From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 8 Jul 2015 20:46:52 -0400 Subject: Initial commit --- pkg/xtools/ranges.x | 245 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 245 insertions(+) create mode 100644 pkg/xtools/ranges.x (limited to 'pkg/xtools/ranges.x') diff --git a/pkg/xtools/ranges.x b/pkg/xtools/ranges.x new file mode 100644 index 00000000..ce008b12 --- /dev/null +++ b/pkg/xtools/ranges.x @@ -0,0 +1,245 @@ +include +include + +define FIRST 1 # Default starting range +define LAST MAX_INT # Default ending range +define STEP 1 # Default step +define EOLIST 0 # End of list + +# DECODE_RANGES -- Parse a string containing a list of integer numbers or +# ranges, delimited by either spaces or commas. Return as output a list +# of ranges defining a list of numbers, and the count of list numbers. +# Range limits must be positive nonnegative integers. ERR is returned as +# the function value if a conversion error occurs. The list of ranges is +# delimited by EOLIST. + +int procedure decode_ranges (range_string, ranges, max_ranges, nvalues) + +char range_string[ARB] # Range string to be decoded +int ranges[3, max_ranges] # Range array +int max_ranges # Maximum number of ranges +int nvalues # The number of values in the ranges + +int ip, nrange, first, last, step, ctoi() + +begin + ip = 1 + nvalues = 0 + + do nrange = 1, max_ranges - 1 { + # Defaults to all nonnegative integers + first = FIRST + last = LAST + step = STEP + + # Skip delimiters + while (IS_WHITE(range_string[ip]) || range_string[ip] == ',') + ip = ip + 1 + + # Get first limit. + # Must be a number, '-', 'x', or EOS. If not return ERR. + if (range_string[ip] == EOS) { # end of list + if (nrange == 1) { + # Null string defaults + ranges[1, 1] = first + ranges[2, 1] = last + ranges[3, 1] = step + ranges[1, 2] = EOLIST + nvalues = MAX_INT + return (OK) + } else { + ranges[1, nrange] = EOLIST + return (OK) + } + } else if (range_string[ip] == '-') + ; + else if (range_string[ip] == 'x') + ; + else if (IS_DIGIT(range_string[ip])) { # ,n.. + if (ctoi (range_string, ip, first) == 0) + return (ERR) + } else + return (ERR) + + # Skip delimiters + while (IS_WHITE(range_string[ip]) || range_string[ip] == ',') + ip = ip + 1 + + # Get last limit + # Must be '-', or 'x' otherwise last = first. + if (range_string[ip] == 'x') + ; + else if (range_string[ip] == '-') { + ip = ip + 1 + while (IS_WHITE(range_string[ip]) || range_string[ip] == ',') + ip = ip + 1 + if (range_string[ip] == EOS) + ; + else if (IS_DIGIT(range_string[ip])) { + if (ctoi (range_string, ip, last) == 0) + return (ERR) + } else if (range_string[ip] == 'x') + ; + else + return (ERR) + } else + last = first + + # Skip delimiters + while (IS_WHITE(range_string[ip]) || range_string[ip] == ',') + ip = ip + 1 + + # Get step. + # Must be 'x' or assume default step. + if (range_string[ip] == 'x') { + ip = ip + 1 + while (IS_WHITE(range_string[ip]) || range_string[ip] == ',') + ip = ip + 1 + if (range_string[ip] == EOS) + ; + else if (IS_DIGIT(range_string[ip])) { + if (ctoi (range_string, ip, step) == 0) + ; + if (step == 0) + return (ERR) + } else if (range_string[ip] == '-') + ; + else + return (ERR) + } + + # Output the range triple. + ranges[1, nrange] = first + ranges[2, nrange] = last + ranges[3, nrange] = step + nvalues = nvalues + abs (last-first) / step + 1 + } + + return (ERR) # ran out of space +end + + +# GET_NEXT_NUMBER -- Given a list of ranges and the current file number, +# find and return the next file number. Selection is done in such a way +# that list numbers are always returned in monotonically increasing order, +# regardless of the order in which the ranges are given. Duplicate entries +# are ignored. EOF is returned at the end of the list. + +int procedure get_next_number (ranges, number) + +int ranges[ARB] # Range array +int number # Both input and output parameter + +int ip, first, last, step, next_number, remainder + +begin + # If number+1 is anywhere in the list, that is the next number, + # otherwise the next number is the smallest number in the list which + # is greater than number+1. + + number = number + 1 + next_number = MAX_INT + + for (ip=1; ranges[ip] != EOLIST; ip=ip+3) { + first = min (ranges[ip], ranges[ip+1]) + last = max (ranges[ip], ranges[ip+1]) + step = ranges[ip+2] + if (step == 0) + call error (1, "Step size of zero in range list") + if (number >= first && number <= last) { + remainder = mod (number - first, step) + if (remainder == 0) + return (number) + if (number - remainder + step <= last) + next_number = number - remainder + step + } else if (first > number) + next_number = min (next_number, first) + } + + if (next_number == MAX_INT) + return (EOF) + else { + number = next_number + return (number) + } +end + + +# GET_PREVIOUS_NUMBER -- Given a list of ranges and the current file number, +# find and return the previous file number. Selection is done in such a way +# that list numbers are always returned in monotonically decreasing order, +# regardless of the order in which the ranges are given. Duplicate entries +# are ignored. EOF is returned at the end of the list. + +int procedure get_previous_number (ranges, number) + +int ranges[ARB] # Range array +int number # Both input and output parameter + +int ip, first, last, step, next_number, remainder + +begin + # If number-1 is anywhere in the list, that is the previous number, + # otherwise the previous number is the largest number in the list which + # is less than number-1. + + number = number - 1 + next_number = 0 + + for (ip=1; ranges[ip] != EOLIST; ip=ip+3) { + first = min (ranges[ip], ranges[ip+1]) + last = max (ranges[ip], ranges[ip+1]) + step = ranges[ip+2] + if (step == 0) + call error (1, "Step size of zero in range list") + if (number >= first && number <= last) { + remainder = mod (number - first, step) + if (remainder == 0) + return (number) + if (number - remainder >= first) + next_number = number - remainder + } else if (last < number) { + remainder = mod (last - first, step) + if (remainder == 0) + next_number = max (next_number, last) + else if (last - remainder >= first) + next_number = max (next_number, last - remainder) + } + } + + if (next_number == 0) + return (EOF) + else { + number = next_number + return (number) + } +end + + +# IS_IN_RANGE -- Test number to see if it is in range. +# If the number is INDEFI then it is mapped to the maximum integer. + +bool procedure is_in_range (ranges, number) + +int ranges[ARB] # Range array +int number # Number to be tested against ranges + +int ip, first, last, step, num + +begin + if (IS_INDEFI (number)) + num = MAX_INT + else + num = number + + for (ip=1; ranges[ip] != EOLIST; ip=ip+3) { + first = min (ranges[ip], ranges[ip+1]) + last = max (ranges[ip], ranges[ip+1]) + step = ranges[ip+2] + if (num >= first && num <= last) + if (mod (num - first, step) == 0) + return (true) + } + + return (false) +end -- cgit