xref: /sqlite-3.40.0/src/printf.c (revision 8a29dfde)
1 /*
2 ** The "printf" code that follows dates from the 1980's.  It is in
3 ** the public domain.  The original comments are included here for
4 ** completeness.  They are very out-of-date but might be useful as
5 ** an historical reference.  Most of the "enhancements" have been backed
6 ** out so that the functionality is now the same as standard printf().
7 **
8 **************************************************************************
9 **
10 ** The following modules is an enhanced replacement for the "printf" subroutines
11 ** found in the standard C library.  The following enhancements are
12 ** supported:
13 **
14 **      +  Additional functions.  The standard set of "printf" functions
15 **         includes printf, fprintf, sprintf, vprintf, vfprintf, and
16 **         vsprintf.  This module adds the following:
17 **
18 **           *  snprintf -- Works like sprintf, but has an extra argument
19 **                          which is the size of the buffer written to.
20 **
21 **           *  mprintf --  Similar to sprintf.  Writes output to memory
22 **                          obtained from malloc.
23 **
24 **           *  xprintf --  Calls a function to dispose of output.
25 **
26 **           *  nprintf --  No output, but returns the number of characters
27 **                          that would have been output by printf.
28 **
29 **           *  A v- version (ex: vsnprintf) of every function is also
30 **              supplied.
31 **
32 **      +  A few extensions to the formatting notation are supported:
33 **
34 **           *  The "=" flag (similar to "-") causes the output to be
35 **              be centered in the appropriately sized field.
36 **
37 **           *  The %b field outputs an integer in binary notation.
38 **
39 **           *  The %c field now accepts a precision.  The character output
40 **              is repeated by the number of times the precision specifies.
41 **
42 **           *  The %' field works like %c, but takes as its character the
43 **              next character of the format string, instead of the next
44 **              argument.  For example,  printf("%.78'-")  prints 78 minus
45 **              signs, the same as  printf("%.78c",'-').
46 **
47 **      +  When compiled using GCC on a SPARC, this version of printf is
48 **         faster than the library printf for SUN OS 4.1.
49 **
50 **      +  All functions are fully reentrant.
51 **
52 */
53 #include "sqliteInt.h"
54 
55 /*
56 ** Conversion types fall into various categories as defined by the
57 ** following enumeration.
58 */
59 #define etRADIX       1 /* Integer types.  %d, %x, %o, and so forth */
60 #define etFLOAT       2 /* Floating point.  %f */
61 #define etEXP         3 /* Exponentional notation. %e and %E */
62 #define etGENERIC     4 /* Floating or exponential, depending on exponent. %g */
63 #define etSIZE        5 /* Return number of characters processed so far. %n */
64 #define etSTRING      6 /* Strings. %s */
65 #define etDYNSTRING   7 /* Dynamically allocated strings. %z */
66 #define etPERCENT     8 /* Percent symbol. %% */
67 #define etCHARX       9 /* Characters. %c */
68 /* The rest are extensions, not normally found in printf() */
69 #define etCHARLIT    10 /* Literal characters.  %' */
70 #define etSQLESCAPE  11 /* Strings with '\'' doubled.  %q */
71 #define etSQLESCAPE2 12 /* Strings with '\'' doubled and enclosed in '',
72                           NULL pointers replaced by SQL NULL.  %Q */
73 #define etTOKEN      13 /* a pointer to a Token structure */
74 #define etSRCLIST    14 /* a pointer to a SrcList */
75 #define etPOINTER    15 /* The %p conversion */
76 #define etSQLESCAPE3 16 /* %w -> Strings with '\"' doubled */
77 #define etORDINAL    17 /* %r -> 1st, 2nd, 3rd, 4th, etc.  English only */
78 
79 
80 /*
81 ** An "etByte" is an 8-bit unsigned value.
82 */
83 typedef unsigned char etByte;
84 
85 /*
86 ** Each builtin conversion character (ex: the 'd' in "%d") is described
87 ** by an instance of the following structure
88 */
89 typedef struct et_info {   /* Information about each format field */
90   char fmttype;            /* The format field code letter */
91   etByte base;             /* The base for radix conversion */
92   etByte flags;            /* One or more of FLAG_ constants below */
93   etByte type;             /* Conversion paradigm */
94   etByte charset;          /* Offset into aDigits[] of the digits string */
95   etByte prefix;           /* Offset into aPrefix[] of the prefix string */
96 } et_info;
97 
98 /*
99 ** Allowed values for et_info.flags
100 */
101 #define FLAG_SIGNED  1     /* True if the value to convert is signed */
102 #define FLAG_INTERN  2     /* True if for internal use only */
103 #define FLAG_STRING  4     /* Allow infinity precision */
104 
105 
106 /*
107 ** The following table is searched linearly, so it is good to put the
108 ** most frequently used conversion types first.
109 */
110 static const char aDigits[] = "0123456789ABCDEF0123456789abcdef";
111 static const char aPrefix[] = "-x0\000X0";
112 static const et_info fmtinfo[] = {
113   {  'd', 10, 1, etRADIX,      0,  0 },
114   {  's',  0, 4, etSTRING,     0,  0 },
115   {  'g',  0, 1, etGENERIC,    30, 0 },
116   {  'z',  0, 4, etDYNSTRING,  0,  0 },
117   {  'q',  0, 4, etSQLESCAPE,  0,  0 },
118   {  'Q',  0, 4, etSQLESCAPE2, 0,  0 },
119   {  'w',  0, 4, etSQLESCAPE3, 0,  0 },
120   {  'c',  0, 0, etCHARX,      0,  0 },
121   {  'o',  8, 0, etRADIX,      0,  2 },
122   {  'u', 10, 0, etRADIX,      0,  0 },
123   {  'x', 16, 0, etRADIX,      16, 1 },
124   {  'X', 16, 0, etRADIX,      0,  4 },
125 #ifndef SQLITE_OMIT_FLOATING_POINT
126   {  'f',  0, 1, etFLOAT,      0,  0 },
127   {  'e',  0, 1, etEXP,        30, 0 },
128   {  'E',  0, 1, etEXP,        14, 0 },
129   {  'G',  0, 1, etGENERIC,    14, 0 },
130 #endif
131   {  'i', 10, 1, etRADIX,      0,  0 },
132   {  'n',  0, 0, etSIZE,       0,  0 },
133   {  '%',  0, 0, etPERCENT,    0,  0 },
134   {  'p', 16, 0, etPOINTER,    0,  1 },
135   {  'T',  0, 2, etTOKEN,      0,  0 },
136   {  'S',  0, 2, etSRCLIST,    0,  0 },
137   {  'r', 10, 3, etORDINAL,    0,  0 },
138 };
139 #define etNINFO  (sizeof(fmtinfo)/sizeof(fmtinfo[0]))
140 
141 /*
142 ** If SQLITE_OMIT_FLOATING_POINT is defined, then none of the floating point
143 ** conversions will work.
144 */
145 #ifndef SQLITE_OMIT_FLOATING_POINT
146 /*
147 ** "*val" is a double such that 0.1 <= *val < 10.0
148 ** Return the ascii code for the leading digit of *val, then
149 ** multiply "*val" by 10.0 to renormalize.
150 **
151 ** Example:
152 **     input:     *val = 3.14159
153 **     output:    *val = 1.4159    function return = '3'
154 **
155 ** The counter *cnt is incremented each time.  After counter exceeds
156 ** 16 (the number of significant digits in a 64-bit float) '0' is
157 ** always returned.
158 */
159 static int et_getdigit(LONGDOUBLE_TYPE *val, int *cnt){
160   int digit;
161   LONGDOUBLE_TYPE d;
162   if( (*cnt)++ >= 16 ) return '0';
163   digit = (int)*val;
164   d = digit;
165   digit += '0';
166   *val = (*val - d)*10.0;
167   return digit;
168 }
169 #endif /* SQLITE_OMIT_FLOATING_POINT */
170 
171 /*
172 ** Append N space characters to the given string buffer.
173 */
174 static void appendSpace(StrAccum *pAccum, int N){
175   static const char zSpaces[] = "                             ";
176   while( N>=sizeof(zSpaces)-1 ){
177     sqlite3StrAccumAppend(pAccum, zSpaces, sizeof(zSpaces)-1);
178     N -= sizeof(zSpaces)-1;
179   }
180   if( N>0 ){
181     sqlite3StrAccumAppend(pAccum, zSpaces, N);
182   }
183 }
184 
185 /*
186 ** On machines with a small stack size, you can redefine the
187 ** SQLITE_PRINT_BUF_SIZE to be less than 350.  But beware - for
188 ** smaller values some %f conversions may go into an infinite loop.
189 */
190 #ifndef SQLITE_PRINT_BUF_SIZE
191 # define SQLITE_PRINT_BUF_SIZE 350
192 #endif
193 #define etBUFSIZE SQLITE_PRINT_BUF_SIZE  /* Size of the output buffer */
194 
195 /*
196 ** The root program.  All variations call this core.
197 **
198 ** INPUTS:
199 **   func   This is a pointer to a function taking three arguments
200 **            1. A pointer to anything.  Same as the "arg" parameter.
201 **            2. A pointer to the list of characters to be output
202 **               (Note, this list is NOT null terminated.)
203 **            3. An integer number of characters to be output.
204 **               (Note: This number might be zero.)
205 **
206 **   arg    This is the pointer to anything which will be passed as the
207 **          first argument to "func".  Use it for whatever you like.
208 **
209 **   fmt    This is the format string, as in the usual print.
210 **
211 **   ap     This is a pointer to a list of arguments.  Same as in
212 **          vfprint.
213 **
214 ** OUTPUTS:
215 **          The return value is the total number of characters sent to
216 **          the function "func".  Returns -1 on a error.
217 **
218 ** Note that the order in which automatic variables are declared below
219 ** seems to make a big difference in determining how fast this beast
220 ** will run.
221 */
222 static void vxprintf(
223   StrAccum *pAccum,                  /* Accumulate results here */
224   int useExtended,                   /* Allow extended %-conversions */
225   const char *fmt,                   /* Format string */
226   va_list ap                         /* arguments */
227 ){
228   int c;                     /* Next character in the format string */
229   char *bufpt;               /* Pointer to the conversion buffer */
230   int precision;             /* Precision of the current field */
231   int length;                /* Length of the field */
232   int idx;                   /* A general purpose loop counter */
233   int width;                 /* Width of the current field */
234   etByte flag_leftjustify;   /* True if "-" flag is present */
235   etByte flag_plussign;      /* True if "+" flag is present */
236   etByte flag_blanksign;     /* True if " " flag is present */
237   etByte flag_alternateform; /* True if "#" flag is present */
238   etByte flag_altform2;      /* True if "!" flag is present */
239   etByte flag_zeropad;       /* True if field width constant starts with zero */
240   etByte flag_long;          /* True if "l" flag is present */
241   etByte flag_longlong;      /* True if the "ll" flag is present */
242   etByte done;               /* Loop termination flag */
243   sqlite_uint64 longvalue;   /* Value for integer types */
244   LONGDOUBLE_TYPE realvalue; /* Value for real types */
245   const et_info *infop;      /* Pointer to the appropriate info structure */
246   char buf[etBUFSIZE];       /* Conversion buffer */
247   char prefix;               /* Prefix character.  "+" or "-" or " " or '\0'. */
248   etByte errorflag = 0;      /* True if an error is encountered */
249   etByte xtype;              /* Conversion paradigm */
250   char *zExtra;              /* Extra memory used for etTCLESCAPE conversions */
251 #ifndef SQLITE_OMIT_FLOATING_POINT
252   int  exp, e2;              /* exponent of real numbers */
253   double rounder;            /* Used for rounding floating point values */
254   etByte flag_dp;            /* True if decimal point should be shown */
255   etByte flag_rtz;           /* True if trailing zeros should be removed */
256   etByte flag_exp;           /* True to force display of the exponent */
257   int nsd;                   /* Number of significant digits returned */
258 #endif
259 
260   length = 0;
261   bufpt = 0;
262   for(; (c=(*fmt))!=0; ++fmt){
263     if( c!='%' ){
264       int amt;
265       bufpt = (char *)fmt;
266       amt = 1;
267       while( (c=(*++fmt))!='%' && c!=0 ) amt++;
268       sqlite3StrAccumAppend(pAccum, bufpt, amt);
269       if( c==0 ) break;
270     }
271     if( (c=(*++fmt))==0 ){
272       errorflag = 1;
273       sqlite3StrAccumAppend(pAccum, "%", 1);
274       break;
275     }
276     /* Find out what flags are present */
277     flag_leftjustify = flag_plussign = flag_blanksign =
278      flag_alternateform = flag_altform2 = flag_zeropad = 0;
279     done = 0;
280     do{
281       switch( c ){
282         case '-':   flag_leftjustify = 1;     break;
283         case '+':   flag_plussign = 1;        break;
284         case ' ':   flag_blanksign = 1;       break;
285         case '#':   flag_alternateform = 1;   break;
286         case '!':   flag_altform2 = 1;        break;
287         case '0':   flag_zeropad = 1;         break;
288         default:    done = 1;                 break;
289       }
290     }while( !done && (c=(*++fmt))!=0 );
291     /* Get the field width */
292     width = 0;
293     if( c=='*' ){
294       width = va_arg(ap,int);
295       if( width<0 ){
296         flag_leftjustify = 1;
297         width = -width;
298       }
299       c = *++fmt;
300     }else{
301       while( c>='0' && c<='9' ){
302         width = width*10 + c - '0';
303         c = *++fmt;
304       }
305     }
306     if( width > etBUFSIZE-10 ){
307       width = etBUFSIZE-10;
308     }
309     /* Get the precision */
310     if( c=='.' ){
311       precision = 0;
312       c = *++fmt;
313       if( c=='*' ){
314         precision = va_arg(ap,int);
315         if( precision<0 ) precision = -precision;
316         c = *++fmt;
317       }else{
318         while( c>='0' && c<='9' ){
319           precision = precision*10 + c - '0';
320           c = *++fmt;
321         }
322       }
323     }else{
324       precision = -1;
325     }
326     /* Get the conversion type modifier */
327     if( c=='l' ){
328       flag_long = 1;
329       c = *++fmt;
330       if( c=='l' ){
331         flag_longlong = 1;
332         c = *++fmt;
333       }else{
334         flag_longlong = 0;
335       }
336     }else{
337       flag_long = flag_longlong = 0;
338     }
339     /* Fetch the info entry for the field */
340     infop = 0;
341     for(idx=0; idx<etNINFO; idx++){
342       if( c==fmtinfo[idx].fmttype ){
343         infop = &fmtinfo[idx];
344         if( useExtended || (infop->flags & FLAG_INTERN)==0 ){
345           xtype = infop->type;
346         }else{
347           return;
348         }
349         break;
350       }
351     }
352     zExtra = 0;
353     if( infop==0 ){
354       return;
355     }
356 
357 
358     /* Limit the precision to prevent overflowing buf[] during conversion */
359     if( precision>etBUFSIZE-40 && (infop->flags & FLAG_STRING)==0 ){
360       precision = etBUFSIZE-40;
361     }
362 
363     /*
364     ** At this point, variables are initialized as follows:
365     **
366     **   flag_alternateform          TRUE if a '#' is present.
367     **   flag_altform2               TRUE if a '!' is present.
368     **   flag_plussign               TRUE if a '+' is present.
369     **   flag_leftjustify            TRUE if a '-' is present or if the
370     **                               field width was negative.
371     **   flag_zeropad                TRUE if the width began with 0.
372     **   flag_long                   TRUE if the letter 'l' (ell) prefixed
373     **                               the conversion character.
374     **   flag_longlong               TRUE if the letter 'll' (ell ell) prefixed
375     **                               the conversion character.
376     **   flag_blanksign              TRUE if a ' ' is present.
377     **   width                       The specified field width.  This is
378     **                               always non-negative.  Zero is the default.
379     **   precision                   The specified precision.  The default
380     **                               is -1.
381     **   xtype                       The class of the conversion.
382     **   infop                       Pointer to the appropriate info struct.
383     */
384     switch( xtype ){
385       case etPOINTER:
386         flag_longlong = sizeof(char*)==sizeof(i64);
387         flag_long = sizeof(char*)==sizeof(long int);
388         /* Fall through into the next case */
389       case etORDINAL:
390       case etRADIX:
391         if( infop->flags & FLAG_SIGNED ){
392           i64 v;
393           if( flag_longlong )   v = va_arg(ap,i64);
394           else if( flag_long )  v = va_arg(ap,long int);
395           else                  v = va_arg(ap,int);
396           if( v<0 ){
397             longvalue = -v;
398             prefix = '-';
399           }else{
400             longvalue = v;
401             if( flag_plussign )        prefix = '+';
402             else if( flag_blanksign )  prefix = ' ';
403             else                       prefix = 0;
404           }
405         }else{
406           if( flag_longlong )   longvalue = va_arg(ap,u64);
407           else if( flag_long )  longvalue = va_arg(ap,unsigned long int);
408           else                  longvalue = va_arg(ap,unsigned int);
409           prefix = 0;
410         }
411         if( longvalue==0 ) flag_alternateform = 0;
412         if( flag_zeropad && precision<width-(prefix!=0) ){
413           precision = width-(prefix!=0);
414         }
415         bufpt = &buf[etBUFSIZE-1];
416         if( xtype==etORDINAL ){
417           static const char zOrd[] = "thstndrd";
418           int x = longvalue % 10;
419           if( x>=4 || (longvalue/10)%10==1 ){
420             x = 0;
421           }
422           buf[etBUFSIZE-3] = zOrd[x*2];
423           buf[etBUFSIZE-2] = zOrd[x*2+1];
424           bufpt -= 2;
425         }
426         {
427           register const char *cset;      /* Use registers for speed */
428           register int base;
429           cset = &aDigits[infop->charset];
430           base = infop->base;
431           do{                                           /* Convert to ascii */
432             *(--bufpt) = cset[longvalue%base];
433             longvalue = longvalue/base;
434           }while( longvalue>0 );
435         }
436         length = &buf[etBUFSIZE-1]-bufpt;
437         for(idx=precision-length; idx>0; idx--){
438           *(--bufpt) = '0';                             /* Zero pad */
439         }
440         if( prefix ) *(--bufpt) = prefix;               /* Add sign */
441         if( flag_alternateform && infop->prefix ){      /* Add "0" or "0x" */
442           const char *pre;
443           char x;
444           pre = &aPrefix[infop->prefix];
445           if( *bufpt!=pre[0] ){
446             for(; (x=(*pre))!=0; pre++) *(--bufpt) = x;
447           }
448         }
449         length = &buf[etBUFSIZE-1]-bufpt;
450         break;
451       case etFLOAT:
452       case etEXP:
453       case etGENERIC:
454         realvalue = va_arg(ap,double);
455 #ifndef SQLITE_OMIT_FLOATING_POINT
456         if( precision<0 ) precision = 6;         /* Set default precision */
457         if( precision>etBUFSIZE/2-10 ) precision = etBUFSIZE/2-10;
458         if( realvalue<0.0 ){
459           realvalue = -realvalue;
460           prefix = '-';
461         }else{
462           if( flag_plussign )          prefix = '+';
463           else if( flag_blanksign )    prefix = ' ';
464           else                         prefix = 0;
465         }
466         if( xtype==etGENERIC && precision>0 ) precision--;
467 #if 0
468         /* Rounding works like BSD when the constant 0.4999 is used.  Wierd! */
469         for(idx=precision, rounder=0.4999; idx>0; idx--, rounder*=0.1);
470 #else
471         /* It makes more sense to use 0.5 */
472         for(idx=precision, rounder=0.5; idx>0; idx--, rounder*=0.1){}
473 #endif
474         if( xtype==etFLOAT ) realvalue += rounder;
475         /* Normalize realvalue to within 10.0 > realvalue >= 1.0 */
476         exp = 0;
477         if( sqlite3_isnan(realvalue) ){
478           bufpt = "NaN";
479           length = 3;
480           break;
481         }
482         if( realvalue>0.0 ){
483           while( realvalue>=1e32 && exp<=350 ){ realvalue *= 1e-32; exp+=32; }
484           while( realvalue>=1e8 && exp<=350 ){ realvalue *= 1e-8; exp+=8; }
485           while( realvalue>=10.0 && exp<=350 ){ realvalue *= 0.1; exp++; }
486           while( realvalue<1e-8 && exp>=-350 ){ realvalue *= 1e8; exp-=8; }
487           while( realvalue<1.0 && exp>=-350 ){ realvalue *= 10.0; exp--; }
488           if( exp>350 || exp<-350 ){
489             if( prefix=='-' ){
490               bufpt = "-Inf";
491             }else if( prefix=='+' ){
492               bufpt = "+Inf";
493             }else{
494               bufpt = "Inf";
495             }
496             length = strlen(bufpt);
497             break;
498           }
499         }
500         bufpt = buf;
501         /*
502         ** If the field type is etGENERIC, then convert to either etEXP
503         ** or etFLOAT, as appropriate.
504         */
505         flag_exp = xtype==etEXP;
506         if( xtype!=etFLOAT ){
507           realvalue += rounder;
508           if( realvalue>=10.0 ){ realvalue *= 0.1; exp++; }
509         }
510         if( xtype==etGENERIC ){
511           flag_rtz = !flag_alternateform;
512           if( exp<-4 || exp>precision ){
513             xtype = etEXP;
514           }else{
515             precision = precision - exp;
516             xtype = etFLOAT;
517           }
518         }else{
519           flag_rtz = 0;
520         }
521         if( xtype==etEXP ){
522           e2 = 0;
523         }else{
524           e2 = exp;
525         }
526         nsd = 0;
527         flag_dp = (precision>0) | flag_alternateform | flag_altform2;
528         /* The sign in front of the number */
529         if( prefix ){
530           *(bufpt++) = prefix;
531         }
532         /* Digits prior to the decimal point */
533         if( e2<0 ){
534           *(bufpt++) = '0';
535         }else{
536           for(; e2>=0; e2--){
537             *(bufpt++) = et_getdigit(&realvalue,&nsd);
538           }
539         }
540         /* The decimal point */
541         if( flag_dp ){
542           *(bufpt++) = '.';
543         }
544         /* "0" digits after the decimal point but before the first
545         ** significant digit of the number */
546         for(e2++; e2<0 && precision>0; precision--, e2++){
547           *(bufpt++) = '0';
548         }
549         /* Significant digits after the decimal point */
550         while( (precision--)>0 ){
551           *(bufpt++) = et_getdigit(&realvalue,&nsd);
552         }
553         /* Remove trailing zeros and the "." if no digits follow the "." */
554         if( flag_rtz && flag_dp ){
555           while( bufpt[-1]=='0' ) *(--bufpt) = 0;
556           assert( bufpt>buf );
557           if( bufpt[-1]=='.' ){
558             if( flag_altform2 ){
559               *(bufpt++) = '0';
560             }else{
561               *(--bufpt) = 0;
562             }
563           }
564         }
565         /* Add the "eNNN" suffix */
566         if( flag_exp || (xtype==etEXP && exp) ){
567           *(bufpt++) = aDigits[infop->charset];
568           if( exp<0 ){
569             *(bufpt++) = '-'; exp = -exp;
570           }else{
571             *(bufpt++) = '+';
572           }
573           if( exp>=100 ){
574             *(bufpt++) = (exp/100)+'0';                /* 100's digit */
575             exp %= 100;
576           }
577           *(bufpt++) = exp/10+'0';                     /* 10's digit */
578           *(bufpt++) = exp%10+'0';                     /* 1's digit */
579         }
580         *bufpt = 0;
581 
582         /* The converted number is in buf[] and zero terminated. Output it.
583         ** Note that the number is in the usual order, not reversed as with
584         ** integer conversions. */
585         length = bufpt-buf;
586         bufpt = buf;
587 
588         /* Special case:  Add leading zeros if the flag_zeropad flag is
589         ** set and we are not left justified */
590         if( flag_zeropad && !flag_leftjustify && length < width){
591           int i;
592           int nPad = width - length;
593           for(i=width; i>=nPad; i--){
594             bufpt[i] = bufpt[i-nPad];
595           }
596           i = prefix!=0;
597           while( nPad-- ) bufpt[i++] = '0';
598           length = width;
599         }
600 #endif
601         break;
602       case etSIZE:
603         *(va_arg(ap,int*)) = pAccum->nChar;
604         length = width = 0;
605         break;
606       case etPERCENT:
607         buf[0] = '%';
608         bufpt = buf;
609         length = 1;
610         break;
611       case etCHARLIT:
612       case etCHARX:
613         c = buf[0] = (xtype==etCHARX ? va_arg(ap,int) : *++fmt);
614         if( precision>=0 ){
615           for(idx=1; idx<precision; idx++) buf[idx] = c;
616           length = precision;
617         }else{
618           length =1;
619         }
620         bufpt = buf;
621         break;
622       case etSTRING:
623       case etDYNSTRING:
624         bufpt = va_arg(ap,char*);
625         if( bufpt==0 ){
626           bufpt = "";
627         }else if( xtype==etDYNSTRING ){
628           zExtra = bufpt;
629         }
630         length = strlen(bufpt);
631         if( precision>=0 && precision<length ) length = precision;
632         break;
633       case etSQLESCAPE:
634       case etSQLESCAPE2:
635       case etSQLESCAPE3: {
636         int i, j, n, ch, isnull;
637         int needQuote;
638         char q = ((xtype==etSQLESCAPE3)?'"':'\'');   /* Quote character */
639         char *escarg = va_arg(ap,char*);
640         isnull = escarg==0;
641         if( isnull ) escarg = (xtype==etSQLESCAPE2 ? "NULL" : "(NULL)");
642         for(i=n=0; (ch=escarg[i])!=0; i++){
643           if( ch==q )  n++;
644         }
645         needQuote = !isnull && xtype==etSQLESCAPE2;
646         n += i + 1 + needQuote*2;
647         if( n>etBUFSIZE ){
648           bufpt = zExtra = sqlite3_malloc( n );
649           if( bufpt==0 ) return;
650         }else{
651           bufpt = buf;
652         }
653         j = 0;
654         if( needQuote ) bufpt[j++] = q;
655         for(i=0; (ch=escarg[i])!=0; i++){
656           bufpt[j++] = ch;
657           if( ch==q ) bufpt[j++] = ch;
658         }
659         if( needQuote ) bufpt[j++] = q;
660         bufpt[j] = 0;
661         length = j;
662         /* The precision is ignored on %q and %Q */
663         /* if( precision>=0 && precision<length ) length = precision; */
664         break;
665       }
666       case etTOKEN: {
667         Token *pToken = va_arg(ap, Token*);
668         if( pToken && pToken->z ){
669           sqlite3StrAccumAppend(pAccum, (const char*)pToken->z, pToken->n);
670         }
671         length = width = 0;
672         break;
673       }
674       case etSRCLIST: {
675         SrcList *pSrc = va_arg(ap, SrcList*);
676         int k = va_arg(ap, int);
677         struct SrcList_item *pItem = &pSrc->a[k];
678         assert( k>=0 && k<pSrc->nSrc );
679         if( pItem->zDatabase && pItem->zDatabase[0] ){
680           sqlite3StrAccumAppend(pAccum, pItem->zDatabase, -1);
681           sqlite3StrAccumAppend(pAccum, ".", 1);
682         }
683         sqlite3StrAccumAppend(pAccum, pItem->zName, -1);
684         length = width = 0;
685         break;
686       }
687     }/* End switch over the format type */
688     /*
689     ** The text of the conversion is pointed to by "bufpt" and is
690     ** "length" characters long.  The field width is "width".  Do
691     ** the output.
692     */
693     if( !flag_leftjustify ){
694       register int nspace;
695       nspace = width-length;
696       if( nspace>0 ){
697         appendSpace(pAccum, nspace);
698       }
699     }
700     if( length>0 ){
701       sqlite3StrAccumAppend(pAccum, bufpt, length);
702     }
703     if( flag_leftjustify ){
704       register int nspace;
705       nspace = width-length;
706       if( nspace>0 ){
707         appendSpace(pAccum, nspace);
708       }
709     }
710     if( zExtra ){
711       sqlite3_free(zExtra);
712     }
713   }/* End for loop over the format string */
714 } /* End of function */
715 
716 /*
717 ** Append N bytes of text from z to the StrAccum object.
718 */
719 void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
720   if( p->tooBig | p->mallocFailed ){
721     return;
722   }
723   if( N<0 ){
724     N = strlen(z);
725   }
726   if( N==0 ){
727     return;
728   }
729   if( p->nChar+N >= p->nAlloc ){
730     char *zNew;
731     if( !p->useMalloc ){
732       p->tooBig = 1;
733       N = p->nAlloc - p->nChar - 1;
734       if( N<=0 ){
735         return;
736       }
737     }else{
738       i64 szNew = p->nAlloc;
739       szNew += N + 1;
740       if( szNew > p->mxAlloc ){
741         p->nAlloc = p->mxAlloc;
742         if( ((i64)p->nChar)+((i64)N) >= p->nAlloc ){
743           sqlite3StrAccumReset(p);
744           p->tooBig = 1;
745           return;
746         }
747       }else{
748         p->nAlloc = szNew;
749       }
750       zNew = sqlite3_malloc( p->nAlloc );
751       if( zNew ){
752         memcpy(zNew, p->zText, p->nChar);
753         sqlite3StrAccumReset(p);
754         p->zText = zNew;
755       }else{
756         p->mallocFailed = 1;
757         sqlite3StrAccumReset(p);
758         return;
759       }
760     }
761   }
762   memcpy(&p->zText[p->nChar], z, N);
763   p->nChar += N;
764 }
765 
766 /*
767 ** Finish off a string by making sure it is zero-terminated.
768 ** Return a pointer to the resulting string.  Return a NULL
769 ** pointer if any kind of error was encountered.
770 */
771 char *sqlite3StrAccumFinish(StrAccum *p){
772   if( p->zText ){
773     p->zText[p->nChar] = 0;
774     if( p->useMalloc && p->zText==p->zBase ){
775       p->zText = sqlite3_malloc( p->nChar+1 );
776       if( p->zText ){
777         memcpy(p->zText, p->zBase, p->nChar+1);
778       }else{
779         p->mallocFailed = 1;
780       }
781     }
782   }
783   return p->zText;
784 }
785 
786 /*
787 ** Reset an StrAccum string.  Reclaim all malloced memory.
788 */
789 void sqlite3StrAccumReset(StrAccum *p){
790   if( p->zText!=p->zBase ){
791     sqlite3_free(p->zText);
792     p->zText = 0;
793   }
794 }
795 
796 /*
797 ** Initialize a string accumulator
798 */
799 static void sqlite3StrAccumInit(StrAccum *p, char *zBase, int n, int mx){
800   p->zText = p->zBase = zBase;
801   p->nChar = 0;
802   p->nAlloc = n;
803   p->mxAlloc = mx;
804   p->useMalloc = 1;
805   p->tooBig = 0;
806   p->mallocFailed = 0;
807 }
808 
809 /*
810 ** Print into memory obtained from sqliteMalloc().  Use the internal
811 ** %-conversion extensions.
812 */
813 char *sqlite3VMPrintf(sqlite3 *db, const char *zFormat, va_list ap){
814   char *z;
815   char zBase[SQLITE_PRINT_BUF_SIZE];
816   StrAccum acc;
817   sqlite3StrAccumInit(&acc, zBase, sizeof(zBase),
818                       db ? db->aLimit[SQLITE_LIMIT_LENGTH] : SQLITE_MAX_LENGTH);
819   vxprintf(&acc, 1, zFormat, ap);
820   z = sqlite3StrAccumFinish(&acc);
821   if( acc.mallocFailed && db ){
822     db->mallocFailed = 1;
823   }
824   return z;
825 }
826 
827 /*
828 ** Print into memory obtained from sqliteMalloc().  Use the internal
829 ** %-conversion extensions.
830 */
831 char *sqlite3MPrintf(sqlite3 *db, const char *zFormat, ...){
832   va_list ap;
833   char *z;
834   va_start(ap, zFormat);
835   z = sqlite3VMPrintf(db, zFormat, ap);
836   va_end(ap);
837   return z;
838 }
839 
840 /*
841 ** Print into memory obtained from sqlite3_malloc().  Omit the internal
842 ** %-conversion extensions.
843 */
844 char *sqlite3_vmprintf(const char *zFormat, va_list ap){
845   char *z;
846   char zBase[SQLITE_PRINT_BUF_SIZE];
847   StrAccum acc;
848   sqlite3StrAccumInit(&acc, zBase, sizeof(zBase), SQLITE_MAX_LENGTH);
849   vxprintf(&acc, 0, zFormat, ap);
850   z = sqlite3StrAccumFinish(&acc);
851   return z;
852 }
853 
854 /*
855 ** Print into memory obtained from sqlite3_malloc()().  Omit the internal
856 ** %-conversion extensions.
857 */
858 char *sqlite3_mprintf(const char *zFormat, ...){
859   va_list ap;
860   char *z;
861   va_start(ap, zFormat);
862   z = sqlite3_vmprintf(zFormat, ap);
863   va_end(ap);
864   return z;
865 }
866 
867 /*
868 ** sqlite3_snprintf() works like snprintf() except that it ignores the
869 ** current locale settings.  This is important for SQLite because we
870 ** are not able to use a "," as the decimal point in place of "." as
871 ** specified by some locales.
872 */
873 char *sqlite3_snprintf(int n, char *zBuf, const char *zFormat, ...){
874   char *z;
875   va_list ap;
876   StrAccum acc;
877 
878   if( n<=0 ){
879     return zBuf;
880   }
881   sqlite3StrAccumInit(&acc, zBuf, n, 0);
882   acc.useMalloc = 0;
883   va_start(ap,zFormat);
884   vxprintf(&acc, 0, zFormat, ap);
885   va_end(ap);
886   z = sqlite3StrAccumFinish(&acc);
887   return z;
888 }
889 
890 #if defined(SQLITE_TEST) || defined(SQLITE_DEBUG) || defined(SQLITE_MEMDEBUG)
891 /*
892 ** A version of printf() that understands %lld.  Used for debugging.
893 ** The printf() built into some versions of windows does not understand %lld
894 ** and segfaults if you give it a long long int.
895 */
896 void sqlite3DebugPrintf(const char *zFormat, ...){
897   va_list ap;
898   StrAccum acc;
899   char zBuf[500];
900   sqlite3StrAccumInit(&acc, zBuf, sizeof(zBuf), 0);
901   acc.useMalloc = 0;
902   va_start(ap,zFormat);
903   vxprintf(&acc, 0, zFormat, ap);
904   va_end(ap);
905   sqlite3StrAccumFinish(&acc);
906   fprintf(stdout,"%s", zBuf);
907   fflush(stdout);
908 }
909 #endif
910