/**************************************************************************** * libs/libc/time/lib_strftime.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /**************************************************************************** * Private Type Declarations ****************************************************************************/ /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /**************************************************************************** * Public Constant Data ****************************************************************************/ /**************************************************************************** * Public Data ****************************************************************************/ /**************************************************************************** * Private Data ****************************************************************************/ static const char * const g_abbrev_wdayname[7] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" }; static const char * const g_wdayname[7] = { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" }; static const char * const g_abbrev_monthname[12] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" }; static const char * const g_monthname[12] = { "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: strftime * * Description: * The strftime() function formats the broken-down time tm according to * the format specification format and places the result in the character * array s of size max. * * Ordinary characters placed in the format string are copied to s without * conversion. Conversion specifications are introduced by a '%' charac- * ter, and terminated by a conversion specifier character, and are * replaced in s as follows: * * %a The abbreviated weekday name according to the current locale. * %A The full weekday name according to the current locale. * %b The abbreviated month name according to the current locale. * %B The full month name according to the current locale. * %C The century number (year/100) as a 2-digit integer. (SU) * %d The day of the month as a decimal number (range 01 to 31). * %e Like %d, the day of the month as a decimal number, but a leading * zero is replaced by a space. * %h Equivalent to %b. (SU) * %H The hour as a decimal number using a 24-hour clock * (range 00 to 23). * %I The hour as a decimal number using a 12-hour clock * (range 01 to 12). * %j The day of the year as a decimal number (range 001 to 366). * %k The hour (24-hour clock) as a decimal number (range 0 to 23); * single digits are preceded by a blank. (See also %H.) (TZ) * %l The hour (12-hour clock) as a decimal number (range 1 to 12); * single digits are preceded by a blank. (See also %I.) (TZ) * %m The month as a decimal number (range 01 to 12). * %M The minute as a decimal number (range 00 to 59). * %n A newline character. (SU) * %p Either "AM" or "PM" according to the given time value, or the * corresponding strings for the current locale. Noon is treated * as "PM" and midnight as "AM". * %P Like %p but in lowercase: "am" or "pm" or a corresponding string * for the current locale. (GNU) * %s The number of seconds since the Epoch, that is, since 1970-01-01 * 00:00:00 UTC. (TZ) * %S The second as a decimal number (range 00 to 60). (The range is * up to 60 to allow for occasional leap seconds.) * %t A tab character. (SU) * %y The year as a decimal number without a century (range 00 to 99). * %Y The year as a decimal number including the century. * %% A literal '%' character. * * Returned Value: * The strftime() function returns the number of characters placed in the * array s, not including the terminating null byte, provided the string, * including the terminating null byte, fits. Otherwise, it returns 0, * and the contents of the array is undefined. * ****************************************************************************/ size_t strftime(FAR char *s, size_t max, FAR const char *format, FAR const struct tm *tm) { FAR const char *str; FAR char *dest = s; int chleft = max; int value; int len; while (*format && chleft > 0) { /* Just copy regular characters */ if (*format != '%') { *dest++ = *format++; chleft--; continue; } /* Handle the format character */ format++; len = 0; switch (*format++) { /* %a: A three-letter abbreviation for the day of the week. */ case 'a': { if (tm->tm_wday < 7) { str = g_abbrev_wdayname[tm->tm_wday]; len = snprintf(dest, chleft, "%s", str); } } break; /* %A: The full name for the day of the week. */ case 'A': { if (tm->tm_wday < 7) { str = g_wdayname[tm->tm_wday]; len = snprintf(dest, chleft, "%s", str); } } break; /* %h: Equivalent to %b */ case 'h': /* %b: The abbreviated month name according to the current * locale. */ case 'b': { if (tm->tm_mon < 12) { str = g_abbrev_monthname[tm->tm_mon]; len = snprintf(dest, chleft, "%s", str); } } break; /* %B: The full month name according to the current locale. */ case 'B': { if (tm->tm_mon < 12) { str = g_monthname[tm->tm_mon]; len = snprintf(dest, chleft, "%s", str); } } break; /* %C: The century number (year/100) as a 2-digit integer. */ case 'C': { len = snprintf(dest, chleft, "%02d", tm->tm_year / 100); } break; /* %d: The day of the month as a decimal number * (range 01 to 31). */ case 'd': { len = snprintf(dest, chleft, "%02d", tm->tm_mday); } break; /* %e: Like %d, the day of the month as a decimal number, but * a leading zero is replaced by a space. */ case 'e': { len = snprintf(dest, chleft, "%2d", tm->tm_mday); } break; /* %H: The hour as a decimal number using a 24-hour clock * (range 00 to 23). */ case 'H': { len = snprintf(dest, chleft, "%02d", tm->tm_hour); } break; /* %I: The hour as a decimal number using a 12-hour clock * (range 01 to 12). */ case 'I': { len = snprintf(dest, chleft, "%02d", tm->tm_hour % 12); } break; /* %j: The day of the year as a decimal number * (range 001 to 366). */ case 'j': { if (tm->tm_mon < 12) { value = clock_daysbeforemonth(tm->tm_mon, clock_isleapyear(tm->tm_year)) + tm->tm_mday; len = snprintf(dest, chleft, "%03d", value); } } break; /* %k: The hour (24-hour clock) as a decimal number * (range 0 to 23); * single digits are preceded by a blank. */ case 'k': { len = snprintf(dest, chleft, "%2d", tm->tm_hour); } break; /* %l: The hour (12-hour clock) as a decimal number * (range 1 to 12); * single digits are preceded by a blank. */ case 'l': { len = snprintf(dest, chleft, "%2d", tm->tm_hour % 12); } break; /* %m: The month as a decimal number (range 01 to 12). */ case 'm': { len = snprintf(dest, chleft, "%02d", tm->tm_mon + 1); } break; /* %M: The minute as a decimal number (range 00 to 59). */ case 'M': { len = snprintf(dest, chleft, "%02d", tm->tm_min); } break; /* %n: A newline character. */ case 'n': { *dest = '\n'; len = 1; } break; /* %p: Either "AM" or "PM" according to the given time value. */ case 'p': { if (tm->tm_hour >= 12) { str = "PM"; } else { str = "AM"; } len = snprintf(dest, chleft, "%s", str); } break; /* %P: Like %p but in lowercase: "am" or "pm" */ case 'P': { if (tm->tm_hour >= 12) { str = "pm"; } else { str = "am"; } len = snprintf(dest, chleft, "%s", str); } break; /* %s: The number of seconds since the Epoch, that is, * since 1970-01-01 00:00:00 UTC. * Hmmm... mktime argume is not 'const'. */ case 's': { len = snprintf(dest, chleft, "%ju", (uintmax_t)mktime((FAR struct tm *)tm)); } break; /* %S: The second as a decimal number (range 00 to 60). * (The range is up to 60 to allow for occasional leap seconds.) */ case 'S': { len = snprintf(dest, chleft, "%02d", tm->tm_sec); } break; /* %t: A tab character. */ case 't': { *dest = '\t'; len = 1; } break; /* %y: The year as a decimal number without a century * (range 00 to 99). */ case 'y': { len = snprintf(dest, chleft, "%02d", tm->tm_year % 100); } break; /* %Y: The year as a decimal number including the century. */ case 'Y': { len = snprintf(dest, chleft, "%04d", tm->tm_year + 1900); } break; /* %%: A literal '%' character. */ case '%': { *dest = '%'; len = 1; } break; } /* Update counts and pointers */ dest += len; chleft -= len; } /* We get here because either we have reached the end of the format string * or because there is no more space in the user-provided buffer and the * resulting string has been truncated. * * Is there space remaining in the user-provided buffer for the NUL * terminator? */ if (chleft > 0) { /* Yes, append terminating NUL byte */ *dest = '\0'; /* And return the number of bytes in the resulting string (excluding * the NUL terminator). */ return max - chleft; } /* The string was truncated and/or not properly terminated. Return * zero. */ return 0; }