my_vsnprintf.c
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:5k
- /* Copyright (C) 2000 MySQL AB
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- #include <my_global.h>
- #include <m_string.h>
- #include <stdarg.h>
- #include <m_ctype.h>
- /*
- Limited snprintf() implementations
- IMPLEMENTION:
- Supports following formats:
- %#[l]d
- %#[l]u
- %#[l]x
- %#.#s Note first # is ignored
-
- RETURN
- length of result string
- */
- int my_vsnprintf(char *to, size_t n, const char* fmt, va_list ap)
- {
- char *start=to, *end=to+n-1;
- uint length, width, pre_zero, have_long;
- for (; *fmt ; fmt++)
- {
- if (fmt[0] != '%')
- {
- if (to == end) /* End of buffer */
- break;
- *to++= *fmt; /* Copy ordinary char */
- continue;
- }
- fmt++; /* skip '%' */
- /* Read max fill size (only used with %d and %u) */
- if (*fmt == '-')
- fmt++;
- length= width= pre_zero= have_long= 0;
- for (;my_isdigit(&my_charset_latin1,*fmt); fmt++)
- {
- length=length*10+ (uint) (*fmt-'0');
- if (!length)
- pre_zero= 1; /* first digit was 0 */
- }
- if (*fmt == '.')
- for (fmt++;my_isdigit(&my_charset_latin1,*fmt); fmt++)
- width=width*10+ (uint) (*fmt-'0');
- else
- width= ~0;
- if (*fmt == 'l')
- {
- fmt++;
- have_long= 1;
- }
- if (*fmt == 's') /* String parameter */
- {
- reg2 char *par = va_arg(ap, char *);
- uint plen,left_len = (uint)(end-to)+1;
- if (!par) par = (char*)"(null)";
- plen = (uint) strlen(par);
- set_if_smaller(plen,width);
- if (left_len <= plen)
- plen = left_len - 1;
- to=strnmov(to,par,plen);
- continue;
- }
- else if (*fmt == 'd' || *fmt == 'u'|| *fmt== 'x') /* Integer parameter */
- {
- register long larg;
- uint res_length, to_length;
- char *store_start= to, *store_end;
- char buff[32];
- if ((to_length= (uint) (end-to)) < 16 || length)
- store_start= buff;
- if (have_long)
- larg = va_arg(ap, long);
- else
- if (*fmt == 'd')
- larg = va_arg(ap, int);
- else
- larg= (long) (uint) va_arg(ap, int);
- if (*fmt == 'd')
- store_end= int10_to_str(larg, store_start, -10);
- else
- if (*fmt== 'u')
- store_end= int10_to_str(larg, store_start, 10);
- else
- store_end= int2str(larg, store_start, 16, 0);
- if ((res_length= (uint) (store_end - store_start)) > to_length)
- break; /* num doesn't fit in output */
- /* If %#d syntax was used, we have to pre-zero/pre-space the string */
- if (store_start == buff)
- {
- length= min(length, to_length);
- if (res_length < length)
- {
- uint diff= (length- res_length);
- bfill(to, diff, pre_zero ? '0' : ' ');
- to+= diff;
- }
- bmove(to, store_start, res_length);
- }
- to+= res_length;
- continue;
- }
- /* We come here on '%%', unknown code or too long parameter */
- if (to == end)
- break;
- *to++='%'; /* % used as % or unknown code */
- }
- DBUG_ASSERT(to <= end);
- *to=' '; /* End of errmessage */
- return (uint) (to - start);
- }
- int my_snprintf(char* to, size_t n, const char* fmt, ...)
- {
- int result;
- va_list args;
- va_start(args,fmt);
- result= my_vsnprintf(to, n, fmt, args);
- va_end(args);
- return result;
- }
- #ifdef MAIN
- #define OVERRUN_SENTRY 250
- static void my_printf(const char * fmt, ...)
- {
- char buf[33];
- int n;
- va_list ar;
- va_start(ar, fmt);
- buf[sizeof(buf)-1]=OVERRUN_SENTRY;
- n = my_vsnprintf(buf, sizeof(buf)-1,fmt, ar);
- printf(buf);
- printf("n=%d, strlen=%dn", n, strlen(buf));
- if ((uchar) buf[sizeof(buf)-1] != OVERRUN_SENTRY)
- {
- fprintf(stderr, "Buffer overrunn");
- abort();
- }
- va_end(ar);
- }
- int main()
- {
- my_printf("Hellon");
- my_printf("Hello int, %dn", 1);
- my_printf("Hello string '%s'n", "I am a string");
- my_printf("Hello hack hack hack hack hack hack hack %dn", 1);
- my_printf("Hello %d hack %dn", 1, 4);
- my_printf("Hello %d hack hack hack hack hack %dn", 1, 4);
- my_printf("Hello '%s' hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhn", "hack");
- my_printf("Hello hhhhhhhhhhhhhh %d sssssssssssssssn", 1);
- my_printf("Hello %un", 1);
- my_printf("Hex: %lx '%6lx'n", 32, 65);
- my_printf("conn %ld to: '%-.64s' user: '%-.32s' host:
- `%-.64s' (%-.64s)", 1, 0,0,0,0);
- return 0;
- }
- #endif