Add scanf

src/c/stdio.c

@@ -46,3 +46,36 @@ int sprintf(char *s, const char * fmt, ...) {
     va_end(ap);
     return ret;
 }
+
+int vfscanf(FILE * stream, const char * fmt, va_list ap);
+
+int fscanf(FILE * stream, const char * fmt, ...) {
+    int ret;
+    va_list ap;
+    va_start(ap, fmt);
+    ret = vfscanf(stream, fmt, ap);
+    va_end(ap);
+    return ret;
+}
+
+int vscanf(const char * fmt, va_list ap);
+
+int scanf(const char * fmt, ...) {
+    int ret;
+    va_list ap;
+    va_start(ap, fmt);
+    ret = vscanf(fmt, ap);
+    va_end(ap);
+    return ret;
+}
+
+int vsscanf(const char * input, const char * fmt, va_list ap);
+
+int sscanf(const char * input, const char * fmt, ...) {
+    int ret;
+    va_list ap;
+    va_start(ap, fmt);
+    ret = vsscanf(input, fmt, ap);
+    va_end(ap);
+    return ret;
+}

src/platform/src/lib.rs

@@ -82,6 +82,16 @@ impl<'a, W: Write> Write for &'a mut W {
     }
 }
 
+pub trait Read {
+    fn read_u8(&mut self, byte: &mut u8) -> bool;
+}
+
+impl<'a, R: Read> Read for &'a mut R {
+    fn read_u8(&mut self, byte: &mut u8) -> bool {
+        (**self).read_u8(byte)
+    }
+}
+
 pub struct FileWriter(pub c_int);
 
 impl FileWriter {
@@ -112,6 +122,15 @@ impl FileReader {
     }
 }
 
+impl Read for FileReader {
+    fn read_u8(&mut self, byte: &mut u8) -> bool {
+        let mut buf = [*byte];
+        let n = self.read(&mut buf);
+        *byte = buf[0];
+        n > 0
+    }
+}
+
 pub struct StringWriter(pub *mut u8, pub usize);
 
 impl StringWriter {
@@ -174,3 +193,33 @@ impl Write for UnsafeStringWriter {
         Ok(())
     }
 }
+
+pub struct StringReader<'a>(pub &'a [u8]);
+
+impl<'a> Read for StringReader<'a> {
+    fn read_u8(&mut self, byte: &mut u8) -> bool {
+        if self.0.is_empty() {
+            false
+        } else {
+            *byte = self.0[0];
+            self.0 = &self.0[1..];
+            true
+        }
+    }
+}
+
+pub struct UnsafeStringReader(pub *const u8);
+
+impl Read for UnsafeStringReader {
+    fn read_u8(&mut self, byte: &mut u8) -> bool {
+        unsafe {
+            if *self.0 == 0 {
+                false
+            } else {
+                *byte = *self.0;
+                self.0 = self.0.offset(1);
+                true
+            }
+        }
+    }
+}

src/stdio/src/lib.rs

@@ -1,7 +1,10 @@
 //! stdio implementation for Redox, following http://pubs.opengroup.org/onlinepubs/7908799/xsh/stdio.h.html
 
 #![no_std]
+#![feature(alloc)]
+#![feature(global_allocator)]
 
+extern crate alloc;
 extern crate errno;
 extern crate fcntl;
 extern crate platform;
@@ -16,10 +19,11 @@ use core::fmt::Write as WriteFmt;
 use core::sync::atomic::{AtomicBool, Ordering};
 
 use platform::types::*;
-use platform::{c_str, errno, Write};
+use platform::{c_str, errno, Read, Write};
 use errno::STR_ERROR;
 use vl::VaList as va_list;
 
+mod scanf;
 mod printf;
 
 mod default;
@@ -184,6 +188,14 @@ impl Write for FILE {
         }
     }
 }
+impl Read for FILE {
+    fn read_u8(&mut self, byte: &mut u8) -> bool {
+        let mut buf = [*byte];
+        let n = self.read(&mut buf);
+        *byte = buf[0];
+        n > 0
+    }
+}
 
 /// Clears EOF and ERR indicators on a stream
 #[no_mangle]
@@ -882,3 +894,18 @@ pub unsafe extern "C" fn vsnprintf(
 pub unsafe extern "C" fn vsprintf(s: *mut c_char, format: *const c_char, ap: va_list) -> c_int {
     printf::printf(&mut platform::UnsafeStringWriter(s as *mut u8), format, ap)
 }
+
+#[no_mangle]
+pub unsafe extern "C" fn vfscanf(file: &mut FILE, format: *const c_char, ap: va_list) -> c_int {
+    scanf::scanf(file, format, ap)
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn vscanf(format: *const c_char, ap: va_list) -> c_int {
+    vfscanf(&mut *stdin, format, ap)
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn vsscanf(s: *const c_char, format: *const c_char, ap: va_list) -> c_int {
+    scanf::scanf(&mut platform::UnsafeStringReader(s as *const u8), format, ap)
+}

src/stdio/src/scanf.rs

@@ -0,0 +1,546 @@
+use alloc::String;
+use alloc::Vec;
+use platform::types::*;
+use platform::Read;
+#[cfg(not(test))]
+use vl::VaList;
+
+#[derive(PartialEq, Eq)]
+enum IntKind {
+    Byte,
+    Short,
+    Int,
+    Long,
+    LongLong,
+    IntMax,
+    PtrDiff,
+    Size
+}
+
+/// Helper function for progressing a C string
+unsafe fn next_byte(string: &mut *const c_char) -> Result<u8, c_int> {
+    let c = **string as u8;
+    *string = string.offset(1);
+    if c == 0 {
+        Err(-1)
+    } else {
+        Ok(c)
+    }
+}
+
+unsafe fn inner_scanf<R: Read>(mut r: R, mut format: *const c_char, mut ap: VaList) -> Result<c_int, c_int> {
+    let mut matched = 0;
+    let mut byte = 0;
+    let mut skip_read = false;
+    let mut count = 0;
+
+    macro_rules! read {
+        () => {{
+            let n = r.read_u8(&mut byte);
+            if n { count += 1; }
+            n
+        }}
+    }
+
+    macro_rules! maybe_read {
+        () => {
+            maybe_read!(inner false);
+        };
+        (noreset) => {
+            maybe_read!(inner);
+        };
+        (inner $($placeholder:expr)*) => {
+            if !skip_read {
+                if !read!() {
+                    return Ok(matched);
+                }
+            }
+            $(else {
+                // Hacky way of having this optional
+                skip_read = $placeholder;
+            })*
+        }
+    }
+
+    while *format != 0 {
+        let mut c = *format as u8;
+        format = format.offset(1);
+
+        if c == b' ' {
+            maybe_read!(noreset);
+
+            while (byte as char).is_whitespace() {
+                if !read!() {
+                    return Ok(matched);
+                }
+            }
+
+            skip_read = true;
+        } else if c != b'%' {
+            maybe_read!();
+            if c != byte {
+                return Ok(matched);
+            }
+        } else {
+            c = next_byte(&mut format)?;
+
+            let mut ignore = false;
+            if c == b'*' {
+                ignore = true;
+                c = next_byte(&mut format)?;
+            }
+
+            let mut width = String::new();
+            while c >= b'0' && c <= b'9' {
+                width.push(c as char);
+                c = next_byte(&mut format)?;
+            }
+            let mut width = if width.is_empty() {
+                None
+            } else {
+                match width.parse::<usize>() {
+                    Ok(n) => Some(n),
+                    Err(_) => return Err(-1)
+                }
+            };
+
+            let mut kind = IntKind::Int;
+            loop {
+                kind = match c {
+                    b'h' => if kind == IntKind::Short {
+                        IntKind::Byte
+                    } else {
+                        IntKind::Short
+                    },
+                    b'j' => IntKind::IntMax,
+                    b'l' => IntKind::Long,
+                    b'q' | b'L' => IntKind::LongLong,
+                    b't' => IntKind::PtrDiff,
+                    b'z' => IntKind::Size,
+                    _ => break
+                };
+
+                c = next_byte(&mut format)?;
+            }
+
+            if c != b'n' {
+                maybe_read!(noreset);
+            }
+            match c {
+                b'%' => {
+                    while (byte as char).is_whitespace() {
+                        if !read!() {
+                            return Ok(matched);
+                        }
+                    }
+
+                    if byte != b'%' {
+                        return Err(matched);
+                    } else if !read!() {
+                        return Ok(matched);
+                    }
+                },
+                b'd' | b'i' | b'o' | b'u' | b'x' | b'X' | b'f' | b'e' | b'g' | b'E' | b'a' | b'p' => {
+                    while (byte as char).is_whitespace() {
+                        if !read!() {
+                            return Ok(matched);
+                        }
+                    }
+
+                    let pointer = c == b'p';
+                    // Pointers aren't automatic, but we do want to parse "0x"
+                    let auto = c == b'i' || pointer;
+                    let float = c == b'f' || c == b'e' || c == b'g' || c == b'E' || c == b'a';
+
+                    let mut radix = match c {
+                        b'o' => 8,
+                        b'x' | b'X' | b'p' => 16,
+                        _ => 10,
+                    };
+
+                    let mut n = String::new();
+                    let mut dot = false;
+
+                    while width.map(|w| w > 0).unwrap_or(true)
+                            && ((byte >= b'0' && byte <= b'7')
+                                || (radix >= 10 && (byte >= b'8' && byte <= b'9'))
+                                || (float && !dot && byte == b'.')
+                                || (radix == 16 && ((byte >= b'a' && byte <= b'f')
+                                    || (byte >= b'A' && byte <= b'F')))) {
+                        if auto && n.is_empty() && byte == b'0'
+                                && width.map(|w| w > 0).unwrap_or(true) {
+                            if !pointer {
+                                radix = 8;
+                            }
+                            width = width.map(|w| w - 1);
+                            if !read!() {
+                                break;
+                            }
+                            if width.map(|w| w > 0).unwrap_or(true) && (byte == b'x' || byte == b'X') {
+                                radix = 16;
+                                width = width.map(|w| w - 1);
+                                if width.map(|w| w > 0).unwrap_or(true) {
+                                    if !read!() {
+                                        break;
+                                    }
+                                }
+                            }
+                            continue;
+                        }
+                        if byte == b'.' {
+                            // Don't allow another dot
+                            dot = true;
+                        }
+                        n.push(byte as char);
+                        width = width.map(|w| w - 1);
+                        if width.map(|w| w > 0).unwrap_or(true) {
+                            if !read!() {
+                                break;
+                            }
+                        }
+                    }
+
+                    macro_rules! parse_type {
+                        (noformat $type:ident) => {
+                            {
+                                let n = if n.is_empty() { 0 as $type } else {
+                                    n.parse::<$type>()
+                                        .map_err(|_| 0)?
+                                };
+                                if !ignore {
+                                    *ap.get::<*mut $type>() = n;
+                                    matched += 1;
+                                }
+                            }
+                        };
+                        (c_double) => { parse_type!(noformat c_double); };
+                        (c_float) => { parse_type!(noformat c_float); };
+                        ($type:ident) => { parse_type!($type, $type); };
+                        ($type:ident, $final:ty) => {
+                            {
+                                let n = if n.is_empty() { 0 as $type } else {
+                                    $type::from_str_radix(&n, radix)
+                                        .map_err(|_| 0)?
+                                };
+                                if !ignore {
+                                    *ap.get::<*mut $final>() = n as $final;
+                                    matched += 1;
+                                }
+                            }
+                        }
+                    }
+
+                    if float {
+                        if kind == IntKind::Long || kind == IntKind::LongLong {
+                            parse_type!(c_double);
+                        } else {
+                            parse_type!(c_float);
+                        }
+                    } else if c == b'p' {
+                        parse_type!(size_t, *mut c_void);
+                    } else {
+                        let unsigned = c == b'o' || c == b'u' || c == b'x' || c == b'X';
+
+                        match kind {
+                            IntKind::Byte => if unsigned {
+                                parse_type!(c_uchar);
+                            } else {
+                                parse_type!(c_char);
+                            },
+                            IntKind::Short => if unsigned {
+                                parse_type!(c_ushort)
+                            } else {
+                                parse_type!(c_short)
+                            },
+                            IntKind::Int => if unsigned {
+                                parse_type!(c_uint)
+                            } else {
+                                parse_type!(c_int)
+                            },
+                            IntKind::Long => if unsigned {
+                                parse_type!(c_ulong)
+                            } else {
+                                parse_type!(c_long)
+                            },
+                            IntKind::LongLong => if unsigned {
+                                parse_type!(c_ulonglong)
+                            } else {
+                                parse_type!(c_longlong)
+                            },
+                            IntKind::IntMax => if unsigned {
+                                parse_type!(uintmax_t)
+                            } else {
+                                parse_type!(intmax_t)
+                            },
+                            IntKind::PtrDiff => parse_type!(ptrdiff_t),
+                            IntKind::Size => if unsigned {
+                                parse_type!(size_t)
+                            } else {
+                                parse_type!(ssize_t)
+                            }
+                        }
+                    }
+                },
+                b's' => {
+                    while (byte as char).is_whitespace() {
+                        if !read!() {
+                            return Ok(matched);
+                        }
+                    }
+
+                    let mut ptr: Option<*mut c_char> = if ignore { None } else { Some(ap.get()) };
+
+                    while width.map(|w| w > 0).unwrap_or(true) && !(byte as char).is_whitespace() {
+                        if let Some(ref mut ptr) = ptr {
+                            **ptr = byte as c_char;
+                            *ptr = ptr.offset(1);
+                        }
+                        width = width.map(|w| w - 1);
+                        if width.map(|w| w > 0).unwrap_or(true) {
+                            if !read!() {
+                                break;
+                            }
+                        }
+                    }
+
+                    if let Some(ptr) = ptr {
+                        *ptr = 0;
+                        matched += 1;
+                    }
+                },
+                b'c' => {
+                    let mut ptr: Option<*mut c_char> = if ignore { None } else { Some(ap.get()) };
+
+                    for i in 0..width.unwrap_or(1) {
+                        if let Some(ptr) = ptr {
+                            *ptr.offset(i as isize) = byte as c_char;
+                        }
+                        width = width.map(|w| w - 1);
+                        if width.map(|w| w > 0).unwrap_or(true) {
+                            if !read!() {
+                                break;
+                            }
+                        }
+                    }
+
+                    if ptr.is_some() {
+                        matched += 1;
+                    }
+                },
+                b'[' => {
+                    c = next_byte(&mut format)?;
+
+                    let mut matches = Vec::new();
+                    let mut invert = false;
+                    if c == b'^' {
+                        c = next_byte(&mut format)?;
+                        invert = true;
+                    }
+
+                    let mut prev;
+                    loop {
+                        matches.push(c);
+                        prev = c;
+                        c = next_byte(&mut format)?;
+                        if c == b'-' {
+                            if prev == b']' {
+                                continue;
+                            }
+                            c = next_byte(&mut format)?;
+                            if c == b']' {
+                                matches.push(b'-');
+                                break;
+                            }
+                            prev += 1;
+                            while prev < c {
+                                matches.push(prev);
+                                prev += 1;
+                            }
+                        } else if c == b']' {
+                            break;
+                        }
+                    }
+
+                    let mut ptr: Option<*mut c_char> = if ignore { None } else { Some(ap.get()) };
+
+                    while width.map(|w| w > 0).unwrap_or(true) && !invert == matches.contains(&byte) {
+                        if let Some(ref mut ptr) = ptr {
+                            **ptr = byte as c_char;
+                            *ptr = ptr.offset(1);
+                        }
+                        width = width.map(|w| w - 1);
+                        if width.map(|w| w > 0).unwrap_or(true) {
+                            if !read!() {
+                                break;
+                            }
+                        }
+                    }
+
+                    if let Some(ptr) = ptr {
+                        *ptr = 0;
+                        matched += 1;
+                    }
+                },
+                b'n' => {
+                    if !ignore {
+                        *ap.get::<*mut c_int>() = count as c_int;
+                    }
+                },
+                _ => return Err(-1)
+            }
+
+            if width != Some(0) && c != b'n' {
+                // It didn't hit the width, so an extra character was read and matched.
+                // But this character did not match so let's reuse it.
+                skip_read = true;
+            }
+        }
+    }
+    Ok(matched)
+}
+pub unsafe fn scanf<R: Read>(r: R, format: *const c_char, ap: VaList) -> c_int {
+    match inner_scanf(r, format, ap) {
+        Ok(n) => n,
+        Err(n) => n
+    }
+}
+
+#[cfg(test)]
+pub trait VaPrimitive {
+    fn as_mut_ptr(&mut self) -> *mut c_void;
+}
+#[cfg(test)]
+macro_rules! va_primitives {
+    ($($type:ty),+) => {
+        $(impl VaPrimitive for $type {
+            fn as_mut_ptr(&mut self) -> *mut c_void {
+                self as *mut _ as *mut c_void
+            }
+        })+
+    }
+}
+#[cfg(test)]
+va_primitives!(c_uchar, c_ushort, c_uint, c_ulong, c_char, c_short, c_int, c_long, c_float, c_double, *mut c_void);
+
+#[cfg(test)]
+trait FromVoidPtr {
+    fn from_void_ptr(ptr: *mut c_void) -> Self;
+}
+#[cfg(test)]
+macro_rules! from_void_ptr {
+    ($($type:ty),+) => {
+        $(impl FromVoidPtr for *mut $type {
+            fn from_void_ptr(ptr: *mut c_void) -> Self {
+                ptr as *mut _ as Self
+            }
+        })+
+    }
+}
+#[cfg(test)]
+from_void_ptr!(c_uchar, c_ushort, c_uint, c_ulong, c_char, c_short, c_int, c_long, c_float, c_double,
+               size_t, ssize_t, *mut c_void);
+
+#[cfg(test)]
+pub struct VaList<'a> {
+    args: &'a mut [&'a mut VaPrimitive],
+    i: usize
+}
+#[cfg(test)]
+impl<'a> VaList<'a> {
+    pub fn new(args: &'a mut [&'a mut VaPrimitive]) -> VaList<'a> {
+        VaList {
+            args: args,
+            i: 0
+        }
+    }
+    pub fn get<T: FromVoidPtr>(&mut self) -> T {
+        let ptr = T::from_void_ptr(self.args[self.i].as_mut_ptr());
+        self.i += 1;
+        ptr
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use core::ptr;
+    use platform::StringReader;
+    use super::*;
+
+    fn scanf<'a>(format: &str, args: &'a mut [&'a mut VaPrimitive], input: &str) -> c_int {
+        unsafe {
+            let mut format = format.to_string();
+            let format = format.as_bytes_mut();
+            let format = format.as_mut_ptr();
+            let out = super::inner_scanf(StringReader(input.as_bytes()), format as *mut c_char, VaList::new(args))
+                .expect("running test scanf failed");
+            out
+        }
+    }
+
+    #[test]
+    fn ints() {
+        let mut a: c_char = 0;
+        let mut b: c_int = 0;
+        assert_eq!(scanf("%hhd %d\0", &mut [&mut a, &mut b], "12 345"), 2);
+        assert_eq!(a, 12);
+        assert_eq!(b, 345);
+    }
+    #[test]
+    fn formats() {
+        let mut a: c_uint = 0;
+        let mut b: c_int = 0;
+        let mut c: c_int = 0;
+        assert_eq!(scanf("%x %i %i\0", &mut [&mut a, &mut b, &mut c], "12 0x345 010"), 3);
+        assert_eq!(a, 0x12);
+        assert_eq!(b, 0x345);
+        assert_eq!(c, 0o10);
+    }
+    #[test]
+    fn floats() {
+        let mut a: c_float = 0.0;
+        let mut b: c_double = 0.0;
+        assert_eq!(scanf("%f.%lf\0", &mut [&mut a, &mut b], "0.1.0.2"), 2);
+        assert_eq!(a, 0.1);
+        assert_eq!(b, 0.2);
+    }
+    #[test]
+    fn pointer() {
+        let mut a: *mut c_void = ptr::null_mut();
+        assert_eq!(scanf("%p\0", &mut [&mut a], "0xABCDEF"), 1);
+        assert_eq!(a as usize, 0xABCDEF);
+    }
+    #[test]
+    fn string() {
+        let mut a = [1u8; 10];
+        assert_eq!(scanf("%s\0", &mut [&mut (a[0])], "Hello World"), 1);
+        assert_eq!(&a[..6], b"Hello\0");
+        assert_eq!(a[6..], [1; 4]); // nothing else was modified
+    }
+    #[test]
+    fn width() {
+        let mut a: c_int = 0;
+        assert_eq!(scanf("%3i\0", &mut [&mut a], "0xFF"), 1);
+        assert_eq!(a, 0xF);
+    }
+    #[test]
+    fn chars() {
+        let mut a: u8 = 0;
+        let mut b = [1u8; 5];
+        assert_eq!(scanf("%c%3c\0", &mut [&mut a, &mut (b[0])], "hello"), 2);
+        assert_eq!(a, b'h');
+        assert_eq!(&b[..3], b"ell");
+        assert_eq!(&b[3..5], [1; 2]); // nothing else was modified, no trailing NUL-byte
+    }
+    #[test]
+    fn count() {
+        let mut a: c_int = 0;
+        let mut b: c_int = 0;
+        assert_eq!(scanf("test: %2i%n\0", &mut [&mut a, &mut b], "test: 0xFF"), 1);
+        assert_eq!(a, 0);
+        assert_eq!(b, 8);
+    }
+    #[test]
+    fn literal() {
+        assert_eq!(scanf("hello world%%\0", &mut [], "hello world%"), 0);
+    }
+}

tests/.gitignore

@@ -23,6 +23,7 @@
 /printf
 /rmdir
 /rename
+/scanf
 /setid
 /setid
 /sleep

tests/Makefile

@@ -21,6 +21,7 @@ EXPECT_BINS=\
 	printf \
 	rename \
 	rmdir \
+	scanf \
 	sleep \
 	sprintf \
 	stdio/fwrite \

tests/expected/scanf.stdout

@@ -0,0 +1 @@
+success!

tests/scanf.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <malloc.h>
+
+int main(int argc, char ** argv) {
+    int a = 0;
+    int b = 0;
+    int val = sscanf("123 0x321", "%d %i", &a, &b);
+    if (val != 2) {
+        printf("error: %d\n", val);
+    } else {
+        if (a == 123 && b == 0x321) {
+            puts("success!");
+        } else {
+            printf("incorrect results: { a: %d, b: %x }\n", a, b);
+        }
+    }
+}