Initial import.
This commit is contained in:
Brent Simmons
435
RSXML/RSDateParser.m
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435
RSXML/RSDateParser.m
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//
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// RSDateParser.m
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// RSXML
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//
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// Created by Brent Simmons on 3/25/15.
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// Copyright (c) 2015 Ranchero Software, LLC. All rights reserved.
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//
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#import <time.h>
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#import "RSDateParser.h"
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typedef struct {
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const char *abbreviation;
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const NSInteger offsetHours;
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const NSInteger offsetMinutes;
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} RSTimeZoneAbbreviationAndOffset;
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#define kNumberOfTimeZones 96
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static const RSTimeZoneAbbreviationAndOffset timeZoneTable[kNumberOfTimeZones] = {
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{"GMT", 0, 0}, //Most common at top, for performance
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{"PDT", -7, 0}, {"PST", -8, 0}, {"EST", -5, 0}, {"EDT", -4, 0},
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{"MDT", -6, 0}, {"MST", -7, 0}, {"CST", -6, 0}, {"CDT", -5, 0},
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{"ACT", -8, 0}, {"AFT", 4, 30}, {"AMT", 4, 0}, {"ART", -3, 0},
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{"AST", 3, 0}, {"AZT", 4, 0}, {"BIT", -12, 0}, {"BDT", 8, 0},
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{"ACST", 9, 30}, {"AEST", 10, 0}, {"AKST", -9, 0}, {"AMST", 5, 0},
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{"AWST", 8, 0}, {"AZOST", -1, 0}, {"BIOT", 6, 0}, {"BRT", -3, 0},
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{"BST", 6, 0}, {"BTT", 6, 0}, {"CAT", 2, 0}, {"CCT", 6, 30},
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{"CET", 1, 0}, {"CEST", 2, 0}, {"CHAST", 12, 45}, {"ChST", 10, 0},
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{"CIST", -8, 0}, {"CKT", -10, 0}, {"CLT", -4, 0}, {"CLST", -3, 0},
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{"COT", -5, 0}, {"COST", -4, 0}, {"CVT", -1, 0}, {"CXT", 7, 0},
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{"EAST", -6, 0}, {"EAT", 3, 0}, {"ECT", -4, 0}, {"EEST", 3, 0},
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{"EET", 2, 0}, {"FJT", 12, 0}, {"FKST", -4, 0}, {"GALT", -6, 0},
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{"GET", 4, 0}, {"GFT", -3, 0}, {"GILT", 7, 0}, {"GIT", -9, 0},
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{"GST", -2, 0}, {"GYT", -4, 0}, {"HAST", -10, 0}, {"HKT", 8, 0},
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{"HMT", 5, 0}, {"IRKT", 8, 0}, {"IRST", 3, 30}, {"IST", 2, 0},
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{"JST", 9, 0}, {"KRAT", 7, 0}, {"KST", 9, 0}, {"LHST", 10, 30},
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{"LINT", 14, 0}, {"MAGT", 11, 0}, {"MIT", -9, 30}, {"MSK", 3, 0},
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{"MUT", 4, 0}, {"NDT", -2, 30}, {"NFT", 11, 30}, {"NPT", 5, 45},
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{"NT", -3, 30}, {"OMST", 6, 0}, {"PETT", 12, 0}, {"PHOT", 13, 0},
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{"PKT", 5, 0}, {"RET", 4, 0}, {"SAMT", 4, 0}, {"SAST", 2, 0},
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{"SBT", 11, 0}, {"SCT", 4, 0}, {"SLT", 5, 30}, {"SST", 8, 0},
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{"TAHT", -10, 0}, {"THA", 7, 0}, {"UYT", -3, 0}, {"UYST", -2, 0},
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{"VET", -4, 30}, {"VLAT", 10, 0}, {"WAT", 1, 0}, {"WET", 0, 0},
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{"WEST", 1, 0}, {"YAKT", 9, 0}, {"YEKT", 5, 0}
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}; /*See http://en.wikipedia.org/wiki/List_of_time_zone_abbreviations for list*/
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#pragma mark - Parser
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enum {
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RSJanuary = 1,
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RSFebruary,
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RSMarch,
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RSApril,
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RSMay,
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RSJune,
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RSJuly,
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RSAugust,
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RSSeptember,
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RSOctober,
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RSNovember,
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RSDecember
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};
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static NSInteger nextMonthValue(const char *bytes, NSUInteger numberOfBytes, NSUInteger startingIndex, NSUInteger *finalIndex) {
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/*Months are 1-based -- January is 1, Dec is 12.
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Lots of short-circuits here. Not strict. GIGO.*/
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NSUInteger i;// = startingIndex;
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NSUInteger numberOfAlphaCharactersFound = 0;
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char monthCharacters[3] = {0, 0, 0};
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for (i = startingIndex; i < numberOfBytes; i++) {
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*finalIndex = i;
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char character = bytes[i];
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BOOL isAlphaCharacter = (BOOL)isalpha(character);
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if (!isAlphaCharacter && numberOfAlphaCharactersFound < 1)
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continue;
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if (!isAlphaCharacter && numberOfAlphaCharactersFound > 0)
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break;
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numberOfAlphaCharactersFound++;
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if (numberOfAlphaCharactersFound == 1) {
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if (character == 'F' || character == 'f')
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return RSFebruary;
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if (character == 'S' || character == 's')
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return RSSeptember;
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if (character == 'O' || character == 'o')
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return RSOctober;
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if (character == 'N' || character == 'n')
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return RSNovember;
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if (character == 'D' || character == 'd')
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return RSDecember;
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}
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monthCharacters[numberOfAlphaCharactersFound - 1] = character;
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if (numberOfAlphaCharactersFound >=3)
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break;
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}
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if (numberOfAlphaCharactersFound < 2)
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return NSNotFound;
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if (monthCharacters[0] == 'J' || monthCharacters[0] == 'j') { //Jan, Jun, Jul
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if (monthCharacters[1] == 'a' || monthCharacters[i] == 'A')
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return RSJanuary;
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if (monthCharacters[1] == 'u' || monthCharacters[1] == 'U') {
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if (monthCharacters[2] == 'n' || monthCharacters[2] == 'N')
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return RSJune;
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return RSJuly;
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}
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return RSJanuary;
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}
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if (monthCharacters[0] == 'M' || monthCharacters[0] == 'm') { //March, May
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if (monthCharacters[2] == 'y' || monthCharacters[2] == 'Y')
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return RSMay;
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return RSMarch;
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}
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if (monthCharacters[0] == 'A' || monthCharacters[0] == 'a') { //April, August
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if (monthCharacters[1] == 'u' || monthCharacters[1] == 'U')
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return RSAugust;
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return RSApril;
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}
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return RSJanuary; //should never get here
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}
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static NSInteger nextNumericValue(const char *bytes, NSUInteger numberOfBytes, NSUInteger startingIndex, NSUInteger maximumNumberOfDigits, NSUInteger *finalIndex) {
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/*maximumNumberOfDigits has a maximum limit of 4 (for time zone offsets and years).
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*finalIndex will be the index of the last character looked at.*/
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if (maximumNumberOfDigits > 4)
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maximumNumberOfDigits = 4;
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NSUInteger i = 0;
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NSUInteger numberOfDigitsFound = 0;
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NSInteger digits[4] = {0, 0, 0, 0};
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for (i = startingIndex; i < numberOfBytes; i++) {
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*finalIndex = i;
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BOOL isDigit = (BOOL)isdigit(bytes[i]);
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if (!isDigit && numberOfDigitsFound < 1)
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continue;
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if (!isDigit && numberOfDigitsFound > 0)
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break;
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digits[numberOfDigitsFound] = bytes[i] - 48; // '0' is 48
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numberOfDigitsFound++;
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if (numberOfDigitsFound >= maximumNumberOfDigits)
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break;
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}
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if (numberOfDigitsFound < 1)
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return NSNotFound;
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if (numberOfDigitsFound == 1)
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return digits[0];
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if (numberOfDigitsFound == 2)
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return (digits[0] * 10) + digits[1];
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if (numberOfDigitsFound == 3)
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return (digits[0] * 100) + (digits[1] * 10) + digits[2];
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return (digits[0] * 1000) + (digits[1] * 100) + (digits[2] * 10) + digits[3];
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}
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static BOOL hasAtLeastOneAlphaCharacter(const char *s) {
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NSUInteger length = strlen(s);
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NSUInteger i = 0;
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for (i = 0; i < length; i++) {
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if (isalpha(s[i]))
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return YES;
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}
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return NO;
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}
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#pragma mark - Time Zones and offsets
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static NSInteger offsetInSecondsForTimeZoneAbbreviation(const char *abbreviation) {
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/*Linear search should be fine. It's a C array, and short (under 100 items).
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Most common time zones are at the beginning of the array. (We can tweak this as needed.)*/
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NSUInteger i;
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for (i = 0; i < kNumberOfTimeZones; i++) {
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RSTimeZoneAbbreviationAndOffset zone = timeZoneTable[i];
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if (strcmp(abbreviation, zone.abbreviation) == 0) {
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if (zone.offsetHours < 0)
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return (zone.offsetHours * 60 * 60) - (zone.offsetMinutes * 60);
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return (zone.offsetHours * 60 * 60) + (zone.offsetMinutes * 60);
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}
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}
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return 0;
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}
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static NSInteger offsetInSecondsForOffsetCharacters(const char *timeZoneCharacters) {
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BOOL isPlus = timeZoneCharacters[0] == '+';
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NSUInteger finalIndex = 0;
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NSInteger hours = nextNumericValue(timeZoneCharacters, strlen(timeZoneCharacters), 0, 2, &finalIndex);
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NSInteger minutes = nextNumericValue(timeZoneCharacters, strlen(timeZoneCharacters), finalIndex + 1, 2, &finalIndex);
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if (hours == NSNotFound)
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hours = 0;
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if (minutes == NSNotFound)
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minutes = 0;
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if (hours == 0 && minutes == 0)
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return 0;
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NSInteger seconds = (hours * 60 * 60) + (minutes * 60);
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if (!isPlus)
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seconds = 0 - seconds;
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return seconds;
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}
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static const char *rs_GMT = "GMT";
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static const char *rs_UTC = "UTC";
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static NSInteger parsedTimeZoneOffset(const char *bytes, NSUInteger numberOfBytes, NSUInteger startingIndex) {
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/*Examples: GMT Z +0000 -0000 +07:00 -0700 PDT EST
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Parse into char[5] -- drop any colon characters. If numeric, calculate seconds from GMT.
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If alpha, special-case GMT and Z, otherwise look up in time zone list to get offset.*/
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char timeZoneCharacters[6] = {0, 0, 0, 0, 0, 0}; //nil-terminated last character
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NSUInteger i = 0;
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NSUInteger numberOfCharactersFound = 0;
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for (i = startingIndex; i < numberOfBytes; i++) {
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char ch = bytes[i];
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if (ch == ':' || ch == ' ')
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continue;
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if (isdigit(ch) || isalpha(ch) || ch == '+' || ch == '-') {
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numberOfCharactersFound++;
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timeZoneCharacters[numberOfCharactersFound - 1] = ch;
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}
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if (numberOfCharactersFound >= 5)
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break;
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}
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if (numberOfCharactersFound < 1 || timeZoneCharacters[0] == 'Z' || timeZoneCharacters[0] == 'z')
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return 0;
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if (strcasestr(timeZoneCharacters, rs_GMT) != nil || strcasestr(timeZoneCharacters, rs_UTC))
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return 0;
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if (hasAtLeastOneAlphaCharacter(timeZoneCharacters))
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return offsetInSecondsForTimeZoneAbbreviation(timeZoneCharacters);
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return offsetInSecondsForOffsetCharacters(timeZoneCharacters);
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}
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#pragma mark - Date Creation
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static NSDate *dateWithYearMonthDayHourMinuteSecondAndTimeZoneOffset(NSInteger year, NSInteger month, NSInteger day, NSInteger hour, NSInteger minute, NSInteger second, NSInteger milliseconds, NSInteger timeZoneOffset) {
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struct tm timeInfo;
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timeInfo.tm_sec = (int)second;
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timeInfo.tm_min = (int)minute;
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timeInfo.tm_hour = (int)hour;
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timeInfo.tm_mday = (int)day;
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timeInfo.tm_mon = (int)(month - 1); //It's 1-based coming in
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timeInfo.tm_year = (int)(year - 1900); //see time.h -- it's years since 1900
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timeInfo.tm_wday = -1;
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timeInfo.tm_yday = -1;
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timeInfo.tm_isdst = -1;
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timeInfo.tm_gmtoff = 0;//[timeZone secondsFromGMT];
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timeInfo.tm_zone = nil;
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NSTimeInterval rawTime = (NSTimeInterval)(timegm(&timeInfo) - timeZoneOffset); //timegm instead of mktime (which uses local time zone)
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if (rawTime == (time_t)ULONG_MAX) {
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/*NSCalendar is super-amazingly-slow (which is partly why RSDateParser exists), so this is used only when the date is far enough in the future (19 January 2038 03:14:08Z on 32-bit systems) that timegm fails. If profiling says that this is a performance issue, then you've got a weird app that needs to work with dates far in the future.*/
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NSDateComponents *dateComponents = [NSDateComponents new];
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dateComponents.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:timeZoneOffset];
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dateComponents.year = year;
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dateComponents.month = month;
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dateComponents.day = day;
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dateComponents.hour = hour;
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dateComponents.minute = minute;
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dateComponents.second = second + (milliseconds / 1000);
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return [[NSCalendar autoupdatingCurrentCalendar] dateFromComponents:dateComponents];
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}
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if (milliseconds > 0) {
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rawTime += ((float)milliseconds / 1000.0f);
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}
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return [NSDate dateWithTimeIntervalSince1970:rawTime];
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}
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#pragma mark - Standard Formats
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static NSDate *RSParsePubDateWithBytes(const char *bytes, NSUInteger numberOfBytes) {
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/*@"EEE',' dd MMM yyyy HH':'mm':'ss ZZZ"
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@"EEE, dd MMM yyyy HH:mm:ss zzz"
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@"dd MMM yyyy HH:mm zzz"
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@"dd MMM yyyy HH:mm ZZZ"
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@"EEE, dd MMM yyyy"
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@"EEE, dd MMM yyyy HH:mm zzz"
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etc.*/
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NSUInteger finalIndex = 0;
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NSInteger day = 1;
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NSInteger month = RSJanuary;
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NSInteger year = 1970;
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NSInteger hour = 0;
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NSInteger minute = 0;
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NSInteger second = 0;
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NSInteger timeZoneOffset = 0;
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day = nextNumericValue(bytes, numberOfBytes, 0, 2, &finalIndex);
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if (day < 1 || day == NSNotFound)
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day = 1;
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month = nextMonthValue(bytes, numberOfBytes, finalIndex + 1, &finalIndex);
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year = nextNumericValue(bytes, numberOfBytes, finalIndex + 1, 4, &finalIndex);
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hour = nextNumericValue(bytes, numberOfBytes, finalIndex + 1, 2, &finalIndex);
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if (hour == NSNotFound)
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hour = 0;
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minute = nextNumericValue(bytes, numberOfBytes, finalIndex + 1, 2, &finalIndex);
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if (minute == NSNotFound)
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minute = 0;
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NSUInteger currentIndex = finalIndex + 1;
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BOOL hasSeconds = (currentIndex < numberOfBytes) && (bytes[currentIndex] == ':');
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if (hasSeconds)
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second = nextNumericValue(bytes, numberOfBytes, currentIndex, 2, &finalIndex);
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currentIndex = finalIndex + 1;
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BOOL hasTimeZone = (currentIndex < numberOfBytes) && (bytes[currentIndex] == ' ');
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if (hasTimeZone)
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timeZoneOffset = parsedTimeZoneOffset(bytes, numberOfBytes, currentIndex);
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return dateWithYearMonthDayHourMinuteSecondAndTimeZoneOffset(year, month, day, hour, minute, second, 0, timeZoneOffset);
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}
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static NSDate *RSParseW3CWithBytes(const char *bytes, NSUInteger numberOfBytes) {
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/*@"yyyy'-'MM'-'dd'T'HH':'mm':'ss"
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@"yyyy-MM-dd'T'HH:mm:sszzz"
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@"yyyy-MM-dd'T'HH:mm:ss'.'SSSzzz"
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etc.*/
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NSUInteger finalIndex = 0;
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NSInteger day = 1;
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NSInteger month = RSJanuary;
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NSInteger year = 1970;
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NSInteger hour = 0;
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NSInteger minute = 0;
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NSInteger second = 0;
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NSInteger milliseconds = 0;
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NSInteger timeZoneOffset = 0;
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year = nextNumericValue(bytes, numberOfBytes, 0, 4, &finalIndex);
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month = nextNumericValue(bytes, numberOfBytes, finalIndex + 1, 2, &finalIndex);
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day = nextNumericValue(bytes, numberOfBytes, finalIndex + 1, 2, &finalIndex);
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hour = nextNumericValue(bytes, numberOfBytes, finalIndex + 1, 2, &finalIndex);
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minute = nextNumericValue(bytes, numberOfBytes, finalIndex + 1, 2, &finalIndex);
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second = nextNumericValue(bytes, numberOfBytes, finalIndex + 1, 2, &finalIndex);
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NSUInteger currentIndex = finalIndex + 1;
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BOOL hasMilliseconds = (currentIndex < numberOfBytes) && (bytes[currentIndex] == '.');
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if (hasMilliseconds) {
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milliseconds = nextNumericValue(bytes, numberOfBytes, currentIndex, 3, &finalIndex);
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currentIndex = finalIndex + 1;
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}
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timeZoneOffset = parsedTimeZoneOffset(bytes, numberOfBytes, currentIndex);
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return dateWithYearMonthDayHourMinuteSecondAndTimeZoneOffset(year, month, day, hour, minute, second, milliseconds, timeZoneOffset);
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}
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static BOOL dateIsPubDate(const char *bytes, NSUInteger numberOfBytes) {
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NSUInteger i = 0;
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for (i = 0; i < numberOfBytes; i++) {
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if (bytes[i] == ' ' || bytes[i] == ',')
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return YES;
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}
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return NO;
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}
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static BOOL numberOfBytesIsOutsideReasonableRange(NSUInteger numberOfBytes) {
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return numberOfBytes < 6 || numberOfBytes > 50;
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}
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#pragma mark - API
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NSDate *RSDateWithBytes(const char *bytes, NSUInteger numberOfBytes) {
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if (numberOfBytesIsOutsideReasonableRange(numberOfBytes))
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return nil;
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if (dateIsPubDate(bytes, numberOfBytes))
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return RSParsePubDateWithBytes(bytes, numberOfBytes);
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return RSParseW3CWithBytes(bytes, numberOfBytes);
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}
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NSDate *RSDateWithString(NSString *dateString) {
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const char *utf8String = [dateString UTF8String];
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return RSDateWithBytes(utf8String, strlen(utf8String));
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}
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Reference in New Issue
Block a user