/*
- * Copyright 2014 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
*/
#include <folly/String.h>
+
#include <folly/Format.h>
+#include <folly/ScopeGuard.h>
#include <cerrno>
#include <cstdarg>
#include <stdexcept>
#include <iterator>
#include <cctype>
+#include <string.h>
#include <glog/logging.h>
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());
-
+int stringAppendfImplHelper(char* buf,
+ size_t bufsize,
+ const char* format,
+ va_list args) {
va_list args_copy;
va_copy(args_copy, args);
- int bytes_used = vsnprintf(&output[write_point], remaining, format,
- args_copy);
+ int bytes_used = vsnprintf(buf, bufsize, format, args_copy);
va_end(args_copy);
+ return bytes_used;
+}
+
+void stringAppendfImpl(std::string& output, const char* format, va_list args) {
+ // Very simple; first, try to avoid an allocation by using an inline
+ // buffer. If that fails to hold the output string, allocate one on
+ // the heap, use it instead.
+ //
+ // It is hard to guess the proper size of this buffer; some
+ // heuristics could be based on the number of format characters, or
+ // static analysis of a codebase. Or, we can just pick a number
+ // that seems big enough for simple cases (say, one line of text on
+ // a terminal) without being large enough to be concerning as a
+ // stack variable.
+ std::array<char, 128> inline_buffer;
+
+ int bytes_used = stringAppendfImplHelper(
+ inline_buffer.data(), inline_buffer.size(), format, args);
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);
+ throw std::runtime_error(to<std::string>(
+ "Invalid format string; snprintf returned negative "
+ "with format string: ",
+ format));
}
+
+ if (static_cast<size_t>(bytes_used) < inline_buffer.size()) {
+ output.append(inline_buffer.data(), size_t(bytes_used));
+ return;
+ }
+
+ // Couldn't fit. Heap allocate a buffer, oh well.
+ std::unique_ptr<char[]> heap_buffer(new char[size_t(bytes_used + 1)]);
+ int final_bytes_used = stringAppendfImplHelper(
+ heap_buffer.get(), size_t(bytes_used + 1), format, args);
+ // The second call can take fewer bytes if, for example, we were printing a
+ // string buffer with null-terminating char using a width specifier -
+ // vsnprintf("%.*s", buf.size(), buf)
+ CHECK(bytes_used >= final_bytes_used);
+
+ // We don't keep the trailing '\0' in our output string
+ output.append(heap_buffer.get(), size_t(final_bytes_used));
}
-} // anon namespace
+} // 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);
+ SCOPE_EXIT {
+ va_end(ap);
+ };
+ return stringVPrintf(format, ap);
+}
+
+std::string stringVPrintf(const char* format, va_list ap) {
+ std::string ret;
+ stringAppendfImpl(ret, format, ap);
return ret;
}
std::string& stringAppendf(std::string* output, const char* format, ...) {
va_list ap;
va_start(ap, format);
- stringPrintfImpl(*output, format, ap);
- va_end(ap);
+ SCOPE_EXIT {
+ va_end(ap);
+ };
+ return stringVAppendf(output, format, ap);
+}
+
+std::string& stringVAppendf(std::string* output,
+ const char* format,
+ va_list ap) {
+ stringAppendfImpl(*output, format, 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);
+ SCOPE_EXIT {
+ va_end(ap);
+ };
+ return stringVPrintf(output, format, ap);
+}
+
+void stringVPrintf(std::string* output, const char* format, va_list ap) {
+ output->clear();
+ stringAppendfImpl(*output, format, ap);
};
namespace {
{ "z", 1e-21L },
{ "y", 1e-24L },
{ " ", 0 },
- { 0, 0}
+ { 0, 0}
};
const PrettySuffix* const kPrettySuffixes[PRETTY_NUM_TYPES] = {
//TODO:
//1) Benchmark & optimize
-double prettyToDouble(folly::StringPiece *const prettyString,
+double prettyToDouble(folly::StringPiece *const prettyString,
const PrettyType type) {
double value = folly::to<double>(prettyString);
while (prettyString->size() > 0 && std::isspace(prettyString->front())) {
bestPrefixId = j;
}
} else if (prettyString->startsWith(suffixes[j].suffix)) {
- int suffixLen = strlen(suffixes[j].suffix);
+ int suffixLen = int(strlen(suffixes[j].suffix));
//We are looking for a longest suffix matching prefix of the string
//after numeric value. We need this in case suffixes have common prefix.
if (suffixLen > longestPrefixLen) {
"Unable to parse suffix \"",
prettyString->toString(), "\""));
}
- prettyString->advance(longestPrefixLen);
- return suffixes[bestPrefixId].val ? value * suffixes[bestPrefixId].val :
+ prettyString->advance(size_t(longestPrefixLen));
+ return suffixes[bestPrefixId].val ? value * suffixes[bestPrefixId].val :
value;
}
double prettyToDouble(folly::StringPiece prettyString, const PrettyType type){
double result = prettyToDouble(&prettyString, type);
- detail::enforceWhitespace(prettyString.data(),
- prettyString.data() + prettyString.size());
+ detail::enforceWhitespace(prettyString);
return result;
}
// https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man3/strerror_r.3.html
// http://www.kernel.org/doc/man-pages/online/pages/man3/strerror.3.html
-#if defined(__APPLE__) || defined(__FreeBSD__) || \
- ((_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && !_GNU_SOURCE)
+#if defined(_WIN32) && (defined(__MINGW32__) || defined(_MSC_VER))
+ // mingw64 has no strerror_r, but Windows has strerror_s, which C11 added
+ // as well. So maybe we should use this across all platforms (together
+ // with strerrorlen_s). Note strerror_r and _s have swapped args.
+ int r = strerror_s(buf, sizeof(buf), err);
+ if (r != 0) {
+ result = to<fbstring>(
+ "Unknown error ", err,
+ " (strerror_r failed with error ", errno, ")");
+ } else {
+ result.assign(buf);
+ }
+#elif defined(FOLLY_HAVE_XSI_STRERROR_R) || \
+ defined(__APPLE__) || defined(__ANDROID__)
// Using XSI-compatible strerror_r
int r = strerror_r(err, buf, sizeof(buf));
return result;
}
+namespace {
+
+void toLowerAscii8(char& c) {
+ // Branchless tolower, based on the input-rotating trick described
+ // at http://www.azillionmonkeys.com/qed/asmexample.html
+ //
+ // This algorithm depends on an observation: each uppercase
+ // ASCII character can be converted to its lowercase equivalent
+ // by adding 0x20.
+
+ // Step 1: Clear the high order bit. We'll deal with it in Step 5.
+ uint8_t rotated = uint8_t(c & 0x7f);
+ // Currently, the value of rotated, as a function of the original c is:
+ // below 'A': 0- 64
+ // 'A'-'Z': 65- 90
+ // above 'Z': 91-127
+
+ // Step 2: Add 0x25 (37)
+ rotated += 0x25;
+ // Now the value of rotated, as a function of the original c is:
+ // below 'A': 37-101
+ // 'A'-'Z': 102-127
+ // above 'Z': 128-164
+
+ // Step 3: clear the high order bit
+ rotated &= 0x7f;
+ // below 'A': 37-101
+ // 'A'-'Z': 102-127
+ // above 'Z': 0- 36
+
+ // Step 4: Add 0x1a (26)
+ rotated += 0x1a;
+ // below 'A': 63-127
+ // 'A'-'Z': 128-153
+ // above 'Z': 25- 62
+
+ // At this point, note that only the uppercase letters have been
+ // transformed into values with the high order bit set (128 and above).
+
+ // Step 5: Shift the high order bit 2 spaces to the right: the spot
+ // where the only 1 bit in 0x20 is. But first, how we ignored the
+ // high order bit of the original c in step 1? If that bit was set,
+ // we may have just gotten a false match on a value in the range
+ // 128+'A' to 128+'Z'. To correct this, need to clear the high order
+ // bit of rotated if the high order bit of c is set. Since we don't
+ // care about the other bits in rotated, the easiest thing to do
+ // is invert all the bits in c and bitwise-and them with rotated.
+ rotated &= ~c;
+ rotated >>= 2;
+
+ // Step 6: Apply a mask to clear everything except the 0x20 bit
+ // in rotated.
+ rotated &= 0x20;
+
+ // At this point, rotated is 0x20 if c is 'A'-'Z' and 0x00 otherwise
+
+ // Step 7: Add rotated to c
+ c += char(rotated);
+}
+
+void toLowerAscii32(uint32_t& c) {
+ // Besides being branchless, the algorithm in toLowerAscii8() has another
+ // interesting property: None of the addition operations will cause
+ // an overflow in the 8-bit value. So we can pack four 8-bit values
+ // into a uint32_t and run each operation on all four values in parallel
+ // without having to use any CPU-specific SIMD instructions.
+ uint32_t rotated = c & uint32_t(0x7f7f7f7fL);
+ rotated += uint32_t(0x25252525L);
+ rotated &= uint32_t(0x7f7f7f7fL);
+ rotated += uint32_t(0x1a1a1a1aL);
+
+ // Step 5 involves a shift, so some bits will spill over from each
+ // 8-bit value into the next. But that's okay, because they're bits
+ // that will be cleared by the mask in step 6 anyway.
+ rotated &= ~c;
+ rotated >>= 2;
+ rotated &= uint32_t(0x20202020L);
+ c += rotated;
+}
+
+void toLowerAscii64(uint64_t& c) {
+ // 64-bit version of toLower32
+ uint64_t rotated = c & uint64_t(0x7f7f7f7f7f7f7f7fL);
+ rotated += uint64_t(0x2525252525252525L);
+ rotated &= uint64_t(0x7f7f7f7f7f7f7f7fL);
+ rotated += uint64_t(0x1a1a1a1a1a1a1a1aL);
+ rotated &= ~c;
+ rotated >>= 2;
+ rotated &= uint64_t(0x2020202020202020L);
+ c += rotated;
+}
+
+} // anon namespace
+
+void toLowerAscii(char* str, size_t length) {
+ static const size_t kAlignMask64 = 7;
+ static const size_t kAlignMask32 = 3;
+
+ // Convert a character at a time until we reach an address that
+ // is at least 32-bit aligned
+ size_t n = (size_t)str;
+ n &= kAlignMask32;
+ n = std::min(n, length);
+ size_t offset = 0;
+ if (n != 0) {
+ n = std::min(4 - n, length);
+ do {
+ toLowerAscii8(str[offset]);
+ offset++;
+ } while (offset < n);
+ }
+
+ n = (size_t)(str + offset);
+ n &= kAlignMask64;
+ if ((n != 0) && (offset + 4 <= length)) {
+ // The next address is 32-bit aligned but not 64-bit aligned.
+ // Convert the next 4 bytes in order to get to the 64-bit aligned
+ // part of the input.
+ toLowerAscii32(*(uint32_t*)(str + offset));
+ offset += 4;
+ }
+
+ // Convert 8 characters at a time
+ while (offset + 8 <= length) {
+ toLowerAscii64(*(uint64_t*)(str + offset));
+ offset += 8;
+ }
+
+ // Convert 4 characters at a time
+ while (offset + 4 <= length) {
+ toLowerAscii32(*(uint32_t*)(str + offset));
+ offset += 4;
+ }
+
+ // Convert any characters remaining after the last 4-byte aligned group
+ while (offset < length) {
+ toLowerAscii8(str[offset]);
+ offset++;
+ }
+}
+
namespace detail {
size_t hexDumpLine(const void* ptr, size_t offset, size_t size,
}
line.append(16 - n, ' ');
line.push_back('|');
- DCHECK_EQ(line.size(), 78);
+ DCHECK_EQ(line.size(), 78u);
return n;
}
} // namespace detail
+std::string stripLeftMargin(std::string s) {
+ std::vector<StringPiece> pieces;
+ split("\n", s, pieces);
+ auto piecer = range(pieces);
+
+ auto piece = (piecer.end() - 1);
+ auto needle = std::find_if(piece->begin(),
+ piece->end(),
+ [](char c) { return c != ' ' && c != '\t'; });
+ if (needle == piece->end()) {
+ (piecer.end() - 1)->clear();
+ }
+ piece = piecer.begin();
+ needle = std::find_if(piece->begin(),
+ piece->end(),
+ [](char c) { return c != ' ' && c != '\t'; });
+ if (needle == piece->end()) {
+ piecer.erase(piecer.begin(), piecer.begin() + 1);
+ }
+
+ const auto sentinel = std::numeric_limits<size_t>::max();
+ auto indent = sentinel;
+ size_t max_length = 0;
+ for (piece = piecer.begin(); piece != piecer.end(); piece++) {
+ needle = std::find_if(piece->begin(),
+ piece->end(),
+ [](char c) { return c != ' ' && c != '\t'; });
+ if (needle != piece->end()) {
+ indent = std::min<size_t>(indent, size_t(needle - piece->begin()));
+ } else {
+ max_length = std::max<size_t>(piece->size(), max_length);
+ }
+ }
+ indent = indent == sentinel ? max_length : indent;
+ for (piece = piecer.begin(); piece != piecer.end(); piece++) {
+ if (piece->size() < indent) {
+ piece->clear();
+ } else {
+ piece->erase(piece->begin(), piece->begin() + indent);
+ }
+ }
+ return join("\n", piecer);
+}
+
} // namespace folly
#ifdef FOLLY_DEFINED_DMGL
# undef DMGL_TYPES
# undef DMGL_RET_POSTFIX
#endif
-
projects / folly.git / blobdiff