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, 4 insertions, 4 deletions

diff --git a/absl/strings/internal/charconv_bigint.cc b/absl/strings/internal/charconv_bigint.cc
index ebf8c079..282b639e 100644
--- a/absl/strings/internal/charconv_bigint.cc
+++ b/absl/strings/internal/charconv_bigint.cc
@@ -242,7 +242,7 @@ int BigUnsigned<max_words>::ReadDigits(const char* begin, const char* end,
       // decimal exponent to compensate.
       --exponent_adjust;
     }
-    int digit = (*begin - '0');
+    char digit = (*begin - '0');
     --significant_digits;
     if (significant_digits == 0 && std::next(begin) != end &&
         (digit == 0 || digit == 5)) {
@@ -255,7 +255,7 @@ int BigUnsigned<max_words>::ReadDigits(const char* begin, const char* end,
       // 500000...000000000001 to correctly round up, rather than to nearest.
       ++digit;
     }
-    queued = 10 * queued + digit;
+    queued = 10 * queued + static_cast<uint32_t>(digit);
     ++digits_queued;
     if (digits_queued == kMaxSmallPowerOfTen) {
       MultiplyBy(kTenToNth[kMaxSmallPowerOfTen]);
@@ -341,8 +341,8 @@ std::string BigUnsigned<max_words>::ToString() const {
   std::string result;
   // Build result in reverse order
   while (copy.size() > 0) {
-    int next_digit = copy.DivMod<10>();
-    result.push_back('0' + next_digit);
+    uint32_t next_digit = copy.DivMod<10>();
+    result.push_back('0' + static_cast<char>(next_digit));
   }
   if (result.empty()) {
     result.push_back('0');