X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=folly%2FString.cpp;h=097e5bbfd4c7b2cd86ed2b388ee557bea5124952;hb=48d3f5e1691033d00ecc2ef0c3ced83ce148705a;hp=9ccd09288e36159332a59f0f8fde13d62c46e8c0;hpb=0606460a10e0e41f9be09552d771ea1ee327f8ee;p=folly.git diff --git a/folly/String.cpp b/folly/String.cpp index 9ccd0928..097e5bbf 100644 --- a/folly/String.cpp +++ b/folly/String.cpp @@ -1,5 +1,5 @@ /* - * 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. @@ -16,63 +16,109 @@ #include -#include -#include - +#include #include #include #include -#include #include -#include +#include + #include +#include + namespace folly { -namespace { +static inline bool is_oddspace(char c) { + return c == '\n' || c == '\t' || c == '\r'; +} + +StringPiece ltrimWhitespace(StringPiece sp) { + // Spaces other than ' ' characters are less common but should be + // checked. This configuration where we loop on the ' ' + // separately from oddspaces was empirically fastest. + +loop: + for (; !sp.empty() && sp.front() == ' '; sp.pop_front()) { + } + if (!sp.empty() && is_oddspace(sp.front())) { + sp.pop_front(); + goto loop; + } + + return sp; +} + +StringPiece rtrimWhitespace(StringPiece sp) { + // Spaces other than ' ' characters are less common but should be + // checked. This configuration where we loop on the ' ' + // separately from oddspaces was empirically fastest. + +loop: + for (; !sp.empty() && sp.back() == ' '; sp.pop_back()) { + } + if (!sp.empty() && is_oddspace(sp.back())) { + sp.pop_back(); + goto loop; + } -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. + return sp; +} - const auto write_point = output.size(); - auto remaining = output.capacity() - write_point; - output.resize(output.capacity()); +namespace { +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 inline_buffer; + + int bytes_used = stringAppendfImplHelper( + inline_buffer.data(), inline_buffer.size(), format, args); if (bytes_used < 0) { - throw std::runtime_error( - to("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("vsnprint retry did not manage to work " - "with format string: ", format)); - } - output.resize(write_point + bytes_used); + throw std::runtime_error(to( + "Invalid format string; snprintf returned negative " + "with format string: ", + format)); + } + + if (static_cast(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 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 +} // namespace std::string stringPrintf(const char* format, ...) { va_list ap; @@ -84,19 +130,8 @@ std::string stringPrintf(const char* format, ...) { } std::string stringVPrintf(const char* format, va_list ap) { - // 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); - - stringPrintfImpl(ret, format, ap); + std::string ret; + stringAppendfImpl(ret, format, ap); return ret; } @@ -114,7 +149,7 @@ std::string& stringAppendf(std::string* output, const char* format, ...) { std::string& stringVAppendf(std::string* output, const char* format, va_list ap) { - stringPrintfImpl(*output, format, ap); + stringAppendfImpl(*output, format, ap); return *output; } @@ -129,7 +164,7 @@ void stringPrintf(std::string* output, const char* format, ...) { void stringVPrintf(std::string* output, const char* format, va_list ap) { output->clear(); - stringPrintfImpl(*output, format, ap); + stringAppendfImpl(*output, format, ap); }; namespace { @@ -146,7 +181,7 @@ const PrettySuffix kPrettyTimeSuffixes[] = { { "ns", 1e-9L }, { "ps", 1e-12L }, { "s ", 0 }, - { 0, 0 }, + { nullptr, 0 }, }; const PrettySuffix kPrettyBytesMetricSuffixes[] = { @@ -155,7 +190,7 @@ const PrettySuffix kPrettyBytesMetricSuffixes[] = { { "MB", 1e6L }, { "kB", 1e3L }, { "B ", 0L }, - { 0, 0 }, + { nullptr, 0 }, }; const PrettySuffix kPrettyBytesBinarySuffixes[] = { @@ -164,7 +199,7 @@ const PrettySuffix kPrettyBytesBinarySuffixes[] = { { "MB", int64_t(1) << 20 }, { "kB", int64_t(1) << 10 }, { "B ", 0L }, - { 0, 0 }, + { nullptr, 0 }, }; const PrettySuffix kPrettyBytesBinaryIECSuffixes[] = { @@ -173,7 +208,7 @@ const PrettySuffix kPrettyBytesBinaryIECSuffixes[] = { { "MiB", int64_t(1) << 20 }, { "KiB", int64_t(1) << 10 }, { "B ", 0L }, - { 0, 0 }, + { nullptr, 0 }, }; const PrettySuffix kPrettyUnitsMetricSuffixes[] = { @@ -182,7 +217,7 @@ const PrettySuffix kPrettyUnitsMetricSuffixes[] = { { "M", 1e6L }, { "k", 1e3L }, { " ", 0 }, - { 0, 0 }, + { nullptr, 0 }, }; const PrettySuffix kPrettyUnitsBinarySuffixes[] = { @@ -191,7 +226,7 @@ const PrettySuffix kPrettyUnitsBinarySuffixes[] = { { "M", int64_t(1) << 20 }, { "k", int64_t(1) << 10 }, { " ", 0 }, - { 0, 0 }, + { nullptr, 0 }, }; const PrettySuffix kPrettyUnitsBinaryIECSuffixes[] = { @@ -200,7 +235,7 @@ const PrettySuffix kPrettyUnitsBinaryIECSuffixes[] = { { "Mi", int64_t(1) << 20 }, { "Ki", int64_t(1) << 10 }, { " ", 0 }, - { 0, 0 }, + { nullptr, 0 }, }; const PrettySuffix kPrettySISuffixes[] = { @@ -225,7 +260,7 @@ const PrettySuffix kPrettySISuffixes[] = { { "z", 1e-21L }, { "y", 1e-24L }, { " ", 0 }, - { 0, 0} + { nullptr, 0} }; const PrettySuffix* const kPrettySuffixes[PRETTY_NUM_TYPES] = { @@ -239,7 +274,7 @@ const PrettySuffix* const kPrettySuffixes[PRETTY_NUM_TYPES] = { kPrettySISuffixes, }; -} // namespace +} // namespace std::string prettyPrint(double val, PrettyType type, bool addSpace) { char buf[100]; @@ -285,7 +320,7 @@ double prettyToDouble(folly::StringPiece *const prettyString, 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) { @@ -299,15 +334,14 @@ double prettyToDouble(folly::StringPiece *const prettyString, "Unable to parse suffix \"", prettyString->toString(), "\"")); } - prettyString->advance(longestPrefixLen); + 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; } @@ -330,8 +364,20 @@ fbstring errnoStr(int err) { // 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__) || defined(__CYGWIN__) ||\ - ((_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( + "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)); @@ -351,25 +397,6 @@ fbstring errnoStr(int err) { return result; } -StringPiece skipWhitespace(StringPiece sp) { - // Spaces other than ' ' characters are less common but should be - // checked. This configuration where we loop on the ' ' - // separately from oddspaces was empirically fastest. - auto oddspace = [] (char c) { - return c == '\n' || c == '\t' || c == '\r'; - }; - -loop: - for (; !sp.empty() && sp.front() == ' '; sp.pop_front()) { - } - if (!sp.empty() && oddspace(sp.front())) { - sp.pop_front(); - goto loop; - } - - return sp; -} - namespace { void toLowerAscii8(char& c) { @@ -381,7 +408,7 @@ void toLowerAscii8(char& c) { // by adding 0x20. // Step 1: Clear the high order bit. We'll deal with it in Step 5. - unsigned char rotated = c & 0x7f; + 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 @@ -427,7 +454,7 @@ void toLowerAscii8(char& c) { // At this point, rotated is 0x20 if c is 'A'-'Z' and 0x00 otherwise // Step 7: Add rotated to c - c += rotated; + c += char(rotated); } void toLowerAscii32(uint32_t& c) { @@ -462,7 +489,7 @@ void toLowerAscii64(uint64_t& c) { c += rotated; } -} // anon namespace +} // namespace void toLowerAscii(char* str, size_t length) { static const size_t kAlignMask64 = 7; @@ -515,6 +542,7 @@ namespace detail { size_t hexDumpLine(const void* ptr, size_t offset, size_t size, std::string& line) { + static char hexValues[] = "0123456789abcdef"; // Line layout: // 8: address // 1: space @@ -528,13 +556,24 @@ size_t hexDumpLine(const void* ptr, size_t offset, size_t size, line.reserve(78); const uint8_t* p = reinterpret_cast(ptr) + offset; size_t n = std::min(size - offset, size_t(16)); - format("{:08x} ", offset).appendTo(line); + line.push_back(hexValues[(offset >> 28) & 0xf]); + line.push_back(hexValues[(offset >> 24) & 0xf]); + line.push_back(hexValues[(offset >> 20) & 0xf]); + line.push_back(hexValues[(offset >> 16) & 0xf]); + line.push_back(hexValues[(offset >> 12) & 0xf]); + line.push_back(hexValues[(offset >> 8) & 0xf]); + line.push_back(hexValues[(offset >> 4) & 0xf]); + line.push_back(hexValues[offset & 0xf]); + line.push_back(' '); for (size_t i = 0; i < n; i++) { if (i == 8) { line.push_back(' '); } - format(" {:02x}", p[i]).appendTo(line); + + line.push_back(' '); + line.push_back(hexValues[(p[i] >> 4) & 0xf]); + line.push_back(hexValues[p[i] & 0xf]); } // 3 spaces for each byte we're not printing, one separating the halves @@ -548,14 +587,58 @@ 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 -} // namespace folly +std::string stripLeftMargin(std::string s) { + std::vector 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::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(indent, size_t(needle - piece->begin())); + } else { + max_length = std::max(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 FOLLY_DEFINED_DMGL