From: Milan Bulat <milan@peer.inc>
Date: Mon, 29 Jan 2024 03:43:23 +0000 (-0800)
Subject: Make the existence of gz_intmax() unconditional.
X-Git-Tag: 2.2.0~89
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0d2984d0d34e0b4d9426e5d03017b1c4e6795c71;p=thirdparty%2Fzlib-ng.git

Make the existence of gz_intmax() unconditional.

gz_intmax() is noted in zlib.map. This assures it's always there.

madler/zlib#01253ecd7e0a01d311670f2d03c61b82fc12d338
---

diff --git a/gzguts.h b/gzguts.h
index a663844b..dc0ebeb2 100644
--- a/gzguts.h
+++ b/gzguts.h
@@ -139,6 +139,7 @@ void Z_INTERNAL gz_error(gz_state *, int, const char *);
 /* GT_OFF(x), where x is an unsigned value, is true if x > maximum z_off64_t
    value -- needed when comparing unsigned to z_off64_t, which is signed
    (possible z_off64_t types off_t, off64_t, and long are all signed) */
+unsigned Z_INTERNAL gz_intmax(void);
 #define GT_OFF(x) (sizeof(int) == sizeof(z_off64_t) && (x) > INT_MAX)
 
 #endif /* GZGUTS_H_ */
diff --git a/gzlib.c b/gzlib.c
index e613837e..8c7a1dc0 100644
--- a/gzlib.c
+++ b/gzlib.c
@@ -523,3 +523,21 @@ void Z_INTERNAL gz_error(gz_state *state, int err, const char *msg) {
     }
     (void)snprintf(state->msg, strlen(state->path) + strlen(msg) + 3, "%s%s%s", state->path, ": ", msg);
 }
+
+/* portably return maximum value for an int (when limits.h presumed not
+   available) -- we need to do this to cover cases where 2's complement not
+   used, since C standard permits 1's complement and sign-bit representations,
+   otherwise we could just use ((unsigned)-1) >> 1 */
+unsigned Z_INTERNAL gz_intmax(void) {
+#ifdef INT_MAX
+    return INT_MAX;
+#else
+    unsigned p = 1, q;
+    do {
+        q = p;
+        p <<= 1;
+        p++;
+    } while (p > q);
+    return q >> 1;
+#endif
+}