si: change the SI code to a parser

CMakeLists.txt

@@ -606,6 +606,7 @@ if (TESTS)
         rational
         region
         roots/bisection
+        si
         signal
         singleton
         stream

si.cpp

@@ -3,16 +3,51 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
- * Copyright 2011 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2019 Danny Robson <danny@nerdcruft.net>
  */
 
 #include "si.hpp"
 
-uintmax_t to_KiB (uintmax_t bytes) { return bytes >> 10; }
+#include "std.hpp"
-uintmax_t to_MiB (uintmax_t bytes) { return bytes >> 20; }
+#include "parse.hpp"
-uintmax_t to_GiB (uintmax_t bytes) { return bytes >> 30; }
 
-uintmax_t from_KiB (uintmax_t bytes) { return bytes << 10; }
+#include <cruft/util/preprocessor.hpp>
-uintmax_t from_MiB (uintmax_t bytes) { return bytes << 20; }
-uintmax_t from_GiB (uintmax_t bytes) { return bytes << 30; }
 
+#include <charconv>
+
+
+///////////////////////////////////////////////////////////////////////////////
+template <typename ValueT>
+cruft::expected<ValueT, std::errc>
+cruft::si::parse (cruft::view<char const*> const src)
+{
+    auto remain = src;
+    ValueT dst = cruft::parse<ValueT> (remain);
+
+    switch (remain.size ()) {
+    case 0:
+        return dst;
+
+    case 1:
+        switch (remain[0]) {
+            case 'K': case 'k': return dst * 1024;
+            case 'M': case 'm': return dst * 1024 * 1024;
+            case 'G': case 'g': return dst * 1024 * 1024 * 1024;
+            case 'T': case 't': return dst * 1024 * 1024 * 1024 * 1024;
+        }
+
+    default:
+        return cruft::unexpected (std::errc::invalid_argument);
+    }
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+#define INSTANTIATE(KLASS) template cruft::expected<KLASS,std::errc> cruft::si::parse (cruft::view<char const*>);
+
+
+MAP0 (INSTANTIATE,
+    u16, u32, u64,
+    i16, i32, i64,
+         f32, f64
+)

si.hpp

@@ -3,20 +3,19 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
- * Copyright 2011 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2019 Danny Robson <danny@nerdcruft.net>
  */
 
-#ifndef __UTIL_SI_HPP
+#pragma once
-#define __UTIL_SI_HPP
 
-#include <cstdint>
+#include "expected.hpp"
+#include "view.hpp"
 
-uintmax_t to_KiB (uintmax_t bytes);
+#include <system_error>
-uintmax_t to_MiB (uintmax_t bytes);
-uintmax_t to_GiB (uintmax_t bytes);
 
-uintmax_t from_KiB (uintmax_t bytes);
+namespace cruft::si {
-uintmax_t from_MiB (uintmax_t bytes);
+    template <typename ValueT>
-uintmax_t from_GiB (uintmax_t bytes);
+    expected<ValueT, std::errc>
+    parse (cruft::view<char const*>);
+}
 
-#endif

test/si.cpp

@@ -0,0 +1,33 @@
+#include "tap.hpp"
+#include "si.hpp"
+
+
+int main ()
+{
+    cruft::TAP::logger tap;
+
+    struct {
+        char const *str;
+        std::size_t val;
+    } const TESTS[] = {
+        {  "0",                             0u },
+        {  "1",                             1u },
+        { "1K",                          1024u },
+        { "1M",                  1024u * 1024u },
+        { "1G" ,         1024u * 1024u * 1024u },
+        { "1T", 1024ul * 1024u * 1024u * 1024u },
+        { "3M",             3u * 1024u * 1024u },
+        { "3k",                     3u * 1024u },
+    };
+
+    for (auto const &t: TESTS) {
+        auto res = cruft::si::parse<std::size_t> (t.str);
+        if (!res) {
+            tap.fail ("SI parsing %!", t.str);
+        } else {
+            tap.expect_eq (t.val, *res, "SI parsing '%!'", t.str);
+        }
+    }
+
+    return tap.status ();
+}