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- abe587c2360b21f085b7d65a77d840015bc04cf6 Factor an internal interface into its own header, as it w... by Greg Falcon <gfalcon@google.com>

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- 2201f1644336e64280dbd20207d8fbc3bfea2bf4 Internal change. by Abseil Team <absl-team@google.com>
  - 94e6b5b20d2cc754c99a18c575a4f1f3cd1f28d4 Rename no_throw_ctor to nothrow_ctor to match the standar... by Abseil Team <absl-team@google.com>
  - 86aa34d2129c4914c5133b7b619480aae786288e Update header files in debugging target by Tom Manshreck <shreck@google.com>
  - ed234519ced458724a7267b8fdf184eaae1c97c7 Remove CMAKE_CXX_WARNING_VLA from our c++ flags in the cm... by Jon Cohen <cohenjon@google.com>

GitOrigin-RevId: abe587c2360b21f085b7d65a77d840015bc04cf6
Change-Id: I92f9301c69419d3830c358b88984967185aa33f6
This commit is contained in:
Abseil Team 2018-05-14 13:41:38 -07:00 • committed by jueminyang
parent add89fd0e4
commit 04dd99d8c1
13 changed files with 277 additions and 115 deletions
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17
absl/strings/numbers.cc
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@ -32,6 +32,7 @@
#include "absl/base/internal/raw_logging.h"
#include "absl/strings/ascii.h"
#include "absl/strings/internal/bits.h"
#include "absl/strings/internal/memutil.h"
#include "absl/strings/str_cat.h"
@ -302,18 +303,6 @@ char* numbers_internal::FastIntToBuffer(int64_t i, char* buffer) {
return numbers_internal::FastIntToBuffer(u, buffer);
}
// Returns the number of leading 0 bits in a 64-bit value.
// TODO(jorg): Replace with builtin_clzll if available.
// Are we shipping util/bits in absl?
static inline int CountLeadingZeros64(uint64_t n) {
int zeroes = 60;
if (n >> 32) zeroes -= 32, n >>= 32;
if (n >> 16) zeroes -= 16, n >>= 16;
if (n >> 8) zeroes -= 8, n >>= 8;
if (n >> 4) zeroes -= 4, n >>= 4;
return "\4\3\2\2\1\1\1\1\0\0\0\0\0\0\0\0"[n] + zeroes;
}
// Given a 128-bit number expressed as a pair of uint64_t, high half first,
// return that number multiplied by the given 32-bit value. If the result is
// too large to fit in a 128-bit number, divide it by 2 until it fits.
@ -351,7 +340,7 @@ static std::pair<uint64_t, uint64_t> Mul32(std::pair<uint64_t, uint64_t> num,
uint64_t bits128_up = (bits96_127 >> 32) + (bits64_127 < bits64_95);
if (bits128_up == 0) return {bits64_127, bits0_63};
int shift = 64 - CountLeadingZeros64(bits128_up);
int shift = 64 - strings_internal::CountLeadingZeros64(bits128_up);
uint64_t lo = (bits0_63 >> shift) + (bits64_127 << (64 - shift));
uint64_t hi = (bits64_127 >> shift) + (bits128_up << (64 - shift));
return {hi, lo};
@ -382,7 +371,7 @@ static std::pair<uint64_t, uint64_t> PowFive(uint64_t num, int expfive) {
5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5,
5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5};
result = Mul32(result, powers_of_five[expfive & 15]);
int shift = CountLeadingZeros64(result.first);
int shift = strings_internal::CountLeadingZeros64(result.first);
if (shift != 0) {
result.first = (result.first << shift) + (result.second >> (64 - shift));
result.second = (result.second << shift);