From e0dae1215e8e3b8855ea465eb65af71730b67d3b Mon Sep 17 00:00:00 2001
From: "Chris (ChrisJr404)" <11917633+ChrisJr404@users.noreply.github.com>
Date: Wed, 26 Aug 2026 19:02:31 -0400
Subject: [PATCH] Define UTF8PROC_SSIZE_MAX for the maximum utf8proc_ssize_t
 value

---
 test/misc.c | 12 ++++++++++++
 utf8proc.h  | 12 ++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/test/misc.c b/test/misc.c
index 7ea2ebc..6bd6ade 100644
--- a/test/misc.c
+++ b/test/misc.c
@@ -44,11 +44,23 @@ static void issue317(void) /* #317 */
     }
 }
 
+static void issue103(void) /* #103 */
+{
+    /* UTF8PROC_SSIZE_MAX should be the largest value of utf8proc_ssize_t.
+       Since utf8proc_ssize_t is a two's-complement signed type the same
+       size as utf8proc_size_t, that value is all bits set shifted right by one. */
+    utf8proc_ssize_t computed = (utf8proc_ssize_t)((utf8proc_size_t)-1 >> 1);
+    check(UTF8PROC_SSIZE_MAX == computed,
+          "UTF8PROC_SSIZE_MAX (%lld) != computed max (%lld)",
+          (long long)UTF8PROC_SSIZE_MAX, (long long)computed);
+}
+
 int main(void)
 {
     issue128();
     issue102();
     issue317();
+    issue103();
 #ifdef UNICODE_VERSION
     printf("Unicode version: Makefile has %s, has API %s\n", UNICODE_VERSION, utf8proc_unicode_version());
     check(!strcmp(UNICODE_VERSION, utf8proc_unicode_version()), "utf8proc_unicode_version mismatch");
diff --git a/utf8proc.h b/utf8proc.h
index 83bb5f6..34abc4c 100644
--- a/utf8proc.h
+++ b/utf8proc.h
@@ -120,6 +120,18 @@ typedef bool utf8proc_bool;
 #endif
 #include <limits.h>
 
+/** The maximum value representable by the ::utf8proc_ssize_t type, useful
+ *  for checked conversions from ::utf8proc_size_t (or size_t) lengths. */
+#if defined(_MSC_VER) && _MSC_VER < 1800
+#  ifdef _WIN64
+#    define UTF8PROC_SSIZE_MAX _I64_MAX
+#  else
+#    define UTF8PROC_SSIZE_MAX INT_MAX
+#  endif
+#else
+#  define UTF8PROC_SSIZE_MAX PTRDIFF_MAX
+#endif
+
 #ifdef UTF8PROC_STATIC
 #  ifndef UTF8PROC_DLLEXPORT
 #    define UTF8PROC_DLLEXPORT