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/*
* Copyright 2012 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "folly/String.h"
#include "folly/Format.h"
#include <cerrno>
#include <cstdarg>
#include <cstring>
#include <stdexcept>
#include <iterator>
#include <glog/logging.h>
#undef FOLLY_DEMANGLE
#if defined(__GNUG__) && __GNUG__ >= 4
# include <cxxabi.h>
# define FOLLY_DEMANGLE 1
#endif
namespace folly {
namespace {
inline void stringPrintfImpl(std::string& output, const char* format,
va_list args) {
// Tru to the space at the end of output for our output buffer.
// Find out write point then inflate its size temporarily to its
// capacity; we will later shrink it to the size needed to represent
// the formatted string. If this buffer isn't large enough, we do a
// resize and try again.
const auto write_point = output.size();
auto remaining = output.capacity() - write_point;
output.resize(output.capacity());
va_list args_copy;
va_copy(args_copy, args);
int bytes_used = vsnprintf(&output[write_point], remaining, format,
args_copy);
va_end(args_copy);
if (bytes_used < 0) {
throw std::runtime_error(
to<std::string>("Invalid format string; snprintf returned negative "
"with format string: ", format));
} else if (bytes_used < remaining) {
// There was enough room, just shrink and return.
output.resize(write_point + bytes_used);
} else {
output.resize(write_point + bytes_used + 1);
remaining = bytes_used + 1;
va_list args_copy;
va_copy(args_copy, args);
bytes_used = vsnprintf(&output[write_point], remaining, format,
args_copy);
va_end(args_copy);
if (bytes_used + 1 != remaining) {
throw std::runtime_error(
to<std::string>("vsnprint retry did not manage to work "
"with format string: ", format));
}
output.resize(write_point + bytes_used);
}
}
} // anon namespace
std::string stringPrintf(const char* format, ...) {
// snprintf will tell us how large the output buffer should be, but
// we then have to call it a second time, which is costly. By
// guestimating the final size, we avoid the double snprintf in many
// cases, resulting in a performance win. We use this constructor
// of std::string to avoid a double allocation, though it does pad
// the resulting string with nul bytes. Our guestimation is twice
// the format string size, or 32 bytes, whichever is larger. This
// is a hueristic that doesn't affect correctness but attempts to be
// reasonably fast for the most common cases.
std::string ret(std::max(32UL, strlen(format) * 2), '\0');
ret.resize(0);
va_list ap;
va_start(ap, format);
stringPrintfImpl(ret, format, ap);
va_end(ap);
return ret;
}
// Basic declarations; allow for parameters of strings and string
// pieces to be specified.
std::string& stringAppendf(std::string* output, const char* format, ...) {
va_list ap;
va_start(ap, format);
stringPrintfImpl(*output, format, ap);
va_end(ap);
return *output;
}
void stringPrintf(std::string* output, const char* format, ...) {
output->clear();
va_list ap;
va_start(ap, format);
stringPrintfImpl(*output, format, ap);
va_end(ap);
};
namespace {
struct PrettySuffix {
const char* suffix;
double val;
};
const PrettySuffix kPrettyTimeSuffixes[] = {
{ "s ", 1e0L },
{ "ms", 1e-3L },
{ "us", 1e-6L },
{ "ns", 1e-9L },
{ "ps", 1e-12L },
{ "s ", 0 },
{ 0, 0 },
};
const PrettySuffix kPrettyBytesMetricSuffixes[] = {
{ "TB", 1e12L },
{ "GB", 1e9L },
{ "MB", 1e6L },
{ "kB", 1e3L },
{ "B ", 0L },
{ 0, 0 },
};
const PrettySuffix kPrettyBytesBinarySuffixes[] = {
{ "TB", int64_t(1) << 40 },
{ "GB", int64_t(1) << 30 },
{ "MB", int64_t(1) << 20 },
{ "kB", int64_t(1) << 10 },
{ "B ", 0L },
{ 0, 0 },
};
const PrettySuffix kPrettyBytesBinaryIECSuffixes[] = {
{ "TiB", int64_t(1) << 40 },
{ "GiB", int64_t(1) << 30 },
{ "MiB", int64_t(1) << 20 },
{ "KiB", int64_t(1) << 10 },
{ "B ", 0L },
{ 0, 0 },
};
const PrettySuffix kPrettyUnitsMetricSuffixes[] = {
{ "tril", 1e12L },
{ "bil", 1e9L },
{ "M", 1e6L },
{ "k", 1e3L },
{ " ", 0 },
{ 0, 0 },
};
const PrettySuffix kPrettyUnitsBinarySuffixes[] = {
{ "T", int64_t(1) << 40 },
{ "G", int64_t(1) << 30 },
{ "M", int64_t(1) << 20 },
{ "k", int64_t(1) << 10 },
{ " ", 0 },
{ 0, 0 },
};
const PrettySuffix kPrettyUnitsBinaryIECSuffixes[] = {
{ "Ti", int64_t(1) << 40 },
{ "Gi", int64_t(1) << 30 },
{ "Mi", int64_t(1) << 20 },
{ "Ki", int64_t(1) << 10 },
{ " ", 0 },
{ 0, 0 },
};
const PrettySuffix* const kPrettySuffixes[PRETTY_NUM_TYPES] = {
kPrettyTimeSuffixes,
kPrettyBytesMetricSuffixes,
kPrettyBytesBinarySuffixes,
kPrettyBytesBinaryIECSuffixes,
kPrettyUnitsMetricSuffixes,
kPrettyUnitsBinarySuffixes,
kPrettyUnitsBinaryIECSuffixes,
};
} // namespace
std::string prettyPrint(double val, PrettyType type, bool addSpace) {
char buf[100];
// pick the suffixes to use
assert(type >= 0);
assert(type < PRETTY_NUM_TYPES);
const PrettySuffix* suffixes = kPrettySuffixes[type];
// find the first suffix we're bigger than -- then use it
double abs_val = fabs(val);
for (int i = 0; suffixes[i].suffix; ++i) {
if (abs_val >= suffixes[i].val) {
snprintf(buf, sizeof buf, "%.4g%s%s",
(suffixes[i].val ? (val / suffixes[i].val)
: val),
(addSpace ? " " : ""),
suffixes[i].suffix);
return std::string(buf);
}
}
// no suffix, we've got a tiny value -- just print it in sci-notation
snprintf(buf, sizeof buf, "%.4g", val);
return std::string(buf);
}
std::string hexDump(const void* ptr, size_t size) {
std::ostringstream os;
hexDump(ptr, size, std::ostream_iterator<StringPiece>(os, "\n"));
return os.str();
}
fbstring errnoStr(int err) {
int savedErrno = errno;
// Ensure that we reset errno upon exit.
auto guard(makeGuard([&] { errno = savedErrno; }));
char buf[1024];
buf[0] = '\0';
fbstring result;
// http://www.kernel.org/doc/man-pages/online/pages/man3/strerror.3.html
#if (_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600 || \
!FOLLY_HAVE_FEATURES_H) && !_GNU_SOURCE
// Using XSI-compatible strerror_r
int r = strerror_r(err, buf, sizeof(buf));
if (r == -1) {
result = to<fbstring>(
"Unknown error ", err,
" (strerror_r failed with error ", errno, ")");
} else {
result.assign(buf);
}
#else
// Using GNU strerror_r
result.assign(strerror_r(err, buf, sizeof(buf)));
#endif
return result;
}
#ifdef FOLLY_DEMANGLE
fbstring demangle(const char* name) {
int status;
size_t len = 0;
// malloc() memory for the demangled type name
char* demangled = abi::__cxa_demangle(name, nullptr, &len, &status);
if (status != 0) {
return name;
}
// len is the length of the buffer (including NUL terminator and maybe
// other junk)
return fbstring(demangled, strlen(demangled), len, AcquireMallocatedString());
}
#else
fbstring demangle(const char* name) {
return name;
}
#endif
#undef FOLLY_DEMANGLE
namespace detail {
size_t hexDumpLine(const void* ptr, size_t offset, size_t size,
std::string& line) {
// Line layout:
// 8: address
// 1: space
// (1+2)*16: hex bytes, each preceded by a space
// 1: space separating the two halves
// 3: " |"
// 16: characters
// 1: "|"
// Total: 78
line.clear();
line.reserve(78);
const uint8_t* p = reinterpret_cast<const uint8_t*>(ptr) + offset;
size_t n = std::min(size - offset, size_t(16));
format("{:08x} ", offset).appendTo(line);
for (size_t i = 0; i < n; i++) {
if (i == 8) {
line.push_back(' ');
}
format(" {:02x}", p[i]).appendTo(line);
}
// 3 spaces for each byte we're not printing, one separating the halves
// if necessary
line.append(3 * (16 - n) + (n <= 8), ' ');
line.append(" |");
for (size_t i = 0; i < n; i++) {
char c = (p[i] >= 32 && p[i] <= 126 ? static_cast<char>(p[i]) : '.');
line.push_back(c);
}
line.append(16 - n, ' ');
line.push_back('|');
DCHECK_EQ(line.size(), 78);
return n;
}
} // namespace detail
} // namespace folly
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