Remove two_ASCII_digits and replace with a scalar algorithm

PiperOrigin-RevId: 539900072
Change-Id: I675386e3184f6f5ab70b851add970c91d1dde9c5

4 files changed, 21 insertions, 34 deletions

diff --git a/absl/log/internal/log_format.cc b/absl/log/internal/log_format.cc
index 0dcbc795..23cef88a 100644
--- a/absl/log/internal/log_format.cc
+++ b/absl/log/internal/log_format.cc
@@ -113,27 +113,29 @@ size_t FormatBoundedFields(absl::LogSeverity severity, absl::Time timestamp,
   char* p = buf.data();
   *p++ = absl::LogSeverityName(severity)[0];
   const absl::TimeZone::CivilInfo ci = tz->At(timestamp);
-  absl::numbers_internal::PutTwoDigits(static_cast<size_t>(ci.cs.month()), p);
+  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(ci.cs.month()), p);
   p += 2;
-  absl::numbers_internal::PutTwoDigits(static_cast<size_t>(ci.cs.day()), p);
+  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(ci.cs.day()), p);
   p += 2;
   *p++ = ' ';
-  absl::numbers_internal::PutTwoDigits(static_cast<size_t>(ci.cs.hour()), p);
+  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(ci.cs.hour()), p);
   p += 2;
   *p++ = ':';
-  absl::numbers_internal::PutTwoDigits(static_cast<size_t>(ci.cs.minute()), p);
+  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(ci.cs.minute()),
+                                       p);
   p += 2;
   *p++ = ':';
-  absl::numbers_internal::PutTwoDigits(static_cast<size_t>(ci.cs.second()), p);
+  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(ci.cs.second()),
+                                       p);
   p += 2;
   *p++ = '.';
   const int64_t usecs = absl::ToInt64Microseconds(ci.subsecond);
-  absl::numbers_internal::PutTwoDigits(static_cast<size_t>(usecs / 10000), p);
+  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(usecs / 10000), p);
   p += 2;
-  absl::numbers_internal::PutTwoDigits(static_cast<size_t>(usecs / 100 % 100),
+  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(usecs / 100 % 100),
                                        p);
   p += 2;
-  absl::numbers_internal::PutTwoDigits(static_cast<size_t>(usecs % 100), p);
+  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(usecs % 100), p);
   p += 2;
   *p++ = ' ';
   PutLeadingWhitespace(tid, p);
diff --git a/absl/strings/internal/str_format/arg.cc b/absl/strings/internal/str_format/arg.cc
index 7f4057f9..c0a9a28e 100644
--- a/absl/strings/internal/str_format/arg.cc
+++ b/absl/strings/internal/str_format/arg.cc
@@ -106,7 +106,7 @@ class IntDigits {
     char *p = storage_ + sizeof(storage_);
     do {
       p -= 2;
-      numbers_internal::PutTwoDigits(static_cast<size_t>(v % 100), p);
+      numbers_internal::PutTwoDigits(static_cast<uint32_t>(v % 100), p);
       v /= 100;
     } while (v);
     if (p[0] == '0') {
diff --git a/absl/strings/numbers.cc b/absl/strings/numbers.cc
index 7dc89224..c43c6bcc 100644
--- a/absl/strings/numbers.cc
+++ b/absl/strings/numbers.cc
@@ -242,6 +242,15 @@ inline char* EncodeFullU32(uint32_t n, char* out_str) {
 
 }  // namespace
 
+void numbers_internal::PutTwoDigits(uint32_t i, char* buf) {
+  assert(i < 100);
+  uint32_t base = kTwoZeroBytes;
+  uint32_t div10 = (i * kDivisionBy10Mul) / kDivisionBy10Div;
+  uint32_t mod10 = i - 10u * div10;
+  base += div10 + (mod10 << 8);
+  little_endian::Store16(buf, static_cast<uint16_t>(base));
+}
+
 char* numbers_internal::FastIntToBuffer(uint32_t n, char* out_str) {
   if (n < 100) {
     out_str = EncodeHundred(n, out_str);
@@ -1090,25 +1099,6 @@ ABSL_CONST_INIT ABSL_DLL const char kHexTable[513] =
     "e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
     "f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff";
 
-ABSL_CONST_INIT ABSL_DLL const char two_ASCII_digits[100][2] = {
-    {'0', '0'}, {'0', '1'}, {'0', '2'}, {'0', '3'}, {'0', '4'}, {'0', '5'},
-    {'0', '6'}, {'0', '7'}, {'0', '8'}, {'0', '9'}, {'1', '0'}, {'1', '1'},
-    {'1', '2'}, {'1', '3'}, {'1', '4'}, {'1', '5'}, {'1', '6'}, {'1', '7'},
-    {'1', '8'}, {'1', '9'}, {'2', '0'}, {'2', '1'}, {'2', '2'}, {'2', '3'},
-    {'2', '4'}, {'2', '5'}, {'2', '6'}, {'2', '7'}, {'2', '8'}, {'2', '9'},
-    {'3', '0'}, {'3', '1'}, {'3', '2'}, {'3', '3'}, {'3', '4'}, {'3', '5'},
-    {'3', '6'}, {'3', '7'}, {'3', '8'}, {'3', '9'}, {'4', '0'}, {'4', '1'},
-    {'4', '2'}, {'4', '3'}, {'4', '4'}, {'4', '5'}, {'4', '6'}, {'4', '7'},
-    {'4', '8'}, {'4', '9'}, {'5', '0'}, {'5', '1'}, {'5', '2'}, {'5', '3'},
-    {'5', '4'}, {'5', '5'}, {'5', '6'}, {'5', '7'}, {'5', '8'}, {'5', '9'},
-    {'6', '0'}, {'6', '1'}, {'6', '2'}, {'6', '3'}, {'6', '4'}, {'6', '5'},
-    {'6', '6'}, {'6', '7'}, {'6', '8'}, {'6', '9'}, {'7', '0'}, {'7', '1'},
-    {'7', '2'}, {'7', '3'}, {'7', '4'}, {'7', '5'}, {'7', '6'}, {'7', '7'},
-    {'7', '8'}, {'7', '9'}, {'8', '0'}, {'8', '1'}, {'8', '2'}, {'8', '3'},
-    {'8', '4'}, {'8', '5'}, {'8', '6'}, {'8', '7'}, {'8', '8'}, {'8', '9'},
-    {'9', '0'}, {'9', '1'}, {'9', '2'}, {'9', '3'}, {'9', '4'}, {'9', '5'},
-    {'9', '6'}, {'9', '7'}, {'9', '8'}, {'9', '9'}};
-
 bool safe_strto32_base(absl::string_view text, int32_t* value, int base) {
   return safe_int_internal<int32_t>(text, value, base);
 }
diff --git a/absl/strings/numbers.h b/absl/strings/numbers.h
index 86c84ed3..d7630cef 100644
--- a/absl/strings/numbers.h
+++ b/absl/strings/numbers.h
@@ -125,8 +125,6 @@ namespace numbers_internal {
 ABSL_DLL extern const char kHexChar[17];  // 0123456789abcdef
 ABSL_DLL extern const char
     kHexTable[513];  // 000102030405060708090a0b0c0d0e0f1011...
-ABSL_DLL extern const char
-    two_ASCII_digits[100][2];  // 00, 01, 02, 03...
 
 // Writes a two-character representation of 'i' to 'buf'. 'i' must be in the
 // range 0 <= i < 100, and buf must have space for two characters. Example:
@@ -134,10 +132,7 @@ ABSL_DLL extern const char
 //   PutTwoDigits(42, buf);
 //   // buf[0] == '4'
 //   // buf[1] == '2'
-inline void PutTwoDigits(size_t i, char* buf) {
-  assert(i < 100);
-  memcpy(buf, two_ASCII_digits[i], 2);
-}
+void PutTwoDigits(uint32_t i, char* buf);
 
 // safe_strto?() functions for implementing SimpleAtoi()