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Avoid extra memory allocations in core::str::from_cstr{,_len} #1827

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Merged
merged 3 commits into from
Feb 13, 2012
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Avoid extra memory allocations in core::str::from_cstr{,_len} #1827

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e5cc919
Avoid extra memory allocations in core::str::from_cstr_len
uasi Feb 12, 2012
8d29e87
core::str::from_cstr uses from_cstr_len
uasi Feb 12, 2012
4d788be
from_cstr and from_cstr_len are not unsafe, I think
uasi Feb 12, 2012
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28 changes: 13 additions & 15 deletions src/libcore/str.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -194,35 +194,33 @@ Function: from_cstr

Create a Rust string from a null-terminated C string
*/
unsafe fn from_cstr(cstr: sbuf) -> str {
let res = [];
fn from_cstr(cstr: sbuf) -> str unsafe {
let start = cstr;
let curr = start;
let i = 0u;
while *curr != 0u8 {
vec::push(res, *curr);
i += 1u;
curr = ptr::offset(start, i);
}
ret from_bytes(res);
ret from_cstr_len(cstr, i);
}

/*
Function: from_cstr_len

Create a Rust string from a C string of the given length
*/
unsafe fn from_cstr_len(cstr: sbuf, len: uint) -> str {
let res = [];
let start = cstr;
let curr = start;
let i = 0u;
while i < len {
vec::push(res, *curr);
i += 1u;
curr = ptr::offset(start, i);
}
ret from_bytes(res);
fn from_cstr_len(cstr: sbuf, len: uint) -> str unsafe {
let buf: [u8] = [];
vec::reserve(buf, len + 1u);
vec::as_buf(buf) {|b| ptr::memcpy(b, cstr, len); }
vec::unsafe::set_len(buf, len);
buf += [0u8];

assert is_utf8(buf);
let s: str = ::unsafe::reinterpret_cast(buf);
::unsafe::leak(buf);
ret s;
}

/*
Expand Down