asctime.c revision 192625
1/* 2** This file is in the public domain, so clarified as of 3** 1996-06-05 by Arthur David Olson. 4*/ 5 6/* 7** Avoid the temptation to punt entirely to strftime; 8** the output of strftime is supposed to be locale specific 9** whereas the output of asctime is supposed to be constant. 10*/ 11 12#include <sys/cdefs.h> 13#ifndef lint 14#ifndef NOID 15static char elsieid[] __unused = "@(#)asctime.c 8.2"; 16#endif /* !defined NOID */ 17#endif /* !defined lint */ 18__FBSDID("$FreeBSD: head/lib/libc/stdtime/asctime.c 192625 2009-05-23 06:31:50Z edwin $"); 19 20/*LINTLIBRARY*/ 21 22#include "namespace.h" 23#include "private.h" 24#include "un-namespace.h" 25#include "tzfile.h" 26 27/* 28** Some systems only handle "%.2d"; others only handle "%02d"; 29** "%02.2d" makes (most) everybody happy. 30** At least some versions of gcc warn about the %02.2d; 31** we conditionalize below to avoid the warning. 32*/ 33/* 34** All years associated with 32-bit time_t values are exactly four digits long; 35** some years associated with 64-bit time_t values are not. 36** Vintage programs are coded for years that are always four digits long 37** and may assume that the newline always lands in the same place. 38** For years that are less than four digits, we pad the output with 39** leading zeroes to get the newline in the traditional place. 40** The -4 ensures that we get four characters of output even if 41** we call a strftime variant that produces fewer characters for some years. 42** The ISO C 1999 and POSIX 1003.1-2004 standards prohibit padding the year, 43** but many implementations pad anyway; most likely the standards are buggy. 44*/ 45#ifdef __GNUC__ 46#define ASCTIME_FMT "%.3s %.3s%3d %2.2d:%2.2d:%2.2d %-4s\n" 47#else /* !defined __GNUC__ */ 48#define ASCTIME_FMT "%.3s %.3s%3d %02.2d:%02.2d:%02.2d %-4s\n" 49#endif /* !defined __GNUC__ */ 50/* 51** For years that are more than four digits we put extra spaces before the year 52** so that code trying to overwrite the newline won't end up overwriting 53** a digit within a year and truncating the year (operating on the assumption 54** that no output is better than wrong output). 55*/ 56#ifdef __GNUC__ 57#define ASCTIME_FMT_B "%.3s %.3s%3d %2.2d:%2.2d:%2.2d %s\n" 58#else /* !defined __GNUC__ */ 59#define ASCTIME_FMT_B "%.3s %.3s%3d %02.2d:%02.2d:%02.2d %s\n" 60#endif /* !defined __GNUC__ */ 61 62#define STD_ASCTIME_BUF_SIZE 26 63/* 64** Big enough for something such as 65** ??? ???-2147483648 -2147483648:-2147483648:-2147483648 -2147483648\n 66** (two three-character abbreviations, five strings denoting integers, 67** seven explicit spaces, two explicit colons, a newline, 68** and a trailing ASCII nul). 69** The values above are for systems where an int is 32 bits and are provided 70** as an example; the define below calculates the maximum for the system at 71** hand. 72*/ 73#define MAX_ASCTIME_BUF_SIZE (2*3+5*INT_STRLEN_MAXIMUM(int)+7+2+1+1) 74 75static char buf_asctime[MAX_ASCTIME_BUF_SIZE]; 76 77/* 78** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition. 79*/ 80 81char * 82asctime_r(timeptr, buf) 83const struct tm * timeptr; 84char * buf; 85{ 86 static const char wday_name[][3] = { 87 "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" 88 }; 89 static const char mon_name[][3] = { 90 "Jan", "Feb", "Mar", "Apr", "May", "Jun", 91 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" 92 }; 93 const char * wn; 94 const char * mn; 95 char year[INT_STRLEN_MAXIMUM(int) + 2]; 96 char result[MAX_ASCTIME_BUF_SIZE]; 97 98 if (timeptr->tm_wday < 0 || timeptr->tm_wday >= DAYSPERWEEK) 99 wn = "???"; 100 else wn = wday_name[timeptr->tm_wday]; 101 if (timeptr->tm_mon < 0 || timeptr->tm_mon >= MONSPERYEAR) 102 mn = "???"; 103 else mn = mon_name[timeptr->tm_mon]; 104 /* 105 ** Use strftime's %Y to generate the year, to avoid overflow problems 106 ** when computing timeptr->tm_year + TM_YEAR_BASE. 107 ** Assume that strftime is unaffected by other out-of-range members 108 ** (e.g., timeptr->tm_mday) when processing "%Y". 109 */ 110 (void) strftime(year, sizeof year, "%Y", timeptr); 111 /* 112 ** We avoid using snprintf since it's not available on all systems. 113 */ 114 (void) sprintf(result, 115 ((strlen(year) <= 4) ? ASCTIME_FMT : ASCTIME_FMT_B), 116 wn, mn, 117 timeptr->tm_mday, timeptr->tm_hour, 118 timeptr->tm_min, timeptr->tm_sec, 119 year); 120 if (strlen(result) < STD_ASCTIME_BUF_SIZE || buf == buf_asctime) { 121 (void) strcpy(buf, result); 122 return buf; 123 } else { 124#ifdef EOVERFLOW 125 errno = EOVERFLOW; 126#else /* !defined EOVERFLOW */ 127 errno = EINVAL; 128#endif /* !defined EOVERFLOW */ 129 return NULL; 130 } 131} 132 133/* 134** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition. 135*/ 136 137char * 138asctime(timeptr) 139const struct tm * timeptr; 140{ 141 return asctime_r(timeptr, buf_asctime); 142} 143