xref: /sqlite-3.40.0/src/printf.c (revision 6695f47e)
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  They are very out-of-date but might be useful as
5 ** an historical reference.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 etSQLESCAPE  10 /* Strings with '\'' doubled.  %q */
70 #define etSQLESCAPE2 11 /* Strings with '\'' doubled and enclosed in '',
71                           NULL pointers replaced by SQL NULL.  %Q */
72 #define etTOKEN      12 /* a pointer to a Token structure */
73 #define etSRCLIST    13 /* a pointer to a SrcList */
74 #define etPOINTER    14 /* The %p conversion */
75 #define etSQLESCAPE3 15 /* %w -> Strings with '\"' doubled */
76 #define etORDINAL    16 /* %r -> 1st, 2nd, 3rd, 4th, etc.  English only */
77 
78 #define etINVALID     0 /* Any unrecognized conversion type */
79 
80 
81 /*
82 ** An "etByte" is an 8-bit unsigned value.
83 */
84 typedef unsigned char etByte;
85 
86 /*
87 ** Each builtin conversion character (ex: the 'd' in "%d") is described
88 ** by an instance of the following structure
89 */
90 typedef struct et_info {   /* Information about each format field */
91   char fmttype;            /* The format field code letter */
92   etByte base;             /* The base for radix conversion */
93   etByte flags;            /* One or more of FLAG_ constants below */
94   etByte type;             /* Conversion paradigm */
95   etByte charset;          /* Offset into aDigits[] of the digits string */
96   etByte prefix;           /* Offset into aPrefix[] of the prefix string */
97 } et_info;
98 
99 /*
100 ** Allowed values for et_info.flags
101 */
102 #define FLAG_SIGNED  1     /* True if the value to convert is signed */
103 #define FLAG_INTERN  2     /* True if for internal use only */
104 #define FLAG_STRING  4     /* Allow infinity precision */
105 
106 
107 /*
108 ** The following table is searched linearly, so it is good to put the
109 ** most frequently used conversion types first.
110 */
111 static const char aDigits[] = "0123456789ABCDEF0123456789abcdef";
112 static const char aPrefix[] = "-x0\000X0";
113 static const et_info fmtinfo[] = {
114   {  'd', 10, 1, etRADIX,      0,  0 },
115   {  's',  0, 4, etSTRING,     0,  0 },
116   {  'g',  0, 1, etGENERIC,    30, 0 },
117   {  'z',  0, 4, etDYNSTRING,  0,  0 },
118   {  'q',  0, 4, etSQLESCAPE,  0,  0 },
119   {  'Q',  0, 4, etSQLESCAPE2, 0,  0 },
120   {  'w',  0, 4, etSQLESCAPE3, 0,  0 },
121   {  'c',  0, 0, etCHARX,      0,  0 },
122   {  'o',  8, 0, etRADIX,      0,  2 },
123   {  'u', 10, 0, etRADIX,      0,  0 },
124   {  'x', 16, 0, etRADIX,      16, 1 },
125   {  'X', 16, 0, etRADIX,      0,  4 },
126 #ifndef SQLITE_OMIT_FLOATING_POINT
127   {  'f',  0, 1, etFLOAT,      0,  0 },
128   {  'e',  0, 1, etEXP,        30, 0 },
129   {  'E',  0, 1, etEXP,        14, 0 },
130   {  'G',  0, 1, etGENERIC,    14, 0 },
131 #endif
132   {  'i', 10, 1, etRADIX,      0,  0 },
133   {  'n',  0, 0, etSIZE,       0,  0 },
134   {  '%',  0, 0, etPERCENT,    0,  0 },
135   {  'p', 16, 0, etPOINTER,    0,  1 },
136 
137 /* All the rest have the FLAG_INTERN bit set and are thus for internal
138 ** use only */
139   {  'T',  0, 2, etTOKEN,      0,  0 },
140   {  'S',  0, 2, etSRCLIST,    0,  0 },
141   {  'r', 10, 3, etORDINAL,    0,  0 },
142 };
143 
144 /*
145 ** If SQLITE_OMIT_FLOATING_POINT is defined, then none of the floating point
146 ** conversions will work.
147 */
148 #ifndef SQLITE_OMIT_FLOATING_POINT
149 /*
150 ** "*val" is a double such that 0.1 <= *val < 10.0
151 ** Return the ascii code for the leading digit of *val, then
152 ** multiply "*val" by 10.0 to renormalize.
153 **
154 ** Example:
155 **     input:     *val = 3.14159
156 **     output:    *val = 1.4159    function return = '3'
157 **
158 ** The counter *cnt is incremented each time.  After counter exceeds
159 ** 16 (the number of significant digits in a 64-bit float) '0' is
160 ** always returned.
161 */
162 static char et_getdigit(LONGDOUBLE_TYPE *val, int *cnt){
163   int digit;
164   LONGDOUBLE_TYPE d;
165   if( (*cnt)++ >= 16 ) return '0';
166   digit = (int)*val;
167   d = digit;
168   digit += '0';
169   *val = (*val - d)*10.0;
170   return (char)digit;
171 }
172 #endif /* SQLITE_OMIT_FLOATING_POINT */
173 
174 /*
175 ** Append N space characters to the given string buffer.
176 */
177 static void appendSpace(StrAccum *pAccum, int N){
178   static const char zSpaces[] = "                             ";
179   while( N>=(int)sizeof(zSpaces)-1 ){
180     sqlite3StrAccumAppend(pAccum, zSpaces, sizeof(zSpaces)-1);
181     N -= sizeof(zSpaces)-1;
182   }
183   if( N>0 ){
184     sqlite3StrAccumAppend(pAccum, zSpaces, N);
185   }
186 }
187 
188 /*
189 ** On machines with a small stack size, you can redefine the
190 ** SQLITE_PRINT_BUF_SIZE to be less than 350.
191 */
192 #ifndef SQLITE_PRINT_BUF_SIZE
193 # if defined(SQLITE_SMALL_STACK)
194 #   define SQLITE_PRINT_BUF_SIZE 50
195 # else
196 #   define SQLITE_PRINT_BUF_SIZE 350
197 # endif
198 #endif
199 #define etBUFSIZE SQLITE_PRINT_BUF_SIZE  /* Size of the output buffer */
200 
201 /*
202 ** The root program.  All variations call this core.
203 **
204 ** INPUTS:
205 **   func   This is a pointer to a function taking three arguments
206 **            1. A pointer to anything.  Same as the "arg" parameter.
207 **            2. A pointer to the list of characters to be output
208 **               (Note, this list is NOT null terminated.)
209 **            3. An integer number of characters to be output.
210 **               (Note: This number might be zero.)
211 **
212 **   arg    This is the pointer to anything which will be passed as the
213 **          first argument to "func".  Use it for whatever you like.
214 **
215 **   fmt    This is the format string, as in the usual print.
216 **
217 **   ap     This is a pointer to a list of arguments.  Same as in
218 **          vfprint.
219 **
220 ** OUTPUTS:
221 **          The return value is the total number of characters sent to
222 **          the function "func".  Returns -1 on a error.
223 **
224 ** Note that the order in which automatic variables are declared below
225 ** seems to make a big difference in determining how fast this beast
226 ** will run.
227 */
228 void sqlite3VXPrintf(
229   StrAccum *pAccum,                  /* Accumulate results here */
230   int useExtended,                   /* Allow extended %-conversions */
231   const char *fmt,                   /* Format string */
232   va_list ap                         /* arguments */
233 ){
234   int c;                     /* Next character in the format string */
235   char *bufpt;               /* Pointer to the conversion buffer */
236   int precision;             /* Precision of the current field */
237   int length;                /* Length of the field */
238   int idx;                   /* A general purpose loop counter */
239   int width;                 /* Width of the current field */
240   etByte flag_leftjustify;   /* True if "-" flag is present */
241   etByte flag_plussign;      /* True if "+" flag is present */
242   etByte flag_blanksign;     /* True if " " flag is present */
243   etByte flag_alternateform; /* True if "#" flag is present */
244   etByte flag_altform2;      /* True if "!" flag is present */
245   etByte flag_zeropad;       /* True if field width constant starts with zero */
246   etByte flag_long;          /* True if "l" flag is present */
247   etByte flag_longlong;      /* True if the "ll" flag is present */
248   etByte done;               /* Loop termination flag */
249   sqlite_uint64 longvalue;   /* Value for integer types */
250   LONGDOUBLE_TYPE realvalue; /* Value for real types */
251   const et_info *infop;      /* Pointer to the appropriate info structure */
252   char buf[etBUFSIZE];       /* Conversion buffer */
253   char prefix;               /* Prefix character.  "+" or "-" or " " or '\0'. */
254   etByte xtype = 0;          /* Conversion paradigm */
255   char *zExtra;              /* Extra memory used for etTCLESCAPE conversions */
256 #ifndef SQLITE_OMIT_FLOATING_POINT
257   int  exp, e2;              /* exponent of real numbers */
258   double rounder;            /* Used for rounding floating point values */
259   etByte flag_dp;            /* True if decimal point should be shown */
260   etByte flag_rtz;           /* True if trailing zeros should be removed */
261   etByte flag_exp;           /* True to force display of the exponent */
262   int nsd;                   /* Number of significant digits returned */
263 #endif
264 
265   length = 0;
266   bufpt = 0;
267   for(; (c=(*fmt))!=0; ++fmt){
268     if( c!='%' ){
269       int amt;
270       bufpt = (char *)fmt;
271       amt = 1;
272       while( (c=(*++fmt))!='%' && c!=0 ) amt++;
273       sqlite3StrAccumAppend(pAccum, bufpt, amt);
274       if( c==0 ) break;
275     }
276     if( (c=(*++fmt))==0 ){
277       sqlite3StrAccumAppend(pAccum, "%", 1);
278       break;
279     }
280     /* Find out what flags are present */
281     flag_leftjustify = flag_plussign = flag_blanksign =
282      flag_alternateform = flag_altform2 = flag_zeropad = 0;
283     done = 0;
284     do{
285       switch( c ){
286         case '-':   flag_leftjustify = 1;     break;
287         case '+':   flag_plussign = 1;        break;
288         case ' ':   flag_blanksign = 1;       break;
289         case '#':   flag_alternateform = 1;   break;
290         case '!':   flag_altform2 = 1;        break;
291         case '0':   flag_zeropad = 1;         break;
292         default:    done = 1;                 break;
293       }
294     }while( !done && (c=(*++fmt))!=0 );
295     /* Get the field width */
296     width = 0;
297     if( c=='*' ){
298       width = va_arg(ap,int);
299       if( width<0 ){
300         flag_leftjustify = 1;
301         width = -width;
302       }
303       c = *++fmt;
304     }else{
305       while( c>='0' && c<='9' ){
306         width = width*10 + c - '0';
307         c = *++fmt;
308       }
309     }
310     if( width > etBUFSIZE-10 ){
311       width = etBUFSIZE-10;
312     }
313     /* Get the precision */
314     if( c=='.' ){
315       precision = 0;
316       c = *++fmt;
317       if( c=='*' ){
318         precision = va_arg(ap,int);
319         if( precision<0 ) precision = -precision;
320         c = *++fmt;
321       }else{
322         while( c>='0' && c<='9' ){
323           precision = precision*10 + c - '0';
324           c = *++fmt;
325         }
326       }
327     }else{
328       precision = -1;
329     }
330     /* Get the conversion type modifier */
331     if( c=='l' ){
332       flag_long = 1;
333       c = *++fmt;
334       if( c=='l' ){
335         flag_longlong = 1;
336         c = *++fmt;
337       }else{
338         flag_longlong = 0;
339       }
340     }else{
341       flag_long = flag_longlong = 0;
342     }
343     /* Fetch the info entry for the field */
344     infop = &fmtinfo[0];
345     xtype = etINVALID;
346     for(idx=0; idx<ArraySize(fmtinfo); idx++){
347       if( c==fmtinfo[idx].fmttype ){
348         infop = &fmtinfo[idx];
349         if( useExtended || (infop->flags & FLAG_INTERN)==0 ){
350           xtype = infop->type;
351         }else{
352           return;
353         }
354         break;
355       }
356     }
357     zExtra = 0;
358 
359 
360     /* Limit the precision to prevent overflowing buf[] during conversion */
361     if( precision>etBUFSIZE-40 && (infop->flags & FLAG_STRING)==0 ){
362       precision = etBUFSIZE-40;
363     }
364 
365     /*
366     ** At this point, variables are initialized as follows:
367     **
368     **   flag_alternateform          TRUE if a '#' is present.
369     **   flag_altform2               TRUE if a '!' is present.
370     **   flag_plussign               TRUE if a '+' is present.
371     **   flag_leftjustify            TRUE if a '-' is present or if the
372     **                               field width was negative.
373     **   flag_zeropad                TRUE if the width began with 0.
374     **   flag_long                   TRUE if the letter 'l' (ell) prefixed
375     **                               the conversion character.
376     **   flag_longlong               TRUE if the letter 'll' (ell ell) prefixed
377     **                               the conversion character.
378     **   flag_blanksign              TRUE if a ' ' is present.
379     **   width                       The specified field width.  This is
380     **                               always non-negative.  Zero is the default.
381     **   precision                   The specified precision.  The default
382     **                               is -1.
383     **   xtype                       The class of the conversion.
384     **   infop                       Pointer to the appropriate info struct.
385     */
386     switch( xtype ){
387       case etPOINTER:
388         flag_longlong = sizeof(char*)==sizeof(i64);
389         flag_long = sizeof(char*)==sizeof(long int);
390         /* Fall through into the next case */
391       case etORDINAL:
392       case etRADIX:
393         if( infop->flags & FLAG_SIGNED ){
394           i64 v;
395           if( flag_longlong ){
396             v = va_arg(ap,i64);
397           }else if( flag_long ){
398             v = va_arg(ap,long int);
399           }else{
400             v = va_arg(ap,int);
401           }
402           if( v<0 ){
403             longvalue = -v;
404             prefix = '-';
405           }else{
406             longvalue = v;
407             if( flag_plussign )        prefix = '+';
408             else if( flag_blanksign )  prefix = ' ';
409             else                       prefix = 0;
410           }
411         }else{
412           if( flag_longlong ){
413             longvalue = va_arg(ap,u64);
414           }else if( flag_long ){
415             longvalue = va_arg(ap,unsigned long int);
416           }else{
417             longvalue = va_arg(ap,unsigned int);
418           }
419           prefix = 0;
420         }
421         if( longvalue==0 ) flag_alternateform = 0;
422         if( flag_zeropad && precision<width-(prefix!=0) ){
423           precision = width-(prefix!=0);
424         }
425         bufpt = &buf[etBUFSIZE-1];
426         if( xtype==etORDINAL ){
427           static const char zOrd[] = "thstndrd";
428           int x = (int)(longvalue % 10);
429           if( x>=4 || (longvalue/10)%10==1 ){
430             x = 0;
431           }
432           buf[etBUFSIZE-3] = zOrd[x*2];
433           buf[etBUFSIZE-2] = zOrd[x*2+1];
434           bufpt -= 2;
435         }
436         {
437           register const char *cset;      /* Use registers for speed */
438           register int base;
439           cset = &aDigits[infop->charset];
440           base = infop->base;
441           do{                                           /* Convert to ascii */
442             *(--bufpt) = cset[longvalue%base];
443             longvalue = longvalue/base;
444           }while( longvalue>0 );
445         }
446         length = (int)(&buf[etBUFSIZE-1]-bufpt);
447         for(idx=precision-length; idx>0; idx--){
448           *(--bufpt) = '0';                             /* Zero pad */
449         }
450         if( prefix ) *(--bufpt) = prefix;               /* Add sign */
451         if( flag_alternateform && infop->prefix ){      /* Add "0" or "0x" */
452           const char *pre;
453           char x;
454           pre = &aPrefix[infop->prefix];
455           for(; (x=(*pre))!=0; pre++) *(--bufpt) = x;
456         }
457         length = (int)(&buf[etBUFSIZE-1]-bufpt);
458         break;
459       case etFLOAT:
460       case etEXP:
461       case etGENERIC:
462         realvalue = va_arg(ap,double);
463 #ifndef SQLITE_OMIT_FLOATING_POINT
464         if( precision<0 ) precision = 6;         /* Set default precision */
465         if( precision>etBUFSIZE/2-10 ) precision = etBUFSIZE/2-10;
466         if( realvalue<0.0 ){
467           realvalue = -realvalue;
468           prefix = '-';
469         }else{
470           if( flag_plussign )          prefix = '+';
471           else if( flag_blanksign )    prefix = ' ';
472           else                         prefix = 0;
473         }
474         if( xtype==etGENERIC && precision>0 ) precision--;
475 #if 0
476         /* Rounding works like BSD when the constant 0.4999 is used.  Wierd! */
477         for(idx=precision, rounder=0.4999; idx>0; idx--, rounder*=0.1);
478 #else
479         /* It makes more sense to use 0.5 */
480         for(idx=precision, rounder=0.5; idx>0; idx--, rounder*=0.1){}
481 #endif
482         if( xtype==etFLOAT ) realvalue += rounder;
483         /* Normalize realvalue to within 10.0 > realvalue >= 1.0 */
484         exp = 0;
485         if( sqlite3IsNaN((double)realvalue) ){
486           bufpt = "NaN";
487           length = 3;
488           break;
489         }
490         if( realvalue>0.0 ){
491           while( realvalue>=1e32 && exp<=350 ){ realvalue *= 1e-32; exp+=32; }
492           while( realvalue>=1e8 && exp<=350 ){ realvalue *= 1e-8; exp+=8; }
493           while( realvalue>=10.0 && exp<=350 ){ realvalue *= 0.1; exp++; }
494           while( realvalue<1e-8 ){ realvalue *= 1e8; exp-=8; }
495           while( realvalue<1.0 ){ realvalue *= 10.0; exp--; }
496           if( exp>350 ){
497             if( prefix=='-' ){
498               bufpt = "-Inf";
499             }else if( prefix=='+' ){
500               bufpt = "+Inf";
501             }else{
502               bufpt = "Inf";
503             }
504             length = sqlite3Strlen30(bufpt);
505             break;
506           }
507         }
508         bufpt = buf;
509         /*
510         ** If the field type is etGENERIC, then convert to either etEXP
511         ** or etFLOAT, as appropriate.
512         */
513         flag_exp = xtype==etEXP;
514         if( xtype!=etFLOAT ){
515           realvalue += rounder;
516           if( realvalue>=10.0 ){ realvalue *= 0.1; exp++; }
517         }
518         if( xtype==etGENERIC ){
519           flag_rtz = !flag_alternateform;
520           if( exp<-4 || exp>precision ){
521             xtype = etEXP;
522           }else{
523             precision = precision - exp;
524             xtype = etFLOAT;
525           }
526         }else{
527           flag_rtz = 0;
528         }
529         if( xtype==etEXP ){
530           e2 = 0;
531         }else{
532           e2 = exp;
533         }
534         nsd = 0;
535         flag_dp = (precision>0 ?1:0) | flag_alternateform | flag_altform2;
536         /* The sign in front of the number */
537         if( prefix ){
538           *(bufpt++) = prefix;
539         }
540         /* Digits prior to the decimal point */
541         if( e2<0 ){
542           *(bufpt++) = '0';
543         }else{
544           for(; e2>=0; e2--){
545             *(bufpt++) = et_getdigit(&realvalue,&nsd);
546           }
547         }
548         /* The decimal point */
549         if( flag_dp ){
550           *(bufpt++) = '.';
551         }
552         /* "0" digits after the decimal point but before the first
553         ** significant digit of the number */
554         for(e2++; e2<0; precision--, e2++){
555           assert( precision>0 );
556           *(bufpt++) = '0';
557         }
558         /* Significant digits after the decimal point */
559         while( (precision--)>0 ){
560           *(bufpt++) = et_getdigit(&realvalue,&nsd);
561         }
562         /* Remove trailing zeros and the "." if no digits follow the "." */
563         if( flag_rtz && flag_dp ){
564           while( bufpt[-1]=='0' ) *(--bufpt) = 0;
565           assert( bufpt>buf );
566           if( bufpt[-1]=='.' ){
567             if( flag_altform2 ){
568               *(bufpt++) = '0';
569             }else{
570               *(--bufpt) = 0;
571             }
572           }
573         }
574         /* Add the "eNNN" suffix */
575         if( flag_exp || xtype==etEXP ){
576           *(bufpt++) = aDigits[infop->charset];
577           if( exp<0 ){
578             *(bufpt++) = '-'; exp = -exp;
579           }else{
580             *(bufpt++) = '+';
581           }
582           if( exp>=100 ){
583             *(bufpt++) = (char)((exp/100)+'0');        /* 100's digit */
584             exp %= 100;
585           }
586           *(bufpt++) = (char)(exp/10+'0');             /* 10's digit */
587           *(bufpt++) = (char)(exp%10+'0');             /* 1's digit */
588         }
589         *bufpt = 0;
590 
591         /* The converted number is in buf[] and zero terminated. Output it.
592         ** Note that the number is in the usual order, not reversed as with
593         ** integer conversions. */
594         length = (int)(bufpt-buf);
595         bufpt = buf;
596 
597         /* Special case:  Add leading zeros if the flag_zeropad flag is
598         ** set and we are not left justified */
599         if( flag_zeropad && !flag_leftjustify && length < width){
600           int i;
601           int nPad = width - length;
602           for(i=width; i>=nPad; i--){
603             bufpt[i] = bufpt[i-nPad];
604           }
605           i = prefix!=0;
606           while( nPad-- ) bufpt[i++] = '0';
607           length = width;
608         }
609 #endif
610         break;
611       case etSIZE:
612         *(va_arg(ap,int*)) = pAccum->nChar;
613         length = width = 0;
614         break;
615       case etPERCENT:
616         buf[0] = '%';
617         bufpt = buf;
618         length = 1;
619         break;
620       case etCHARX:
621         c = va_arg(ap,int);
622         buf[0] = (char)c;
623         if( precision>=0 ){
624           for(idx=1; idx<precision; idx++) buf[idx] = (char)c;
625           length = precision;
626         }else{
627           length =1;
628         }
629         bufpt = buf;
630         break;
631       case etSTRING:
632       case etDYNSTRING:
633         bufpt = va_arg(ap,char*);
634         if( bufpt==0 ){
635           bufpt = "";
636         }else if( xtype==etDYNSTRING ){
637           zExtra = bufpt;
638         }
639         if( precision>=0 ){
640           for(length=0; length<precision && bufpt[length]; length++){}
641         }else{
642           length = sqlite3Strlen30(bufpt);
643         }
644         break;
645       case etSQLESCAPE:
646       case etSQLESCAPE2:
647       case etSQLESCAPE3: {
648         int i, j, k, n, isnull;
649         int needQuote;
650         char ch;
651         char q = ((xtype==etSQLESCAPE3)?'"':'\'');   /* Quote character */
652         char *escarg = va_arg(ap,char*);
653         isnull = escarg==0;
654         if( isnull ) escarg = (xtype==etSQLESCAPE2 ? "NULL" : "(NULL)");
655         k = precision;
656         for(i=n=0; (ch=escarg[i])!=0 && k!=0; i++, k--){
657           if( ch==q )  n++;
658         }
659         needQuote = !isnull && xtype==etSQLESCAPE2;
660         n += i + 1 + needQuote*2;
661         if( n>etBUFSIZE ){
662           bufpt = zExtra = sqlite3Malloc( n );
663           if( bufpt==0 ){
664             pAccum->mallocFailed = 1;
665             return;
666           }
667         }else{
668           bufpt = buf;
669         }
670         j = 0;
671         if( needQuote ) bufpt[j++] = q;
672         k = i;
673         for(i=0; i<k; i++){
674           bufpt[j++] = ch = escarg[i];
675           if( ch==q ) bufpt[j++] = ch;
676         }
677         if( needQuote ) bufpt[j++] = q;
678         bufpt[j] = 0;
679         length = j;
680         /* The precision in %q and %Q means how many input characters to
681         ** consume, not the length of the output...
682         ** if( precision>=0 && precision<length ) length = precision; */
683         break;
684       }
685       case etTOKEN: {
686         Token *pToken = va_arg(ap, Token*);
687         if( pToken ){
688           sqlite3StrAccumAppend(pAccum, (const char*)pToken->z, pToken->n);
689         }
690         length = width = 0;
691         break;
692       }
693       case etSRCLIST: {
694         SrcList *pSrc = va_arg(ap, SrcList*);
695         int k = va_arg(ap, int);
696         struct SrcList_item *pItem = &pSrc->a[k];
697         assert( k>=0 && k<pSrc->nSrc );
698         if( pItem->zDatabase ){
699           sqlite3StrAccumAppend(pAccum, pItem->zDatabase, -1);
700           sqlite3StrAccumAppend(pAccum, ".", 1);
701         }
702         sqlite3StrAccumAppend(pAccum, pItem->zName, -1);
703         length = width = 0;
704         break;
705       }
706       default: {
707         assert( xtype==etINVALID );
708         return;
709       }
710     }/* End switch over the format type */
711     /*
712     ** The text of the conversion is pointed to by "bufpt" and is
713     ** "length" characters long.  The field width is "width".  Do
714     ** the output.
715     */
716     if( !flag_leftjustify ){
717       register int nspace;
718       nspace = width-length;
719       if( nspace>0 ){
720         appendSpace(pAccum, nspace);
721       }
722     }
723     if( length>0 ){
724       sqlite3StrAccumAppend(pAccum, bufpt, length);
725     }
726     if( flag_leftjustify ){
727       register int nspace;
728       nspace = width-length;
729       if( nspace>0 ){
730         appendSpace(pAccum, nspace);
731       }
732     }
733     if( zExtra ){
734       sqlite3_free(zExtra);
735     }
736   }/* End for loop over the format string */
737 } /* End of function */
738 
739 /*
740 ** Append N bytes of text from z to the StrAccum object.
741 */
742 void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
743   assert( z!=0 || N==0 );
744   if( p->tooBig | p->mallocFailed ){
745     testcase(p->tooBig);
746     testcase(p->mallocFailed);
747     return;
748   }
749   if( N<0 ){
750     N = sqlite3Strlen30(z);
751   }
752   if( N==0 || NEVER(z==0) ){
753     return;
754   }
755   if( p->nChar+N >= p->nAlloc ){
756     char *zNew;
757     if( !p->useMalloc ){
758       p->tooBig = 1;
759       N = p->nAlloc - p->nChar - 1;
760       if( N<=0 ){
761         return;
762       }
763     }else{
764       i64 szNew = p->nChar;
765       szNew += N + 1;
766       if( szNew > p->mxAlloc ){
767         sqlite3StrAccumReset(p);
768         p->tooBig = 1;
769         return;
770       }else{
771         p->nAlloc = (int)szNew;
772       }
773       zNew = sqlite3DbMallocRaw(p->db, p->nAlloc );
774       if( zNew ){
775         memcpy(zNew, p->zText, p->nChar);
776         sqlite3StrAccumReset(p);
777         p->zText = zNew;
778       }else{
779         p->mallocFailed = 1;
780         sqlite3StrAccumReset(p);
781         return;
782       }
783     }
784   }
785   memcpy(&p->zText[p->nChar], z, N);
786   p->nChar += N;
787 }
788 
789 /*
790 ** Finish off a string by making sure it is zero-terminated.
791 ** Return a pointer to the resulting string.  Return a NULL
792 ** pointer if any kind of error was encountered.
793 */
794 char *sqlite3StrAccumFinish(StrAccum *p){
795   if( p->zText ){
796     p->zText[p->nChar] = 0;
797     if( p->useMalloc && p->zText==p->zBase ){
798       p->zText = sqlite3DbMallocRaw(p->db, p->nChar+1 );
799       if( p->zText ){
800         memcpy(p->zText, p->zBase, p->nChar+1);
801       }else{
802         p->mallocFailed = 1;
803       }
804     }
805   }
806   return p->zText;
807 }
808 
809 /*
810 ** Reset an StrAccum string.  Reclaim all malloced memory.
811 */
812 void sqlite3StrAccumReset(StrAccum *p){
813   if( p->zText!=p->zBase ){
814     sqlite3DbFree(p->db, p->zText);
815   }
816   p->zText = 0;
817 }
818 
819 /*
820 ** Initialize a string accumulator
821 */
822 void sqlite3StrAccumInit(StrAccum *p, char *zBase, int n, int mx){
823   p->zText = p->zBase = zBase;
824   p->db = 0;
825   p->nChar = 0;
826   p->nAlloc = n;
827   p->mxAlloc = mx;
828   p->useMalloc = 1;
829   p->tooBig = 0;
830   p->mallocFailed = 0;
831 }
832 
833 /*
834 ** Print into memory obtained from sqliteMalloc().  Use the internal
835 ** %-conversion extensions.
836 */
837 char *sqlite3VMPrintf(sqlite3 *db, const char *zFormat, va_list ap){
838   char *z;
839   char zBase[SQLITE_PRINT_BUF_SIZE];
840   StrAccum acc;
841   assert( db!=0 );
842   sqlite3StrAccumInit(&acc, zBase, sizeof(zBase),
843                       db->aLimit[SQLITE_LIMIT_LENGTH]);
844   acc.db = db;
845   sqlite3VXPrintf(&acc, 1, zFormat, ap);
846   z = sqlite3StrAccumFinish(&acc);
847   if( acc.mallocFailed ){
848     db->mallocFailed = 1;
849   }
850   return z;
851 }
852 
853 /*
854 ** Print into memory obtained from sqliteMalloc().  Use the internal
855 ** %-conversion extensions.
856 */
857 char *sqlite3MPrintf(sqlite3 *db, const char *zFormat, ...){
858   va_list ap;
859   char *z;
860   va_start(ap, zFormat);
861   z = sqlite3VMPrintf(db, zFormat, ap);
862   va_end(ap);
863   return z;
864 }
865 
866 /*
867 ** Like sqlite3MPrintf(), but call sqlite3DbFree() on zStr after formatting
868 ** the string and before returnning.  This routine is intended to be used
869 ** to modify an existing string.  For example:
870 **
871 **       x = sqlite3MPrintf(db, x, "prefix %s suffix", x);
872 **
873 */
874 char *sqlite3MAppendf(sqlite3 *db, char *zStr, const char *zFormat, ...){
875   va_list ap;
876   char *z;
877   va_start(ap, zFormat);
878   z = sqlite3VMPrintf(db, zFormat, ap);
879   va_end(ap);
880   sqlite3DbFree(db, zStr);
881   return z;
882 }
883 
884 /*
885 ** Print into memory obtained from sqlite3_malloc().  Omit the internal
886 ** %-conversion extensions.
887 */
888 char *sqlite3_vmprintf(const char *zFormat, va_list ap){
889   char *z;
890   char zBase[SQLITE_PRINT_BUF_SIZE];
891   StrAccum acc;
892 #ifndef SQLITE_OMIT_AUTOINIT
893   if( sqlite3_initialize() ) return 0;
894 #endif
895   sqlite3StrAccumInit(&acc, zBase, sizeof(zBase), SQLITE_MAX_LENGTH);
896   sqlite3VXPrintf(&acc, 0, zFormat, ap);
897   z = sqlite3StrAccumFinish(&acc);
898   return z;
899 }
900 
901 /*
902 ** Print into memory obtained from sqlite3_malloc()().  Omit the internal
903 ** %-conversion extensions.
904 */
905 char *sqlite3_mprintf(const char *zFormat, ...){
906   va_list ap;
907   char *z;
908 #ifndef SQLITE_OMIT_AUTOINIT
909   if( sqlite3_initialize() ) return 0;
910 #endif
911   va_start(ap, zFormat);
912   z = sqlite3_vmprintf(zFormat, ap);
913   va_end(ap);
914   return z;
915 }
916 
917 /*
918 ** sqlite3_snprintf() works like snprintf() except that it ignores the
919 ** current locale settings.  This is important for SQLite because we
920 ** are not able to use a "," as the decimal point in place of "." as
921 ** specified by some locales.
922 */
923 char *sqlite3_snprintf(int n, char *zBuf, const char *zFormat, ...){
924   char *z;
925   va_list ap;
926   StrAccum acc;
927 
928   if( n<=0 ){
929     return zBuf;
930   }
931   sqlite3StrAccumInit(&acc, zBuf, n, 0);
932   acc.useMalloc = 0;
933   va_start(ap,zFormat);
934   sqlite3VXPrintf(&acc, 0, zFormat, ap);
935   va_end(ap);
936   z = sqlite3StrAccumFinish(&acc);
937   return z;
938 }
939 
940 #if defined(SQLITE_DEBUG)
941 /*
942 ** A version of printf() that understands %lld.  Used for debugging.
943 ** The printf() built into some versions of windows does not understand %lld
944 ** and segfaults if you give it a long long int.
945 */
946 void sqlite3DebugPrintf(const char *zFormat, ...){
947   va_list ap;
948   StrAccum acc;
949   char zBuf[500];
950   sqlite3StrAccumInit(&acc, zBuf, sizeof(zBuf), 0);
951   acc.useMalloc = 0;
952   va_start(ap,zFormat);
953   sqlite3VXPrintf(&acc, 0, zFormat, ap);
954   va_end(ap);
955   sqlite3StrAccumFinish(&acc);
956   fprintf(stdout,"%s", zBuf);
957   fflush(stdout);
958 }
959 #endif
960 
961 #ifndef SQLITE_OMIT_TRACE
962 /*
963 ** variable-argument wrapper around sqlite3VXPrintf().
964 */
965 void sqlite3XPrintf(StrAccum *p, const char *zFormat, ...){
966   va_list ap;
967   va_start(ap,zFormat);
968   sqlite3VXPrintf(p, 1, zFormat, ap);
969   va_end(ap);
970 }
971 #endif
972