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

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');

absl/strings/internal/charconv_parse.cc

@@ -190,11 +190,11 @@ bool IsDigit<16>(char ch) {
 
 template <>
 unsigned ToDigit<10>(char ch) {
-  return ch - '0';
+  return static_cast<unsigned>(ch - '0');
 }
 template <>
 unsigned ToDigit<16>(char ch) {
-  return kAsciiToInt[static_cast<unsigned char>(ch)];
+  return static_cast<unsigned>(kAsciiToInt[static_cast<unsigned char>(ch)]);
 }
 
 template <>

absl/strings/internal/cord_internal.h

@@ -129,8 +129,9 @@ class RefcountAndFlags {
   }
 
   // Returns the current reference count using acquire semantics.
-  inline int32_t Get() const {
-    return count_.load(std::memory_order_acquire) >> kNumFlags;
+  inline size_t Get() const {
+    return static_cast<size_t>(count_.load(std::memory_order_acquire) >>
+                               kNumFlags);
   }
 
   // Returns whether the atomic integer is 1.

absl/strings/internal/cord_rep_btree.cc

@@ -17,6 +17,7 @@
 #include <cassert>
 #include <cstdint>
 #include <iostream>
+#include <ostream>
 #include <string>
 
 #include "absl/base/attributes.h"
@@ -55,8 +56,10 @@ inline bool exhaustive_validation() {
 // Prints the entire tree structure or 'rep'. External callers should
 // not specify 'depth' and leave it to its default (0) value.
 // Rep may be a CordRepBtree tree, or a SUBSTRING / EXTERNAL / FLAT node.
-void DumpAll(const CordRep* rep, bool include_contents, std::ostream& stream,
-             int depth = 0) {
+void DumpAll(const CordRep* rep,
+             bool include_contents,
+             std::ostream& stream,
+             size_t depth = 0) {
   // Allow for full height trees + substring -> flat / external nodes.
   assert(depth <= CordRepBtree::kMaxDepth + 2);
   std::string sharing = const_cast<CordRep*>(rep)->refcount.IsOne()

absl/strings/internal/cord_rep_btree.h

@@ -95,8 +95,9 @@ class CordRepBtree : public CordRep {
   // local stack variable compared to Cord's current near 400 bytes stack use.
   // The maximum `height` value of a node is then `kMaxDepth - 1` as node height
   // values start with a value of 0 for leaf nodes.
-  static constexpr int kMaxDepth = 12;
-  static constexpr int kMaxHeight = kMaxDepth - 1;
+  static constexpr size_t kMaxDepth = 12;
+  // See comments on height() for why this is an int and not a size_t.
+  static constexpr int kMaxHeight = static_cast<int>(kMaxDepth - 1);
 
   // `Action` defines the action for unwinding changes done at the btree's leaf
   // level that need to be propagated up to the parent node(s). Each operation

absl/strings/internal/cord_rep_btree_navigator.cc

@@ -90,7 +90,7 @@ CordRepBtreeNavigator::Position CordRepBtreeNavigator::Skip(size_t n) {
   // edges that must be skipped.
   while (height > 0) {
     node = edge->btree();
-    index_[height] = index;
+    index_[height] = static_cast<uint8_t>(index);
     node_[--height] = node;
     index = node->begin();
     edge = node->Edge(index);
@@ -101,7 +101,7 @@ CordRepBtreeNavigator::Position CordRepBtreeNavigator::Skip(size_t n) {
       edge = node->Edge(index);
     }
   }
-  index_[0] = index;
+  index_[0] = static_cast<uint8_t>(index);
   return {edge, n};
 }
 
@@ -126,7 +126,7 @@ ReadResult CordRepBtreeNavigator::Read(size_t edge_offset, size_t n) {
   do {
     length -= edge->length;
     while (++index == node->end()) {
-      index_[height] = index;
+      index_[height] = static_cast<uint8_t>(index);
       if (++height > height_) {
         subtree->set_end(subtree_end);
         if (length == 0) return {subtree, 0};
@@ -154,7 +154,7 @@ ReadResult CordRepBtreeNavigator::Read(size_t edge_offset, size_t n) {
   // edges that must be read, adding 'down' nodes to `subtree`.
   while (height > 0) {
     node = edge->btree();
-    index_[height] = index;
+    index_[height] = static_cast<uint8_t>(index);
     node_[--height] = node;
     index = node->begin();
     edge = node->Edge(index);
@@ -178,7 +178,7 @@ ReadResult CordRepBtreeNavigator::Read(size_t edge_offset, size_t n) {
     subtree->edges_[subtree_end++] = Substring(edge, 0, length);
   }
   subtree->set_end(subtree_end);
-  index_[0] = index;
+  index_[0] = static_cast<uint8_t>(index);
   return {tree, length};
 }
 

absl/strings/internal/cordz_info.cc

@@ -35,7 +35,7 @@ namespace cord_internal {
 using ::absl::base_internal::SpinLockHolder;
 
 #ifdef ABSL_INTERNAL_NEED_REDUNDANT_CONSTEXPR_DECL
-constexpr int CordzInfo::kMaxStackDepth;
+constexpr size_t CordzInfo::kMaxStackDepth;
 #endif
 
 ABSL_CONST_INIT CordzInfo::List CordzInfo::global_list_{absl::kConstInit};
@@ -291,7 +291,7 @@ CordzInfo::MethodIdentifier CordzInfo::GetParentMethod(const CordzInfo* src) {
                                                            : src->method_;
 }
 
-int CordzInfo::FillParentStack(const CordzInfo* src, void** stack) {
+size_t CordzInfo::FillParentStack(const CordzInfo* src, void** stack) {
   assert(stack);
   if (src == nullptr) return 0;
   if (src->parent_stack_depth_) {
@@ -302,11 +302,14 @@ int CordzInfo::FillParentStack(const CordzInfo* src, void** stack) {
   return src->stack_depth_;
 }
 
-CordzInfo::CordzInfo(CordRep* rep, const CordzInfo* src,
+CordzInfo::CordzInfo(CordRep* rep,
+                     const CordzInfo* src,
                      MethodIdentifier method)
     : rep_(rep),
-      stack_depth_(absl::GetStackTrace(stack_, /*max_depth=*/kMaxStackDepth,
-                                       /*skip_count=*/1)),
+      stack_depth_(
+          static_cast<size_t>(absl::GetStackTrace(stack_,
+                                                  /*max_depth=*/kMaxStackDepth,
+                                                  /*skip_count=*/1))),
       parent_stack_depth_(FillParentStack(src, parent_stack_)),
       method_(method),
       parent_method_(GetParentMethod(src)),

absl/strings/internal/cordz_info.h

@@ -196,7 +196,7 @@ class ABSL_LOCKABLE CordzInfo : public CordzHandle {
     std::atomic<CordzInfo*> head ABSL_GUARDED_BY(mutex){nullptr};
   };
 
-  static constexpr int kMaxStackDepth = 64;
+  static constexpr size_t kMaxStackDepth = 64;
 
   explicit CordzInfo(CordRep* rep, const CordzInfo* src,
                      MethodIdentifier method);
@@ -216,7 +216,7 @@ class ABSL_LOCKABLE CordzInfo : public CordzHandle {
   // `stack_` depending on `parent_stack_` being empty, returning the size of
   // the parent stack.
   // Returns 0 if `src` is null.
-  static int FillParentStack(const CordzInfo* src, void** stack);
+  static size_t FillParentStack(const CordzInfo* src, void** stack);
 
   void ODRCheck() const {
 #ifndef NDEBUG
@@ -244,8 +244,8 @@ class ABSL_LOCKABLE CordzInfo : public CordzHandle {
 
   void* stack_[kMaxStackDepth];
   void* parent_stack_[kMaxStackDepth];
-  const int stack_depth_;
-  const int parent_stack_depth_;
+  const size_t stack_depth_;
+  const size_t parent_stack_depth_;
   const MethodIdentifier method_;
   const MethodIdentifier parent_method_;
   CordzUpdateTracker update_tracker_;

absl/strings/internal/cordz_statistics.h

@@ -45,12 +45,12 @@ struct CordzStatistics {
   };
 
   // The size of the cord in bytes. This matches the result of Cord::size().
-  int64_t size = 0;
+  size_t size = 0;
 
   // The estimated memory used by the sampled cord. This value matches the
   // value as reported by Cord::EstimatedMemoryUsage().
   // A value of 0 implies the property has not been recorded.
-  int64_t estimated_memory_usage = 0;
+  size_t estimated_memory_usage = 0;
 
   // The effective memory used by the sampled cord, inversely weighted by the
   // effective indegree of each allocated node. This is a representation of the
@@ -59,14 +59,14 @@ struct CordzStatistics {
   // by multiple Cord instances, and for cases where a Cord includes the same
   // node multiple times (either directly or indirectly).
   // A value of 0 implies the property has not been recorded.
-  int64_t estimated_fair_share_memory_usage = 0;
+  size_t estimated_fair_share_memory_usage = 0;
 
   // The total number of nodes referenced by this cord.
   // For ring buffer Cords, this includes the 'ring buffer' node.
   // For btree Cords, this includes all 'CordRepBtree' tree nodes as well as all
   // the substring, flat and external nodes referenced by the tree.
   // A value of 0 implies the property has not been recorded.
-  int64_t node_count = 0;
+  size_t node_count = 0;
 
   // Detailed node counts per type
   NodeCounts node_counts;

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

absl/strings/internal/str_format/arg.cc

@@ -77,7 +77,7 @@ class IntDigits {
       v >>= 3;
     } while (v);
     start_ = p;
-    size_ = storage_ + sizeof(storage_) - p;
+    size_ = static_cast<size_t>(storage_ + sizeof(storage_) - p);
   }
 
   // Print the signed or unsigned integer as decimal.
@@ -86,7 +86,8 @@ class IntDigits {
   void PrintAsDec(T v) {
     static_assert(std::is_integral<T>::value, "");
     start_ = storage_;
-    size_ = numbers_internal::FastIntToBuffer(v, storage_) - storage_;
+    size_ = static_cast<size_t>(numbers_internal::FastIntToBuffer(v, storage_) -
+                                storage_);
   }
 
   void PrintAsDec(int128 v) {
@@ -115,7 +116,7 @@ class IntDigits {
     if (add_neg) {
       *--p = '-';
     }
-    size_ = storage_ + sizeof(storage_) - p;
+    size_ = static_cast<size_t>(storage_ + sizeof(storage_) - p);
     start_ = p;
   }
 
@@ -138,7 +139,7 @@ class IntDigits {
       ++p;
     }
     start_ = p;
-    size_ = storage_ + sizeof(storage_) - p;
+    size_ = static_cast<size_t>(storage_ + sizeof(storage_) - p);
   }
 
   // Print the unsigned integer as hex using uppercase.
@@ -154,7 +155,7 @@ class IntDigits {
       v >>= 4;
     } while (v);
     start_ = p;
-    size_ = storage_ + sizeof(storage_) - p;
+    size_ = static_cast<size_t>(storage_ + sizeof(storage_) - p);
   }
 
   // The printed value including the '-' sign if available.
@@ -208,10 +209,12 @@ string_view SignColumn(bool neg, const FormatConversionSpecImpl conv) {
   return {};
 }
 
-bool ConvertCharImpl(unsigned char v, const FormatConversionSpecImpl conv,
-                     FormatSinkImpl *sink) {
+bool ConvertCharImpl(char v,
+                     const FormatConversionSpecImpl conv,
+                     FormatSinkImpl* sink) {
   size_t fill = 0;
-  if (conv.width() >= 0) fill = conv.width();
+  if (conv.width() >= 0)
+    fill = static_cast<size_t>(conv.width());
   ReducePadding(1, &fill);
   if (!conv.has_left_flag()) sink->Append(fill, ' ');
   sink->Append(1, v);
@@ -225,7 +228,8 @@ bool ConvertIntImplInnerSlow(const IntDigits &as_digits,
   // Print as a sequence of Substrings:
   //   [left_spaces][sign][base_indicator][zeroes][formatted][right_spaces]
   size_t fill = 0;
-  if (conv.width() >= 0) fill = conv.width();
+  if (conv.width() >= 0)
+    fill = static_cast<size_t>(conv.width());
 
   string_view formatted = as_digits.without_neg_or_zero();
   ReducePadding(formatted, &fill);
@@ -236,18 +240,17 @@ bool ConvertIntImplInnerSlow(const IntDigits &as_digits,
   string_view base_indicator = BaseIndicator(as_digits, conv);
   ReducePadding(base_indicator, &fill);
 
-  int precision = conv.precision();
-  bool precision_specified = precision >= 0;
-  if (!precision_specified)
-    precision = 1;
+  bool precision_specified = conv.precision() >= 0;
+  size_t precision =
+      precision_specified ? static_cast<size_t>(conv.precision()) : size_t{1};
 
   if (conv.has_alt_flag() &&
       conv.conversion_char() == FormatConversionCharInternal::o) {
     // From POSIX description of the '#' (alt) flag:
     //   "For o conversion, it increases the precision (if necessary) to
     //   force the first digit of the result to be zero."
     if (formatted.empty() || *formatted.begin() != '0') {
-      int needed = static_cast<int>(formatted.size()) + 1;
+      size_t needed = formatted.size() + 1;
       precision = std::max(precision, needed);
     }
   }
@@ -287,7 +290,7 @@ bool ConvertIntArg(T v, const FormatConversionSpecImpl conv,
   // FormatConversionChar is declared, but not defined.
   switch (static_cast<uint8_t>(conv.conversion_char())) {
     case static_cast<uint8_t>(FormatConversionCharInternal::c):
-      return ConvertCharImpl(static_cast<unsigned char>(v), conv, sink);
+      return ConvertCharImpl(static_cast<char>(v), conv, sink);
 
     case static_cast<uint8_t>(FormatConversionCharInternal::o):
       as_digits.PrintAsOct(static_cast<U>(v));
@@ -375,7 +378,7 @@ FormatConvertImpl(const char *v, const FormatConversionSpecImpl conv,
     len = std::strlen(v);
   } else {
     // If precision is set, we look for the NUL-terminator on the valid range.
-    len = std::find(v, v + conv.precision(), '\0') - v;
+    len = static_cast<size_t>(std::find(v, v + conv.precision(), '\0') - v);
   }
   return {ConvertStringArg(string_view(v, len), conv, sink)};
 }