'G',  0, 1, etGENERIC,    14, 0 },
90 #endif
91   {  'i', 10, 1, etDECIMAL,    0,  0 },
92   {  'n',  0, 0, etSIZE,       0,  0 },
93   {  '%',  0, 0, etPERCENT,    0,  0 },
94   {  'p', 16, 0, etPOINTER,    0,  1 },
95 
96   /* All the rest are undocumented and are for internal use only */
97   {  'T',  0, 0, etTOKEN,      0,  0 },
98   {  'S',  0, 0, etSRCLIST,    0,  0 },
99   {  'r', 10, 1, etORDINAL,    0,  0 },
100 };
101 
102 /*
103 ** If SQLITE_OMIT_FLOATING_POINT is defined, then none of the floating point
104 ** conversions will work.
105 */
106 #ifndef SQLITE_OMIT_FLOATING_POINT
107 /*
108 ** "*val" is a double such that 0.1 <= *val < 10.0
109 ** Return the ascii code for the leading digit of *val, then
110 ** multiply "*val" by 10.0 to renormalize.
111 **
112 ** Example:
113 **     input:     *val = 3.14159
114 **     output:    *val = 1.4159    function return = '3'
115 **
116 ** The counter *cnt is incremented each time.  After counter exceeds
117 ** 16 (the number of significant digits in a 64-bit float) '0' is
118 ** always returned.
119 */
120 static char et_getdigit(LONGDOUBLE_TYPE *val, int *cnt){
121   int digit;
122   LONGDOUBLE_TYPE d;
123   if( (*cnt)<=0 ) return '0';
124   (*cnt)--;
125   digit = (int)*val;
126   d = digit;
127   digit += '0';
128   *val = (*val - d)*10.0;
129   return (char)digit;
130 }
131 #endif /* SQLITE_OMIT_FLOATING_POINT */
132 
133 /*
134 ** Set the StrAccum object to an error mode.
135 */
136 static void setStrAccumError(StrAccum *p, u8 eError){
137   assert( eError==STRACCUM_NOMEM || eError==STRACCUM_TOOBIG );
138   p->accError = eError;
139   p->nAlloc = 0;
140 }
141 
142 /*
143 ** Extra argument values from a PrintfArguments object
144 */
145 static sqlite3_int64 getIntArg(PrintfArguments *p){
146   if( p->nArg<=p->nUsed ) return 0;
147   return sqlite3_value_int64(p->apArg[p->nUsed++]);
148 }
149 static double getDoubleArg(PrintfArguments *p){
150   if( p->nArg<=p->nUsed ) return 0.0;
151   return sqlite3_value_double(p->apArg[p->nUsed++]);
152 }
153 static char *getTextArg(PrintfArguments *p){
154   if( p->nArg<=p->nUsed ) return 0;
155   return (char*)sqlite3_value_text(p->apArg[p->nUsed++]);
156 }
157 
158 
159 /*
160 ** On machines with a small stack size, you can redefine the
161 ** SQLITE_PRINT_BUF_SIZE to be something smaller, if desired.
162 */
163 #ifndef SQLITE_PRINT_BUF_SIZE
164 # define SQLITE_PRINT_BUF_SIZE 70
165 #endif
166 #define etBUFSIZE SQLITE_PRINT_BUF_SIZE  /* Size of the output buffer */
167 
168 /*
169 ** Render a string given by "fmt" into the StrAccum object.
170 */
171 void sqlite3VXPrintf(
172   StrAccum *pAccum,          /* Accumulate results here */
173   const char *fmt,           /* Format string */
174   va_list ap                 /* arguments */
175 ){
176   int c;                     /* Next character in the format string */
177   char *bufpt;               /* Pointer to the conversion buffer */
178   int precision;             /* Precision of the current field */
179   int length;                /* Length of the field */
180   int idx;                   /* A general purpose loop counter */
181   int width;                 /* Width of the current field */
182   etByte flag_leftjustify;   /* True if "-" flag is present */
183   etByte flag_prefix;        /* '+' or ' ' or 0 for prefix */
184   etByte flag_alternateform; /* True if "#" flag is present */
185   etByte flag_altform2;      /* True if "!" flag is present */
186   etByte flag_zeropad;       /* True if field width constant starts with zero */
187   etByte flag_long;          /* 1 for the "l" flag, 2 for "ll", 0 by default */
188   etByte done;               /* Loop termination flag */
189   etByte cThousand;          /* Thousands separator for %d and %u */
190   etByte xtype = etINVALID;  /* Conversion paradigm */
191   u8 bArgList;               /* True for SQLITE_PRINTF_SQLFUNC */
192   char prefix;               /* Prefix character.  "+" or "-" or " " or '\0'. */
193   sqlite_uint64 longvalue;   /* Value for integer types */
194   LONGDOUBLE_TYPE realvalue; /* Value for real types */
195   const et_info *infop;      /* Pointer to the appropriate info structure */
196   char *zOut;                /* Rendering buffer */
197   int nOut;                  /* Size of the rendering buffer */
198   char *zExtra = 0;          /* Malloced memory used by some conversion */
199 #ifndef SQLITE_OMIT_FLOATING_POINT
200   int  exp, e2;              /* exponent of real numbers */
201   int nsd;                   /* Number of significant digits returned */
202   double rounder;            /* Used for rounding floating point values */
203   etByte flag_dp;            /* True if decimal point should be shown */
204   etByte flag_rtz;           /* True if trailing zeros should be removed */
205 #endif
206   PrintfArguments *pArgList = 0; /* Arguments for SQLITE_PRINTF_SQLFUNC */
207   char buf[etBUFSIZE];       /* Conversion buffer */
208 
209   /* pAccum never starts out with an empty buffer that was obtained from
210   ** malloc().  This precondition is required by the mprintf("%z...")
211   ** optimization. */
212   assert( pAccum->nChar>0 || (pAccum->printfFlags&SQLITE_PRINTF_MALLOCED)==0 );
213 
214   bufpt = 0;
215   if( (pAccum->printfFlags & SQLITE_PRINTF_SQLFUNC)!=0 ){
216     pArgList = va_arg(ap, PrintfArguments*);
217     bArgList = 1;
218   }else{
219     bArgList = 0;
220   }
221   for(; (c=(*fmt))!=0; ++fmt){
222     if( c!='%' ){
223       bufpt = (char *)fmt;
224 #if HAVE_STRCHRNUL
225       fmt = strchrnul(fmt, '%');
226 #else
227       do{ fmt++; }while( *fmt && *fmt != '%' );
228 #endif
229       sqlite3StrAccumAppend(pAccum, bufpt, (int)(fmt - bufpt));
230       if( *fmt==0 ) break;
231     }
232     if( (c=(*++fmt))==0 ){
233       sqlite3StrAccumAppend(pAccum, "%", 1);
234       break;
235     }
236     /* Find out what flags are present */
237     flag_leftjustify = flag_prefix = cThousand =
238      flag_alternateform = flag_altform2 = flag_zeropad = 0;
239     done = 0;
240     do{
241       switch( c ){
242         case '-':   flag_leftjustify = 1;     break;
243         case '+':   flag_prefix = '+';        break;
244         case ' ':   flag_prefix = ' ';        break;
245         case '#':   flag_alternateform = 1;   break;
246         case '!':   flag_altform2 = 1;        break;
247         case '0':   flag_zeropad = 1;         break;
248         case ',':   cThousand = ',';          break;
249         default:    done = 1;                 break;
250       }
251     }while( !done && (c=(*++fmt))!=0 );
252     /* Get the field width */
253     if( c=='*' ){
254       if( bArgList ){
255         width = (int)getIntArg(pArgList);
256       }else{
257         width = va_arg(ap,int);
258       }
259       if( width<0 ){
260         flag_leftjustify = 1;
261         width = width >= -2147483647 ? -width : 0;
262       }
263       c = *++fmt;
264     }else{
265       unsigned wx = 0;
266       while( c>='0' && c<='9' ){
267         wx = wx*10 + c - '0';
268         c = *++fmt;
269       }
270       testcase( wx>0x7fffffff );
271       width = wx & 0x7fffffff;
272     }
273     assert( width>=0 );
274 #ifdef SQLITE_PRINTF_PRECISION_LIMIT
275     if( width>SQLITE_PRINTF_PRECISION_LIMIT ){
276       width = SQLITE_PRINTF_PRECISION_LIMIT;
277     }
278 #endif
279 
280     /* Get the precision */
281     if( c=='.' ){
282       c = *++fmt;
283       if( c=='*' ){
284         if( bArgList ){
285           precision = (int)getIntArg(pArgList);
286         }else{
287           precision = va_arg(ap,int);
288         }
289         c = *++fmt;
290         if( precision<0 ){
291           precision = precision >= -2147483647 ? -precision : -1;
292         }
293       }else{
294         unsigned px = 0;
295         while( c>='0' && c<='9' ){
296           px = px*10 + c - '0';
297           c = *++fmt;
298         }
299         testcase( px>0x7fffffff );
300         precision = px & 0x7fffffff;
301       }
302     }else{
303       precision = -1;
304     }
305     assert( precision>=(-1) );
306 #ifdef SQLITE_PRINTF_PRECISION_LIMIT
307     if( precision>SQLITE_PRINTF_PRECISION_LIMIT ){
308       precision = SQLITE_PRINTF_PRECISION_LIMIT;
309     }
310 #endif
311 
312 
313     /* Get the conversion type modifier */
314     if( c=='l' ){
315       flag_long = 1;
316       c = *++fmt;
317       if( c=='l' ){
318         flag_long = 2;
319         c = *++fmt;
320       }
321     }else{
322       flag_long = 0;
323     }
324     /* Fetch the info entry for the field */
325     infop = &fmtinfo[0];
326     xtype = etINVALID;
327     for(idx=0; idx<ArraySize(fmtinfo); idx++){
328       if( c==fmtinfo[idx].fmttype ){
329         infop = &fmtinfo[idx];
330         xtype = infop->type;
331         break;
332       }
333     }
334 
335     /*
336     ** At this point, variables are initialized as follows:
337     **
338     **   flag_alternateform          TRUE if a '#' is present.
339     **   flag_altform2               TRUE if a '!' is present.
340     **   flag_prefix                 '+' or ' ' or zero
341     **   flag_leftjustify            TRUE if a '-' is present or if the
342     **                               field width was negative.
343     **   flag_zeropad                TRUE if the width began with 0.
344     **   flag_long                   1 for "l", 2 for "ll"
345     **   width                       The specified field width.  This is
346     **                               always non-negative.  Zero is the default.
347     **   precision                   The specified precision.  The default
348     **                               is -1.
349     **   xtype                       The class of the conversion.
350     **   infop                       Pointer to the appropriate info struct.
351     */
352     switch( xtype ){
353       case etPOINTER:
354         flag_long = sizeof(char*)==sizeof(i64) ? 2 :
355                      sizeof(char*)==sizeof(long int) ? 1 : 0;
356         /* Fall through into the next case */
357       case etORDINAL:
358       case etRADIX:
359         cThousand = 0;
360         /* Fall through into the next case */
361       case etDECIMAL:
362         if( infop->flags & FLAG_SIGNED ){
363           i64 v;
364           if( bArgList ){
365             v = getIntArg(pArgList);
366           }else if( flag_long ){
367             if( flag_long==2 ){
368               v = va_arg(ap,i64) ;
369             }else{
370               v = va_arg(ap,long int);
371             }
372           }else{
373             v = va_arg(ap,int);
374           }
375           if( v<0 ){
376             if( v==SMALLEST_INT64 ){
377               longvalue = ((u64)1)<<63;
378             }else{
379               longvalue = -v;
380             }
381             prefix = '-';
382           }else{
383             longvalue = v;
384             prefix = flag_prefix;
385           }
386         }else{
387           if( bArgList ){
388             longvalue = (u64)getIntArg(pArgList);
389           }else if( flag_long ){
390             if( flag_long==2 ){
391               longvalue = va_arg(ap,u64);
392             }else{
393               longvalue = va_arg(ap,unsigned long int);
394             }
395           }else{
396             longvalue = va_arg(ap,unsigned int);
397           }
398           prefix = 0;
399         }
400         if( longvalue==0 ) flag_alternateform = 0;
401         if( flag_zeropad && precision<width-(prefix!=0) ){
402           precision = width-(prefix!=0);
403         }
404         if( precision<etBUFSIZE-10-etBUFSIZE/3 ){
405           nOut = etBUFSIZE;
406           zOut = buf;
407         }else{
408           u64 n = (u64)precision + 10 + precision/3;
409           zOut = zExtra = sqlite3Malloc( n );
410           if( zOut==0 ){
411             setStrAccumError(pAccum, STRACCUM_NOMEM);
412             return;
413           }
414           nOut = (int)n;
415         }
416         bufpt = &zOut[nOut-1];
417         if( xtype==etORDINAL ){
418           static const char zOrd[] = "thstndrd";
419           int x = (int)(longvalue % 10);
420           if( x>=4 || (longvalue/10)%10==1 ){
421             x = 0;
422           }
423           *(--bufpt) = zOrd[x*2+1];
424           *(--bufpt) = zOrd[x*2];
425         }
426         {
427           const char *cset = &aDigits[infop->charset];
428           u8 base = infop->base;
429           do{                                           /* Convert to ascii */
430             *(--bufpt) = cset[longvalue%base];
431             longvalue = longvalue/base;
432           }while( longvalue>0 );
433         }
434         length = (int)(&zOut[nOut-1]-bufpt);
435         while( precision>length ){
436           *(--bufpt) = '0';                             /* Zero pad */
437           length++;
438         }
439         if( cThousand ){
440           int nn = (length - 1)/3;  /* Number of "," to insert */
441           int ix = (length - 1)%3 + 1;
442           bufpt -= nn;
443           for(idx=0; nn>0; idx++){
444             bufpt[idx] = bufpt[idx+nn];
445             ix--;
446             if( ix==0 ){
447               bufpt[++idx] = cThousand;
448               nn--;
449               ix = 3;
450             }
451           }
452         }
453         if( prefix ) *(--bufpt) = prefix;               /* Add sign */
454         if( flag_alternateform && infop->prefix ){      /* Add "0" or "0x" */
455           const char *pre;
456           char x;
457           pre = &aPrefix[infop->prefix];
458           for(; (x=(*pre))!=0; pre++) *(--bufpt) = x;
459         }
460         length = (int)(&zOut[nOut-1]-bufpt);
461         break;
462       case etFLOAT:
463       case etEXP:
464       case etGENERIC:
465         if( bArgList ){
466           realvalue = getDoubleArg(pArgList);
467         }else{
468           realvalue = va_arg(ap,double);
469         }
470 #ifdef SQLITE_OMIT_FLOATING_POINT
471         length = 0;
472 #else
473         if( precision<0 ) precision = 6;         /* Set default precision */
474         if( realvalue<0.0 ){
475           realvalue = -realvalue;
476           prefix = '-';
477         }else{
478           prefix = flag_prefix;
479         }
480         if( xtype==etGENERIC && precision>0 ) precision--;
481         testcase( precision>0xfff );
482         for(idx=precision&0xfff, rounder=0.5; idx>0; idx--, rounder*=0.1){}
483         if( xtype==etFLOAT ) realvalue += rounder;
484         /* Normalize realvalue to within 10.0 > realvalue >= 1.0 */
485         exp = 0;
486         if( sqlite3IsNaN((double)realvalue) ){
487           bufpt = "NaN";
488           length = 3;
489           break;
490         }
491         if( realvalue>0.0 ){
492           LONGDOUBLE_TYPE scale = 1.0;
493           while( realvalue>=1e100*scale && exp<=350 ){ scale *= 1e100;exp+=100;}
494           while( realvalue>=1e10*scale && exp<=350 ){ scale *= 1e10; exp+=10; }
495           while( realvalue>=10.0*scale && exp<=350 ){ scale *= 10.0; exp++; }
496           realvalue /= scale;
497           while( realvalue<1e-8 ){ realvalue *= 1e8; exp-=8; }
498           while( realvalue<1.0 ){ realvalue *= 10.0; exp--; }
499           if( exp>350 ){
500             bufpt = buf;
501             buf[0] = prefix;
502             memcpy(buf+(prefix!=0),"Inf",4);
503             length = 3+(prefix!=0);
504             break;
505           }
506         }
507         bufpt = buf;
508         /*
509         ** If the field type is etGENERIC, then convert to either etEXP
510         ** or etFLOAT, as appropriate.
511         */
512         if( xtype!=etFLOAT ){
513           realvalue += rounder;
514           if( realvalue>=10.0 ){ realvalue *= 0.1; exp++; }
515         }
516         if( xtype==etGENERIC ){
517           flag_rtz = !flag_alternateform;
518           if( exp<-4 || exp>precision ){
519             xtype = etEXP;
520           }else{
521             precision = precision - exp;
522             xtype = etFLOAT;
523           }
524         }else{
525           flag_rtz = flag_altform2;
526         }
527         if( xtype==etEXP ){
528           e2 = 0;
529         }else{
530           e2 = exp;
531         }
532         if( MAX(e2,0)+(i64)precision+(i64)width > etBUFSIZE - 15 ){
533           bufpt = zExtra
534               = sqlite3Malloc( MAX(e2,0)+(i64)precision+(i64)width+15 );
535           if( bufpt==0 ){
536             setStrAccumError(pAccum, STRACCUM_NOMEM);
537             return;
538           }
539         }
540         zOut = bufpt;
541         nsd = 16 + flag_altform2*10;
542         flag_dp = (precision>0 ?1:0) | flag_alternateform | flag_altform2;
543         /* The sign in front of the number */
544         if( prefix ){
545           *(bufpt++) = prefix;
546         }
547         /* Digits prior to the decimal point */
548         if( e2<0 ){
549           *(bufpt++) = '0';
550         }else{
551           for(; e2>=0; e2--){
552             *(bufpt++) = et_getdigit(&realvalue,&nsd);
553           }
554         }
555         /* The decimal point */
556         if( flag_dp ){
557           *(bufpt++) = '.';
558         }
559         /* "0" digits after the decimal point but before the first
560         ** significant digit of the number */
561         for(e2++; e2<0; precision--, e2++){
562           assert( precision>0 );
563           *(bufpt++) = '0';
564         }
565         /* Significant digits after the decimal point */
566         while( (precision--)>0 ){
567           *(bufpt++) = et_getdigit(&realvalue,&nsd);
568         }
569         /* Remove trailing zeros and the "." if no digits follow the "." */
570         if( flag_rtz && flag_dp ){
571           while( bufpt[-1]=='0' ) *(--bufpt) = 0;
572           assert( bufpt>zOut );
573           if( bufpt[-1]=='.' ){
574             if( flag_altform2 ){
575               *(bufpt++) = '0';
576             }else{
577               *(--bufpt) = 0;
578             }
579           }
580         }
581         /* Add the "eNNN" suffix */
582         if( xtype==etEXP ){
583           *(bufpt++) = aDigits[infop->charset];
584           if( exp<0 ){
585             *(bufpt++) = '-'; exp = -exp;
586           }else{
587             *(bufpt++) = '+';
588           }
589           if( exp>=100 ){
590             *(bufpt++) = (char)((exp/100)+'0');        /* 100's digit */
591             exp %= 100;
592           }
593           *(bufpt++) = (char)(exp/10+'0');             /* 10's digit */
594           *(bufpt++) = (char)(exp%10+'0');             /* 1's digit */
595         }
596         *bufpt = 0;
597 
598         /* The converted number is in buf[] and zero terminated. Output it.
599         ** Note that the number is in the usual order, not reversed as with
600         ** integer conversions. */
601         length = (int)(bufpt-zOut);
602         bufpt = zOut;
603 
604         /* Special case:  Add leading zeros if the flag_zeropad flag is
605         ** set and we are not left justified */
606         if( flag_zeropad && !flag_leftjustify && length < width){
607           int i;
608           int nPad = width - length;
609           for(i=width; i>=nPad; i--){
610             bufpt[i] = bufpt[i-nPad];
611           }
612           i = prefix!=0;
613           while( nPad-- ) bufpt[i++] = '0';
614           length = width;
615         }
616 #endif /* !defined(SQLITE_OMIT_FLOATING_POINT) */
617         break;
618       case etSIZE:
619         if( !bArgList ){
620           *(va_arg(ap,int*)) = pAccum->nChar;
621         }
622         length = width = 0;
623         break;
624       case etPERCENT:
625         buf[0] = '%';
626         bufpt = buf;
627         length = 1;
628         break;
629       case etCHARX:
630         if( bArgList ){
631           bufpt = getTextArg(pArgList);
632           length = 1;
633           if( bufpt ){
634             buf[0] = c = *(bufpt++);
635             if( (c&0xc0)==0xc0 ){
636               while( length<4 && (bufpt[0]&0xc0)==0x80 ){
637                 buf[length++] = *(bufpt++);
638               }
639             }
640           }else{
641             buf[0] = 0;
642           }
643         }else{
644           unsigned int ch = va_arg(ap,unsigned int);
645           if( ch<0x00080 ){
646             buf[0] = ch & 0xff;
647             length = 1;
648           }else if( ch<0x00800 ){
649             buf[0] = 0xc0 + (u8)((ch>>6)&0x1f);
650             buf[1] = 0x80 + (u8)(ch & 0x3f);
651             length = 2;
652           }else if( ch<0x10000 ){
653             buf[0] = 0xe0 + (u8)((ch>>12)&0x0f);
654             buf[1] = 0x80 + (u8)((ch>>6) & 0x3f);
655             buf[2] = 0x80 + (u8)(ch & 0x3f);
656             length = 3;
657           }else{
658             buf[0] = 0xf0 + (u8)((ch>>18) & 0x07);
659             buf[1] = 0x80 + (u8)((ch>>12) & 0x3f);
660             buf[2] = 0x80 + (u8)((ch>>6) & 0x3f);
661             buf[3] = 0x80 + (u8)(ch & 0x3f);
662             length = 4;
663           }
664         }
665         if( precision>1 ){
666           width -= precision-1;
667           if( width>1 && !flag_leftjustify ){
668             sqlite3AppendChar(pAccum, width-1, ' ');
669             width = 0;
670           }
671           while( precision-- > 1 ){
672             sqlite3StrAccumAppend(pAccum, buf, length);
673           }
674         }
675         bufpt = buf;
676         flag_altform2 = 1;
677         goto adjust_width_for_utf8;
678       case etSTRING:
679       case etDYNSTRING:
680         if( bArgList ){
681           bufpt = getTextArg(pArgList);
682           xtype = etSTRING;
683         }else{
684           bufpt = va_arg(ap,char*);
685         }
686         if( bufpt==0 ){
687           bufpt = "";
688         }else if( xtype==etDYNSTRING ){
689           if( pAccum->nChar==0 && pAccum->mxAlloc && width==0 && precision<0 ){
690             /* Special optimization for sqlite3_mprintf("%z..."):
691             ** Extend an existing memory allocation rather than creating
692             ** a new one. */
693             assert( (pAccum->printfFlags&SQLITE_PRINTF_MALLOCED)==0 );
694             pAccum->zText = bufpt;
695             pAccum->nAlloc = sqlite3DbMallocSize(pAccum->db, bufpt);
696             pAccum->nChar = 0x7fffffff & (int)strlen(bufpt);
697             pAccum->printfFlags |= SQLITE_PRINTF_MALLOCED;
698             length = 0;
699             break;
700           }
701           zExtra = bufpt;
702         }
703         if( precision>=0 ){
704           if( flag_altform2 ){
705             /* Set length to the number of bytes needed in order to display
706             ** precision characters */
707             unsigned char *z = (unsigned char*)bufpt;
708             while( precision-- > 0 && z[0] ){
709               SQLITE_SKIP_UTF8(z);
710             }
711             length = (int)(z - (unsigned char*)bufpt);
712           }else{
713             for(length=0; length<precision && bufpt[length]; length++){}
714           }
715         }else{
716           length = 0x7fffffff & (int)strlen(bufpt);
717         }
718       adjust_width_for_utf8:
719         if( flag_altform2 && width>0 ){
720           /* Adjust width to account for extra bytes in UTF-8 characters */
721           int ii = length - 1;
722           while( ii>=0 ) if( (bufpt[ii--] & 0xc0)==0x80 ) width++;
723         }
724         break;
725       case etSQLESCAPE:           /* %q: Escape ' characters */
726       case etSQLESCAPE2:          /* %Q: Escape ' and enclose in '...' */
727       case etSQLESCAPE3: {        /* %w: Escape " characters */
728         int i, j, k, n, isnull;
729         int needQuote;
730         char ch;
731         char q = ((xtype==etSQLESCAPE3)?'"':'\'');   /* Quote character */
732         char *escarg;
733 
734         if( bArgList ){
735           escarg = getTextArg(pArgList);
736         }else{
737           escarg = va_arg(ap,char*);
738         }
739         isnull = escarg==0;
740         if( isnull ) escarg = (xtype==etSQLESCAPE2 ? "NULL" : "(NULL)");
741         /* For %q, %Q, and %w, the precision is the number of byte (or
742         ** characters if the ! flags is present) to use from the input.
743         ** Because of the extra quoting characters inserted, the number
744         ** of output characters may be larger than the precision.
745         */
746         k = precision;
747         for(i=n=0; k!=0 && (ch=escarg[i])!=0; i++, k--){
748           if( ch==q )  n++;
749           if( flag_altform2 && (ch&0xc0)==0xc0 ){
750             while( (escarg[i+1]&0xc0)==0x80 ){ i++; }
751           }
752         }
753         needQuote = !isnull && xtype==etSQLESCAPE2;
754         n += i + 3;
755         if( n>etBUFSIZE ){
756           bufpt = zExtra = sqlite3Malloc( n );
757           if( bufpt==0 ){
758             setStrAccumError(pAccum, STRACCUM_NOMEM);
759             return;
760           }
761         }else{
762           bufpt = buf;
763         }
764         j = 0;
765         if( needQuote ) bufpt[j++] = q;
766         k = i;
767         for(i=0; i<k; i++){
768           bufpt[j++] = ch = escarg[i];
769           if( ch==q ) bufpt[j++] = ch;
770         }
771         if( needQuote ) bufpt[j++] = q;
772         bufpt[j] = 0;
773         length = j;
774         goto adjust_width_for_utf8;
775       }
776       case etTOKEN: {
777         Token *pToken;
778         if( (pAccum->printfFlags & SQLITE_PRINTF_INTERNAL)==0 ) return;
779         pToken = va_arg(ap, Token*);
780         assert( bArgList==0 );
781         if( pToken && pToken->n ){
782           sqlite3StrAccumAppend(pAccum, (const char*)pToken->z, pToken->n);
783         }
784         length = width = 0;
785         break;
786       }
787       case etSRCLIST: {
788         SrcList *pSrc;
789         int k;
790         struct SrcList_item *pItem;
791         if( (pAccum->printfFlags & SQLITE_PRINTF_INTERNAL)==0 ) return;
792         pSrc = va_arg(ap, SrcList*);
793         k = va_arg(ap, int);
794         pItem = &pSrc->a[k];
795         assert( bArgList==0 );
796         assert( k>=0 && k<pSrc->nSrc );
797         if( pItem->zDatabase ){
798           sqlite3StrAccumAppendAll(pAccum, pItem->zDatabase);
799           sqlite3StrAccumAppend(pAccum, ".", 1);
800         }
801         sqlite3StrAccumAppendAll(pAccum, pItem->zName);
802         length = width = 0;
803         break;
804       }
805       default: {
806         assert( xtype==etINVALID );
807         return;
808       }
809     }/* End switch over the format type */
810     /*
811     ** The text of the conversion is pointed to by "bufpt" and is
812     ** "length" characters long.  The field width is "width".  Do
813     ** the output.  Both length and width are in bytes, not characters,
814     ** at this point.  If the "!" flag was present on string conversions
815     ** indicating that width and precision should be expressed in characters,
816     ** then the values have been translated prior to reaching this point.
817     */
818     width -= length;
819     if( width>0 ){
820       if( !flag_leftjustify ) sqlite3AppendChar(pAccum, width, ' ');
821       sqlite3StrAccumAppend(pAccum, bufpt, length);
822       if( flag_leftjustify ) sqlite3AppendChar(pAccum, width, ' ');
823     }else{
824       sqlite3StrAccumAppend(pAccum, bufpt, length);
825     }
826 
827     if( zExtra ){
828       sqlite3DbFree(pAccum->db, zExtra);
829       zExtra = 0;
830     }
831   }/* End for loop over the format string */
832 } /* End of function */
833 
834 /*
835 ** Enlarge the memory allocation on a StrAccum object so that it is
836 ** able to accept at least N more bytes of text.
837 **
838 ** Return the number of bytes of text that StrAccum is able to accept
839 ** after the attempted enlargement.  The value returned might be zero.
840 */
841 static int sqlite3StrAccumEnlarge(StrAccum *p, int N){
842   char *zNew;
843   assert( p->nChar+(i64)N >= p->nAlloc ); /* Only called if really needed */
844   if( p->accError ){
845     testcase(p->accError==STRACCUM_TOOBIG);
846     testcase(p->accError==STRACCUM_NOMEM);
847     return 0;
848   }
849   if( p->mxAlloc==0 ){
850     N = p->nAlloc - p->nChar - 1;
851     setStrAccumError(p, STRACCUM_TOOBIG);
852     return N;
853   }else{
854     char *zOld = isMalloced(p) ? p->zText : 0;
855     i64 szNew = p->nChar;
856     szNew += N + 1;
857     if( szNew+p->nChar<=p->mxAlloc ){
858       /* Force exponential buffer size growth as long as it does not overflow,
859       ** to avoid having to call this routine too often */
860       szNew += p->nChar;
861     }
862     if( szNew > p->mxAlloc ){
863       sqlite3StrAccumReset(p);
864       setStrAccumError(p, STRACCUM_TOOBIG);
865       return 0;
866     }else{
867       p->nAlloc = (int)szNew;
868     }
869     if( p->db ){
870       zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
871     }else{
872       zNew = sqlite3_realloc64(zOld, p->nAlloc);
873     }
874     if( zNew ){
875       assert( p->zText!=0 || p->nChar==0 );
876       if( !isMalloced(p) && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
877       p->zText = zNew;
878       p->nAlloc = sqlite3DbMallocSize(p->db, zNew);
879       p->printfFlags |= SQLITE_PRINTF_MALLOCED;
880     }else{
881       sqlite3StrAccumReset(p);
882       setStrAccumError(p, STRACCUM_NOMEM);
883       return 0;
884     }
885   }
886   return N;
887 }
888 
889 /*
890 ** Append N copies of character c to the given string buffer.
891 */
892 void sqlite3AppendChar(StrAccum *p, int N, char c){
893   testcase( p->nChar + (i64)N > 0x7fffffff );
894   if( p->nChar+(i64)N >= p->nAlloc && (N = sqlite3StrAccumEnlarge(p, N))<=0 ){
895     return;
896   }
897   while( (N--)>0 ) p->zText[p->nChar++] = c;
898 }
899 
900 /*
901 ** The StrAccum "p" is not large enough to accept N new bytes of z[].
902 ** So enlarge if first, then do the append.
903 **
904 ** This is a helper routine to sqlite3StrAccumAppend() that does special-case
905 ** work (enlarging the buffer) using tail recursion, so that the
906 ** sqlite3StrAccumAppend() routine can use fast calling semantics.
907 */
908 static void SQLITE_NOINLINE enlargeAndAppend(StrAccum *p, const char *z, int N){
909   N = sqlite3StrAccumEnlarge(p, N);
910   if( N>0 ){
911     memcpy(&p->zText[p->nChar], z, N);
912     p->nChar += N;
913   }
914 }
915 
916 /*
917 ** Append N bytes of text from z to the StrAccum object.  Increase the
918 ** size of the memory allocation for StrAccum if necessary.
919 */
920 void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
921   assert( z!=0 || N==0 );
922   assert( p->zText!=0 || p->nChar==0 || p->accError );
923   assert( N>=0 );
924   assert( p->accError==0 || p->nAlloc==0 );
925   if( p->nChar+N >= p->nAlloc ){
926     enlargeAndAppend(p,z,N);
927   }else if( N ){
928     assert( p->zText );
929     p->nChar += N;
930     memcpy(&p->zText[p->nChar-N], z, N);
931   }
932 }
933 
934 /*
935 ** Append the complete text of zero-terminated string z[] to the p string.
936 */
937 void sqlite3StrAccumAppendAll(StrAccum *p, const char *z){
938   sqlite3StrAccumAppend(p, z, sqlite3Strlen30(z));
939 }
940 
941 
942 /*
943 ** Finish off a string by making sure it is zero-terminated.
944 ** Return a pointer to the resulting string.  Return a NULL
945 ** pointer if any kind of error was encountered.
946 */
947 static SQLITE_NOINLINE char *strAccumFinishRealloc(StrAccum *p){
948   char *zText;
949   assert( p->mxAlloc>0 && !isMalloced(p) );
950   zText = sqlite3DbMallocRaw(p->db, p->nChar+1 );
951   if( zText ){
952     memcpy(zText, p->zText, p->nChar+1);
953     p->printfFlags |= SQLITE_PRINTF_MALLOCED;
954   }else{
955     setStrAccumError(p, STRACCUM_NOMEM);
956   }
957   p->zText = zText;
958   return zText;
959 }
960 char *sqlite3StrAccumFinish(StrAccum *p){
961   if( p->zText ){
962     p->zText[p->nChar] = 0;
963     if( p->mxAlloc>0 && !isMalloced(p) ){
964       return strAccumFinishRealloc(p);
965     }
966   }
967   return p->zText;
968 }
969 
970 /*
971 ** Reset an StrAccum string.  Reclaim all malloced memory.
972 */
973 void sqlite3StrAccumReset(StrAccum *p){
974   if( isMalloced(p) ){
975     sqlite3DbFree(p->db, p->zText);
976     p->printfFlags &= ~SQLITE_PRINTF_MALLOCED;
977   }
978   p->zText = 0;
979 }
980 
981 /*
982 ** Initialize a string accumulator.
983 **
984 ** p:     The accumulator to be initialized.
985 ** db:    Pointer to a database connection.  May be NULL.  Lookaside
986 **        memory is used if not NULL. db->mallocFailed is set appropriately
987 **        when not NULL.
988 ** zBase: An initial buffer.  May be NULL in which case the initial buffer
989 **        is malloced.
990 ** n:     Size of zBase in bytes.  If total space requirements never exceed
991 **        n then no memory allocations ever occur.
992 ** mx:    Maximum number of bytes to accumulate.  If mx==0 then no memory
993 **        allocations will ever occur.
994 */
995 void sqlite3StrAccumInit(StrAccum *p, sqlite3 *db, char *zBase, int n, int mx){
996   p->zText = zBase;
997   p->db = db;
998   p->nAlloc = n;
999   p->mxAlloc = mx;
1000   p->nChar = 0;
1001   p->accError = 0;
1002   p->printfFlags = 0;
1003 }
1004 
1005 /*
1006 ** Print into memory obtained from sqliteMalloc().  Use the internal
1007 ** %-conversion extensions.
1008 */
1009 char *sqlite3VMPrintf(sqlite3 *db, const char *zFormat, va_list ap){
1010   char *z;
1011   char zBase[SQLITE_PRINT_BUF_SIZE];
1012   StrAccum acc;
1013   assert( db!=0 );
1014   sqlite3StrAccumInit(&acc, db, zBase, sizeof(zBase),
1015                       db->aLimit[SQLITE_LIMIT_LENGTH]);
1016   acc.printfFlags = SQLITE_PRINTF_INTERNAL;
1017   sqlite3VXPrintf(&acc, zFormat, ap);
1018   z = sqlite3StrAccumFinish(&acc);
1019   if( acc.accError==STRACCUM_NOMEM ){
1020     sqlite3OomFault(db);
1021   }
1022   return z;
1023 }
1024 
1025 /*
1026 ** Print into memory obtained from sqliteMalloc().  Use the internal
1027 ** %-conversion extensions.
1028 */
1029 char *sqlite3MPrintf(sqlite3 *db, const char *zFormat, ...){
1030   va_list ap;
1031   char *z;
1032   va_start(ap, zFormat);
1033   z = sqlite3VMPrintf(db, zFormat, ap);
1034   va_end(ap);
1035   return z;
1036 }
1037 
1038 /*
1039 ** Print into memory obtained from sqlite3_malloc().  Omit the internal
1040 ** %-conversion extensions.
1041 */
1042 char *sqlite3_vmprintf(const char *zFormat, va_list ap){
1043   char *z;
1044   char zBase[SQLITE_PRINT_BUF_SIZE];
1045   StrAccum acc;
1046 
1047 #ifdef SQLITE_ENABLE_API_ARMOR
1048   if( zFormat==0 ){
1049     (void)SQLITE_MISUSE_BKPT;
1050     return 0;
1051   }
1052 #endif
1053 #ifndef SQLITE_OMIT_AUTOINIT
1054   if( sqlite3_initialize() ) return 0;
1055 #endif
1056   sqlite3StrAccumInit(&acc, 0, zBase, sizeof(zBase), SQLITE_MAX_LENGTH);
1057   sqlite3VXPrintf(&acc, zFormat, ap);
1058   z = sqlite3StrAccumFinish(&acc);
1059   return z;
1060 }
1061 
1062 /*
1063 ** Print into memory obtained from sqlite3_malloc()().  Omit the internal
1064 ** %-conversion extensions.
1065 */
1066 char *sqlite3_mprintf(const char *zFormat, ...){
1067   va_list ap;
1068   char *z;
1069 #ifndef SQLITE_OMIT_AUTOINIT
1070   if( sqlite3_initialize() ) return 0;
1071 #endif
1072   va_start(ap, zFormat);
1073   z = sqlite3_vmprintf(zFormat, ap);
1074   va_end(ap);
1075   return z;
1076 }
1077 
1078 /*
1079 ** sqlite3_snprintf() works like snprintf() except that it ignores the
1080 ** current locale settings.  This is important for SQLite because we
1081 ** are not able to use a "," as the decimal point in place of "." as
1082 ** specified by some locales.
1083 **
1084 ** Oops:  The first two arguments of sqlite3_snprintf() are backwards
1085 ** from the snprintf() standard.  Unfortunately, it is too late to change
1086 ** this without breaking compatibility, so we just have to live with the
1087 ** mistake.
1088 **
1089 ** sqlite3_vsnprintf() is the varargs version.
1090 */
1091 char *sqlite3_vsnprintf(int n, char *zBuf, const char *zFormat, va_list ap){
1092   StrAccum acc;
1093   if( n<=0 ) return zBuf;
1094 #ifdef SQLITE_ENABLE_API_ARMOR
1095   if( zBuf==0 || zFormat==0 ) {
1096     (void)SQLITE_MISUSE_BKPT;
1097     if( zBuf ) zBuf[0] = 0;
1098     return zBuf;
1099   }
1100 #endif
1101   sqlite3StrAccumInit(&acc, 0, zBuf, n, 0);
1102   sqlite3VXPrintf(&acc, zFormat, ap);
1103   zBuf[acc.nChar] = 0;
1104   return zBuf;
1105 }
1106 char *sqlite3_snprintf(int n, char *zBuf, const char *zFormat, ...){
1107   char *z;
1108   va_list ap;
1109   va_start(ap,zFormat);
1110   z = sqlite3_vsnprintf(n, zBuf, zFormat, ap);
1111   va_end(ap);
1112   return z;
1113 }
1114 
1115 /*
1116 ** This is the routine that actually formats the sqlite3_log() message.
1117 ** We house it in a separate routine from sqlite3_log() to avoid using
1118 ** stack space on small-stack systems when logging is disabled.
1119 **
1120 ** sqlite3_log() must render into a static buffer.  It cannot dynamically
1121 ** allocate memory because it might be called while the memory allocator
1122 ** mutex is held.
1123 **
1124 ** sqlite3VXPrintf() might ask for *temporary* memory allocations for
1125 ** certain format characters (%q) or for very large precisions or widths.
1126 ** Care must be taken that any sqlite3_log() calls that occur while the
1127 ** memory mutex is held do not use these mechanisms.
1128 */
1129 static void renderLogMsg(int iErrCode, const char *zFormat, va_list ap){
1130   StrAccum acc;                          /* String accumulator */
1131   char zMsg[SQLITE_PRINT_BUF_SIZE*3];    /* Complete log message */
1132 
1133   sqlite3StrAccumInit(&acc, 0, zMsg, sizeof(zMsg), 0);
1134   sqlite3VXPrintf(&acc, zFormat, ap);
1135   sqlite3GlobalConfig.xLog(sqlite3GlobalConfig.pLogArg, iErrCode,
1136                            sqlite3StrAccumFinish(&acc));
1137 }
1138 
1139 /*
1140 ** Format and write a message to the log if logging is enabled.
1141 */
1142 void sqlite3_log(int iErrCode, const char *zFormat, ...){
1143   va_list ap;                             /* Vararg list */
1144   if( sqlite3GlobalConfig.xLog ){
1145     va_start(ap, zFormat);
1146     renderLogMsg(iErrCode, zFormat, ap);
1147     va_end(ap);
1148   }
1149 }
1150 
1151 #if defined(SQLITE_DEBUG) || defined(SQLITE_HAVE_OS_TRACE)
1152 /*
1153 ** A version of printf() that understands %lld.  Used for debugging.
1154 ** The printf() built into some versions of windows does not understand %lld
1155 ** and segfaults if you give it a long long int.
1156 */
1157 void sqlite3DebugPrintf(const char *zFormat, ...){
1158   va_list ap;
1159   StrAccum acc;
1160   char zBuf[500];
1161   sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
1162   va_start(ap,zFormat);
1163   sqlite3VXPrintf(&acc, zFormat, ap);
1164   va_end(ap);
1165   sqlite3StrAccumFinish(&acc);
1166 #ifdef SQLITE_OS_TRACE_PROC
1167   {
1168     extern void SQLITE_OS_TRACE_PROC(const char *zBuf, int nBuf);
1169     SQLITE_OS_TRACE_PROC(zBuf, sizeof(zBuf));
1170   }
1171 #else
1172   fprintf(stdout,"%s", zBuf);
1173   fflush(stdout);
1174 #endif
1175 }
1176 #endif
1177 
1178 
1179 /*
1180 ** variable-argument wrapper around sqlite3VXPrintf().  The bFlags argument
1181 ** can contain the bit SQLITE_PRINTF_INTERNAL enable internal formats.
1182 */
1183 void sqlite3XPrintf(StrAccum *p, const char *zFormat, ...){
1184   va_list ap;
1185   va_start(ap,zFormat);
1186   sqlite3VXPrintf(p, zFormat, ap);
1187   va_end(ap);
1188 }
1189