Fix "unsafe narrowing" warnings in absl, 5/n.

Addresses failures with the following, in some files:
-Wshorten-64-to-32
-Wimplicit-int-conversion
-Wsign-compare
-Wsign-conversion
-Wtautological-unsigned-zero-compare

(This specific CL focuses on .cc files in strings/internal/.)

Bug: chromium:1292951
PiperOrigin-RevId: 468215101
Change-Id: I07fa487bcf2cf62d403489c3be7a5997cdef8987

1 files changed, 9 insertions, 6 deletions

diff --git a/absl/strings/internal/memutil.cc b/absl/strings/internal/memutil.cc
index 2519c688..44996a75 100644
--- a/absl/strings/internal/memutil.cc
+++ b/absl/strings/internal/memutil.cc
@@ -54,10 +54,11 @@ size_t memspn(const char* s, size_t slen, const char* accept) {
 
 cont:
   c = *p++;
-  if (slen-- == 0) return p - 1 - s;
+  if (slen-- == 0)
+    return static_cast<size_t>(p - 1 - s);
   for (spanp = accept; (sc = *spanp++) != '\0';)
     if (sc == c) goto cont;
-  return p - 1 - s;
+  return static_cast<size_t>(p - 1 - s);
 }
 
 size_t memcspn(const char* s, size_t slen, const char* reject) {
@@ -68,9 +69,10 @@ size_t memcspn(const char* s, size_t slen, const char* reject) {
   while (slen-- != 0) {
     c = *p++;
     for (spanp = reject; (sc = *spanp++) != '\0';)
-      if (sc == c) return p - 1 - s;
+      if (sc == c)
+        return static_cast<size_t>(p - 1 - s);
   }
-  return p - s;
+  return static_cast<size_t>(p - s);
 }
 
 char* mempbrk(const char* s, size_t slen, const char* accept) {
@@ -97,8 +99,9 @@ const char* memmatch(const char* phaystack, size_t haylen, const char* pneedle,
   const char* hayend = phaystack + haylen - neelen + 1;
   // A static cast is used here to work around the fact that memchr returns
   // a void* on Posix-compliant systems and const void* on Windows.
-  while ((match = static_cast<const char*>(
-              memchr(phaystack, pneedle[0], hayend - phaystack)))) {
+  while (
+      (match = static_cast<const char*>(memchr(
+           phaystack, pneedle[0], static_cast<size_t>(hayend - phaystack))))) {
     if (memcmp(match, pneedle, neelen) == 0)
       return match;
     else