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elemental-ircd/bandb/rsdb_snprintf.c

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/*
* libString, Copyright (C) 1999 Patrick Alken
* This library comes with absolutely NO WARRANTY
*
* Should you choose to use and/or modify this source code, please
* do so under the terms of the GNU General Public License under which
* this library is distributed.
*
*/
#include "stdinc.h"
#include "rsdb.h"
/*
* This table is arranged in chronological order from 0-999,
* however the numbers are written backwards, so the number 100
* is expressed in this table as "001".
* It's purpose is to ensure fast conversions from integers to
* ASCII strings. When an integer variable is encountered, a
* simple hash algorithm is used to determine where to look
* in this array for the corresponding string.
* This outperforms continually dividing by 10 and using the
* digit obtained as a character, because we can now divide by
* 1000 and use the remainder directly, thus cutting down on
* the number of costly divisions needed. For an integer's worst
* case, 2 divisions are needed because it can only go up to
* 32767, so after 2 divisions by 1000, and some algebra, we will
* be left with 327 which we can get from this table. This is much
* better than the 5 divisions by 10 that we would need if we did
* it the conventional way. Of course, if we made this table go
* from 0-9999, only 1 division would be needed.
* Longs and unsigned ints of course, are another matter :-).
*
* Patrick Alken <wnder@underworld.net>
*/
/*
* Set this to the number of indices (numbers) in our table
*/
#define TABLE_MAX 1000
static const char *IntTable[] = {
"000", "100", "200", "300", "400",
"500", "600", "700", "800", "900",
"010", "110", "210", "310", "410",
"510", "610", "710", "810", "910",
"020", "120", "220", "320", "420",
"520", "620", "720", "820", "920",
"030", "130", "230", "330", "430",
"530", "630", "730", "830", "930",
"040", "140", "240", "340", "440",
"540", "640", "740", "840", "940",
"050", "150", "250", "350", "450",
"550", "650", "750", "850", "950",
"060", "160", "260", "360", "460",
"560", "660", "760", "860", "960",
"070", "170", "270", "370", "470",
"570", "670", "770", "870", "970",
"080", "180", "280", "380", "480",
"580", "680", "780", "880", "980",
"090", "190", "290", "390", "490",
"590", "690", "790", "890", "990",
"001", "101", "201", "301", "401",
"501", "601", "701", "801", "901",
"011", "111", "211", "311", "411",
"511", "611", "711", "811", "911",
"021", "121", "221", "321", "421",
"521", "621", "721", "821", "921",
"031", "131", "231", "331", "431",
"531", "631", "731", "831", "931",
"041", "141", "241", "341", "441",
"541", "641", "741", "841", "941",
"051", "151", "251", "351", "451",
"551", "651", "751", "851", "951",
"061", "161", "261", "361", "461",
"561", "661", "761", "861", "961",
"071", "171", "271", "371", "471",
"571", "671", "771", "871", "971",
"081", "181", "281", "381", "481",
"581", "681", "781", "881", "981",
"091", "191", "291", "391", "491",
"591", "691", "791", "891", "991",
"002", "102", "202", "302", "402",
"502", "602", "702", "802", "902",
"012", "112", "212", "312", "412",
"512", "612", "712", "812", "912",
"022", "122", "222", "322", "422",
"522", "622", "722", "822", "922",
"032", "132", "232", "332", "432",
"532", "632", "732", "832", "932",
"042", "142", "242", "342", "442",
"542", "642", "742", "842", "942",
"052", "152", "252", "352", "452",
"552", "652", "752", "852", "952",
"062", "162", "262", "362", "462",
"562", "662", "762", "862", "962",
"072", "172", "272", "372", "472",
"572", "672", "772", "872", "972",
"082", "182", "282", "382", "482",
"582", "682", "782", "882", "982",
"092", "192", "292", "392", "492",
"592", "692", "792", "892", "992",
"003", "103", "203", "303", "403",
"503", "603", "703", "803", "903",
"013", "113", "213", "313", "413",
"513", "613", "713", "813", "913",
"023", "123", "223", "323", "423",
"523", "623", "723", "823", "923",
"033", "133", "233", "333", "433",
"533", "633", "733", "833", "933",
"043", "143", "243", "343", "443",
"543", "643", "743", "843", "943",
"053", "153", "253", "353", "453",
"553", "653", "753", "853", "953",
"063", "163", "263", "363", "463",
"563", "663", "763", "863", "963",
"073", "173", "273", "373", "473",
"573", "673", "773", "873", "973",
"083", "183", "283", "383", "483",
"583", "683", "783", "883", "983",
"093", "193", "293", "393", "493",
"593", "693", "793", "893", "993",
"004", "104", "204", "304", "404",
"504", "604", "704", "804", "904",
"014", "114", "214", "314", "414",
"514", "614", "714", "814", "914",
"024", "124", "224", "324", "424",
"524", "624", "724", "824", "924",
"034", "134", "234", "334", "434",
"534", "634", "734", "834", "934",
"044", "144", "244", "344", "444",
"544", "644", "744", "844", "944",
"054", "154", "254", "354", "454",
"554", "654", "754", "854", "954",
"064", "164", "264", "364", "464",
"564", "664", "764", "864", "964",
"074", "174", "274", "374", "474",
"574", "674", "774", "874", "974",
"084", "184", "284", "384", "484",
"584", "684", "784", "884", "984",
"094", "194", "294", "394", "494",
"594", "694", "794", "894", "994",
"005", "105", "205", "305", "405",
"505", "605", "705", "805", "905",
"015", "115", "215", "315", "415",
"515", "615", "715", "815", "915",
"025", "125", "225", "325", "425",
"525", "625", "725", "825", "925",
"035", "135", "235", "335", "435",
"535", "635", "735", "835", "935",
"045", "145", "245", "345", "445",
"545", "645", "745", "845", "945",
"055", "155", "255", "355", "455",
"555", "655", "755", "855", "955",
"065", "165", "265", "365", "465",
"565", "665", "765", "865", "965",
"075", "175", "275", "375", "475",
"575", "675", "775", "875", "975",
"085", "185", "285", "385", "485",
"585", "685", "785", "885", "985",
"095", "195", "295", "395", "495",
"595", "695", "795", "895", "995",
"006", "106", "206", "306", "406",
"506", "606", "706", "806", "906",
"016", "116", "216", "316", "416",
"516", "616", "716", "816", "916",
"026", "126", "226", "326", "426",
"526", "626", "726", "826", "926",
"036", "136", "236", "336", "436",
"536", "636", "736", "836", "936",
"046", "146", "246", "346", "446",
"546", "646", "746", "846", "946",
"056", "156", "256", "356", "456",
"556", "656", "756", "856", "956",
"066", "166", "266", "366", "466",
"566", "666", "766", "866", "966",
"076", "176", "276", "376", "476",
"576", "676", "776", "876", "976",
"086", "186", "286", "386", "486",
"586", "686", "786", "886", "986",
"096", "196", "296", "396", "496",
"596", "696", "796", "896", "996",
"007", "107", "207", "307", "407",
"507", "607", "707", "807", "907",
"017", "117", "217", "317", "417",
"517", "617", "717", "817", "917",
"027", "127", "227", "327", "427",
"527", "627", "727", "827", "927",
"037", "137", "237", "337", "437",
"537", "637", "737", "837", "937",
"047", "147", "247", "347", "447",
"547", "647", "747", "847", "947",
"057", "157", "257", "357", "457",
"557", "657", "757", "857", "957",
"067", "167", "267", "367", "467",
"567", "667", "767", "867", "967",
"077", "177", "277", "377", "477",
"577", "677", "777", "877", "977",
"087", "187", "287", "387", "487",
"587", "687", "787", "887", "987",
"097", "197", "297", "397", "497",
"597", "697", "797", "897", "997",
"008", "108", "208", "308", "408",
"508", "608", "708", "808", "908",
"018", "118", "218", "318", "418",
"518", "618", "718", "818", "918",
"028", "128", "228", "328", "428",
"528", "628", "728", "828", "928",
"038", "138", "238", "338", "438",
"538", "638", "738", "838", "938",
"048", "148", "248", "348", "448",
"548", "648", "748", "848", "948",
"058", "158", "258", "358", "458",
"558", "658", "758", "858", "958",
"068", "168", "268", "368", "468",
"568", "668", "768", "868", "968",
"078", "178", "278", "378", "478",
"578", "678", "778", "878", "978",
"088", "188", "288", "388", "488",
"588", "688", "788", "888", "988",
"098", "198", "298", "398", "498",
"598", "698", "798", "898", "998",
"009", "109", "209", "309", "409",
"509", "609", "709", "809", "909",
"019", "119", "219", "319", "419",
"519", "619", "719", "819", "919",
"029", "129", "229", "329", "429",
"529", "629", "729", "829", "929",
"039", "139", "239", "339", "439",
"539", "639", "739", "839", "939",
"049", "149", "249", "349", "449",
"549", "649", "749", "849", "949",
"059", "159", "259", "359", "459",
"559", "659", "759", "859", "959",
"069", "169", "269", "369", "469",
"569", "669", "769", "869", "969",
"079", "179", "279", "379", "479",
"579", "679", "779", "879", "979",
"089", "189", "289", "389", "489",
"589", "689", "789", "889", "989",
"099", "199", "299", "399", "499",
"599", "699", "799", "899", "999"
};
/*
* Since we calculate the right-most digits for %d %u etc first,
* we need a temporary buffer to store them in until we get
* to the left-most digits
*/
#define TEMPBUF_MAX 20
static char TempBuffer[TEMPBUF_MAX];
/*
vSnprintf()
Backend to Snprintf() - performs the construction of 'dest'
using the string 'format' and the given arguments. Also makes sure
not more than 'bytes' characters are copied to 'dest'
We always allow room for a terminating \0 character, so at most,
bytes - 1 characters will be written to dest.
Return: Number of characters written, NOT including the terminating
\0 character which is *always* placed at the end of the string
NOTE: This function handles the following flags only:
%s %d %c %u %ld %lu
In addition, this function performs *NO* precision, padding,
or width formatting. If it receives an unknown % character,
it will call vsprintf() to complete the remainder of the
string.
*/
int
rs_vsnprintf(char *dest, const size_t bytes, const char *format, va_list args)
{
char ch;
int written = 0; /* bytes written so far */
int maxbytes = bytes - 1;
while((ch = *format++) && (written < maxbytes))
{
if(ch == '%')
{
/*
* Advance past the %
*/
ch = *format++;
/*
* Put the most common cases first - %s %d etc
*/
if(ch == 's')
{
const char *str = va_arg(args, const char *);
while((*dest = *str))
{
++dest;
++str;
if(++written >= maxbytes)
break;
}
continue;
}
if(ch == 'd')
{
int num = va_arg(args, int);
int quotient;
const char *str;
char *digitptr = TempBuffer;
/*
* We have to special-case "0" unfortunately
*/
if(num == 0)
{
*dest++ = '0';
++written;
continue;
}
if(num < 0)
{
*dest++ = '-';
if(++written >= maxbytes)
continue;
num = -num;
}
do
{
quotient = num / TABLE_MAX;
/*
* We'll start with the right-most digits of 'num'.
* Dividing by TABLE_MAX cuts off all but the X
* right-most digits, where X is such that:
*
* 10^X = TABLE_MAX
*
* For example, if num = 1200, and TABLE_MAX = 1000,
* quotient will be 1. Multiplying this by 1000 and
* subtracting from 1200 gives: 1200 - (1 * 1000) = 200.
* We then go right to slot 200 in our array and behold!
* The string "002" (200 backwards) is conveniently
* waiting for us. Then repeat the process with the
* digits left.
*
* The reason we need to have the integers written
* backwards, is because we don't know how many digits
* there are. If we want to express the number 12130
* for example, our first pass would leave us with 130,
* whose slot in the array yields "031", which we
* plug into our TempBuffer[]. The next pass gives us
* 12, whose slot yields "21" which we append to
* TempBuffer[], leaving us with "03121". This is the
* exact number we want, only backwards, so it is
* a simple matter to reverse the string. If we used
* straightfoward numbers, we would have a TempBuffer
* looking like this: "13012" which would be a nightmare
* to deal with.
*/
str = IntTable[num - (quotient * TABLE_MAX)];
while((*digitptr = *str))
{
++digitptr;
++str;
}
}
while((num = quotient) != 0);
/*
* If the last quotient was a 1 or 2 digit number, there
* will be one or more leading zeroes in TempBuffer[] -
* get rid of them.
*/
while(*(digitptr - 1) == '0')
--digitptr;
while(digitptr != TempBuffer)
{
*dest++ = *--digitptr;
if(++written >= maxbytes)
break;
}
continue;
} /* if (ch == 'd') */
if(ch == 'c')
{
*dest++ = va_arg(args, int);
++written;
continue;
} /* if (ch == 'c') */
if(ch == 'u')
{
unsigned int num = va_arg(args, unsigned int);
unsigned int quotient;
const char *str;
char *digitptr = TempBuffer;
if(num == 0)
{
*dest++ = '0';
++written;
continue;
}
do
{
quotient = num / TABLE_MAX;
/*
* Very similar to case 'd'
*/
str = IntTable[num - (quotient * TABLE_MAX)];
while((*digitptr = *str))
{
++digitptr;
++str;
}
}
while((num = quotient) != 0);
while(*(digitptr - 1) == '0')
--digitptr;
while(digitptr != TempBuffer)
{
*dest++ = *--digitptr;
if(++written >= maxbytes)
break;
}
continue;
} /* if (ch == 'u') */
if(ch == 'Q')
{
const char *arg = va_arg(args, const char *);
if(arg == NULL)
continue;
const char *str = rsdb_quote(arg);
while((*dest = *str))
{
++dest;
++str;
if(++written >= maxbytes)
break;
}
continue;
}
if(ch == 'l')
{
if(*format == 'u')
{
unsigned long num = va_arg(args, unsigned long);
unsigned long quotient;
const char *str;
char *digitptr = TempBuffer;
++format;
if(num == 0)
{
*dest++ = '0';
++written;
continue;
}
do
{
quotient = num / TABLE_MAX;
/*
* Very similar to case 'u'
*/
str = IntTable[num - (quotient * TABLE_MAX)];
while((*digitptr = *str))
{
++digitptr;
++str;
}
}
while((num = quotient) != 0);
while(*(digitptr - 1) == '0')
--digitptr;
while(digitptr != TempBuffer)
{
*dest++ = *--digitptr;
if(++written >= maxbytes)
break;
}
continue;
}
else
/* if (*format == 'u') */ if(*format == 'd')
{
long num = va_arg(args, long);
long quotient;
const char *str;
char *digitptr = TempBuffer;
++format;
if(num == 0)
{
*dest++ = '0';
++written;
continue;
}
if(num < 0)
{
*dest++ = '-';
if(++written >= maxbytes)
continue;
num = -num;
}
do
{
quotient = num / TABLE_MAX;
str = IntTable[num - (quotient * TABLE_MAX)];
while((*digitptr = *str))
{
++digitptr;
++str;
}
}
while((num = quotient) != 0);
while(*(digitptr - 1) == '0')
--digitptr;
while(digitptr != TempBuffer)
{
*dest++ = *--digitptr;
if(++written >= maxbytes)
break;
}
continue;
}
else /* if (*format == 'd') */
{
/* XXX error */
exit(1);
}
} /* if (ch == 'l') */
if(ch != '%')
{
/* XXX error */
exit(1);
} /* if (ch != '%') */
} /* if (ch == '%') */
*dest++ = ch;
++written;
} /* while ((ch = *format++) && (written < maxbytes)) */
/*
* Terminate the destination buffer with a \0
*/
*dest = '\0';
return (written);
} /* vSnprintf() */
/*
rs_snprintf()
Optimized version of snprintf().
Inputs: dest - destination string
bytes - number of bytes to copy
format - formatted string
args - args to 'format'
Return: number of characters copied, NOT including the terminating
NULL which is always placed at the end of the string
*/
int
rs_snprintf(char *dest, const size_t bytes, const char *format, ...)
{
va_list args;
int count;
va_start(args, format);
count = rs_vsnprintf(dest, bytes, format, args);
va_end(args);
return (count);
} /* Snprintf() */
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