Fix "unsafe narrowing" warnings in absl, 2/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 dirs a-h.)

Bug: chromium:1292951
PiperOrigin-RevId: 464541951
Change-Id: If23b63ccea8e9b730159ff1c7288e9300a40b6bd

5 files changed, 16 insertions, 12 deletions

diff --git a/absl/base/internal/low_level_alloc.cc b/absl/base/internal/low_level_alloc.cc
index 229ab916..aa6c3c3c 100644
--- a/absl/base/internal/low_level_alloc.cc
+++ b/absl/base/internal/low_level_alloc.cc
@@ -364,7 +364,7 @@ LowLevelAlloc::Arena::Arena(uint32_t flags_value)
 }
 
 // L < meta_data_arena->mu
-LowLevelAlloc::Arena *LowLevelAlloc::NewArena(int32_t flags) {
+LowLevelAlloc::Arena *LowLevelAlloc::NewArena(uint32_t flags) {
   Arena *meta_data_arena = DefaultArena();
 #ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
   if ((flags & LowLevelAlloc::kAsyncSignalSafe) != 0) {
diff --git a/absl/base/internal/low_level_alloc.h b/absl/base/internal/low_level_alloc.h
index db91951c..eabb14a9 100644
--- a/absl/base/internal/low_level_alloc.h
+++ b/absl/base/internal/low_level_alloc.h
@@ -103,7 +103,7 @@ class LowLevelAlloc {
   // the provided flags.  For example, the call NewArena(kAsyncSignalSafe)
   // is itself async-signal-safe, as well as generatating an arena that provides
   // async-signal-safe Alloc/Free.
-  static Arena *NewArena(int32_t flags);
+  static Arena *NewArena(uint32_t flags);
 
   // Destroys an arena allocated by NewArena and returns true,
   // provided no allocated blocks remain in the arena.
diff --git a/absl/base/internal/raw_logging.cc b/absl/base/internal/raw_logging.cc
index a5d9fa59..6273e847 100644
--- a/absl/base/internal/raw_logging.cc
+++ b/absl/base/internal/raw_logging.cc
@@ -89,12 +89,14 @@ constexpr char kTruncated[] = " ... (message truncated)\n";
 bool VADoRawLog(char** buf, int* size, const char* format, va_list ap)
     ABSL_PRINTF_ATTRIBUTE(3, 0);
 bool VADoRawLog(char** buf, int* size, const char* format, va_list ap) {
-  int n = vsnprintf(*buf, *size, format, ap);
+  if (*size < 0)
+    return false;
+  int n = vsnprintf(*buf, static_cast<size_t>(*size), format, ap);
   bool result = true;
   if (n < 0 || n > *size) {
     result = false;
     if (static_cast<size_t>(*size) > sizeof(kTruncated)) {
-      n = *size - sizeof(kTruncated);  // room for truncation message
+      n = *size - static_cast<int>(sizeof(kTruncated));
     } else {
       n = 0;  // no room for truncation message
     }
@@ -116,9 +118,11 @@ constexpr int kLogBufSize = 3000;
 bool DoRawLog(char** buf, int* size, const char* format, ...)
     ABSL_PRINTF_ATTRIBUTE(3, 4);
 bool DoRawLog(char** buf, int* size, const char* format, ...) {
+  if (*size < 0)
+    return false;
   va_list ap;
   va_start(ap, format);
-  int n = vsnprintf(*buf, *size, format, ap);
+  int n = vsnprintf(*buf, static_cast<size_t>(*size), format, ap);
   va_end(ap);
   if (n < 0 || n > *size) return false;
   *size -= n;
@@ -206,7 +210,7 @@ void AsyncSignalSafeWriteToStderr(const char* s, size_t len) {
 #elif defined(ABSL_HAVE_POSIX_WRITE)
   write(STDERR_FILENO, s, len);
 #elif defined(ABSL_HAVE_RAW_IO)
-  _write(/* stderr */ 2, s, len);
+  _write(/* stderr */ 2, s, static_cast<unsigned>(len));
 #else
   // stderr logging unsupported on this platform
   (void) s;
diff --git a/absl/base/internal/strerror.cc b/absl/base/internal/strerror.cc
index 0d6226fd..de91c05e 100644
--- a/absl/base/internal/strerror.cc
+++ b/absl/base/internal/strerror.cc
@@ -66,8 +66,8 @@ constexpr int kSysNerr = 135;
 
 std::array<std::string, kSysNerr>* NewStrErrorTable() {
   auto* table = new std::array<std::string, kSysNerr>;
-  for (int i = 0; i < static_cast<int>(table->size()); ++i) {
-    (*table)[i] = StrErrorInternal(i);
+  for (size_t i = 0; i < table->size(); ++i) {
+    (*table)[i] = StrErrorInternal(static_cast<int>(i));
   }
   return table;
 }
@@ -77,8 +77,8 @@ std::array<std::string, kSysNerr>* NewStrErrorTable() {
 std::string StrError(int errnum) {
   absl::base_internal::ErrnoSaver errno_saver;
   static const auto* table = NewStrErrorTable();
-  if (errnum >= 0 && errnum < static_cast<int>(table->size())) {
-    return (*table)[errnum];
+  if (errnum >= 0 && static_cast<size_t>(errnum) < table->size()) {
+    return (*table)[static_cast<size_t>(errnum)];
   }
   return StrErrorInternal(errnum);
 }
diff --git a/absl/base/internal/sysinfo.cc b/absl/base/internal/sysinfo.cc
index c8366df1..a3e08b93 100644
--- a/absl/base/internal/sysinfo.cc
+++ b/absl/base/internal/sysinfo.cc
@@ -117,7 +117,7 @@ int Win32NumCPUs() {
     }
   }
   free(info);
-  return logicalProcessorCount;
+  return static_cast<int>(logicalProcessorCount);
 }
 
 #endif
@@ -128,7 +128,7 @@ static int GetNumCPUs() {
 #if defined(__myriad2__)
   return 1;
 #elif defined(_WIN32)
-  const unsigned hardware_concurrency = Win32NumCPUs();
+  const int hardware_concurrency = Win32NumCPUs();
   return hardware_concurrency ? hardware_concurrency : 1;
 #elif defined(_AIX)
   return sysconf(_SC_NPROCESSORS_ONLN);