Merge pull request #46 from darlentar/master

add of_substring.

lib/stdint.ml

@@ -93,6 +93,7 @@ module type Int = sig
   val of_uint128 : uint128 -> t
   val to_uint128 : t -> uint128
 
+  val of_substring : string -> pos:int -> (t * int)
   val of_string : string -> t
   val to_string : t -> string
 

lib/stdint.mli

@@ -279,6 +279,15 @@ module type Int = sig
   (** Convert an integer of type [t] to an integer of type [uint128]. *)
 (** {6 String conversion functions} *)
 
+  val of_substring : string -> pos:int -> (t * int)
+  (** Convert the given substring starting at the given offset [pos]
+      to an integer of type [t] and return the offset.
+      The string is read in decimal (by default) or in hexadecimal, octal
+      or binary if the string begins with [0x], [0o] or [0b] respectively.
+      Raise [Failure "*_of_substring"] if the given string is not a valid
+      representation of an integer, or if the integer represented exceeds
+      the range of integers representable in type [t]. *)
+
   val of_string : string -> t
   (** Convert the given string to an integer of type [t].
       The string is read in decimal (by default) or in hexadecimal, octal

lib/str_conv.ml

@@ -16,6 +16,7 @@ end
 
 module type S = sig
   type t
+  val of_substring : string -> pos:int -> (t * int)
   val of_string : string -> t
   val to_string : t -> string
   val to_string_bin : t -> string
@@ -30,26 +31,22 @@ end
 module Make (I : IntSig) : S with type t = I.t = struct
   type t = I.t
 
-  let digit_of_char c =
-    let disp =
-      if c >= '0' && c <= '9' then 48
-      else if c >= 'A' && c <= 'F' then 55
-      else if c >= 'a' && c <= 'f' then 87
-      else failwith (I.name ^ ".of_string") in
-    int_of_char c - disp
+  exception NotDigit of I.t * int
 
-  let of_string s =
-    let fail () = invalid_arg (I.name ^ ".of_string") in
-    let len = String.length s in
+  (** Base function for *of_string* and *of_substring*
+    * functions *)
+  let _of_substring start_off s func_name =
+    let fail () = invalid_arg (I.name ^ func_name) in
+    let len = String.length s - start_off in
     (* is this supposed to be a negative number? *)
     let negative, off =
-      if len = 0 then fail ();
-      if s.[0] = '-' then
-        true, 1
-      else if s.[0] = '+' then
-        false, 1
+      if len <= 0 then fail ();
+      if s.[start_off] = '-' then
+        true, 1+start_off
+      else if s.[start_off] = '+' then
+        false, 1+start_off
       else
-        false, 0 in
+        false, start_off in
     (* does the string have a base-prefix and what base is it? *)
     let base, off =
       if len - off < 3 then (* no space for a prefix in there *)
@@ -73,11 +70,19 @@ module Make (I : IntSig) : S with type t = I.t = struct
         (I.divmod I.max_int base, I.add, -1) in
     let rec loop off (n : I.t) =
       if off = len then
-        n
+        n, off
       else begin
         let c = s.[off] in
         if c <> '_' then begin
-          let d = I.of_int (digit_of_char c) in
+          let disp =
+            if c >= '0' && c <= '9' then 48
+            else if c >= 'A' && c <= 'F' then 55
+            else if c >= 'a' && c <= 'f' then 87
+            else raise (NotDigit (n, off)) in
+          let disp = int_of_char c - disp in
+          let d = I.of_int disp in
+          (* do not accept digit larger than the base *)
+          if d >= base then fail () ;
           (* will we overflow? *)
           (match compare n thresh with
           | 0 ->
@@ -93,6 +98,18 @@ module Make (I : IntSig) : S with type t = I.t = struct
     in
     loop off I.zero
 
+  let of_substring s ~pos =
+    try
+      _of_substring pos s ".of_substring"
+    with
+      | NotDigit (n, off) -> n, off
+
+  let of_string s =
+    try
+      let n, _ = _of_substring 0 s ".of_string" in n
+    with
+      | NotDigit _ -> invalid_arg (I.name ^ ".of_string")
+
   let to_string_base base prefix x =
     let prefixlen = String.length prefix in
     let base = I.of_int base in

lib/str_conv.mli

@@ -16,6 +16,7 @@ end
 
 module type S = sig
   type t
+  val of_substring : string -> pos:int -> (t * int)
   val of_string : string -> t
   val to_string : t -> string
   val to_string_bin : t -> string

stdint.opam

@@ -1,5 +1,23 @@
 # This file is generated by dune, edit dune-project instead
 opam-version: "2.0"
+build: [
+  ["dune" "subst"] {pinned}
+  ["dune" "build" "-p" name "-j" jobs]
+  ["dune" "runtest" "-p" name "-j" jobs] {with-test}
+  ["dune" "build" "-p" name "@doc"] {with-doc}
+]
+maintainer: ["Markus W. Weissmann <markus.weissmann@in.tum.de>"]
+authors: [
+  "Andre Nathan <andre@digirati.com.br>"
+  "Jeff Shaw <shawjef3@msu.edu>"
+  "Markus W. Weissmann <markus.weissmann@in.tum.de>"
+  "Florian Pichlmeier <florian.pichlmeier@mytum.de>"
+]
+bug-reports: "https://github.com/andrenth/ocaml-stdint/issues"
+homepage: "https://github.com/andrenth/ocaml-stdint"
+doc: "https://andrenth.github.io/ocaml-stdint/"
+license: "MIT"
+dev-repo: "git+https://github.com/andrenth/ocaml-stdint.git"
 synopsis: "Signed and unsigned integer types having specified widths"
 description: """
 The stdint library provides signed and unsigned integer types of various fixed
@@ -11,33 +29,7 @@ like maximum and minimum values, infix operators conversion to and from every
 other integer type (including int, float and nativeint), parsing from and
 conversion to readable strings (binary, octal, decimal, hexademical), conversion
 to and from buffers in both big endian and little endian byte order."""
-maintainer: ["Markus W. Weissmann <markus.weissmann@in.tum.de>"]
-authors: [
-  "Andre Nathan <andre@digirati.com.br>"
-  "Jeff Shaw <shawjef3@msu.edu>"
-  "Markus W. Weissmann <markus.weissmann@in.tum.de>"
-  "Florian Pichlmeier <florian.pichlmeier@mytum.de>"
-]
-license: "MIT"
-homepage: "https://github.com/andrenth/ocaml-stdint"
-doc: "https://andrenth.github.io/ocaml-stdint/"
-bug-reports: "https://github.com/andrenth/ocaml-stdint/issues"
 depends: [
   "ocaml" {>= "4.03"}
-  "dune" {>= "1.4"}
+  "dune" {>= "1.10"}
 ]
-build: [
-  ["dune" "subst"] {pinned}
-  [
-    "dune"
-    "build"
-    "-p"
-    name
-    "-j"
-    jobs
-    "@install"
-    "@runtest" {with-test}
-    "@doc" {with-doc}
-  ]
-]
-dev-repo: "git+https://github.com/andrenth/ocaml-stdint.git"

tests/stdint_test.ml

@@ -94,16 +94,20 @@ struct
   let max_str = I.(to_string max_int)
   let max_str_len = String.length max_str
 
-  let str_gen =
+  let integer_str_gen =
     QCheck.(string_gen_of_size (Gen.return max_str_len) Gen.numeral |>
               map_same_type (fun s ->
                 if s <= max_str then s else String.sub s 1 (max_str_len - 1)))
 
+  let str_gen =
+    QCheck.pair integer_str_gen (
+    QCheck.(string_gen_of_size (Gen.return 1) (Gen.oneofl ['k';'!'])))
+
   open I
 
   let tests = [
     test "An integer should be converted from strings correctly"
-      str_gen (fun s ->
+      integer_str_gen (fun s ->
         let str = Str.(replace_first (regexp "^0+") "" s) in
         to_string (of_string str) = str &&
         (try
@@ -112,15 +116,22 @@ struct
         with e -> true)) ;
 
     test "An integer should be converted from signed (+) strings correctly"
-      str_gen (fun s ->
+      integer_str_gen (fun s ->
         let str = Str.(replace_first (regexp "^0+") "" s) in
         to_string (of_string ("+" ^ str)) = str) ;
 
     test "An integer should be converted from signed (-) strings correctly"
-      str_gen (fun s ->
+      integer_str_gen (fun s ->
         let str = "-" ^ Str.(replace_first (regexp "^0+") "" s) in
         min_int = zero ||
         to_string (of_string str) = str) ;
+
+    test "An integer should be converted from strings with right offset correctly"
+      str_gen (fun (i, s) ->
+        let i_str = Str.(replace_first (regexp "^0+") "" i) in
+        let str = i_str ^ s in
+        let s, o = of_substring ~pos:0 str in
+        to_string s = i_str && o = String.length i_str) ;
   ]
 end