87 lines
1.8 KiB
Rust
87 lines
1.8 KiB
Rust
/*
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Module: rand
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Random number generation
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*/
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#[abi = "cdecl"]
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native mod rustrt {
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type rctx;
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fn rand_new() -> rctx;
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fn rand_next(c: rctx) -> u32;
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fn rand_free(c: rctx);
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}
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/* Section: Types */
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/*
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Obj: rng
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A random number generator
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*/
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type rng = obj {
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/*
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Method: next
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Return the next random integer
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*/
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fn next() -> u32;
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/*
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Method: next_float
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Return the next random float
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*/
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fn next_float() -> float;
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/*
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Method: gen_str
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Return a random string composed of A-Z, a-z, 0-9.
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*/
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fn gen_str(len: uint) -> str;
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};
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resource rand_res(c: rustrt::rctx) { rustrt::rand_free(c); }
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/* Section: Operations */
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/*
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Function: mk_rng
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Create a random number generator
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*/
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fn mk_rng() -> rng {
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obj rt_rng(c: @rand_res) {
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fn next() -> u32 { ret rustrt::rand_next(**c); }
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fn next_float() -> float {
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let u1 = rustrt::rand_next(**c) as float;
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let u2 = rustrt::rand_next(**c) as float;
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let u3 = rustrt::rand_next(**c) as float;
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let scale = u32::max_value as float;
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ret ((u1 / scale + u2) / scale + u3) / scale;
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}
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fn gen_str(len: uint) -> str {
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let charset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
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"abcdefghijklmnopqrstuvwxyz" +
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"0123456789";
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let s = "";
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let i = 0u;
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while (i < len) {
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let n = rustrt::rand_next(**c) as uint %
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str::char_len(charset);
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s = s + str::from_char(str::char_at(charset, n));
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i += 1u;
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}
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s
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}
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}
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ret rt_rng(@rand_res(rustrt::rand_new()));
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}
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// Local Variables:
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// mode: rust;
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// fill-column: 78;
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// indent-tabs-mode: nil
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// c-basic-offset: 4
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// buffer-file-coding-system: utf-8-unix
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// End:
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