43 lines
1.5 KiB
Zig
43 lines
1.5 KiB
Zig
const std = @import("std");
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pub const IntersectionIterator = struct {
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ref: std.mem.TokenIterator(u8),
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rest: []const []const u8,
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/// Returns the next occurrence or null. Returned value is owned by originally passed slice
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pub fn next(self: *IntersectionIterator) ?[]const u8{
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// If this returns null, there's no more items to check. We're finished.
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const needle = self.ref.next() orelse return null;
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// Search into every one of the strings
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haystack: for (self.rest) |haystack| {
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// The items are separated by spaces, iterate through those
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var haystack_iter = std.mem.tokenize(u8, haystack, " ");
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// If the word is found, it short circuits and tries the next haystack
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while (haystack_iter.next()) |hay_blade| {
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if (std.mem.eql(u8, hay_blade, needle)) continue :haystack;
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}
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// If this point is reached, the needle wasn't found.
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// Try the next one
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return self.next();
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}
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// If we got here, no not-matching haysack was found. A match!
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return needle;
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}
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};
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/// Finds the common tokens inside space separated strings
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/// and returns a slice to the first token that matches
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pub fn intersection(slices: []const []const u8) IntersectionIterator {
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// Tokenize the first entry and save the rest as references to check
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return IntersectionIterator{
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.ref = std.mem.tokenize(u8, slices[0], " "),
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.rest = slices[1..],
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};
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}
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