From 9163e8842f7cd775ac5c84b76148433c77cb2c82 Mon Sep 17 00:00:00 2001
From: Daniel Kroening <dkr@amazon.com>
Date: Mon, 11 May 2026 22:05:25 -0700
Subject: [PATCH] use std::string_view for safe_string2int

The variants of safe_string2int now accept an std::string_view, instead of
an std::string, in the hope of avoiding copies.
---
 src/util/string2int.cpp | 10 +++++-----
 src/util/string2int.h   | 25 +++++++++++++------------
 2 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/src/util/string2int.cpp b/src/util/string2int.cpp
index 02a90120a52..f2b4e372a61 100644
--- a/src/util/string2int.cpp
+++ b/src/util/string2int.cpp
@@ -13,14 +13,14 @@ Author: Michael Tautschnig, michael.tautschnig@cs.ox.ac.uk
 
 #include "invariant.h"
 
-unsigned safe_string2unsigned(const std::string &str, int base)
+unsigned safe_string2unsigned(const std::string_view &str, int base)
 {
   auto converted = string2optional<unsigned>(str, base);
   CHECK_RETURN(converted.has_value());
   return *converted;
 }
 
-std::size_t safe_string2size_t(const std::string &str, int base)
+std::size_t safe_string2size_t(const std::string_view &str, int base)
 {
   auto converted = string2optional<std::size_t>(str, base);
   CHECK_RETURN(converted.has_value());
@@ -56,19 +56,19 @@ unsigned long long int unsafe_string2unsignedlonglong(
   return *string2optional<unsigned long long>(str, base);
 }
 
-std::optional<int> string2optional_int(const std::string &str, int base)
+std::optional<int> string2optional_int(const std::string_view &str, int base)
 {
   return string2optional<int>(str, base);
 }
 
 std::optional<unsigned>
-string2optional_unsigned(const std::string &str, int base)
+string2optional_unsigned(const std::string_view &str, int base)
 {
   return string2optional<unsigned>(str, base);
 }
 
 std::optional<std::size_t>
-string2optional_size_t(const std::string &str, int base)
+string2optional_size_t(const std::string_view &str, int base)
 {
   return string2optional<std::size_t>(str, base);
 }
diff --git a/src/util/string2int.h b/src/util/string2int.h
index f158323be52..bde6c318a94 100644
--- a/src/util/string2int.h
+++ b/src/util/string2int.h
@@ -15,44 +15,45 @@ Author: Michael Tautschnig, michael.tautschnig@cs.ox.ac.uk
 #include <charconv>
 #include <optional>
 #include <string>
+#include <string_view>
 #include <type_traits>
 
 // These check that the string is indeed a valid number,
 // and fail an assertion otherwise.
 // We use those for data types that C++11's std::stoi etc. do not
 // cover.
-unsigned safe_string2unsigned(const std::string &str, int base=10);
-std::size_t safe_string2size_t(const std::string &str, int base=10);
+unsigned safe_string2unsigned(const std::string_view &, int base = 10);
+std::size_t safe_string2size_t(const std::string_view &, int base = 10);
 
 // The below mimic C's atoi/atol: any errors are silently ignored.
 // They are meant to replace atoi/atol.
-int unsafe_string2int(const std::string &str, int base=10);
-unsigned unsafe_string2unsigned(const std::string &str, int base=10);
-std::size_t unsafe_string2size_t(const std::string &str, int base=10);
+int unsafe_string2int(const std::string &, int base = 10);
+unsigned unsafe_string2unsigned(const std::string &, int base = 10);
+std::size_t unsafe_string2size_t(const std::string &, int base = 10);
 
 // Same for atoll
-long long int unsafe_string2signedlonglong(const std::string &str, int base=10);
-long long unsigned int unsafe_string2unsignedlonglong(
-  const std::string &str, int base=10);
+long long int unsafe_string2signedlonglong(const std::string &, int base = 10);
+long long unsigned int
+unsafe_string2unsignedlonglong(const std::string_view &, int base = 10);
 
 // if we had a `resultt` á la Boost.Outcome (https://ned14.github.io/outcome/)
 // we could also return the reason why the conversion failed
 
 /// Convert string to integer as per stoi, but return nullopt when
 /// stoi would throw
-std::optional<int> string2optional_int(const std::string &, int base = 10);
+std::optional<int> string2optional_int(const std::string_view &, int base = 10);
 
 /// Convert string to unsigned similar to the stoul or stoull functions,
 /// return nullopt when the conversion fails.
 /// Note: Unlike stoul or stoull negative inputs are disallowed
 std::optional<unsigned>
-string2optional_unsigned(const std::string &, int base = 10);
+string2optional_unsigned(const std::string_view &, int base = 10);
 
 /// Convert string to size_t similar to the stoul or stoull functions,
 /// return nullopt when the conversion fails.
 /// Note: Unlike stoul or stoull negative inputs are disallowed
 std::optional<std::size_t>
-string2optional_size_t(const std::string &, int base = 10);
+string2optional_size_t(const std::string_view &, int base = 10);
 
 /// Convert a string to an integer, given the base of the representation,
 /// works with signed and unsigned integer types,
@@ -62,7 +63,7 @@ string2optional_size_t(const std::string &, int base = 10);
 /// rejects any trailing non-numerical suffix.
 /// A prefix such as 0, 0x, 0X to change base is _not_ supported.
 template <typename T>
-std::optional<T> string2optional(const std::string &str, int base = 10)
+std::optional<T> string2optional(const std::string_view &str, int base = 10)
 {
   PRECONDITION(base == 2 || base == 8 || base == 10 || base == 16);