From c610b1d62deb15edca4779c72dc0a459af88877d Mon Sep 17 00:00:00 2001
From: Jean Pierre Cimalando <jp-dev@inbox.ru>
Date: Sun, 21 Mar 2021 12:33:18 +0100
Subject: [PATCH] Move the value reading helpers out of Opcode

---
 src/sfizz/Opcode.cpp          | 46 ++++++------------
 src/sfizz/StringViewHelpers.h | 88 ++++++++++++++++++++++++++++++++++-
 2 files changed, 102 insertions(+), 32 deletions(-)

diff --git a/src/sfizz/Opcode.cpp b/src/sfizz/Opcode.cpp
index 406032dc..0f1adfb2 100644
--- a/src/sfizz/Opcode.cpp
+++ b/src/sfizz/Opcode.cpp
@@ -147,21 +147,20 @@ absl::optional<T> readInt_(OpcodeSpec<T> spec, absl::string_view v)
 {
     using Limits = std::numeric_limits<T>;
 
-    size_t numberEnd = 0;
-
-    if (numberEnd < v.size() && (v[numberEnd] == '+' || v[numberEnd] == '-'))
-        ++numberEnd;
-
-    while (numberEnd < v.size() && absl::ascii_isdigit(v[numberEnd]))
-        ++numberEnd;
-
-    if (numberEnd == 0 && (spec.flags & kCanBeNote))
-        return readNoteValue(v);
-
-    v = v.substr(0, numberEnd);
-
     int64_t returnedValue;
-    if (!absl::SimpleAtoi(v, &returnedValue))
+    bool readValueSuccess = false;
+
+    if (readLeadingInt(v, &returnedValue))
+        readValueSuccess = true;
+
+    if (!readValueSuccess && (spec.flags & kCanBeNote)) {
+        if (absl::optional<uint8_t> noteValue = readNoteValue(v)) {
+            returnedValue = *noteValue;
+            readValueSuccess = true;
+        }
+    }
+
+    if (!readValueSuccess)
         return absl::nullopt;
 
     if (returnedValue > static_cast<int64_t>(spec.bounds.getEnd())) {
@@ -201,23 +200,8 @@ INSTANTIATE_FOR_INTEGRAL(int64_t)
 template <typename T>
 absl::optional<T> readFloat_(OpcodeSpec<T> spec, absl::string_view v)
 {
-    size_t numberEnd = 0;
-
-    if (numberEnd < v.size() && (v[numberEnd] == '+' || v[numberEnd] == '-'))
-        ++numberEnd;
-    while (numberEnd < v.size() && absl::ascii_isdigit(v[numberEnd]))
-        ++numberEnd;
-
-    if (numberEnd < v.size() && v[numberEnd] == '.') {
-        ++numberEnd;
-        while (numberEnd < v.size() && absl::ascii_isdigit(v[numberEnd]))
-            ++numberEnd;
-    }
-
-    v = v.substr(0, numberEnd);
-
-    float returnedValue;
-    if (!absl::SimpleAtof(v, &returnedValue))
+    T returnedValue;
+    if (!readLeadingFloat(v, &returnedValue))
         return absl::nullopt;
 
     if (spec.flags & kWrapPhase)
diff --git a/src/sfizz/StringViewHelpers.h b/src/sfizz/StringViewHelpers.h
index 11026f34..b865f8a3 100644
--- a/src/sfizz/StringViewHelpers.h
+++ b/src/sfizz/StringViewHelpers.h
@@ -11,7 +11,9 @@
  */
 
 #pragma once
-#include "absl/strings/string_view.h"
+#include <absl/strings/ascii.h>
+#include <absl/strings/numbers.h>
+#include <absl/strings/string_view.h>
 #include <cstdint>
 
 /**
@@ -101,3 +103,87 @@ uint64_t hashNumber(Int i, uint64_t h = Fnv1aBasis)
                   "The hashed object must be of arithmetic type");
     return hash(absl::string_view(reinterpret_cast<const char*>(&i), sizeof(i)), h);
 }
+
+/**
+ * @brief Read a floating-point number from a string non-permissively
+ *
+ * @param[in]  input  a string to read from
+ * @param[out] result address of the value where the result is stored
+ * @return whether the conversion is successful
+ */
+template <class F>
+bool readFloat(absl::string_view input, F* result);
+
+template <>
+inline bool readFloat<float>(absl::string_view input, float* result)
+{
+    return absl::SimpleAtof(input, result);
+}
+
+template <>
+inline bool readFloat<double>(absl::string_view input, double* result)
+{
+    return absl::SimpleAtod(input, result);
+}
+
+/**
+ * @brief Read an integer from a string, permitting extra trailing characters.
+ *
+ * @param[in]  input  a string to read from
+ * @param[out] result address of the value where the result is stored
+ * @param[out] rest   optional address which receives the unprocessed tail of the input
+ * @return whether the conversion is successful
+ */
+template <class I>
+bool readLeadingInt(absl::string_view input, I* result, absl::string_view* rest = nullptr)
+{
+    size_t numberEnd = 0;
+
+    if (numberEnd < input.size() && (input[numberEnd] == '+' || input[numberEnd] == '-'))
+        ++numberEnd;
+
+    while (numberEnd < input.size() && absl::ascii_isdigit(input[numberEnd]))
+        ++numberEnd;
+
+    if (!absl::SimpleAtoi(input.substr(0, numberEnd), result))
+        return false;
+
+    if (rest)
+        *rest = input.substr(numberEnd);
+
+    return true;
+}
+
+/**
+ * @brief Read a floating-point number from a string, permitting extra
+ * trailing characters.
+ *
+ * @param[in]  input  a string to read from
+ * @param[out] result address of the value where the result is stored
+ * @param[out] rest   optional address which receives the unprocessed tail of the input
+ * @return whether the conversion is successful
+ */
+template <class F>
+bool readLeadingFloat(absl::string_view input, F* result, absl::string_view* rest = nullptr)
+{
+    size_t numberEnd = 0;
+
+    if (numberEnd < input.size() && (input[numberEnd] == '+' || input[numberEnd] == '-'))
+        ++numberEnd;
+    while (numberEnd < input.size() && absl::ascii_isdigit(input[numberEnd]))
+        ++numberEnd;
+
+    if (numberEnd < input.size() && input[numberEnd] == '.') {
+        ++numberEnd;
+        while (numberEnd < input.size() && absl::ascii_isdigit(input[numberEnd]))
+            ++numberEnd;
+    }
+
+    if (!readFloat(input.substr(0, numberEnd), result))
+        return false;
+
+    if (rest)
+        *rest = input.substr(numberEnd);
+
+    return true;
+}