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turbonss/src/cmph.zig

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2022-02-23 15:25:55 +02:00
const std = @import("std");
const Allocator = std.mem.Allocator;
const bdz = @import("bdz.zig");
const c = @cImport({
@cInclude("cmph.h");
});
// pack packs cmph hashes for the given input and returns a slice ("cmph
// userdata") for further storage. The slice must be freed by the caller.
const packErr = Allocator.Error || error{Overflow};
pub fn pack(allocator: Allocator, input: [][*:0]const u8) packErr![]const u8 {
var cvector = @ptrCast([*c][*c]u8, input.ptr);
const len = try std.math.cast(c_uint, input.len);
var source = c.cmph_io_vector_adapter(cvector, len);
defer c.cmph_io_vector_adapter_destroy(source);
var config: *c.cmph_config_t = c.cmph_config_new(source) orelse return error.OutOfMemory;
c.cmph_config_set_algo(config, c.CMPH_BDZ);
c.cmph_config_set_b(config, 7);
var hash: *c.cmph_t = c.cmph_new(config) orelse return error.OutOfMemory;
c.cmph_config_destroy(config);
const size = c.cmph_packed_size(hash);
var buf = try allocator.alloc(u8, size);
c.cmph_pack(hash, &buf[0]);
c.cmph_destroy(hash);
return buf;
}
const testing = std.testing;
const items = .{
"aaaaaaaaaa",
"bbbbbbbbbb",
"cccccccccc",
"dddddddddd",
"eeeeeeeeee",
"ffffffffff",
"gggggggggg",
"hhhhhhhhhh",
"iiiiiiiiii",
"jjjjjjjjjj",
};
const items_len = items.len;
fn samplePack(allocator: Allocator) ![]const u8 {
var vector = std.ArrayList([*:0]const u8).init(allocator);
defer vector.deinit();
try vector.appendSlice(&items);
return pack(allocator, vector.items);
}
test "basic pack/unpack" {
const buf = try samplePack(testing.allocator);
defer testing.allocator.free(buf);
try testing.expect(buf.len < 100);
var used: [items_len]bool = undefined;
inline for (items) |elem| {
const hashed = try bdz.search_packed(buf, elem);
used[hashed] = true;
}
for (used) |item| {
try testing.expect(item);
}
}