Improved string safety, and slight performance considerations

src/cformat.jl

@@ -48,44 +48,46 @@ function generate_formatter( fmt::String )
 end
 
 function addcommasreal(s)
-    dpos = findfirst( isequal('.'), s )
-    dpos !== nothing && return string(addcommas( s[1:dpos-1] ), s[ dpos:end ])
+    dpos = findfirst(==('.'), s)
+    firstind = firstindex(s)
+    dpos !== nothing && return string(addcommas(SubString(s, firstind, prevind(s, dpos))), SubString(s, dpos))
     # find the rightmost digit
-    for i in length( s ):-1:1
-        isdigit( s[i] ) && return string(addcommas( s[1:i] ), s[i+1:end])
+    for i in Iterators.reverse(eachindex(s))
+        isdigit(s[i]) && return string(addcommas(SubString(s, firstind, i)), SubString(s, nextind(s, i)))
     end
-    s
+    return s
 end
 
 function addcommasrat(s)
     # commas are added to only the numerator
-    spos = findfirst( isequal('/'), s )
-    string(addcommas( s[1:spos-1] ), s[spos:end])
+    spos = findfirst('/', s)
+    string(addcommas(SubString(s, firstindex(s), prevind(s, spos))), SubString(s, spos))
 end
 
 function checkcommas(s)
-    for i in length( s ):-1:1
-        if isdigit( s[i] )
-            s = string(addcommas( s[1:i] ), s[i+1:end])
-            break
+    firstind = firstindex(s)
+    for i in Iterators.reverse(eachindex(s))
+        if isdigit(s[i])
+            return string(addcommas(SubString(s, firstind, i)), SubString(s, nextind(s, i)))
         end
     end
-    s
+    return s
 end
 
-
-function addcommas( s::String )
+function addcommas(s::S) where {S <: AbstractString}
     len = length(s)
+    inds = eachindex(s)
+    firstind = firstindex(s)
     t = ""
     for i in 1:3:len
-        subs = s[max(1,len-i-1):len-i+1]
+        substr = SubString(s, max(firstind, prevind(s, len, i + 1)), nextind(s, prevind(s, len, i)))
         if i == 1
-            t = subs
+            t = substr
         else
-            if match( r"[0-9]", subs ) != nothing
-                t = subs * "," * t
+            if any(isdigit, substr)
+                t = substr * "," * t
             else
-                t = subs * t
+                t = substr * t
             end
         end
     end
@@ -289,38 +291,43 @@ function format( x::T;
             checkwidth = true
         end
     elseif stripzeros && in( actualconv[1], "fFeEs" )
-        dpos = findfirst( isequal('.'), s )
+        dpos = findfirst('.', s)
         if in( actualconv[1], "eEs" )
             if in( actualconv[1], "es" )
-                epos = findfirst( isequal('e'), s )
+                epos = findfirst('e', s)
             else
-                epos = findfirst( isequal('E'), s )
+                epos = findfirst('E', s)
             end
             if epos === nothing
-                rpos = length( s )
+                rpos = lastindex(s)
             else
-                rpos = epos-1
+                rpos = prevind(s, epos)
             end
         else
             rpos = length(s)
         end
         # rpos at this point is the rightmost possible char to start
         # stripping
-        stripfrom = rpos+1
-        for i = rpos:-1:dpos+1
+        stripfrom = nextind(s, rpos)
+        lower_ind = nextind(s, dpos)
+        # for i = rpos:-1:dpos+1
+        for i in Iterators.reverse(eachindex(s))
+            if i > rpos || i < lower_ind
+                continue
+            end
             if s[i] == '0'
                 stripfrom = i
-            elseif s[i] ==' '
+            elseif s[i] == ' '
                 continue
             else
                 break
             end
         end
         if stripfrom <= rpos
-            if stripfrom == dpos+1 # everything after decimal is 0, so strip the decimal too
+            if stripfrom == nextind(s, dpos) # everything after decimal is 0, so strip the decimal too
                 stripfrom = dpos
             end
-            s = s[1:stripfrom-1] * s[rpos+1:end]
+            s = string(SubString(s, firstindex(s), prevind(s, stripfrom)), SubString(s, nextind(s, rpos)))
             checkwidth = true
         end
     end

src/formatexpr.jl

@@ -28,12 +28,12 @@ function make_argspec(s::AbstractString, pos::Int)
     if !isempty(s)
         filrange = findfirst("|>", s)
         if filrange === nothing
-            iarg = parse(Int,s)
+            iarg = parse(Int, s)
         else
             ifil = first(filrange)
-            iarg = ifil > 1 ? parse(Int,s[1:prevind(s, ifil)]) : -1
+            iarg = ifil > 1 ? parse(Int, SubString(s, 1, prevind(s, ifil))) : -1
             hasfil = true
-            ff = eval(Symbol(s[ifil+2:end]))
+            ff = eval(Symbol(SubString(s, nextind(s, ifil, 2))))
         end
     end
 
@@ -62,15 +62,16 @@ struct FormatEntry
 end
 
 function make_formatentry(s::AbstractString, pos::Int)
-    @assert s[1] == '{' && s[end] == '}'
-    sc = s[2:prevind(s, lastindex(s))]
-    icolon = findfirst(isequal(':'), sc)
+    @assert s[firstindex(s)] == '{' && s[lastindex(s)] == '}'
+    firstind = firstindex(s)
+    sc = SubString(s, nextind(s, firstind), prevind(s, lastindex(s)))
+    icolon = findfirst(':', sc)
     if icolon === nothing  # no colon
         (argspec, pos) = make_argspec(sc, pos)
         spec = FormatSpec('s')
     else
-        (argspec, pos) = make_argspec(sc[1:prevind(sc, icolon)], pos)
-        spec = FormatSpec(sc[nextind(sc, icolon):end])
+        (argspec, pos) = make_argspec(SubString(sc, firstind, prevind(sc, icolon)), pos)
+        spec = FormatSpec(SubString(sc, nextind(sc, icolon)))
     end
     return (FormatEntry(argspec, spec), pos)
 end
@@ -89,14 +90,14 @@ _raise_unmatched_lbrace() = error("Unmatched { in format expression.")
 
 function find_next_entry_open(s::AbstractString, si::Int)
     slen = lastindex(s)
-    p = findnext(isequal('{'), s, si)
+    p = findnext('{', s, si)
     (p === nothing || p < slen) || _raise_unmatched_lbrace()
-    while p !== nothing && s[p+1] == '{'  # escape `{{`
-        p = findnext(isequal('{'), s, p+2)
+    while p !== nothing && s[nextind(s, p)] == '{'  # escape `{{`
+        p = findnext('{', s, nextind(s, p, 2))
         (p === nothing || p < slen) || _raise_unmatched_lbrace()
     end
     # println("open at $p")
-    pre = p !== nothing ? s[si:prevind(s, p)] : s[si:end]
+    pre = p !== nothing ? SubString(s, si, prevind(s, p)) : SubString(s, si)
     if !isempty(pre)
         pre = replace(pre, "{{" => '{')
         pre = replace(pre, "}}" => '}')
@@ -105,7 +106,7 @@ function find_next_entry_open(s::AbstractString, si::Int)
 end
 
 function find_next_entry_close(s::AbstractString, si::Int)
-    p = findnext(isequal('}'), s, si)
+    p = findnext('}', s, si)
     p !== nothing || _raise_unmatched_lbrace()
     # println("close at $p")
     return p