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rust/src/libcore/str.rs

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/*
Module: str
String manipulation
Strings are a packed UTF-8 representation of text, stored as null terminated
buffers of u8 bytes. Strings should be considered by character,
for correctness, but some UTF-8 unsafe functions are also provided.
For some heavy-duty uses, we recommend trying std::rope.
*/
export
// Creating a string
from_bytes,
from_byte,
//push_utf8_bytes,
from_char,
from_chars,
from_cstr,
concat,
connect,
// Adding things to and removing things from a string
push_char,
pop_char,
shift_char,
unshift_char,
push_byte,
//push_bytes,
pop_byte,
shift_byte,
trim_left,
trim_right,
trim,
// Transforming strings
bytes,
chars,
substr,
char_slice,
slice,
safe_slice,
split,
splitn,
split_str,
split_func,
split_char,
lines,
lines_any,
words,
windowed,
to_lower,
to_upper,
replace,
escape,
// Comparing strings
eq,
lteq,
hash,
// Iterating through strings
all,
any,
map,
bytes_iter,
chars_iter,
split_chars_iter,
splitn_chars_iter,
words_iter,
lines_iter,
// Searching
index,
rindex,
find,
contains,
starts_with,
ends_with,
// String properties
is_ascii,
is_empty,
is_not_empty,
is_whitespace,
byte_len,
char_len,
// Misc
// FIXME: perhaps some more of this section shouldn't be exported?
is_utf8,
char_len_range,
byte_len_range,
utf8_char_width,
char_range_at,
char_at,
substr_all,
escape_char,
as_buf,
//buf,
sbuf;
#[abi = "cdecl"]
native mod rustrt {
fn rust_str_push(&s: str, ch: u8);
}
// FIXME: add pure to a lot of functions
/*
Section: Creating a string
*/
/*
Function: from_bytes
Convert a vector of bytes to a UTF-8 string. Fails if invalid UTF-8.
*/
fn from_bytes(vv: [u8]) -> str unsafe {
assert is_utf8(vv);
ret unsafe::from_bytes(vv);
}
/*
Function: from_byte
Convert a byte to a UTF-8 string. Fails if invalid UTF-8.
*/
fn from_byte(uu: u8) -> str {
from_bytes([uu])
}
fn push_utf8_bytes(&s: str, ch: char) {
let code = ch as uint;
let bytes =
if code < max_one_b {
[code as u8]
} else if code < max_two_b {
[code >> 6u & 31u | tag_two_b as u8, code & 63u | tag_cont as u8]
} else if code < max_three_b {
[code >> 12u & 15u | tag_three_b as u8,
code >> 6u & 63u | tag_cont as u8, code & 63u | tag_cont as u8]
} else if code < max_four_b {
[code >> 18u & 7u | tag_four_b as u8,
code >> 12u & 63u | tag_cont as u8,
code >> 6u & 63u | tag_cont as u8, code & 63u | tag_cont as u8]
} else if code < max_five_b {
[code >> 24u & 3u | tag_five_b as u8,
code >> 18u & 63u | tag_cont as u8,
code >> 12u & 63u | tag_cont as u8,
code >> 6u & 63u | tag_cont as u8, code & 63u | tag_cont as u8]
} else {
[code >> 30u & 1u | tag_six_b as u8,
code >> 24u & 63u | tag_cont as u8,
code >> 18u & 63u | tag_cont as u8,
code >> 12u & 63u | tag_cont as u8,
code >> 6u & 63u | tag_cont as u8, code & 63u | tag_cont as u8]
};
push_bytes(s, bytes);
}
/*
Function: from_char
Convert a char to a string
*/
fn from_char(ch: char) -> str {
let buf = "";
push_utf8_bytes(buf, ch);
ret buf;
}
/*
Function: from_chars
Convert a vector of chars to a string
*/
fn from_chars(chs: [char]) -> str {
let buf = "";
for ch: char in chs { push_utf8_bytes(buf, ch); }
ret buf;
}
/*
Function: from_cstr
Create a Rust string from a null-terminated C string
*/
unsafe fn from_cstr(cstr: sbuf) -> str {
let res = [];
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);
}
/*
Function: concat
Concatenate a vector of strings
*/
fn concat(v: [str]) -> str {
let s: str = "";
for ss: str in v { s += ss; }
ret s;
}
/*
Function: connect
Concatenate a vector of strings, placing a given separator between each
*/
fn connect(v: [str], sep: str) -> str {
let s: str = "";
let first: bool = true;
for ss: str in v {
if first { first = false; } else { s += sep; }
s += ss;
}
ret s;
}
/*
Section: Adding to and removing from a string
*/
/*
Function: push_char
Append a character to a string
*/
fn push_char(&s: str, ch: char) { s += from_char(ch); }
/*
Function: pop_char
Remove the final character from a string and return it.
Failure:
If the string does not contain any characters.
*/
fn pop_char(&s: str) -> char {
let end = byte_len(s);
while end > 0u && s[end - 1u] & 192u8 == tag_cont_u8 { end -= 1u; }
assert (end > 0u);
let ch = char_at(s, end - 1u);
s = substr(s, 0u, end - 1u);
ret ch;
}
/*
Function: shift_char
Remove the first character from a string and return it.
Failure:
If the string does not contain any characters.
*/
fn shift_char(&s: str) -> char {
let r = char_range_at(s, 0u);
s = substr(s, r.next, byte_len(s) - r.next);
ret r.ch;
}
/*
Function: unshift_char
Prepend a char to a string
*/
fn unshift_char(&s: str, ch: char) { s = from_char(ch) + s; }
/*
Function: push_byte
Appends a byte to a string.
This function is not unicode-safe.
*/
fn push_byte(&s: str, b: u8) { rustrt::rust_str_push(s, b); }
/*
Function: push_bytes
Appends a vector of bytes to a string.
This function is not unicode-safe.
*/
fn push_bytes(&s: str, bytes: [u8]) {
for byte in bytes { rustrt::rust_str_push(s, byte); }
}
/*
Function: pop_byte
Removes the last byte from a string and returns it.
This function is not unicode-safe.
*/
fn pop_byte(&s: str) -> u8 {
let len = byte_len(s);
assert (len > 0u);
let b = s[len - 1u];
s = substr(s, 0u, len - 1u);
ret b;
}
/*
Function: shift_byte
Removes the first byte from a string and returns it.
This function is not unicode-safe.
*/
fn shift_byte(&s: str) -> u8 {
let len = byte_len(s);
assert (len > 0u);
let b = s[0];
s = substr(s, 1u, len - 1u);
ret b;
}
/*
Function: trim_left
Returns a string with leading whitespace removed.
*/
fn trim_left(s: str) -> str {
fn count_whities(s: [char]) -> uint {
let i = 0u;
while i < vec::len(s) {
if !char::is_whitespace(s[i]) { break; }
i += 1u;
}
ret i;
}
let chars = chars(s);
let whities = count_whities(chars);
ret from_chars(vec::slice(chars, whities, vec::len(chars)));
}
/*
Function: trim_right
Returns a string with trailing whitespace removed.
*/
fn trim_right(s: str) -> str {
fn count_whities(s: [char]) -> uint {
let i = vec::len(s);
while 0u < i {
if !char::is_whitespace(s[i - 1u]) { break; }
i -= 1u;
}
ret i;
}
let chars = chars(s);
let whities = count_whities(chars);
ret from_chars(vec::slice(chars, 0u, whities));
}
/*
Function: trim
Returns a string with leading and trailing whitespace removed
*/
fn trim(s: str) -> str { trim_left(trim_right(s)) }
/*
Section: Transforming strings
*/
/*
Function: bytes
Converts a string to a vector of bytes. The result vector is not
null-terminated.
*/
fn bytes(s: str) -> [u8] unsafe {
let v = ::unsafe::reinterpret_cast(s);
let vcopy = vec::slice(v, 0u, vec::len(v) - 1u);
::unsafe::leak(v);
ret vcopy;
}
/*
Function: chars
Convert a string to a vector of characters
FIXME: rename to 'chars'
*/
fn chars(s: str) -> [char] {
let buf: [char] = [];
let i = 0u;
let len = byte_len(s);
while i < len {
let cur = char_range_at(s, i);
buf += [cur.ch];
i = cur.next;
}
ret buf;
}
/*
Function: substr
Take a substring of another. Returns a string containing `len` bytes
starting at byte offset `begin`.
FIXME: This function is not unicode-safe.
Failure:
If `begin` + `len` is is greater than the byte length of the string
*/
fn substr(s: str, begin: uint, len: uint) -> str {
ret slice(s, begin, begin + len);
}
/*
Function: char_slice
Unicode-safe slice. Returns a slice of the given string containing
the characters in the range [`begin`..`end`). `begin` and `end` are
character indexes, not byte indexes.
Failure:
- If begin is greater than end
- If end is greater than the character length of the string
FIXME: rename to slice(), make faster by avoiding char conversion
*/
fn char_slice(s: str, begin: uint, end: uint) -> str {
from_chars(vec::slice(chars(s), begin, end))
}
/*
Function: slice
Takes a bytewise slice from a string. Returns the substring from
[`begin`..`end`).
This function is not unicode-safe.
Failure:
- If begin is greater than end.
- If end is greater than the length of the string.
FIXME: rename to slice_byte or slice_byte_unsafe
*/
fn slice(s: str, begin: uint, end: uint) -> str unsafe {
// FIXME: Typestate precondition
assert (begin <= end);
assert (end <= byte_len(s));
let v: [u8] = ::unsafe::reinterpret_cast(s);
let v2 = vec::slice(v, begin, end);
::unsafe::leak(v);
v2 += [0u8];
let s2: str = ::unsafe::reinterpret_cast(v2);
::unsafe::leak(v2);
ret s2;
}
/*
Function: safe_slice
FIXME: make sure char_slice / slice / byte_slice
have these preconditions and assertions
FIXME: this shouldn't be mistaken for a UTF-8 safe slice
*/
fn safe_slice(s: str, begin: uint, end: uint) : uint::le(begin, end) -> str {
// would need some magic to make this a precondition
assert (end <= byte_len(s));
ret slice(s, begin, end);
}
/*
Function: split
Split a string at each occurance of a given separator
Returns:
A vector containing all the strings between each occurance of the separator
FIXME: should be renamed to split_byte
*/
fn split(s: str, sep: u8) -> [str] {
let v: [str] = [];
let accum: str = "";
let ends_with_sep: bool = false;
for c: u8 in s {
if c == sep {
v += [accum];
accum = "";
ends_with_sep = true;
} else { accum += from_byte(c); ends_with_sep = false; }
}
if byte_len(accum) != 0u || ends_with_sep { v += [accum]; }
ret v;
}
/*
Function: splitn
Split a string at each occurance of a given separator up to count times.
Returns:
A vector containing all the strings between each occurance of the separator
FIXME: rename to 'splitn_char'
*/
fn splitn(s: str, sep: u8, count: uint) -> [str] {
let v = [];
let accum = "";
let n = count;
let ends_with_sep: bool = false;
for c in s {
if n > 0u && c == sep {
n -= 1u;
v += [accum];
accum = "";
ends_with_sep = true;
} else { accum += from_byte(c); ends_with_sep = false; }
}
if byte_len(accum) != 0u || ends_with_sep { v += [accum]; }
ret v;
}
/*
Function: split_str
Splits a string at each occurrence of the given separator string. Empty
leading fields are suppressed, and empty trailing fields are preserved.
Returns:
A vector containing all the strings between each occurrence of the separator.
FIXME: should behave like split and split_char:
assert ["", "XXX", "YYY", ""] == split_str(".XXX.YYY.", ".");
*/
fn split_str(s: str, sep: str) -> [str] {
assert byte_len(sep) > 0u;
let v: [str] = [], accum = [], sep_match = 0u, leading = true;
for c: u8 in s {
// Did we match the entire separator?
if sep_match == byte_len(sep) {
if !leading { vec::push(v, from_bytes(accum)); }
accum = [];
sep_match = 0u;
}
if c == sep[sep_match] {
sep_match += 1u;
} else {
sep_match = 0u;
vec::push(accum, c);
leading = false;
}
}
if vec::len(accum) > 0u { vec::push(v, from_bytes(accum)); }
if sep_match == byte_len(sep) { vec::push(v, ""); }
ret v;
}
/*
Function: split_func
Splits a string into substrings using a function
(unicode safe)
FIXME: rename to 'split'
*/
fn split_func(ss: str, sepfn: fn(cc: char)->bool) -> [str] {
let vv: [str] = [];
let accum: str = "";
let ends_with_sep: bool = false;
chars_iter(ss, {|cc| if sepfn(cc) {
vv += [accum];
accum = "";
ends_with_sep = true;
} else {
str::push_char(accum, cc);
ends_with_sep = false;
}
});
if char_len(accum) >= 0u || ends_with_sep {
vv += [accum];
}
ret vv;
}
/*
Function: split_char
Splits a string into a vector of the substrings separated by a given character
*/
fn split_char(ss: str, cc: char) -> [str] {
split_func(ss, {|kk| kk == cc})
}
/*
Function: lines
Splits a string into a vector of the substrings
separated by LF ('\n')
*/
fn lines(ss: str) -> [str] {
split_func(ss, {|cc| cc == '\n'})
}
/*
Function: lines_any
Splits a string into a vector of the substrings
separated by LF ('\n') and/or CR LF ('\r\n')
*/
fn lines_any(ss: str) -> [str] {
vec::map(lines(ss), {|s| trim_right(s)})
}
/*
Function: words
Splits a string into a vector of the substrings
separated by whitespace
*/
fn words(ss: str) -> [str] {
ret vec::filter( split_func(ss, {|cc| char::is_whitespace(cc)}),
{|w| 0u < str::char_len(w)});
}
/*
Function: windowed
Create a vector of substrings of size `nn`
*/
fn windowed(nn: uint, ss: str) -> [str] {
let ww = [];
let len = str::char_len(ss);
assert 1u <= nn;
let ii = 0u;
while ii+nn <= len {
let w = char_slice( ss, ii, ii+nn );
vec::push(ww,w);
ii += 1u;
}
ret ww;
}
/*
Function: to_lower
Convert a string to lowercase
*/
fn to_lower(s: str) -> str {
map(s, char::to_lower)
}
/*
Function: to_upper
Convert a string to uppercase
*/
fn to_upper(s: str) -> str {
map(s, char::to_upper)
}
// FIXME: This is super-inefficient
/*
Function: replace
Replace all occurances of one string with another
Parameters:
s - The string containing substrings to replace
from - The string to replace
to - The replacement string
Returns:
The original string with all occurances of `from` replaced with `to`
*/
fn replace(s: str, from: str, to: str) : is_not_empty(from) -> str {
// FIXME (694): Shouldn't have to check this
check (is_not_empty(from));
if byte_len(s) == 0u {
ret "";
} else if starts_with(s, from) {
ret to + replace(slice(s, byte_len(from), byte_len(s)), from, to);
} else {
let idx = find(s, from);
if idx == -1 {
ret s;
}
ret char_slice(s, 0u, idx as uint) + to +
replace(char_slice(s, idx as uint + char_len(from), char_len(s)),
from, to);
}
}
/*
Function: escape
Escapes special characters inside the string, making it safe for transfer.
*/
fn escape(s: str) -> str {
let r = "";
all(s, { |c| r += escape_char(c); true });
r
}
/*
Section: Comparing strings
*/
/*
Function: eq
Bytewise string equality
*/
pure fn eq(&&a: str, &&b: str) -> bool { a == b }
/*
Function: lteq
Bytewise less than or equal
*/
pure fn lteq(&&a: str, &&b: str) -> bool { a <= b }
/*
Function: hash
String hash function
*/
fn hash(&&s: str) -> uint {
// djb hash.
// FIXME: replace with murmur.
let u: uint = 5381u;
for c: u8 in s { u *= 33u; u += c as uint; }
ret u;
}
/*
Section: Iterating through strings
*/
/*
Function: all
Return true if a predicate matches all characters or
if the string contains no characters
*/
fn all(s: str, it: fn(char) -> bool) -> bool{
ret substr_all(s, 0u, byte_len(s), it);
}
/*
Function: any
Return true if a predicate matches any character
(and false if it matches none or there are no characters)
*/
fn any(ss: str, pred: fn(char) -> bool) -> bool {
!all(ss, {|cc| !pred(cc)})
}
/*
Function: map
Apply a function to each character
*/
fn map(ss: str, ff: fn(char) -> char) -> str {
let result = "";
chars_iter(ss, {|cc|
str::push_char(result, ff(cc));
});
ret result;
}
/*
Function: bytes_iter
Iterate over the bytes in a string
*/
fn bytes_iter(ss: str, it: fn(u8)) {
let pos = 0u;
let len = byte_len(ss);
while (pos < len) {
it(ss[pos]);
pos += 1u;
}
}
/*
Function: chars_iter
Iterate over the characters in a string
*/
fn chars_iter(s: str, it: fn(char)) {
let pos = 0u, len = byte_len(s);
while (pos < len) {
let {ch, next} = char_range_at(s, pos);
pos = next;
it(ch);
}
}
/*
Function: split_chars_iter
Apply a function to each substring after splitting
by character
*/
fn split_chars_iter(ss: str, cc: char, ff: fn(&&str)) {
vec::iter(split_char(ss, cc), ff)
}
/*
Function: splitn_chars_iter
Apply a function to each substring after splitting
by character, up to nn times
FIXME: make this use chars when splitn/splitn_char is fixed
*/
fn splitn_chars_iter(ss: str, sep: u8, count: uint, ff: fn(&&str)) {
vec::iter(splitn(ss, sep, count), ff)
}
/*
Function: words_iter
Apply a function to each word
*/
fn words_iter(ss: str, ff: fn(&&str)) {
vec::iter(words(ss), ff)
}
/*
Function: lines_iter
Apply a function to each lines (by '\n')
*/
fn lines_iter(ss: str, ff: fn(&&str)) {
vec::iter(lines(ss), ff)
}
/*
Section: Searching
*/
/*
Function: index
Returns the index of the first matching byte. Returns -1 if
no match is found.
*/
fn index(s: str, c: u8) -> int {
let i: int = 0;
for k: u8 in s { if k == c { ret i; } i += 1; }
ret -1;
}
/*
Function: rindex
Returns the index of the last matching byte. Returns -1
if no match is found.
*/
fn rindex(s: str, c: u8) -> int {
let n: int = byte_len(s) as int;
while n >= 0 { if s[n] == c { ret n; } n -= 1; }
ret n;
}
/*
Function: find
Finds the index of the first matching substring.
Returns -1 if `haystack` does not contain `needle`.
Parameters:
haystack - The string to look in
needle - The string to look for
Returns:
The index of the first occurance of `needle`, or -1 if not found.
*/
fn find(haystack: str, needle: str) -> int {
let haystack_len: int = byte_len(haystack) as int;
let needle_len: int = byte_len(needle) as int;
if needle_len == 0 { ret 0; }
fn match_at(haystack: str, needle: str, i: int) -> bool {
let j: int = i;
for c: u8 in needle { if haystack[j] != c { ret false; } j += 1; }
ret true;
}
let i: int = 0;
while i <= haystack_len - needle_len {
if match_at(haystack, needle, i) { ret i; }
i += 1;
}
ret -1;
}
/*
Function: contains
Returns true if one string contains another
Parameters:
haystack - The string to look in
needle - The string to look for
*/
fn contains(haystack: str, needle: str) -> bool {
0 <= find(haystack, needle)
}
/*
Function: starts_with
Returns true if one string starts with another
Parameters:
haystack - The string to look in
needle - The string to look for
*/
fn starts_with(haystack: str, needle: str) -> bool {
let haystack_len: uint = byte_len(haystack);
let needle_len: uint = byte_len(needle);
if needle_len == 0u { ret true; }
if needle_len > haystack_len { ret false; }
ret eq(substr(haystack, 0u, needle_len), needle);
}
/*
Function: ends_with
Returns true if one string ends with another
haystack - The string to look in
needle - The string to look for
*/
fn ends_with(haystack: str, needle: str) -> bool {
let haystack_len: uint = byte_len(haystack);
let needle_len: uint = byte_len(needle);
ret if needle_len == 0u {
true
} else if needle_len > haystack_len {
false
} else {
eq(substr(haystack, haystack_len - needle_len, needle_len),
needle)
};
}
/*
Section: String properties
*/
/*
Function: is_ascii
Determines if a string contains only ASCII characters
FIXME: possibly implement using char::is_ascii when it exists
*/
fn is_ascii(s: str) -> bool {
let i: uint = byte_len(s);
while i > 0u { i -= 1u; if s[i] & 128u8 != 0u8 { ret false; } }
ret true;
}
/*
Predicate: is_empty
Returns true if the string has length 0
*/
pure fn is_empty(s: str) -> bool { for c: u8 in s { ret false; } ret true; }
/*
Predicate: is_not_empty
Returns true if the string has length greater than 0
*/
pure fn is_not_empty(s: str) -> bool { !is_empty(s) }
/*
Function: is_whitespace
Returns true if the string contains only whitespace
*/
fn is_whitespace(s: str) -> bool {
ret all(s, char::is_whitespace);
}
/*
Function: byte_len
Returns the length in bytes of a string
FIXME: rename to 'len_bytes'?
*/
pure fn byte_len(s: str) -> uint unsafe {
let v: [u8] = ::unsafe::reinterpret_cast(s);
let vlen = vec::len(v);
::unsafe::leak(v);
// There should always be a null terminator
assert (vlen > 0u);
ret vlen - 1u;
}
/*
Function: char_len
Count the number of unicode characters in a string
FIXME: rename to 'len_chars'?
*/
fn char_len(s: str) -> uint {
ret char_len_range(s, 0u, byte_len(s));
}
/*
Section: Misc
*/
/*
Function: is_utf8
Determines if a vector of bytes contains valid UTF-8
*/
fn is_utf8(v: [u8]) -> bool {
let i = 0u;
let total = vec::len::<u8>(v);
while i < total {
let chsize = utf8_char_width(v[i]);
if chsize == 0u { ret false; }
if i + chsize > total { ret false; }
i += 1u;
while chsize > 1u {
if v[i] & 192u8 != tag_cont_u8 { ret false; }
i += 1u;
chsize -= 1u;
}
}
ret true;
}
/*
Function: char_len_range
As char_len but for a slice of a string
Parameters:
s - A valid string
byte_start - The position inside `s` where to start counting in bytes.
byte_len - The number of bytes of `s` to take into account.
Returns:
The number of Unicode characters in `s` in
segment [byte_start, byte_start+len( .
Safety note:
- This function does not check whether the substring is valid.
- This function fails if `byte_offset` or `byte_len` do not
represent valid positions inside `s`
FIXME: rename to 'substr_len_chars'
*/
fn char_len_range(s: str, byte_start: uint, byte_len: uint) -> uint {
let i = byte_start;
let len = 0u;
while i < byte_len {
let chsize = utf8_char_width(s[i]);
assert (chsize > 0u);
len += 1u;
i += chsize;
}
assert (i == byte_len);
ret len;
}
/*
Function: byte_len_range
As byte_len but for a substring
Parameters:
s - A string
byte_offset - The byte offset at which to start in the string
char_len - The number of chars (not bytes!) in the range
Returns:
The number of bytes in the substring starting at `byte_offset` and
containing `char_len` chars.
Safety note:
This function fails if `byte_offset` or `char_len` do not represent
valid positions in `s`
FIXME: rename to 'substr_len_bytes'
*/
fn byte_len_range(s: str, byte_offset: uint, char_len: uint) -> uint {
let i = byte_offset;
let chars = 0u;
while chars < char_len {
let chsize = utf8_char_width(s[i]);
assert (chsize > 0u);
i += chsize;
chars += 1u;
}
ret i - byte_offset;
}
/*
Function: utf8_char_width
Given a first byte, determine how many bytes are in this UTF-8 character
*/
pure fn utf8_char_width(b: u8) -> uint {
let byte: uint = b as uint;
if byte < 128u { ret 1u; }
if byte < 192u {
ret 0u; // Not a valid start byte
}
if byte < 224u { ret 2u; }
if byte < 240u { ret 3u; }
if byte < 248u { ret 4u; }
if byte < 252u { ret 5u; }
ret 6u;
}
/*
Function: char_range_at
Pluck a character out of a string and return the index of the next character.
This function can be used to iterate over the unicode characters of a string.
Example:
> let s = "中华Việt Nam";
> let i = 0u;
> while i < str::byte_len(s) {
> let {ch, next} = str::char_range_at(s, i);
> std::io::println(#fmt("%u: %c",i,ch));
> i = next;
> }
Example output:
0: 中
3: 华
6: V
7: i
8: ệ
11: t
12:
13: N
14: a
15: m
Parameters:
s - The string
i - The byte offset of the char to extract
Returns:
A record {ch: char, next: uint} containing the char value and the byte
index of the next unicode character.
Failure:
If `i` is greater than or equal to the length of the string.
If `i` is not the index of the beginning of a valid UTF-8 character.
*/
fn char_range_at(s: str, i: uint) -> {ch: char, next: uint} {
let b0 = s[i];
let w = utf8_char_width(b0);
assert (w != 0u);
if w == 1u { ret {ch: b0 as char, next: i + 1u}; }
let val = 0u;
let end = i + w;
let i = i + 1u;
while i < end {
let byte = s[i];
assert (byte & 192u8 == tag_cont_u8);
val <<= 6u;
val += byte & 63u8 as uint;
i += 1u;
}
// Clunky way to get the right bits from the first byte. Uses two shifts,
// the first to clip off the marker bits at the left of the byte, and then
// a second (as uint) to get it to the right position.
val += (b0 << (w + 1u as u8) as uint) << ((w - 1u) * 6u - w - 1u);
ret {ch: val as char, next: i};
}
/*
Function: char_at
Pluck a character out of a string
*/
fn char_at(s: str, i: uint) -> char { ret char_range_at(s, i).ch; }
/*
Function: substr_all
Loop through a substring, char by char
Parameters:
s - A string to traverse. It may be empty.
byte_offset - The byte offset at which to start in the string.
byte_len - The number of bytes to traverse in the string
it - A block to execute with each consecutive character of `s`.
Return `true` to continue, `false` to stop.
Returns:
`true` If execution proceeded correctly, `false` if it was interrupted,
that is if `it` returned `false` at any point.
Safety note:
- This function does not check whether the substring is valid.
- This function fails if `byte_offset` or `byte_len` do not
represent valid positions inside `s`
*/
fn substr_all(s: str, byte_offset: uint, byte_len: uint,
it: fn(char) -> bool) -> bool {
let i = byte_offset;
let result = true;
while i < byte_len {
let {ch, next} = char_range_at(s, i);
if !it(ch) {result = false; break;}
i = next;
}
ret result;
}
/*
Function: escape_char
Escapes a single character.
*/
fn escape_char(c: char) -> str {
alt c {
'"' { "\\\"" }
'\\' { "\\\\" }
'\n' { "\\n" }
'\t' { "\\t" }
'\r' { "\\r" }
// FIXME: uncomment this when extfmt is moved to core
// in a snapshot.
// '\x00' to '\x1f' { #fmt["\\x%02x", c as uint] }
v { from_char(c) }
}
}
// UTF-8 tags and ranges
const tag_cont_u8: u8 = 128u8;
const tag_cont: uint = 128u;
const max_one_b: uint = 128u;
const tag_two_b: uint = 192u;
const max_two_b: uint = 2048u;
const tag_three_b: uint = 224u;
const max_three_b: uint = 65536u;
const tag_four_b: uint = 240u;
const max_four_b: uint = 2097152u;
const tag_five_b: uint = 248u;
const max_five_b: uint = 67108864u;
const tag_six_b: uint = 252u;
// NB: This is intentionally unexported because it's easy to misuse (there's
// no guarantee that the string is rooted). Instead, use as_buf below.
unsafe fn buf(s: str) -> sbuf {
let saddr = ptr::addr_of(s);
let vaddr: *[u8] = ::unsafe::reinterpret_cast(saddr);
let buf = vec::to_ptr(*vaddr);
ret buf;
}
/*
Function: as_buf
Work with the byte buffer of a string. Allows for unsafe manipulation
of strings, which is useful for native interop.
Example:
> let s = str::as_buf("PATH", { |path_buf| libc::getenv(path_buf) });
*/
fn as_buf<T>(s: str, f: fn(sbuf) -> T) -> T unsafe {
let buf = buf(s); f(buf)
}
/*
Type: sbuf
An unsafe buffer of bytes. Corresponds to a C char pointer.
*/
type sbuf = *u8;
// Module: unsafe
//
// These functions may create invalid UTF-8 strings and eat your baby.
mod unsafe {
export
// UNSAFE
from_bytes,
from_byte;
// Function: unsafe::from_bytes
//
// Converts a vector of bytes to a string. Does not verify that the
// vector contains valid UTF-8.
unsafe fn from_bytes(v: [const u8]) -> str unsafe {
let vcopy: [u8] = v + [0u8];
let scopy: str = ::unsafe::reinterpret_cast(vcopy);
::unsafe::leak(vcopy);
ret scopy;
}
// Function: unsafe::from_byte
//
// Converts a byte to a string. Does not verify that the byte is
// valid UTF-8.
unsafe fn from_byte(u: u8) -> str { unsafe::from_bytes([u]) }
}
#[cfg(test)]
mod tests {
#[test]
fn test_eq() {
assert (eq("", ""));
assert (eq("foo", "foo"));
assert (!eq("foo", "bar"));
}
#[test]
fn test_lteq() {
assert (lteq("", ""));
assert (lteq("", "foo"));
assert (lteq("foo", "foo"));
assert (!eq("foo", "bar"));
}
#[test]
fn test_bytes_len() {
assert (byte_len("") == 0u);
assert (byte_len("hello world") == 11u);
assert (byte_len("\x63") == 1u);
assert (byte_len("\xa2") == 2u);
assert (byte_len("\u03c0") == 2u);
assert (byte_len("\u2620") == 3u);
assert (byte_len("\U0001d11e") == 4u);
}
#[test]
fn test_index_and_rindex() {
assert (index("hello", 'e' as u8) == 1);
assert (index("hello", 'o' as u8) == 4);
assert (index("hello", 'z' as u8) == -1);
assert (rindex("hello", 'l' as u8) == 3);
assert (rindex("hello", 'h' as u8) == 0);
assert (rindex("hello", 'z' as u8) == -1);
}
#[test]
fn test_split() {
fn t(s: str, c: char, u: [str]) {
log(debug, "split: " + s);
let v = split(s, c as u8);
#debug("split to: ");
log(debug, v);
assert (vec::all2(v, u, { |a,b| a == b }));
}
t("abc.hello.there", '.', ["abc", "hello", "there"]);
t(".hello.there", '.', ["", "hello", "there"]);
t("...hello.there.", '.', ["", "", "", "hello", "there", ""]);
}
#[test]
fn test_splitn() {
fn t(s: str, c: char, n: uint, u: [str]) {
log(debug, "splitn: " + s);
let v = splitn(s, c as u8, n);
#debug("split to: ");
log(debug, v);
#debug("comparing vs. ");
log(debug, u);
assert (vec::all2(v, u, { |a,b| a == b }));
}
t("abc.hello.there", '.', 0u, ["abc.hello.there"]);
t("abc.hello.there", '.', 1u, ["abc", "hello.there"]);
t("abc.hello.there", '.', 2u, ["abc", "hello", "there"]);
t("abc.hello.there", '.', 3u, ["abc", "hello", "there"]);
t(".hello.there", '.', 0u, [".hello.there"]);
t(".hello.there", '.', 1u, ["", "hello.there"]);
t("...hello.there.", '.', 3u, ["", "", "", "hello.there."]);
t("...hello.there.", '.', 5u, ["", "", "", "hello", "there", ""]);
}
#[test]
fn test_split_str() {
fn t(s: str, sep: str, i: int, k: str) {
let v = split_str(s, sep);
assert eq(v[i], k);
}
//FIXME: should behave like split and split_char:
//assert ["", "XXX", "YYY", ""] == split_str(".XXX.YYY.", ".");
t("abc::hello::there", "::", 0, "abc");
t("abc::hello::there", "::", 1, "hello");
t("abc::hello::there", "::", 2, "there");
t("::hello::there", "::", 0, "hello");
t("hello::there::", "::", 2, "");
t("::hello::there::", "::", 2, "");
t("ประเทศไทย中华Việt Nam", "中华", 0, "ประเทศไทย");
t("ประเทศไทย中华Việt Nam", "中华", 1, "Việt Nam");
}
#[test]
fn test_split_func () {
let data = "ประเทศไทย中华Việt Nam";
assert ["ประเทศไทย中", "Việt Nam"]
== split_func (data, {|cc| cc == '华'});
assert ["", "", "XXX", "YYY", ""]
== split_func("zzXXXzYYYz", char::is_lowercase);
assert ["zz", "", "", "z", "", "", "z"]
== split_func("zzXXXzYYYz", char::is_uppercase);
assert ["",""] == split_func("z", {|cc| cc == 'z'});
assert [""] == split_func("", {|cc| cc == 'z'});
assert ["ok"] == split_func("ok", {|cc| cc == 'z'});
}
#[test]
fn test_split_char () {
let data = "ประเทศไทย中华Việt Nam";
assert ["ประเทศไทย中", "Việt Nam"]
== split_char(data, '华');
assert ["", "", "XXX", "YYY", ""]
== split_char("zzXXXzYYYz", 'z');
assert ["",""] == split_char("z", 'z');
assert [""] == split_char("", 'z');
assert ["ok"] == split_char("ok", 'z');
}
#[test]
fn test_lines () {
let lf = "\nMary had a little lamb\nLittle lamb\n";
let crlf = "\r\nMary had a little lamb\r\nLittle lamb\r\n";
assert ["", "Mary had a little lamb", "Little lamb", ""]
== lines(lf);
assert ["", "Mary had a little lamb", "Little lamb", ""]
== lines_any(lf);
assert ["\r", "Mary had a little lamb\r", "Little lamb\r", ""]
== lines(crlf);
assert ["", "Mary had a little lamb", "Little lamb", ""]
== lines_any(crlf);
assert [""] == lines ("");
assert [""] == lines_any("");
assert ["",""] == lines ("\n");
assert ["",""] == lines_any("\n");
assert ["banana"] == lines ("banana");
assert ["banana"] == lines_any("banana");
}
#[test]
fn test_words () {
let data = "\nMary had a little lamb\nLittle lamb\n";
assert ["Mary","had","a","little","lamb","Little","lamb"]
== words(data);
assert ["ok"] == words("ok");
assert [] == words("");
}
#[test]
fn test_find() {
fn t(haystack: str, needle: str, i: int) {
let j: int = find(haystack, needle);
log(debug, "searched for " + needle);
log(debug, j);
assert (i == j);
}
t("this is a simple", "is a", 5);
t("this is a simple", "is z", -1);
t("this is a simple", "", 0);
t("this is a simple", "simple", 10);
t("this", "simple", -1);
}
#[test]
fn test_substr() {
fn t(a: str, b: str, start: int) {
assert (eq(substr(a, start as uint, byte_len(b)), b));
}
t("hello", "llo", 2);
t("hello", "el", 1);
t("substr should not be a challenge", "not", 14);
}
#[test]
fn test_concat() {
fn t(v: [str], s: str) { assert (eq(concat(v), s)); }
t(["you", "know", "I'm", "no", "good"], "youknowI'mnogood");
let v: [str] = [];
t(v, "");
t(["hi"], "hi");
}
#[test]
fn test_connect() {
fn t(v: [str], sep: str, s: str) {
assert (eq(connect(v, sep), s));
}
t(["you", "know", "I'm", "no", "good"], " ", "you know I'm no good");
let v: [str] = [];
t(v, " ", "");
t(["hi"], " ", "hi");
}
#[test]
fn test_to_upper() {
// char::to_upper, and hence str::to_upper
// are culturally insensitive: I'm not sure they
// really work for anything but English ASCII, but YMMV
let unicode = "\u65e5\u672c";
let input = "abcDEF" + unicode + "xyz:.;";
let expected = "ABCDEF" + unicode + "XYZ:.;";
let actual = to_upper(input);
assert (eq(expected, actual));
}
#[test]
fn test_to_lower() {
assert "" == map("", char::to_lower);
assert "ymca" == map("YMCA", char::to_lower);
}
#[test]
fn test_slice() {
assert (eq("ab", slice("abc", 0u, 2u)));
assert (eq("bc", slice("abc", 1u, 3u)));
assert (eq("", slice("abc", 1u, 1u)));
fn a_million_letter_a() -> str {
let i = 0;
let rs = "";
while i < 100000 { rs += "aaaaaaaaaa"; i += 1; }
ret rs;
}
fn half_a_million_letter_a() -> str {
let i = 0;
let rs = "";
while i < 100000 { rs += "aaaaa"; i += 1; }
ret rs;
}
assert (eq(half_a_million_letter_a(),
slice(a_million_letter_a(), 0u, 500000u)));
}
#[test]
fn test_starts_with() {
assert (starts_with("", ""));
assert (starts_with("abc", ""));
assert (starts_with("abc", "a"));
assert (!starts_with("a", "abc"));
assert (!starts_with("", "abc"));
}
#[test]
fn test_ends_with() {
assert (ends_with("", ""));
assert (ends_with("abc", ""));
assert (ends_with("abc", "c"));
assert (!ends_with("a", "abc"));
assert (!ends_with("", "abc"));
}
#[test]
fn test_is_empty() {
assert (is_empty(""));
assert (!is_empty("a"));
}
#[test]
fn test_is_not_empty() {
assert (is_not_empty("a"));
assert (!is_not_empty(""));
}
#[test]
fn test_replace() {
let a = "a";
check (is_not_empty(a));
assert (replace("", a, "b") == "");
assert (replace("a", a, "b") == "b");
assert (replace("ab", a, "b") == "bb");
let test = "test";
check (is_not_empty(test));
assert (replace(" test test ", test, "toast") == " toast toast ");
assert (replace(" test test ", test, "") == " ");
}
#[test]
fn test_char_slice() {
assert (eq("ab", char_slice("abc", 0u, 2u)));
assert (eq("bc", char_slice("abc", 1u, 3u)));
assert (eq("", char_slice("abc", 1u, 1u)));
assert (eq("\u65e5", char_slice("\u65e5\u672c", 0u, 1u)));
let data = "ประเทศไทย中华";
assert (eq("ป", char_slice(data, 0u, 1u)));
assert (eq("ร", char_slice(data, 1u, 2u)));
assert (eq("华", char_slice(data, 10u, 11u)));
assert (eq("", char_slice(data, 1u, 1u)));
fn a_million_letter_X() -> str {
let i = 0;
let rs = "";
while i < 100000 { rs += "华华华华华华华华华华"; i += 1; }
ret rs;
}
fn half_a_million_letter_X() -> str {
let i = 0;
let rs = "";
while i < 100000 { rs += "华华华华华"; i += 1; }
ret rs;
}
assert (eq(half_a_million_letter_X(),
char_slice(a_million_letter_X(), 0u, 500000u)));
}
#[test]
fn test_trim_left() {
assert (trim_left("") == "");
assert (trim_left("a") == "a");
assert (trim_left(" ") == "");
assert (trim_left(" blah") == "blah");
assert (trim_left(" \u3000 wut") == "wut");
assert (trim_left("hey ") == "hey ");
}
#[test]
fn test_trim_right() {
assert (trim_right("") == "");
assert (trim_right("a") == "a");
assert (trim_right(" ") == "");
assert (trim_right("blah ") == "blah");
assert (trim_right("wut \u3000 ") == "wut");
assert (trim_right(" hey") == " hey");
}
#[test]
fn test_trim() {
assert (trim("") == "");
assert (trim("a") == "a");
assert (trim(" ") == "");
assert (trim(" blah ") == "blah");
assert (trim("\nwut \u3000 ") == "wut");
assert (trim(" hey dude ") == "hey dude");
}
#[test]
fn test_is_whitespace() {
assert (is_whitespace(""));
assert (is_whitespace(" "));
assert (is_whitespace("\u2009")); // Thin space
assert (is_whitespace(" \n\t "));
assert (!is_whitespace(" _ "));
}
#[test]
fn test_is_ascii() {
assert (is_ascii(""));
assert (is_ascii("a"));
assert (!is_ascii("\u2009"));
}
#[test]
fn test_shift_byte() {
let s = "ABC";
let b = shift_byte(s);
assert (s == "BC");
assert (b == 65u8);
}
#[test]
fn test_pop_byte() {
let s = "ABC";
let b = pop_byte(s);
assert (s == "AB");
assert (b == 67u8);
}
#[test]
fn test_unsafe_from_bytes() unsafe {
let a = [65u8, 65u8, 65u8, 65u8, 65u8, 65u8, 65u8];
let b = unsafe::from_bytes(a);
assert (b == "AAAAAAA");
}
#[test]
fn test_from_bytes() {
let ss = "ศไทย中华Việt Nam";
let bb = [0xe0_u8, 0xb8_u8, 0xa8_u8,
0xe0_u8, 0xb9_u8, 0x84_u8,
0xe0_u8, 0xb8_u8, 0x97_u8,
0xe0_u8, 0xb8_u8, 0xa2_u8,
0xe4_u8, 0xb8_u8, 0xad_u8,
0xe5_u8, 0x8d_u8, 0x8e_u8,
0x56_u8, 0x69_u8, 0xe1_u8,
0xbb_u8, 0x87_u8, 0x74_u8,
0x20_u8, 0x4e_u8, 0x61_u8,
0x6d_u8];
assert ss == from_bytes(bb);
}
#[test]
#[should_fail]
fn test_from_bytes_fail() {
let bb = [0xff_u8, 0xb8_u8, 0xa8_u8,
0xe0_u8, 0xb9_u8, 0x84_u8,
0xe0_u8, 0xb8_u8, 0x97_u8,
0xe0_u8, 0xb8_u8, 0xa2_u8,
0xe4_u8, 0xb8_u8, 0xad_u8,
0xe5_u8, 0x8d_u8, 0x8e_u8,
0x56_u8, 0x69_u8, 0xe1_u8,
0xbb_u8, 0x87_u8, 0x74_u8,
0x20_u8, 0x4e_u8, 0x61_u8,
0x6d_u8];
let _x = from_bytes(bb);
}
#[test]
fn test_from_cstr() unsafe {
let a = [65u8, 65u8, 65u8, 65u8, 65u8, 65u8, 65u8, 0u8];
let b = vec::to_ptr(a);
let c = from_cstr(b);
assert (c == "AAAAAAA");
}
#[test]
fn test_as_buf() unsafe {
let a = "Abcdefg";
let b = as_buf(a, {|buf| assert (*buf == 65u8); 100 });
assert (b == 100);
}
#[test]
fn test_as_buf_small() unsafe {
let a = "A";
let b = as_buf(a, {|buf| assert (*buf == 65u8); 100 });
assert (b == 100);
}
#[test]
fn test_as_buf2() unsafe {
let s = "hello";
let sb = as_buf(s, {|b| b });
let s_cstr = from_cstr(sb);
assert (eq(s_cstr, s));
}
#[test]
fn vec_str_conversions() {
let s1: str = "All mimsy were the borogoves";
let v: [u8] = bytes(s1);
let s2: str = from_bytes(v);
let i: uint = 0u;
let n1: uint = byte_len(s1);
let n2: uint = vec::len::<u8>(v);
assert (n1 == n2);
while i < n1 {
let a: u8 = s1[i];
let b: u8 = s2[i];
log(debug, a);
log(debug, b);
assert (a == b);
i += 1u;
}
}
#[test]
fn test_contains() {
assert contains("abcde", "bcd");
assert contains("abcde", "abcd");
assert contains("abcde", "bcde");
assert contains("abcde", "");
assert contains("", "");
assert !contains("abcde", "def");
assert !contains("", "a");
}
#[test]
fn test_chars_iter() {
let i = 0;
chars_iter("x\u03c0y") {|ch|
alt i {
0 { assert ch == 'x'; }
1 { assert ch == '\u03c0'; }
2 { assert ch == 'y'; }
}
i += 1;
}
chars_iter("") {|_ch| fail; } // should not fail
}
#[test]
fn test_bytes_iter() {
let i = 0;
bytes_iter("xyz") {|bb|
alt i {
0 { assert bb == 'x' as u8; }
1 { assert bb == 'y' as u8; }
2 { assert bb == 'z' as u8; }
}
i += 1;
}
bytes_iter("") {|bb| assert bb == 0u8; }
}
#[test]
fn test_split_chars_iter() {
let data = "\nMary had a little lamb\nLittle lamb\n";
let ii = 0;
split_chars_iter(data, ' ') {|xx|
alt ii {
0 { assert "\nMary" == xx; }
1 { assert "had" == xx; }
2 { assert "a" == xx; }
3 { assert "little" == xx; }
_ { () }
}
ii += 1;
}
}
#[test]
fn test_splitn_chars_iter() {
let data = "\nMary had a little lamb\nLittle lamb\n";
let ii = 0;
splitn_chars_iter(data, ' ' as u8, 2u) {|xx|
alt ii {
0 { assert "\nMary" == xx; }
1 { assert "had" == xx; }
2 { assert "a little lamb\nLittle lamb\n" == xx; }
_ { () }
}
ii += 1;
}
}
#[test]
fn test_words_iter() {
let data = "\nMary had a little lamb\nLittle lamb\n";
let ii = 0;
words_iter(data) {|ww|
alt ii {
0 { assert "Mary" == ww; }
1 { assert "had" == ww; }
2 { assert "a" == ww; }
3 { assert "little" == ww; }
_ { () }
}
ii += 1;
}
words_iter("") {|_x| fail; } // should not fail
}
#[test]
fn test_lines_iter () {
let lf = "\nMary had a little lamb\nLittle lamb\n";
let ii = 0;
lines_iter(lf) {|x|
alt ii {
0 { assert "" == x; }
1 { assert "Mary had a little lamb" == x; }
2 { assert "Little lamb" == x; }
3 { assert "" == x; }
_ { () }
}
ii += 1;
}
}
#[test]
fn test_escape() {
assert(escape("abcdef") == "abcdef");
assert(escape("abc\\def") == "abc\\\\def");
assert(escape("abc\ndef") == "abc\\ndef");
assert(escape("abc\"def") == "abc\\\"def");
}
#[test]
fn test_map() {
assert "" == map("", char::to_upper);
assert "YMCA" == map("ymca", char::to_upper);
}
#[test]
fn test_all() {
assert true == all("", char::is_uppercase);
assert false == all("ymca", char::is_uppercase);
assert true == all("YMCA", char::is_uppercase);
assert false == all("yMCA", char::is_uppercase);
assert false == all("YMCy", char::is_uppercase);
}
#[test]
fn test_any() {
assert false == any("", char::is_uppercase);
assert false == any("ymca", char::is_uppercase);
assert true == any("YMCA", char::is_uppercase);
assert true == any("yMCA", char::is_uppercase);
assert true == any("Ymcy", char::is_uppercase);
}
#[test]
fn test_windowed() {
let data = "ประเทศไทย中";
assert ["ประ", "ระเ", "ะเท", "เทศ", "ทศไ", "ศไท", "ไทย", "ทย中"]
== windowed(3u, data);
assert [data] == windowed(10u, data);
assert [] == windowed(6u, "abcd");
}
#[test]
#[should_fail]
fn test_windowed_() {
let _x = windowed(0u, "abcd");
}
#[test]
fn test_chars() {
let ss = "ศไทย中华Việt Nam";
assert ['ศ','ไ','ท','ย','中','华','V','i','ệ','t',' ','N','a','m']
== chars(ss);
}
}
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