xref: /sqlite-3.40.0/src/printf.c (revision 1ed93e90)
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  They are very out-of-date but might be useful as
5 ** an historical reference.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 ** $Id: printf.c,v 1.103 2009/05/04 20:20:16 drh Exp $
9 **
10 **************************************************************************
11 **
12 ** The following modules is an enhanced replacement for the "printf" subroutines
13 ** found in the standard C library.  The following enhancements are
14 ** supported:
15 **
16 **      +  Additional functions.  The standard set of "printf" functions
17 **         includes printf, fprintf, sprintf, vprintf, vfprintf, and
18 **         vsprintf.  This module adds the following:
19 **
20 **           *  snprintf -- Works like sprintf, but has an extra argument
21 **                          which is the size of the buffer written to.
22 **
23 **           *  mprintf --  Similar to sprintf.  Writes output to memory
24 **                          obtained from malloc.
25 **
26 **           *  xprintf --  Calls a function to dispose of output.
27 **
28 **           *  nprintf --  No output, but returns the number of characters
29 **                          that would have been output by printf.
30 **
31 **           *  A v- version (ex: vsnprintf) of every function is also
32 **              supplied.
33 **
34 **      +  A few extensions to the formatting notation are supported:
35 **
36 **           *  The "=" flag (similar to "-") causes the output to be
37 **              be centered in the appropriately sized field.
38 **
39 **           *  The %b field outputs an integer in binary notation.
40 **
41 **           *  The %c field now accepts a precision.  The character output
42 **              is repeated by the number of times the precision specifies.
43 **
44 **           *  The %' field works like %c, but takes as its character the
45 **              next character of the format string, instead of the next
46 **              argument.  For example,  printf("%.78'-")  prints 78 minus
47 **              signs, the same as  printf("%.78c",'-').
48 **
49 **      +  When compiled using GCC on a SPARC, this version of printf is
50 **         faster than the library printf for SUN OS 4.1.
51 **
52 **      +  All functions are fully reentrant.
53 **
54 */
55 #include "sqliteInt.h"
56 
57 /*
58 ** Conversion types fall into various categories as defined by the
59 ** following enumeration.
60 */
61 #define etRADIX       1 /* Integer types.  %d, %x, %o, and so forth */
62 #define etFLOAT       2 /* Floating point.  %f */
63 #define etEXP         3 /* Exponentional notation. %e and %E */
64 #define etGENERIC     4 /* Floating or exponential, depending on exponent. %g */
65 #define etSIZE        5 /* Return number of characters processed so far. %n */
66 #define etSTRING      6 /* Strings. %s */
67 #define etDYNSTRING   7 /* Dynamically allocated strings. %z */
68 #define etPERCENT     8 /* Percent symbol. %% */
69 #define etCHARX       9 /* Characters. %c */
70 /* The rest are extensions, not normally found in printf() */
71 #define etSQLESCAPE  10 /* Strings with '\'' doubled.  %q */
72 #define etSQLESCAPE2 11 /* Strings with '\'' doubled and enclosed in '',
73                           NULL pointers replaced by SQL NULL.  %Q */
74 #define etTOKEN      12 /* a pointer to a Token structure */
75 #define etSRCLIST    13 /* a pointer to a SrcList */
76 #define etPOINTER    14 /* The %p conversion */
77 #define etSQLESCAPE3 15 /* %w -> Strings with '\"' doubled */
78 #define etORDINAL    16 /* %r -> 1st, 2nd, 3rd, 4th, etc.  English only */
79 
80 #define etINVALID     0 /* Any unrecognized conversion type */
81 
82 
83 /*
84 ** An "etByte" is an 8-bit unsigned value.
85 */
86 typedef unsigned char etByte;
87 
88 /*
89 ** Each builtin conversion character (ex: the 'd' in "%d") is described
90 ** by an instance of the following structure
91 */
92 typedef struct et_info {   /* Information about each format field */
93   char fmttype;            /* The format field code letter */
94   etByte base;             /* The base for radix conversion */
95   etByte flags;            /* One or more of FLAG_ constants below */
96   etByte type;             /* Conversion paradigm */
97   etByte charset;          /* Offset into aDigits[] of the digits string */
98   etByte prefix;           /* Offset into aPrefix[] of the prefix string */
99 } et_info;
100 
101 /*
102 ** Allowed values for et_info.flags
103 */
104 #define FLAG_SIGNED  1     /* True if the value to convert is signed */
105 #define FLAG_INTERN  2     /* True if for internal use only */
106 #define FLAG_STRING  4     /* Allow infinity precision */
107 
108 
109 /*
110 ** The following table is searched linearly, so it is good to put the
111 ** most frequently used conversion types first.
112 */
113 static const char aDigits[] = "0123456789ABCDEF0123456789abcdef";
114 static const char aPrefix[] = "-x0\000X0";
115 static const et_info fmtinfo[] = {
116   {  'd', 10, 1, etRADIX,      0,  0 },
117   {  's',  0, 4, etSTRING,     0,  0 },
118   {  'g',  0, 1, etGENERIC,    30, 0 },
119   {  'z',  0, 4, etDYNSTRING,  0,  0 },
120   {  'q',  0, 4, etSQLESCAPE,  0,  0 },
121   {  'Q',  0, 4, etSQLESCAPE2, 0,  0 },
122   {  'w',  0, 4, etSQLESCAPE3, 0,  0 },
123   {  'c',  0, 0, etCHARX,      0,  0 },
124   {  'o',  8, 0, etRADIX,      0,  2 },
125   {  'u', 10, 0, etRADIX,      0,  0 },
126   {  'x', 16, 0, etRADIX,      16, 1 },
127   {  'X', 16, 0, etRADIX,      0,  4 },
128 #ifndef SQLITE_OMIT_FLOATING_POINT
129   {  'f',  0, 1, etFLOAT,      0,  0 },
130   {  'e',  0, 1, etEXP,        30, 0 },
131   {  'E',  0, 1, etEXP,        14, 0 },
132   {  'G',  0, 1, etGENERIC,    14, 0 },
133 #endif
134   {  'i', 10, 1, etRADIX,      0,  0 },
135   {  'n',  0, 0, etSIZE,       0,  0 },
136   {  '%',  0, 0, etPERCENT,    0,  0 },
137   {  'p', 16, 0, etPOINTER,    0,  1 },
138 
139 /* All the rest have the FLAG_INTERN bit set and are thus for internal
140 ** use only */
141   {  'T',  0, 2, etTOKEN,      0,  0 },
142   {  'S',  0, 2, etSRCLIST,    0,  0 },
143   {  'r', 10, 3, etORDINAL,    0,  0 },
144 };
145 
146 /*
147 ** If SQLITE_OMIT_FLOATING_POINT is defined, then none of the floating point
148 ** conversions will work.
149 */
150 #ifndef SQLITE_OMIT_FLOATING_POINT
151 /*
152 ** "*val" is a double such that 0.1 <= *val < 10.0
153 ** Return the ascii code for the leading digit of *val, then
154 ** multiply "*val" by 10.0 to renormalize.
155 **
156 ** Example:
157 **     input:     *val = 3.14159
158 **     output:    *val = 1.4159    function return = '3'
159 **
160 ** The counter *cnt is incremented each time.  After counter exceeds
161 ** 16 (the number of significant digits in a 64-bit float) '0' is
162 ** always returned.
163 */
164 static char et_getdigit(LONGDOUBLE_TYPE *val, int *cnt){
165   int digit;
166   LONGDOUBLE_TYPE d;
167   if( (*cnt)++ >= 16 ) return '0';
168   digit = (int)*val;
169   d = digit;
170   digit += '0';
171   *val = (*val - d)*10.0;
172   return (char)digit;
173 }
174 #endif /* SQLITE_OMIT_FLOATING_POINT */
175 
176 /*
177 ** Append N space characters to the given string buffer.
178 */
179 static void appendSpace(StrAccum *pAccum, int N){
180   static const char zSpaces[] = "                             ";
181   while( N>=(int)sizeof(zSpaces)-1 ){
182     sqlite3StrAccumAppend(pAccum, zSpaces, sizeof(zSpaces)-1);
183     N -= sizeof(zSpaces)-1;
184   }
185   if( N>0 ){
186     sqlite3StrAccumAppend(pAccum, zSpaces, N);
187   }
188 }
189 
190 /*
191 ** On machines with a small stack size, you can redefine the
192 ** SQLITE_PRINT_BUF_SIZE to be less than 350.  But beware - for
193 ** smaller values some %f conversions may go into an infinite loop.
194 */
195 #ifndef SQLITE_PRINT_BUF_SIZE
196 # define SQLITE_PRINT_BUF_SIZE 350
197 #endif
198 #define etBUFSIZE SQLITE_PRINT_BUF_SIZE  /* Size of the output buffer */
199 
200 /*
201 ** The root program.  All variations call this core.
202 **
203 ** INPUTS:
204 **   func   This is a pointer to a function taking three arguments
205 **            1. A pointer to anything.  Same as the "arg" parameter.
206 **            2. A pointer to the list of characters to be output
207 **               (Note, this list is NOT null terminated.)
208 **            3. An integer number of characters to be output.
209 **               (Note: This number might be zero.)
210 **
211 **   arg    This is the pointer to anything which will be passed as the
212 **          first argument to "func".  Use it for whatever you like.
213 **
214 **   fmt    This is the format string, as in the usual print.
215 **
216 **   ap     This is a pointer to a list of arguments.  Same as in
217 **          vfprint.
218 **
219 ** OUTPUTS:
220 **          The return value is the total number of characters sent to
221 **          the function "func".  Returns -1 on a error.
222 **
223 ** Note that the order in which automatic variables are declared below
224 ** seems to make a big difference in determining how fast this beast
225 ** will run.
226 */
227 void sqlite3VXPrintf(
228   StrAccum *pAccum,                  /* Accumulate results here */
229   int useExtended,                   /* Allow extended %-conversions */
230   const char *fmt,                   /* Format string */
231   va_list ap                         /* arguments */
232 ){
233   int c;                     /* Next character in the format string */
234   char *bufpt;               /* Pointer to the conversion buffer */
235   int precision;             /* Precision of the current field */
236   int length;                /* Length of the field */
237   int idx;                   /* A general purpose loop counter */
238   int width;                 /* Width of the current field */
239   etByte flag_leftjustify;   /* True if "-" flag is present */
240   etByte flag_plussign;      /* True if "+" flag is present */
241   etByte flag_blanksign;     /* True if " " flag is present */
242   etByte flag_alternateform; /* True if "#" flag is present */
243   etByte flag_altform2;      /* True if "!" flag is present */
244   etByte flag_zeropad;       /* True if field width constant starts with zero */
245   etByte flag_long;          /* True if "l" flag is present */
246   etByte flag_longlong;      /* True if the "ll" flag is present */
247   etByte done;               /* Loop termination flag */
248   sqlite_uint64 longvalue;   /* Value for integer types */
249   LONGDOUBLE_TYPE realvalue; /* Value for real types */
250   const et_info *infop;      /* Pointer to the appropriate info structure */
251   char buf[etBUFSIZE];       /* Conversion buffer */
252   char prefix;               /* Prefix character.  "+" or "-" or " " or '\0'. */
253   etByte xtype = 0;          /* Conversion paradigm */
254   char *zExtra;              /* Extra memory used for etTCLESCAPE conversions */
255 #ifndef SQLITE_OMIT_FLOATING_POINT
256   int  exp, e2;              /* exponent of real numbers */
257   double rounder;            /* Used for rounding floating point values */
258   etByte flag_dp;            /* True if decimal point should be shown */
259   etByte flag_rtz;           /* True if trailing zeros should be removed */
260   etByte flag_exp;           /* True to force display of the exponent */
261   int nsd;                   /* Number of significant digits returned */
262 #endif
263 
264   length = 0;
265   bufpt = 0;
266   for(; (c=(*fmt))!=0; ++fmt){
267     if( c!='%' ){
268       int amt;
269       bufpt = (char *)fmt;
270       amt = 1;
271       while( (c=(*++fmt))!='%' && c!=0 ) amt++;
272       sqlite3StrAccumAppend(pAccum, bufpt, amt);
273       if( c==0 ) break;
274     }
275     if( (c=(*++fmt))==0 ){
276       sqlite3StrAccumAppend(pAccum, "%", 1);
277       break;
278     }
279     /* Find out what flags are present */
280     flag_leftjustify = flag_plussign = flag_blanksign =
281      flag_alternateform = flag_altform2 = flag_zeropad = 0;
282     done = 0;
283     do{
284       switch( c ){
285         case '-':   flag_leftjustify = 1;     break;
286         case '+':   flag_plussign = 1;        break;
287         case ' ':   flag_blanksign = 1;       break;
288         case '#':   flag_alternateform = 1;   break;
289         case '!':   flag_altform2 = 1;        break;
290         case '0':   flag_zeropad = 1;         break;
291         default:    done = 1;                 break;
292       }
293     }while( !done && (c=(*++fmt))!=0 );
294     /* Get the field width */
295     width = 0;
296     if( c=='*' ){
297       width = va_arg(ap,int);
298       if( width<0 ){
299         flag_leftjustify = 1;
300         width = -width;
301       }
302       c = *++fmt;
303     }else{
304       while( c>='0' && c<='9' ){
305         width = width*10 + c - '0';
306         c = *++fmt;
307       }
308     }
309     if( width > etBUFSIZE-10 ){
310       width = etBUFSIZE-10;
311     }
312     /* Get the precision */
313     if( c=='.' ){
314       precision = 0;
315       c = *++fmt;
316       if( c=='*' ){
317         precision = va_arg(ap,int);
318         if( precision<0 ) precision = -precision;
319         c = *++fmt;
320       }else{
321         while( c>='0' && c<='9' ){
322           precision = precision*10 + c - '0';
323           c = *++fmt;
324         }
325       }
326     }else{
327       precision = -1;
328     }
329     /* Get the conversion type modifier */
330     if( c=='l' ){
331       flag_long = 1;
332       c = *++fmt;
333       if( c=='l' ){
334         flag_longlong = 1;
335         c = *++fmt;
336       }else{
337         flag_longlong = 0;
338       }
339     }else{
340       flag_long = flag_longlong = 0;
341     }
342     /* Fetch the info entry for the field */
343     infop = &fmtinfo[0];
344     xtype = etINVALID;
345     for(idx=0; idx<ArraySize(fmtinfo); idx++){
346       if( c==fmtinfo[idx].fmttype ){
347         infop = &fmtinfo[idx];
348         if( useExtended || (infop->flags & FLAG_INTERN)==0 ){
349           xtype = infop->type;
350         }else{
351           return;
352         }
353         break;
354       }
355     }
356     zExtra = 0;
357 
358 
359     /* Limit the precision to prevent overflowing buf[] during conversion */
360     if( precision>etBUFSIZE-40 && (infop->flags & FLAG_STRING)==0 ){
361       precision = etBUFSIZE-40;
362     }
363 
364     /*
365     ** At this point, variables are initialized as follows:
366     **
367     **   flag_alternateform          TRUE if a '#' is present.
368     **   flag_altform2               TRUE if a '!' is present.
369     **   flag_plussign               TRUE if a '+' is present.
370     **   flag_leftjustify            TRUE if a '-' is present or if the
371     **                               field width was negative.
372     **   flag_zeropad                TRUE if the width began with 0.
373     **   flag_long                   TRUE if the letter 'l' (ell) prefixed
374     **                               the conversion character.
375     **   flag_longlong               TRUE if the letter 'll' (ell ell) prefixed
376     **                               the conversion character.
377     **   flag_blanksign              TRUE if a ' ' is present.
378     **   width                       The specified field width.  This is
379     **                               always non-negative.  Zero is the default.
380     **   precision                   The specified precision.  The default
381     **                               is -1.
382     **   xtype                       The class of the conversion.
383     **   infop                       Pointer to the appropriate info struct.
384     */
385     switch( xtype ){
386       case etPOINTER:
387         flag_longlong = sizeof(char*)==sizeof(i64);
388         flag_long = sizeof(char*)==sizeof(long int);
389         /* Fall through into the next case */
390       case etORDINAL:
391       case etRADIX:
392         if( infop->flags & FLAG_SIGNED ){
393           i64 v;
394           if( flag_longlong ){
395             v = va_arg(ap,i64);
396           }else if( flag_long ){
397             v = va_arg(ap,long int);
398           }else{
399             v = va_arg(ap,int);
400           }
401           if( v<0 ){
402             longvalue = -v;
403             prefix = '-';
404           }else{
405             longvalue = v;
406             if( flag_plussign )        prefix = '+';
407             else if( flag_blanksign )  prefix = ' ';
408             else                       prefix = 0;
409           }
410         }else{
411           if( flag_longlong ){
412             longvalue = va_arg(ap,u64);
413           }else if( flag_long ){
414             longvalue = va_arg(ap,unsigned long int);
415           }else{
416             longvalue = va_arg(ap,unsigned int);
417           }
418           prefix = 0;
419         }
420         if( longvalue==0 ) flag_alternateform = 0;
421         if( flag_zeropad && precision<width-(prefix!=0) ){
422           precision = width-(prefix!=0);
423         }
424         bufpt = &buf[etBUFSIZE-1];
425         if( xtype==etORDINAL ){
426           static const char zOrd[] = "thstndrd";
427           int x = (int)(longvalue % 10);
428           if( x>=4 || (longvalue/10)%10==1 ){
429             x = 0;
430           }
431           buf[etBUFSIZE-3] = zOrd[x*2];
432           buf[etBUFSIZE-2] = zOrd[x*2+1];
433           bufpt -= 2;
434         }
435         {
436           register const char *cset;      /* Use registers for speed */
437           register int base;
438           cset = &aDigits[infop->charset];
439           base = infop->base;
440           do{                                           /* Convert to ascii */
441             *(--bufpt) = cset[longvalue%base];
442             longvalue = longvalue/base;
443           }while( longvalue>0 );
444         }
445         length = (int)(&buf[etBUFSIZE-1]-bufpt);
446         for(idx=precision-length; idx>0; idx--){
447           *(--bufpt) = '0';                             /* Zero pad */
448         }
449         if( prefix ) *(--bufpt) = prefix;               /* Add sign */
450         if( flag_alternateform && infop->prefix ){      /* Add "0" or "0x" */
451           const char *pre;
452           char x;
453           pre = &aPrefix[infop->prefix];
454           for(; (x=(*pre))!=0; pre++) *(--bufpt) = x;
455         }
456         length = (int)(&buf[etBUFSIZE-1]-bufpt);
457         break;
458       case etFLOAT:
459       case etEXP:
460       case etGENERIC:
461         realvalue = va_arg(ap,double);
462 #ifndef SQLITE_OMIT_FLOATING_POINT
463         if( precision<0 ) precision = 6;         /* Set default precision */
464         if( precision>etBUFSIZE/2-10 ) precision = etBUFSIZE/2-10;
465         if( realvalue<0.0 ){
466           realvalue = -realvalue;
467           prefix = '-';
468         }else{
469           if( flag_plussign )          prefix = '+';
470           else if( flag_blanksign )    prefix = ' ';
471           else                         prefix = 0;
472         }
473         if( xtype==etGENERIC && precision>0 ) precision--;
474 #if 0
475         /* Rounding works like BSD when the constant 0.4999 is used.  Wierd! */
476         for(idx=precision, rounder=0.4999; idx>0; idx--, rounder*=0.1);
477 #else
478         /* It makes more sense to use 0.5 */
479         for(idx=precision, rounder=0.5; idx>0; idx--, rounder*=0.1){}
480 #endif
481         if( xtype==etFLOAT ) realvalue += rounder;
482         /* Normalize realvalue to within 10.0 > realvalue >= 1.0 */
483         exp = 0;
484         if( sqlite3IsNaN((double)realvalue) ){
485           bufpt = "NaN";
486           length = 3;
487           break;
488         }
489         if( realvalue>0.0 ){
490           while( realvalue>=1e32 && exp<=350 ){ realvalue *= 1e-32; exp+=32; }
491           while( realvalue>=1e8 && exp<=350 ){ realvalue *= 1e-8; exp+=8; }
492           while( realvalue>=10.0 && exp<=350 ){ realvalue *= 0.1; exp++; }
493           while( realvalue<1e-8 ){ realvalue *= 1e8; exp-=8; }
494           while( realvalue<1.0 ){ realvalue *= 10.0; exp--; }
495           if( exp>350 ){
496             if( prefix=='-' ){
497               bufpt = "-Inf";
498             }else if( prefix=='+' ){
499               bufpt = "+Inf";
500             }else{
501               bufpt = "Inf";
502             }
503             length = sqlite3Strlen30(bufpt);
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         flag_exp = xtype==etEXP;
513         if( xtype!=etFLOAT ){
514           realvalue += rounder;
515           if( realvalue>=10.0 ){ realvalue *= 0.1; exp++; }
516         }
517         if( xtype==etGENERIC ){
518           flag_rtz = !flag_alternateform;
519           if( exp<-4 || exp>precision ){
520             xtype = etEXP;
521           }else{
522             precision = precision - exp;
523             xtype = etFLOAT;
524           }
525         }else{
526           flag_rtz = 0;
527         }
528         if( xtype==etEXP ){
529           e2 = 0;
530         }else{
531           e2 = exp;
532         }
533         nsd = 0;
534         flag_dp = (precision>0 ?1:0) | flag_alternateform | flag_altform2;
535         /* The sign in front of the number */
536         if( prefix ){
537           *(bufpt++) = prefix;
538         }
539         /* Digits prior to the decimal point */
540         if( e2<0 ){
541           *(bufpt++) = '0';
542         }else{
543           for(; e2>=0; e2--){
544             *(bufpt++) = et_getdigit(&realvalue,&nsd);
545           }
546         }
547         /* The decimal point */
548         if( flag_dp ){
549           *(bufpt++) = '.';
550         }
551         /* "0" digits after the decimal point but before the first
552         ** significant digit of the number */
553         for(e2++; e2<0; precision--, e2++){
554           assert( precision>0 );
555           *(bufpt++) = '0';
556         }
557         /* Significant digits after the decimal point */
558         while( (precision--)>0 ){
559           *(bufpt++) = et_getdigit(&realvalue,&nsd);
560         }
561         /* Remove trailing zeros and the "." if no digits follow the "." */
562         if( flag_rtz && flag_dp ){
563           while( bufpt[-1]=='0' ) *(--bufpt) = 0;
564           assert( bufpt>buf );
565           if( bufpt[-1]=='.' ){
566             if( flag_altform2 ){
567               *(bufpt++) = '0';
568             }else{
569               *(--bufpt) = 0;
570             }
571           }
572         }
573         /* Add the "eNNN" suffix */
574         if( flag_exp || xtype==etEXP ){
575           *(bufpt++) = aDigits[infop->charset];
576           if( exp<0 ){
577             *(bufpt++) = '-'; exp = -exp;
578           }else{
579             *(bufpt++) = '+';
580           }
581           if( exp>=100 ){
582             *(bufpt++) = (char)((exp/100)+'0');        /* 100's digit */
583             exp %= 100;
584           }
585           *(bufpt++) = (char)(exp/10+'0');             /* 10's digit */
586           *(bufpt++) = (char)(exp%10+'0');             /* 1's digit */
587         }
588         *bufpt = 0;
589 
590         /* The converted number is in buf[] and zero terminated. Output it.
591         ** Note that the number is in the usual order, not reversed as with
592         ** integer conversions. */
593         length = (int)(bufpt-buf);
594         bufpt = buf;
595 
596         /* Special case:  Add leading zeros if the flag_zeropad flag is
597         ** set and we are not left justified */
598         if( flag_zeropad && !flag_leftjustify && length < width){
599           int i;
600           int nPad = width - length;
601           for(i=width; i>=nPad; i--){
602             bufpt[i] = bufpt[i-nPad];
603           }
604           i = prefix!=0;
605           while( nPad-- ) bufpt[i++] = '0';
606           length = width;
607         }
608 #endif
609         break;
610       case etSIZE:
611         *(va_arg(ap,int*)) = pAccum->nChar;
612         length = width = 0;
613         break;
614       case etPERCENT:
615         buf[0] = '%';
616         bufpt = buf;
617         length = 1;
618         break;
619       case etCHARX:
620         c = va_arg(ap,int);
621         buf[0] = (char)c;
622         if( precision>=0 ){
623           for(idx=1; idx<precision; idx++) buf[idx] = (char)c;
624           length = precision;
625         }else{
626           length =1;
627         }
628         bufpt = buf;
629         break;
630       case etSTRING:
631       case etDYNSTRING:
632         bufpt = va_arg(ap,char*);
633         if( bufpt==0 ){
634           bufpt = "";
635         }else if( xtype==etDYNSTRING ){
636           zExtra = bufpt;
637         }
638         if( precision>=0 ){
639           for(length=0; length<precision && bufpt[length]; length++){}
640         }else{
641           length = sqlite3Strlen30(bufpt);
642         }
643         break;
644       case etSQLESCAPE:
645       case etSQLESCAPE2:
646       case etSQLESCAPE3: {
647         int i, j, n, isnull;
648         int needQuote;
649         char ch;
650         char q = ((xtype==etSQLESCAPE3)?'"':'\'');   /* Quote character */
651         char *escarg = va_arg(ap,char*);
652         isnull = escarg==0;
653         if( isnull ) escarg = (xtype==etSQLESCAPE2 ? "NULL" : "(NULL)");
654         for(i=n=0; (ch=escarg[i])!=0; i++){
655           if( ch==q )  n++;
656         }
657         needQuote = !isnull && xtype==etSQLESCAPE2;
658         n += i + 1 + needQuote*2;
659         if( n>etBUFSIZE ){
660           bufpt = zExtra = sqlite3Malloc( n );
661           if( bufpt==0 ){
662             pAccum->mallocFailed = 1;
663             return;
664           }
665         }else{
666           bufpt = buf;
667         }
668         j = 0;
669         if( needQuote ) bufpt[j++] = q;
670         for(i=0; (ch=escarg[i])!=0; i++){
671           bufpt[j++] = ch;
672           if( ch==q ) bufpt[j++] = ch;
673         }
674         if( needQuote ) bufpt[j++] = q;
675         bufpt[j] = 0;
676         length = j;
677         /* The precision is ignored on %q and %Q */
678         /* if( precision>=0 && precision<length ) length = precision; */
679         break;
680       }
681       case etTOKEN: {
682         Token *pToken = va_arg(ap, Token*);
683         if( pToken ){
684           sqlite3StrAccumAppend(pAccum, (const char*)pToken->z, pToken->n);
685         }
686         length = width = 0;
687         break;
688       }
689       case etSRCLIST: {
690         SrcList *pSrc = va_arg(ap, SrcList*);
691         int k = va_arg(ap, int);
692         struct SrcList_item *pItem = &pSrc->a[k];
693         assert( k>=0 && k<pSrc->nSrc );
694         if( pItem->zDatabase ){
695           sqlite3StrAccumAppend(pAccum, pItem->zDatabase, -1);
696           sqlite3StrAccumAppend(pAccum, ".", 1);
697         }
698         sqlite3StrAccumAppend(pAccum, pItem->zName, -1);
699         length = width = 0;
700         break;
701       }
702       default: {
703         assert( xtype==etINVALID );
704         return;
705       }
706     }/* End switch over the format type */
707     /*
708     ** The text of the conversion is pointed to by "bufpt" and is
709     ** "length" characters long.  The field width is "width".  Do
710     ** the output.
711     */
712     if( !flag_leftjustify ){
713       register int nspace;
714       nspace = width-length;
715       if( nspace>0 ){
716         appendSpace(pAccum, nspace);
717       }
718     }
719     if( length>0 ){
720       sqlite3StrAccumAppend(pAccum, bufpt, length);
721     }
722     if( flag_leftjustify ){
723       register int nspace;
724       nspace = width-length;
725       if( nspace>0 ){
726         appendSpace(pAccum, nspace);
727       }
728     }
729     if( zExtra ){
730       sqlite3_free(zExtra);
731     }
732   }/* End for loop over the format string */
733 } /* End of function */
734 
735 /*
736 ** Append N bytes of text from z to the StrAccum object.
737 */
738 void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){
739   assert( z!=0 || N==0 );
740   if( p->tooBig | p->mallocFailed ){
741     testcase(p->tooBig);
742     testcase(p->mallocFailed);
743     return;
744   }
745   if( N<0 ){
746     N = sqlite3Strlen30(z);
747   }
748   if( N==0 || NEVER(z==0) ){
749     return;
750   }
751   if( p->nChar+N >= p->nAlloc ){
752     char *zNew;
753     if( !p->useMalloc ){
754       p->tooBig = 1;
755       N = p->nAlloc - p->nChar - 1;
756       if( N<=0 ){
757         return;
758       }
759     }else{
760       i64 szNew = p->nChar;
761       szNew += N + 1;
762       if( szNew > p->mxAlloc ){
763         sqlite3StrAccumReset(p);
764         p->tooBig = 1;
765         return;
766       }else{
767         p->nAlloc = (int)szNew;
768       }
769       zNew = sqlite3DbMallocRaw(p->db, p->nAlloc );
770       if( zNew ){
771         memcpy(zNew, p->zText, p->nChar);
772         sqlite3StrAccumReset(p);
773         p->zText = zNew;
774       }else{
775         p->mallocFailed = 1;
776         sqlite3StrAccumReset(p);
777         return;
778       }
779     }
780   }
781   memcpy(&p->zText[p->nChar], z, N);
782   p->nChar += N;
783 }
784 
785 /*
786 ** Finish off a string by making sure it is zero-terminated.
787 ** Return a pointer to the resulting string.  Return a NULL
788 ** pointer if any kind of error was encountered.
789 */
790 char *sqlite3StrAccumFinish(StrAccum *p){
791   if( p->zText ){
792     p->zText[p->nChar] = 0;
793     if( p->useMalloc && p->zText==p->zBase ){
794       p->zText = sqlite3DbMallocRaw(p->db, p->nChar+1 );
795       if( p->zText ){
796         memcpy(p->zText, p->zBase, p->nChar+1);
797       }else{
798         p->mallocFailed = 1;
799       }
800     }
801   }
802   return p->zText;
803 }
804 
805 /*
806 ** Reset an StrAccum string.  Reclaim all malloced memory.
807 */
808 void sqlite3StrAccumReset(StrAccum *p){
809   if( p->zText!=p->zBase ){
810     sqlite3DbFree(p->db, p->zText);
811   }
812   p->zText = 0;
813 }
814 
815 /*
816 ** Initialize a string accumulator
817 */
818 void sqlite3StrAccumInit(StrAccum *p, char *zBase, int n, int mx){
819   p->zText = p->zBase = zBase;
820   p->db = 0;
821   p->nChar = 0;
822   p->nAlloc = n;
823   p->mxAlloc = mx;
824   p->useMalloc = 1;
825   p->tooBig = 0;
826   p->mallocFailed = 0;
827 }
828 
829 /*
830 ** Print into memory obtained from sqliteMalloc().  Use the internal
831 ** %-conversion extensions.
832 */
833 char *sqlite3VMPrintf(sqlite3 *db, const char *zFormat, va_list ap){
834   char *z;
835   char zBase[SQLITE_PRINT_BUF_SIZE];
836   StrAccum acc;
837   assert( db!=0 );
838   sqlite3StrAccumInit(&acc, zBase, sizeof(zBase),
839                       db->aLimit[SQLITE_LIMIT_LENGTH]);
840   acc.db = db;
841   sqlite3VXPrintf(&acc, 1, zFormat, ap);
842   z = sqlite3StrAccumFinish(&acc);
843   if( acc.mallocFailed ){
844     db->mallocFailed = 1;
845   }
846   return z;
847 }
848 
849 /*
850 ** Print into memory obtained from sqliteMalloc().  Use the internal
851 ** %-conversion extensions.
852 */
853 char *sqlite3MPrintf(sqlite3 *db, const char *zFormat, ...){
854   va_list ap;
855   char *z;
856   va_start(ap, zFormat);
857   z = sqlite3VMPrintf(db, zFormat, ap);
858   va_end(ap);
859   return z;
860 }
861 
862 /*
863 ** Like sqlite3MPrintf(), but call sqlite3DbFree() on zStr after formatting
864 ** the string and before returnning.  This routine is intended to be used
865 ** to modify an existing string.  For example:
866 **
867 **       x = sqlite3MPrintf(db, x, "prefix %s suffix", x);
868 **
869 */
870 char *sqlite3MAppendf(sqlite3 *db, char *zStr, const char *zFormat, ...){
871   va_list ap;
872   char *z;
873   va_start(ap, zFormat);
874   z = sqlite3VMPrintf(db, zFormat, ap);
875   va_end(ap);
876   sqlite3DbFree(db, zStr);
877   return z;
878 }
879 
880 /*
881 ** Print into memory obtained from sqlite3_malloc().  Omit the internal
882 ** %-conversion extensions.
883 */
884 char *sqlite3_vmprintf(const char *zFormat, va_list ap){
885   char *z;
886   char zBase[SQLITE_PRINT_BUF_SIZE];
887   StrAccum acc;
888 #ifndef SQLITE_OMIT_AUTOINIT
889   if( sqlite3_initialize() ) return 0;
890 #endif
891   sqlite3StrAccumInit(&acc, zBase, sizeof(zBase), SQLITE_MAX_LENGTH);
892   sqlite3VXPrintf(&acc, 0, zFormat, ap);
893   z = sqlite3StrAccumFinish(&acc);
894   return z;
895 }
896 
897 /*
898 ** Print into memory obtained from sqlite3_malloc()().  Omit the internal
899 ** %-conversion extensions.
900 */
901 char *sqlite3_mprintf(const char *zFormat, ...){
902   va_list ap;
903   char *z;
904 #ifndef SQLITE_OMIT_AUTOINIT
905   if( sqlite3_initialize() ) return 0;
906 #endif
907   va_start(ap, zFormat);
908   z = sqlite3_vmprintf(zFormat, ap);
909   va_end(ap);
910   return z;
911 }
912 
913 /*
914 ** sqlite3_snprintf() works like snprintf() except that it ignores the
915 ** current locale settings.  This is important for SQLite because we
916 ** are not able to use a "," as the decimal point in place of "." as
917 ** specified by some locales.
918 */
919 char *sqlite3_snprintf(int n, char *zBuf, const char *zFormat, ...){
920   char *z;
921   va_list ap;
922   StrAccum acc;
923 
924   if( n<=0 ){
925     return zBuf;
926   }
927   sqlite3StrAccumInit(&acc, zBuf, n, 0);
928   acc.useMalloc = 0;
929   va_start(ap,zFormat);
930   sqlite3VXPrintf(&acc, 0, zFormat, ap);
931   va_end(ap);
932   z = sqlite3StrAccumFinish(&acc);
933   return z;
934 }
935 
936 #if defined(SQLITE_DEBUG)
937 /*
938 ** A version of printf() that understands %lld.  Used for debugging.
939 ** The printf() built into some versions of windows does not understand %lld
940 ** and segfaults if you give it a long long int.
941 */
942 void sqlite3DebugPrintf(const char *zFormat, ...){
943   va_list ap;
944   StrAccum acc;
945   char zBuf[500];
946   sqlite3StrAccumInit(&acc, zBuf, sizeof(zBuf), 0);
947   acc.useMalloc = 0;
948   va_start(ap,zFormat);
949   sqlite3VXPrintf(&acc, 0, zFormat, ap);
950   va_end(ap);
951   sqlite3StrAccumFinish(&acc);
952   fprintf(stdout,"%s", zBuf);
953   fflush(stdout);
954 }
955 #endif
956