CA2234991A1 - System and method for storing and processing date information which spans more than one century - Google Patents
System and method for storing and processing date information which spans more than one century Download PDFInfo
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- CA2234991A1 CA2234991A1 CA 2234991 CA2234991A CA2234991A1 CA 2234991 A1 CA2234991 A1 CA 2234991A1 CA 2234991 CA2234991 CA 2234991 CA 2234991 A CA2234991 A CA 2234991A CA 2234991 A1 CA2234991 A1 CA 2234991A1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F8/00—Arrangements for software engineering
- G06F8/70—Software maintenance or management
- G06F8/78—Methods to solve the "Year 2000" [Y2K] problem
Abstract
A system for reading and writing overloaded dates is provided in which six digits are used to represent dates including century information in a manner which maintains sorting and indexing. A three digit prefix is determined from the year and century information using windowing if necessary, and a three digit suffix is determined from the day and month information.
Description
System and Method for Storing and Processing Date Information Which Spans More than One Century Field of the Invention The invention relates to systems and methods for storing and processing date information which spans more than one century.
Background of the Invention The "year 2000 problem" is now a well known phenomenon which has resulted from the fact that most existing application software particularly in the business data processing area stores and processes date information in a six-digit format which does not include any century information. The date might for example be stored using the day/month/year format in which case the date January 21, 1999 would be stored as 210199.
Until recently, it was an acceptable assumption to make that any and all years stored belonged to the 20th century and as such there was no ambiguity in such dates.
However, now it is necessary to be capable of processing dates for years belonging to the 21st century. This presents a problem both for storing and processing the date information.
It would be desirable to be able to include century information without changing storage requirements as this would require substantive changes to software accessing the date information. For processing, conventional applications can sort date information within a given century but cannot sort dates from different centuries. Consider for example that a date having the year 2005 would have a year field equal to 05, and a date having the year 1995 would have a year field equal to 95 which would be incorrectly interpreted as being after the stored version of the date 2005. Furthermore, files containing date information are often indexed by that date information. It should be possible to use the date information to uniquely index stored information and clearly this is not possible when the century is ambiguous.
Various solutions have been proposed. U.S. patent Number 5,600,836 to Alter entitled "System and Method for Processing Date-Dependent Information which Spans One or Two Centuries" which issued on February 4, 1997 involves using "zone data files" which contain dates which have been converted to "zone times" and "local data files" which contain the dates in the conventional format. This requires significant calculation and logic to encode and decode the date information.
U.S. Patent Number 5,644,762 to Soeder entitled "System and method for Processing Date-Dependent Information which Spans One or Two Centuries" which issued on July l, 1997 discloses a solution for storing the century in a six digit date by adding the century and converting the century and year combination to a binary value. While this will work for some applications, it has the disadvantages of requiring a mixed mode storage strategy.
U.S. Patent Number 5,668,989 to Mao entitled "Two-Digit Hybrid Radix Year Numbers for Year 2000 and Beyond"
which issued September 16, 1997 treats the higher digit of a two digit year number as hexadecimal but displayed in a decimal-like format with font patterns such as 0 - 9 and '0 -'5 so that the year 1900 is represented and processed as 00 while the year 2000 is represented and processed as '00. This will only handle dates up to 2059.
Finally, other methods include full expansion which requires 33% more storage space, windowing, the "Roman Format", packed format, and extended Julian.
Background of the Invention The "year 2000 problem" is now a well known phenomenon which has resulted from the fact that most existing application software particularly in the business data processing area stores and processes date information in a six-digit format which does not include any century information. The date might for example be stored using the day/month/year format in which case the date January 21, 1999 would be stored as 210199.
Until recently, it was an acceptable assumption to make that any and all years stored belonged to the 20th century and as such there was no ambiguity in such dates.
However, now it is necessary to be capable of processing dates for years belonging to the 21st century. This presents a problem both for storing and processing the date information.
It would be desirable to be able to include century information without changing storage requirements as this would require substantive changes to software accessing the date information. For processing, conventional applications can sort date information within a given century but cannot sort dates from different centuries. Consider for example that a date having the year 2005 would have a year field equal to 05, and a date having the year 1995 would have a year field equal to 95 which would be incorrectly interpreted as being after the stored version of the date 2005. Furthermore, files containing date information are often indexed by that date information. It should be possible to use the date information to uniquely index stored information and clearly this is not possible when the century is ambiguous.
Various solutions have been proposed. U.S. patent Number 5,600,836 to Alter entitled "System and Method for Processing Date-Dependent Information which Spans One or Two Centuries" which issued on February 4, 1997 involves using "zone data files" which contain dates which have been converted to "zone times" and "local data files" which contain the dates in the conventional format. This requires significant calculation and logic to encode and decode the date information.
U.S. Patent Number 5,644,762 to Soeder entitled "System and method for Processing Date-Dependent Information which Spans One or Two Centuries" which issued on July l, 1997 discloses a solution for storing the century in a six digit date by adding the century and converting the century and year combination to a binary value. While this will work for some applications, it has the disadvantages of requiring a mixed mode storage strategy.
U.S. Patent Number 5,668,989 to Mao entitled "Two-Digit Hybrid Radix Year Numbers for Year 2000 and Beyond"
which issued September 16, 1997 treats the higher digit of a two digit year number as hexadecimal but displayed in a decimal-like format with font patterns such as 0 - 9 and '0 -'5 so that the year 1900 is represented and processed as 00 while the year 2000 is represented and processed as '00. This will only handle dates up to 2059.
Finally, other methods include full expansion which requires 33% more storage space, windowing, the "Roman Format", packed format, and extended Julian.
Summary of the Invention It is an object of the invention to obviate or mitigate one or more of the above identified disadvantages.
According to a first broad aspect, the invention provides a series of operational steps to be performed on or with the aid of a computer, said steps comprising:
a) whenever necessary, determining a six digit overloaded date from day, month and year information by performing the steps of:
al) determining a three digit prefix from the year information which maintains sort order and includes century information;
a2) determining a three digit suffix from the day and month information which maintains sort order; and a3) determining a six digit overloaded date by combining the three digit prefix and the three digit suffix.
According to a second broad aspect, the invention provides a series of operational steps to be performed on or with the aid of a computer, said steps comprising:
b) whenever necessary determining day, month, year and century information from a six digit overloaded date by performing the steps of:
bl) determining a three digit prefix and a three digit suffix from the six digit overloaded date;
b2) determining the year and century information from the three digit prefix; and b3) determining the day and month information from the three digit suffix.
According to a third broad aspect, a method is provided including the steps of the first and second broad aspects described above. Preferably in such an aspect, step al) comprises the steps of:
i) determining if the year information includes century information;
According to a first broad aspect, the invention provides a series of operational steps to be performed on or with the aid of a computer, said steps comprising:
a) whenever necessary, determining a six digit overloaded date from day, month and year information by performing the steps of:
al) determining a three digit prefix from the year information which maintains sort order and includes century information;
a2) determining a three digit suffix from the day and month information which maintains sort order; and a3) determining a six digit overloaded date by combining the three digit prefix and the three digit suffix.
According to a second broad aspect, the invention provides a series of operational steps to be performed on or with the aid of a computer, said steps comprising:
b) whenever necessary determining day, month, year and century information from a six digit overloaded date by performing the steps of:
bl) determining a three digit prefix and a three digit suffix from the six digit overloaded date;
b2) determining the year and century information from the three digit prefix; and b3) determining the day and month information from the three digit suffix.
According to a third broad aspect, a method is provided including the steps of the first and second broad aspects described above. Preferably in such an aspect, step al) comprises the steps of:
i) determining if the year information includes century information;
ii) if the result of step i) is false, determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information;
iii) if the result of step i) is true, determining the prefix to be the year information and preferably the year information minus a predetermined base year;
step a2) comprises the steps of subtracting one from the month information, multiplying by 31 and adding the day information;
step bl) comprises the steps of:
i) dividing the six digit overloaded date by 1000 to get the three digit prefix;
ii) subtracting 1000 times the prefix from the six digit overloaded date to get the three digit suffix;
step b2) comprises the steps of:
i) dividing the three digit prefix by 100000 to get a century index;
ii) subtracting 100 times the century index from the prefix to get the year information;
and step b3) comprises the steps of subtracting one from the suffix and then dividing by 31 to get a number of prior months, and adding one to the number of prior months to get the month information, and determining the day information to be the suffix minus the number of prior months times 31.
Advantageously, the method allows the overloaded date to be stored in six numeric decimal digits. The overloaded date maintains sort sequence. The processing overhead introduces is not unreasonable.
Preferably, the six numeric digits computed for a given overloaded date can be stored in three bytes.
Preferably, the date is mathematically calculated.
iii) if the result of step i) is true, determining the prefix to be the year information and preferably the year information minus a predetermined base year;
step a2) comprises the steps of subtracting one from the month information, multiplying by 31 and adding the day information;
step bl) comprises the steps of:
i) dividing the six digit overloaded date by 1000 to get the three digit prefix;
ii) subtracting 1000 times the prefix from the six digit overloaded date to get the three digit suffix;
step b2) comprises the steps of:
i) dividing the three digit prefix by 100000 to get a century index;
ii) subtracting 100 times the century index from the prefix to get the year information;
and step b3) comprises the steps of subtracting one from the suffix and then dividing by 31 to get a number of prior months, and adding one to the number of prior months to get the month information, and determining the day information to be the suffix minus the number of prior months times 31.
Advantageously, the method allows the overloaded date to be stored in six numeric decimal digits. The overloaded date maintains sort sequence. The processing overhead introduces is not unreasonable.
Preferably, the six numeric digits computed for a given overloaded date can be stored in three bytes.
Preferably, the date is mathematically calculated.
Preferably, the century is determined using windowing, windowing being a process of inferring the century based on the year portion of a date such that a year less than a given number is deemed to be in the latter century.
Brief Description of the Drawings Preferred embodiments of the invention will now be described with reference to the attached drawings in which:
Figure 1 is a flowchart for a method of determining an overloaded date according to an embodiment of the invention;
Figures 2A - 2C are flowcharts for the step of determining the year prefix appearing in Figure 1;
Figures 3A and 3B are flowcharts for methods of determining a six or eight digit date representation respectively from an overloaded date determined with the method of Figure 1; and Figure 4 is a block diagram of a computing device according to an embodiment of the invention.
Detailed Description of the Preferred Embodiments Referring now to Figure 1 a method of determining an overloaded date according to an embodiment of the invention has as its input a date which includes day, month and year information and may or may not include century information.
The method will be described in detail with respect to the example date of 25 November 2012 for the case where century information is included, or 25 November '12 for the case where century information is not included.
In the first step 202 the number of complete previous months that year is determined by subtracting one from the numeric representation of the month. In this example, the number is 11 (numeric representation of November) minus 1 equals 10. In the second step 204, the results of the previous step 202 are multiplied by 31 and added to the day field of the date to give a suffix quantity. In this example, this yields 10 x 31 + 25 = 335 as the suffix. In step 206 a three digit year prefix is determined according to one of the methods described in detail below. For the purposes of this example, assume that the year prefix is 112. In step 208 the overloaded date is determined by multiplying the year prefix (output of step 206A) by 1000 and adding the suffix (output of step 204). In our example, this yields 1000 x 112 + 335 -112335 as the overloaded date.
Various methods may be used to determine the year prefix, the important factor being that it may be stored in three digits (i.e. prefix less than or equal to 999) and maintains sorting and indexing of years.
The methods used may depend upon the format of the year information being input to the method and more particularly whether it includes century information. First of all, a "base year" must be selected, this preferably being a century year. The method will be incapable of representing dates prior to the base year. For most applications currently contemplated the base year would be 1900.
For input data which does not include century information an assumption about the century must be made. For the 1900 base year example, the year 2012 would have a two digit year field of 12 in input data which does not include century information. For this case, an assumption may be made that all two digit years equal to or greater than a certain year which will be referred to herein as the "pivot year"
belong to the century beginning with the base year and that all years less than the pivot year belong to the century following the base year. The flowchart of Figure 2A will be used to describe the processing of such input information and this will be referred to as "method A". In step 232 the year field is compared with the pivot year. If the year input is less than the pivot year then step 234 is executed, this consisting of determining the prefix to be the year input +
100. If the year input is not less than the pivot year then step 236 is executed, this consisting of determining the prefix to be the year input.
For data for which no assumption regarding century needs to be made, the year prefix may be determined simply by subtracting the base year from the year information. For example, if the year is 2012, then the year prefix is determined from 2012 - 1900 = 112. This is depicted in flowchart form in Figure 2B and will be referred to as "method B.. .
For data which is mixed in the sense that it may or may not include century information, either method A or method B may be executed. This is depicted in Figure 2C wherein a test (step 240) is used to determine which method to use, method A or method B. If the year is greater than 99 then century information must be present and method B can be used.
Otherwise method A is used. In either case, the first digit of the prefix is an indicator of the century of the year with respect to the base year and will be referred to as the century index. For years within 100 years of the base year, the century index is "0", for years within between 100 and 200 years of the base year, the century index is "1" and so on.
The date information may then be stored in any conventional fashion, and more particularly can be stored in as little as three bytes using conventional storage techniques.
In order to present either a six digit or an eight digit date in conventional format from the overloaded date requires the above process to be reversed. A method for obtaining the date in six digit format (two digit year) will be described with reference to the flowchart in Figure 3A in the context of the above developed overloaded date of 112335.
_ g _ The first step 302 is to divide the overloaded date by 100000 and to take the integer part thereby yielding the century index. For the example this yields a century indicator of "1". The next 304 step is to divide the overloaded date by 1000 and to take the integer part to produce the prefix. For the example this yields a prefix of 112. In the next step 306A to get the two digit year, 100 times the century index is subtracted from the prefix determined in step 304. In the example this yields 112 - 100 x 1 = 12. In step 308, to get the suffix, 1000 times the prefix is subtracted from the overloaded date. In our example, this yields a suffix of 335.
In step 310, the month is retrieved by carrying out steps 312, 314 and 316. Step 312 consists of subtracting one from the suffix computed in step 308 to prevent incorrectly determining the subsequent month when dividing by 31 if the day is the 31st. Step 314 comprises dividing the result by 31 to get the number of prior months. In our example, this yields 10 as the number of prior months. Finally step 316 comprises adding one to the result of step 314 to get the actual month. In our example, the month is determined to be 11. In step 318, the day information is determined by subtracting the number of previous months times 31 from the suffix. In our example, the day is determined to be 25.
When an eight digit date is to be produced (four digit year) the prefix is determined by dividing the overloaded date by 1000. The year is determined by adding the base year to the prefix. The remaining steps are the same as for the six digit format. This is shown in Figure 3B which is the same as Figure 3A with the exception that step 306B is executed in place of step 306A.
Figure 4 shows a computing device for implementing the invention. Computing device 348 includes storage 360 for storing dates, these normally forming part of some larger records. Read/write device 358 reads from and writes to the storage under control of a processor such as microprocessor 350. The microprocessor 350 has logic circuitry for executing the methods of Figures 1-3 described above, or may be a computing device appropriately programmed to execute the methods. The device may include any or all of input 352, printer 354, or display 356 as needed, for example. The storage 360 may be a permanent storage medium such as a disk or tape in which case the read/write device 358 provides access to this permanent storage medium. Alternatively, storage 360 may be any type of volatile storage such as RAM or microprocessor registers for example in which case the functionality of the read/write device 358 may be part of the functionality of the microprocessor.
In the above described examples, the suffix is determined by subtracting one from the current month, multiplying by 31, and adding the day. More generally, any technique of sortably representing the day and month in three digits may be used. For example, the month may be multiplied by any "month multiplier" between 31 and 80 inclusive may be used to create a number which when added to the day will yield a number less than 1000, the requirement for three digit storage. Furthermore, if a number greater than 31 is used, then steps 204,312, and 316 described previously are not required. For example, if 32 is used, then for our November 25, 2012 date the suffix would simply be 11*32+15=377. The month would be recoverable from the suffix by dividing the suffix by the month multiplier (in our example 377/32 - 11) and the day would be recoverable by subtracting the month times the month multiplier from the suffix (in our example 377 - 11*32 - 25).
In the above examples, the prefix and suffix are determined using numerical methods, and require no string manipulations. This is desirable because string manipulations are slow to perform. However, in the case that string manipulations are permissible, even though there is no apparent advantage to doing so, the three digits of the suffix and the three digits of the prefix may be arranged in any predetermined order since the suffix and prefix would still be recoverable. In addition, different methods of generating the prefix and suffix may be used which are self-evident from the above described numerical methods.
Should input dates be available in the format yy/ddd where ddd is from 1-366, the suffix may simply be selected to equal the ddd field if it is understood that all dates will be in that format since this satisfies the requirement that the suffix be sortable and contain values less than 999.
Otherwise, the input date must be converted to a day/month format and the methods described previously are then executed.
Any of the above described methods may be used to convert an entire array of dates to overloaded dates.
Alternatively, the methods may be used one at a time each time a date is accessed.
It is to be understood that any processing means capable of executing the above described methods could be used to implement the invention including computers, microprocessors, ASICs (application specific integrated circuits), FPGAs (field programmable gate arrays) etc.
Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practised otherwise than as specifically described herein.
Brief Description of the Drawings Preferred embodiments of the invention will now be described with reference to the attached drawings in which:
Figure 1 is a flowchart for a method of determining an overloaded date according to an embodiment of the invention;
Figures 2A - 2C are flowcharts for the step of determining the year prefix appearing in Figure 1;
Figures 3A and 3B are flowcharts for methods of determining a six or eight digit date representation respectively from an overloaded date determined with the method of Figure 1; and Figure 4 is a block diagram of a computing device according to an embodiment of the invention.
Detailed Description of the Preferred Embodiments Referring now to Figure 1 a method of determining an overloaded date according to an embodiment of the invention has as its input a date which includes day, month and year information and may or may not include century information.
The method will be described in detail with respect to the example date of 25 November 2012 for the case where century information is included, or 25 November '12 for the case where century information is not included.
In the first step 202 the number of complete previous months that year is determined by subtracting one from the numeric representation of the month. In this example, the number is 11 (numeric representation of November) minus 1 equals 10. In the second step 204, the results of the previous step 202 are multiplied by 31 and added to the day field of the date to give a suffix quantity. In this example, this yields 10 x 31 + 25 = 335 as the suffix. In step 206 a three digit year prefix is determined according to one of the methods described in detail below. For the purposes of this example, assume that the year prefix is 112. In step 208 the overloaded date is determined by multiplying the year prefix (output of step 206A) by 1000 and adding the suffix (output of step 204). In our example, this yields 1000 x 112 + 335 -112335 as the overloaded date.
Various methods may be used to determine the year prefix, the important factor being that it may be stored in three digits (i.e. prefix less than or equal to 999) and maintains sorting and indexing of years.
The methods used may depend upon the format of the year information being input to the method and more particularly whether it includes century information. First of all, a "base year" must be selected, this preferably being a century year. The method will be incapable of representing dates prior to the base year. For most applications currently contemplated the base year would be 1900.
For input data which does not include century information an assumption about the century must be made. For the 1900 base year example, the year 2012 would have a two digit year field of 12 in input data which does not include century information. For this case, an assumption may be made that all two digit years equal to or greater than a certain year which will be referred to herein as the "pivot year"
belong to the century beginning with the base year and that all years less than the pivot year belong to the century following the base year. The flowchart of Figure 2A will be used to describe the processing of such input information and this will be referred to as "method A". In step 232 the year field is compared with the pivot year. If the year input is less than the pivot year then step 234 is executed, this consisting of determining the prefix to be the year input +
100. If the year input is not less than the pivot year then step 236 is executed, this consisting of determining the prefix to be the year input.
For data for which no assumption regarding century needs to be made, the year prefix may be determined simply by subtracting the base year from the year information. For example, if the year is 2012, then the year prefix is determined from 2012 - 1900 = 112. This is depicted in flowchart form in Figure 2B and will be referred to as "method B.. .
For data which is mixed in the sense that it may or may not include century information, either method A or method B may be executed. This is depicted in Figure 2C wherein a test (step 240) is used to determine which method to use, method A or method B. If the year is greater than 99 then century information must be present and method B can be used.
Otherwise method A is used. In either case, the first digit of the prefix is an indicator of the century of the year with respect to the base year and will be referred to as the century index. For years within 100 years of the base year, the century index is "0", for years within between 100 and 200 years of the base year, the century index is "1" and so on.
The date information may then be stored in any conventional fashion, and more particularly can be stored in as little as three bytes using conventional storage techniques.
In order to present either a six digit or an eight digit date in conventional format from the overloaded date requires the above process to be reversed. A method for obtaining the date in six digit format (two digit year) will be described with reference to the flowchart in Figure 3A in the context of the above developed overloaded date of 112335.
_ g _ The first step 302 is to divide the overloaded date by 100000 and to take the integer part thereby yielding the century index. For the example this yields a century indicator of "1". The next 304 step is to divide the overloaded date by 1000 and to take the integer part to produce the prefix. For the example this yields a prefix of 112. In the next step 306A to get the two digit year, 100 times the century index is subtracted from the prefix determined in step 304. In the example this yields 112 - 100 x 1 = 12. In step 308, to get the suffix, 1000 times the prefix is subtracted from the overloaded date. In our example, this yields a suffix of 335.
In step 310, the month is retrieved by carrying out steps 312, 314 and 316. Step 312 consists of subtracting one from the suffix computed in step 308 to prevent incorrectly determining the subsequent month when dividing by 31 if the day is the 31st. Step 314 comprises dividing the result by 31 to get the number of prior months. In our example, this yields 10 as the number of prior months. Finally step 316 comprises adding one to the result of step 314 to get the actual month. In our example, the month is determined to be 11. In step 318, the day information is determined by subtracting the number of previous months times 31 from the suffix. In our example, the day is determined to be 25.
When an eight digit date is to be produced (four digit year) the prefix is determined by dividing the overloaded date by 1000. The year is determined by adding the base year to the prefix. The remaining steps are the same as for the six digit format. This is shown in Figure 3B which is the same as Figure 3A with the exception that step 306B is executed in place of step 306A.
Figure 4 shows a computing device for implementing the invention. Computing device 348 includes storage 360 for storing dates, these normally forming part of some larger records. Read/write device 358 reads from and writes to the storage under control of a processor such as microprocessor 350. The microprocessor 350 has logic circuitry for executing the methods of Figures 1-3 described above, or may be a computing device appropriately programmed to execute the methods. The device may include any or all of input 352, printer 354, or display 356 as needed, for example. The storage 360 may be a permanent storage medium such as a disk or tape in which case the read/write device 358 provides access to this permanent storage medium. Alternatively, storage 360 may be any type of volatile storage such as RAM or microprocessor registers for example in which case the functionality of the read/write device 358 may be part of the functionality of the microprocessor.
In the above described examples, the suffix is determined by subtracting one from the current month, multiplying by 31, and adding the day. More generally, any technique of sortably representing the day and month in three digits may be used. For example, the month may be multiplied by any "month multiplier" between 31 and 80 inclusive may be used to create a number which when added to the day will yield a number less than 1000, the requirement for three digit storage. Furthermore, if a number greater than 31 is used, then steps 204,312, and 316 described previously are not required. For example, if 32 is used, then for our November 25, 2012 date the suffix would simply be 11*32+15=377. The month would be recoverable from the suffix by dividing the suffix by the month multiplier (in our example 377/32 - 11) and the day would be recoverable by subtracting the month times the month multiplier from the suffix (in our example 377 - 11*32 - 25).
In the above examples, the prefix and suffix are determined using numerical methods, and require no string manipulations. This is desirable because string manipulations are slow to perform. However, in the case that string manipulations are permissible, even though there is no apparent advantage to doing so, the three digits of the suffix and the three digits of the prefix may be arranged in any predetermined order since the suffix and prefix would still be recoverable. In addition, different methods of generating the prefix and suffix may be used which are self-evident from the above described numerical methods.
Should input dates be available in the format yy/ddd where ddd is from 1-366, the suffix may simply be selected to equal the ddd field if it is understood that all dates will be in that format since this satisfies the requirement that the suffix be sortable and contain values less than 999.
Otherwise, the input date must be converted to a day/month format and the methods described previously are then executed.
Any of the above described methods may be used to convert an entire array of dates to overloaded dates.
Alternatively, the methods may be used one at a time each time a date is accessed.
It is to be understood that any processing means capable of executing the above described methods could be used to implement the invention including computers, microprocessors, ASICs (application specific integrated circuits), FPGAs (field programmable gate arrays) etc.
Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practised otherwise than as specifically described herein.
Claims (19)
1. A series of operational steps to be performed on or with the aid of a computer, said steps comprising:
a) whenever necessary, determining a six digit overloaded date from day, month and year information by performing the steps of:
a1) determining a three digit prefix from the year information which maintains sort order and includes century information;
a2) determining a three digit suffix from the day and month information which maintains sort order; and a3) determining a six digit overloaded date by combining the three digit prefix and the three digit suffix.
a) whenever necessary, determining a six digit overloaded date from day, month and year information by performing the steps of:
a1) determining a three digit prefix from the year information which maintains sort order and includes century information;
a2) determining a three digit suffix from the day and month information which maintains sort order; and a3) determining a six digit overloaded date by combining the three digit prefix and the three digit suffix.
2. A series of operational steps to be performed on or with the aid of a computer, said steps comprising:
a) whenever necessary determining day, month, year and century information from a six digit overloaded date by performing the steps of:
a1) determining a three digit prefix and a three digit suffix from the six digit overloaded date;
a2) determining the year and century information from the three digit prefix; and a3) determining the day and month information from the three digit suffix.
a) whenever necessary determining day, month, year and century information from a six digit overloaded date by performing the steps of:
a1) determining a three digit prefix and a three digit suffix from the six digit overloaded date;
a2) determining the year and century information from the three digit prefix; and a3) determining the day and month information from the three digit suffix.
3. A series of operational steps to be performed on or with the aid of a computer, said steps comprising:
a) whenever necessary, determining a six digit overloaded date from day, month and year information by performing the steps of:
a1) determining a three digit prefix from the year information which maintains sort order and include century information;
a2) determining a three digit suffix from the day and month information which maintains sort order;
a3) determining a six digit overloaded date by combining the three digit prefix and the three digit suffix;
b) whenever necessary determining day, month, year and century information from a six digit overloaded date by performing the steps of:
b1) determining a three digit prefix and a three digit suffix from the six digit overloaded date;
b2) determining the year and century information from the three digit prefix; and b3) determining the day and month information from the three digit suffix.
a) whenever necessary, determining a six digit overloaded date from day, month and year information by performing the steps of:
a1) determining a three digit prefix from the year information which maintains sort order and include century information;
a2) determining a three digit suffix from the day and month information which maintains sort order;
a3) determining a six digit overloaded date by combining the three digit prefix and the three digit suffix;
b) whenever necessary determining day, month, year and century information from a six digit overloaded date by performing the steps of:
b1) determining a three digit prefix and a three digit suffix from the six digit overloaded date;
b2) determining the year and century information from the three digit prefix; and b3) determining the day and month information from the three digit suffix.
4. A series of operational steps according to claim 1 wherein the year information is a two digit year and step a1) comprises the steps of:
i) determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information.
i) determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information.
5. A series of operational steps according to claim 1 wherein the year information is a four digit year and step a1) comprises the steps of:
i) determining the prefix to be the year information minus a predetermined base year.
i) determining the prefix to be the year information minus a predetermined base year.
6. A series of operational steps according to claim 1 wherein step a1) comprises the steps of:
i) determining if the year information includes century information;
ii) if the result of step i) is false, determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information; and iii) if the result of step i) is true, determining the prefix to be the year information minus a predetermined base year.
i) determining if the year information includes century information;
ii) if the result of step i) is false, determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information; and iii) if the result of step i) is true, determining the prefix to be the year information minus a predetermined base year.
7. A series of operational steps according to claim 1 wherein step a2) comprises the steps of subtracting one from the month information, multiplying by 31 and adding the day information.
8. A series of operational steps according to claim 1 wherein step a2) comprises the steps of multiplying the month information by a predetermined month multiplier between 32 and 80 and adding the day information.
9. A series of operational steps according to claim 2 wherein step a1) comprises the steps of:
i) dividing the six digit overloaded date by 1000 to get the three digit prefix; and ii) subtracting 1000 times the prefix from the six digit overloaded date to get the three digit suffix.
i) dividing the six digit overloaded date by 1000 to get the three digit prefix; and ii) subtracting 1000 times the prefix from the six digit overloaded date to get the three digit suffix.
10. A series of operational steps according to claim 2 wherein step a2) comprises the steps of:
i) dividing the three digit prefix by 100000 to get a century index; and ii) subtracting 100 times the century index from the prefix to get the year information.
i) dividing the three digit prefix by 100000 to get a century index; and ii) subtracting 100 times the century index from the prefix to get the year information.
11. A series of operational steps according to claim 2 wherein step a2) comprises the step of adding a predetermined base year to the prefix to get the year and century information.
12. A series of operational steps according to claim 2 wherein step a3) comprises dividing the suffix by a predetermined month multiplier to get the month information, and subtracting the month information times the predetermined month multiplier from the suffix to get the day information.
13. A series of operational steps according to claim 2 wherein step a3) comprises the steps of subtracting one from the suffix and then dividing by 31 to get a number of prior months, and adding one to the number of prior months to get the month information, and determining the day information to be the suffix minus the number of prior months times 31.
14. A series of operational steps according to claim 1 wherein step a1) comprises the steps of:
i) determining if the year information includes century information;
ii) if the result of step i) is false, determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information;
iii) if the result of step i) is true, determining the prefix to be the year information minus a predetermined base year; and wherein step a2) comprises the steps of subtracting one from the month information, multiplying by 31 and adding the day information.
i) determining if the year information includes century information;
ii) if the result of step i) is false, determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information;
iii) if the result of step i) is true, determining the prefix to be the year information minus a predetermined base year; and wherein step a2) comprises the steps of subtracting one from the month information, multiplying by 31 and adding the day information.
15. A series of operational steps according to claim 1 wherein step a1) comprises the steps of:
i) determining if the year information includes the century information;
ii) if the result of step i) is false, determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information;
iii) if the result of step i) is true, determining the prefix to be the year information minus a predetermined base year; and wherein step a2) comprises the steps of multiplying the month information by a predetermined month multiplier between 32 and 80 and adding the day information.
i) determining if the year information includes the century information;
ii) if the result of step i) is false, determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information;
iii) if the result of step i) is true, determining the prefix to be the year information minus a predetermined base year; and wherein step a2) comprises the steps of multiplying the month information by a predetermined month multiplier between 32 and 80 and adding the day information.
16. A series of operational steps according to claim 2 wherein step a1) comprises the steps of:
i) dividing the six digit overloaded date by 1000 to get the three digit prefix; and ii) subtracting 1000 times the prefix from the six digit overloaded date to get the three digit suffix;
wherein step a2) comprises the steps of:
i) dividing the three digit prefix by 100000 to get a century index;
ii) subtracting 100 times the century index from the prefix to get the year information;
and wherein step a3) comprises dividing the suffix by a predetermined month multiplier between 32 and 80 to get the month information, and subtracting the month information times the predetermined month multiplier from the suffix to get the day information.
i) dividing the six digit overloaded date by 1000 to get the three digit prefix; and ii) subtracting 1000 times the prefix from the six digit overloaded date to get the three digit suffix;
wherein step a2) comprises the steps of:
i) dividing the three digit prefix by 100000 to get a century index;
ii) subtracting 100 times the century index from the prefix to get the year information;
and wherein step a3) comprises dividing the suffix by a predetermined month multiplier between 32 and 80 to get the month information, and subtracting the month information times the predetermined month multiplier from the suffix to get the day information.
17. A series of operational steps according to claim 2 wherein step a1) comprises the steps of:
i) dividing the six digit overloaded date by 1000 to get the three digit prefix;
ii) subtracting 1000 times the prefix from the six digit overloaded date to get the three digit suffix;
wherein step a2) comprises the steps of:
i) dividing the three digit prefix by 100000 to get a century index;
ii) subtracting 100 times the century index from the prefix to get the year information;
and wherein step a3) comprises the steps of subtracting one from the suffix and then dividing by 31 to get a number of prior months, and adding one to the number of prior months to get the month information, and determining the day information to be the suffix minus the number of prior months times 31.
i) dividing the six digit overloaded date by 1000 to get the three digit prefix;
ii) subtracting 1000 times the prefix from the six digit overloaded date to get the three digit suffix;
wherein step a2) comprises the steps of:
i) dividing the three digit prefix by 100000 to get a century index;
ii) subtracting 100 times the century index from the prefix to get the year information;
and wherein step a3) comprises the steps of subtracting one from the suffix and then dividing by 31 to get a number of prior months, and adding one to the number of prior months to get the month information, and determining the day information to be the suffix minus the number of prior months times 31.
18. A series of operational steps according to claim 3 wherein step a1) comprises the steps of:
i) determining if the year information includes century information;
ii) if the result of step i) is false, determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information;
iii) if the result of step i) is true, determining the prefix to be the year information minus a predetermined base year;
wherein step a2) comprises the steps of multiplying the month information by a predetermined month multiplier between 32 and 80 and adding the day information;
wherein step b1) comprises the steps of:
i) dividing the six digit overloaded date by 1000 to get the three digit prefix;
ii) subtracting 1000 times the prefix from the six digit overloaded date to get the three digit suffix;
wherein step b2) comprises the steps of:
i) dividing the three digit prefix by 100000 to get a century index;
ii) subtracting 100 times the century index from the prefix to get the year information;
and wherein step b3) comprises dividing the suffix by the predetermined month multiplier to get the month information, and subtracting the month information times the predetermined month multiplier from the suffix to get the day information.
i) determining if the year information includes century information;
ii) if the result of step i) is false, determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information;
iii) if the result of step i) is true, determining the prefix to be the year information minus a predetermined base year;
wherein step a2) comprises the steps of multiplying the month information by a predetermined month multiplier between 32 and 80 and adding the day information;
wherein step b1) comprises the steps of:
i) dividing the six digit overloaded date by 1000 to get the three digit prefix;
ii) subtracting 1000 times the prefix from the six digit overloaded date to get the three digit suffix;
wherein step b2) comprises the steps of:
i) dividing the three digit prefix by 100000 to get a century index;
ii) subtracting 100 times the century index from the prefix to get the year information;
and wherein step b3) comprises dividing the suffix by the predetermined month multiplier to get the month information, and subtracting the month information times the predetermined month multiplier from the suffix to get the day information.
19. A series of operational steps according to claim 3 wherein step a1) comprises the steps of:
i) determining if the year information includes century information;
ii) if the result of step i) is false, determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information;
iii) if the result of step i) is true, determining the prefix to be the year information minus a predetermined base year;
wherein step a2) comprises the steps of subtracting one from the month information, multiplying by 31 and adding the day information;
wherein step b1) comprises the steps of:
i) dividing the six digit overloaded date by 1000 to get the three digit prefix;
ii) subtracting 1000 times the prefix from the six digit overloaded date to get the three digit suffix;
wherein step b2) comprises the steps of:
i) dividing the three digit prefix by 100000 to get a century index;
ii) subtracting 100 times the century index from the prefix to get the year information;
and wherein step b3) comprises the steps of subtracting one from the suffix and then dividing by 31 to get a number of prior months, and adding one to the number of prior months to get the month information, and determining the day information to be the suffix minus the number of prior months times 31.
i) determining if the year information includes century information;
ii) if the result of step i) is false, determining if the year information is less than a predetermined pivot year and if so determining the three digit prefix to be one hundred plus the year information and if not determining the prefix to be the year information;
iii) if the result of step i) is true, determining the prefix to be the year information minus a predetermined base year;
wherein step a2) comprises the steps of subtracting one from the month information, multiplying by 31 and adding the day information;
wherein step b1) comprises the steps of:
i) dividing the six digit overloaded date by 1000 to get the three digit prefix;
ii) subtracting 1000 times the prefix from the six digit overloaded date to get the three digit suffix;
wherein step b2) comprises the steps of:
i) dividing the three digit prefix by 100000 to get a century index;
ii) subtracting 100 times the century index from the prefix to get the year information;
and wherein step b3) comprises the steps of subtracting one from the suffix and then dividing by 31 to get a number of prior months, and adding one to the number of prior months to get the month information, and determining the day information to be the suffix minus the number of prior months times 31.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2234991 CA2234991A1 (en) | 1998-04-16 | 1998-04-16 | System and method for storing and processing date information which spans more than one century |
| CA002238083A CA2238083A1 (en) | 1998-04-16 | 1998-05-20 | System and method for storing and processing date information capable of spanning centuries |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2234991 CA2234991A1 (en) | 1998-04-16 | 1998-04-16 | System and method for storing and processing date information which spans more than one century |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2234991A1 true CA2234991A1 (en) | 1999-10-16 |
Family
ID=29275561
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2234991 Abandoned CA2234991A1 (en) | 1998-04-16 | 1998-04-16 | System and method for storing and processing date information which spans more than one century |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2234991A1 (en) |
-
1998
- 1998-04-16 CA CA 2234991 patent/CA2234991A1/en not_active Abandoned
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