105 lines
1.7 KiB
V
105 lines
1.7 KiB
V
fn test_ptr_assign() {
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v := [int(5), 6, 77, 1]
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unsafe {
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mut p := &v[0]
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(*p)++
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p++ // p now points to v[1]
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(*p) += 2
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p += 2 // p now points to v[3]
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*p = 31
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}
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assert v[0] == 6
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assert v[1] == 8
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assert v[2] == 77
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assert v[3] == 31
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}
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fn test_double_ptr() {
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i := 5
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j := 7
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unsafe {
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mut x := &i
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mut p := &x
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(*p) = &j
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assert x == &j
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}
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// ///////
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mut x := &int(0)
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unsafe {
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mut p := &x
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(*p) = &int(1)
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}
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assert ptr_str(x) == ptr_str(&int(1))
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}
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fn test_ptr_infix() {
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v := 4
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mut q := unsafe { &v - 1 }
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q = unsafe { q + 3 }
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assert ptr_str(q) == ptr_str(unsafe { &v + 2 })
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}
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struct S1 {
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}
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[unsafe]
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fn (s S1) f() {
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}
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fn test_funcs() {
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s := S1{}
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unsafe { s.f() }
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_ = C.strerror(0) // [trusted] function prototype in builtin/cfns.c.v
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}
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fn test_if_expr_unsafe() {
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i := 4
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ii := 123
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p := if true { unsafe { &i } } else { unsafe { &ii } }
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assert *p == 4
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}
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fn unsafe_if_stmt() int {
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i := 4
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unsafe {
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if true {
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return (&i)[0]
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}
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}
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return i
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}
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fn test_unsafe_if_stmt() {
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x := unsafe_if_stmt()
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assert x == 4
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}
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const fixedbytes = [100]u8{}
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fn test_unsafe_pointers() {
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fsize := fixedbytes.len
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src := &fixedbytes[0]
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//
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b := []u8{}
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eprintln('b.data before: $b.data')
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eprintln('b.len before: $b.len')
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eprintln('b.cap before: $b.cap')
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assert b.len == 0
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unsafe {
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// here b will be setup to work with the mmaped region
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mut pdata := &b.data
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mut plen := &b.len
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mut pcap := &b.cap
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// note that pdata, plen, pcap are used here:
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*pdata = src
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*plen = int(fsize)
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*pcap = int(fsize)
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}
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assert b.len == 100
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assert b.cap == 100
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assert b.data == src
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eprintln('b.data after: $b.data')
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eprintln('b.len after: $b.len')
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eprintln('b.cap after: $b.cap')
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}
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