eatwspace: use ios_peekutf8 rather than position & seek

base/char.jl

@@ -86,32 +86,3 @@ for f = (:iswalnum, :iswalpha, :iswblank, :iswcntrl, :iswdigit,
          )
     @eval ($f)(c::Char) = bool(ccall($expr(:quote,f), Int32, (Char,), c))
 end
-
-## IOStream character manipulation ##
-
-function eatwspace(s::IOStream)
-    p = position(s)
-    c = read(s, Char)
-    while iswspace(c) && !eof(s)
-        p = position(s)
-        c = read(s, Char)
-    end
-    if !iswspace(c)
-        seek(s, p)
-    end
-end
-
-function eatwspace_comment(s::IOStream, cmt::Char)
-    p = position(s)
-    c = read(s, Char)
-    while (iswspace(c) || c == cmt) && !eof(s)
-        if c == cmt
-            readline(s)
-        end
-        p = position(s)
-        c = read(s, Char)
-    end
-    if !(iswspace(c) || c == cmt)
-        seek(s, p)
-    end
-end

base/io.jl

@@ -404,3 +404,24 @@ begin
               readfds.nfds, readfds.data, C_NULL, C_NULL, tout)
     end
 end
+
+## Character streams ##
+_wstmp = Array(Char, 1)
+function eatwspace(s::IOStream)
+    status = ccall(:ios_peekutf8, Int32, (Ptr{Void}, Ptr{Uint32}), s.ios, _wstmp)
+    while status > 0 && iswspace(_wstmp[1])
+        c = read(s, Char)  # advance one character
+        status = ccall(:ios_peekutf8, Int32, (Ptr{Void}, Ptr{Uint32}), s.ios, _wstmp)
+    end
+end
+
+function eatwspace_comment(s::IOStream, cmt::Char)
+    status = ccall(:ios_peekutf8, Int32, (Ptr{Void}, Ptr{Uint32}), s.ios, _wstmp)
+    while status > 0 && (iswspace(_wstmp[1]) || _wstmp[1] == cmt)
+        if _wstmp[1] == cmt
+            readline(s)
+        end
+        c = read(s, Char)  # advance one character
+        status = ccall(:ios_peekutf8, Int32, (Ptr{Void}, Ptr{Uint32}), s.ios, _wstmp)
+    end
+end

base/sysimg.jl

@@ -110,7 +110,9 @@ export
     den,depth,deserialize,det,dfill,diag,diagm,diagmm,diagmm!,dict,diff,
     dist,distdim,distribute,div,dlmread,dlmwrite,dlopen,dlsym,done,dones,dot,
     drand,drandn,dump,dup2,dzeros,each_col,each_col!,each_line,each_match,
-    each_row,each_row!,each_search,each_vec,each_vec!,edit,eig,elements,eltype,
+    each_row,each_row!,each_search,each_vec,each_vec!,
+    eatwspace,eatwspace_comment,
+    edit,eig,elements,eltype,
     ends_with,enq_work,enqueue,enumerate,eof,eps,erf,erfc,errno,error,
     esc,escape_string,exec,exit,exp,exp2,expm1,expr,exprnd,eye,
     factor,factorial,falses,fd,fdio,fetch,fft,fft2,fft3,fft_num_threads,

src/julia.expmap

@@ -99,6 +99,7 @@
     ios_pututf8;
     ios_getc;
     ios_getutf8;
+    ios_peekutf8;
     jl_getutf8;
     u8_isvalid;
     u8_strwidth;

src/support/ios.h

@@ -121,7 +121,7 @@ DLLEXPORT int ios_vprintf(ios_t *s, const char *format, va_list args);
 /* high-level stream functions - input */
 int ios_getnum(ios_t *s, char *data, uint32_t type);
 DLLEXPORT int ios_getutf8(ios_t *s, uint32_t *pwc);
-int ios_peekutf8(ios_t *s, uint32_t *pwc);
+DLLEXPORT int ios_peekutf8(ios_t *s, uint32_t *pwc);
 int ios_ungetutf8(ios_t *s, uint32_t wc);
 //int ios_getstringz(ios_t *dest, ios_t *src);
 //int ios_getstringn(ios_t *dest, ios_t *src, size_t nchars);