Merge pull request #8125 from vaci/vaci/hash_to_string_copy

Avoid a string copy during Hash::to_string

2 files changed, 8 insertions, 7 deletions

diff --git a/src/libutil/hash.cc b/src/libutil/hash.cc
index d2fd0c15a..5735e4715 100644
--- a/src/libutil/hash.cc
+++ b/src/libutil/hash.cc
@@ -71,12 +71,13 @@ const std::string base16Chars = "0123456789abcdef";
 
 static std::string printHash16(const Hash & hash)
 {
-    char buf[hash.hashSize * 2];
+    std::string buf;
+    buf.reserve(hash.hashSize * 2);
     for (unsigned int i = 0; i < hash.hashSize; i++) {
-        buf[i * 2] = base16Chars[hash.hash[i] >> 4];
-        buf[i * 2 + 1] = base16Chars[hash.hash[i] & 0x0f];
+        buf.push_back(base16Chars[hash.hash[i] >> 4]);
+        buf.push_back(base16Chars[hash.hash[i] & 0x0f]);
     }
-    return std::string(buf, hash.hashSize * 2);
+    return buf;
 }
 
 
@@ -130,7 +131,7 @@ std::string Hash::to_string(Base base, bool includeType) const
         break;
     case Base64:
     case SRI:
-        s += base64Encode(std::string((const char *) hash, hashSize));
+        s += base64Encode(std::string_view((const char *) hash, hashSize));
         break;
     }
     return s;
@@ -403,7 +404,7 @@ HashType parseHashType(std::string_view s)
         throw UsageError("unknown hash algorithm '%1%'", s);
 }
 
-std::string printHashType(HashType ht)
+std::string_view printHashType(HashType ht)
 {
     switch (ht) {
     case htMD5: return "md5";
diff --git a/src/libutil/hash.hh b/src/libutil/hash.hh
index 00f70a572..38d09646e 100644
--- a/src/libutil/hash.hh
+++ b/src/libutil/hash.hh
@@ -133,7 +133,7 @@ HashType parseHashType(std::string_view s);
 std::optional<HashType> parseHashTypeOpt(std::string_view s);
 
 /* And the reverse. */
-std::string printHashType(HashType ht);
+std::string_view printHashType(HashType ht);
 
 
 union Ctx;