diff options
| -rw-r--r-- | src/libcore/str.rs | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/src/libcore/str.rs b/src/libcore/str.rs index 0a5ff9935dc..3fbfd3e32cd 100644 --- a/src/libcore/str.rs +++ b/src/libcore/str.rs @@ -1539,6 +1539,21 @@ fn as_c_str<T>(s: str, f: fn(*libc::c_char) -> T) -> T unsafe { as_buf(s) {|buf| f(buf as *libc::c_char) } } + +#[doc = " +Work with the byte buffer and length of a slice. + +The unpacked length is one byte longer than the 'official' indexable +length of the string. This is to permit probing the byte past the +indexable area for a null byte, as is the case in slices pointing +to full strings, or suffixes of them. +"] +fn unpack_slice<T>(s: str/&, f: fn(*u8, uint) -> T) -> T unsafe { + let v : *(*u8,uint) = ::unsafe::reinterpret_cast(ptr::addr_of(s)); + let (buf,len) = *v; + f(buf, len) +} + #[doc = " Reserves capacity for exactly `n` bytes in the given string, not including the null terminator. @@ -2706,4 +2721,16 @@ mod tests { } assert found_b; } + + #[test] + fn test_unpack_slice() unsafe { + let a = "hello"; + unpack_slice(a) {|buf, len| + assert a[0] == 'h' as u8; + assert *buf == 'h' as u8; + assert len == 6u; + assert *ptr::offset(buf,4u) == 'o' as u8; + assert *ptr::offset(buf,5u) == 0u8; + } + } } |