X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=folly%2FString.cpp;h=5042cec97a53a1a05daf50c4be5f4fa3425107f4;hb=0347a79f57ee6e1179c0482adacf3a7e6ff890ff;hp=89373e10f5e0df4d97ee95319ce3494924c8219c;hpb=56c7e2070808ff450f31033da626aea6747921c1;p=folly.git diff --git a/folly/String.cpp b/folly/String.cpp index 89373e10..5042cec9 100644 --- a/folly/String.cpp +++ b/folly/String.cpp @@ -1,5 +1,5 @@ /* - * Copyright 2013 Facebook, Inc. + * Copyright 2015 Facebook, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -14,114 +14,89 @@ * limitations under the License. */ -#include "folly/String.h" -#include "folly/Format.h" +#include + +#include +#include #include #include #include #include #include +#include +#include #include -#if FOLLY_HAVE_CPLUS_DEMANGLE_V3_CALLBACK -# include - -// From libiberty -// -// TODO(tudorb): Detect this with autoconf for the open-source version. -// -// __attribute__((weak)) doesn't work, because cplus_demangle_v3_callback -// is exported by an object file in libiberty.a, and the ELF spec says -// "The link editor does not extract archive members to resolve undefined weak -// symbols" (but, interestingly enough, will resolve undefined weak symbols -// with definitions from archive members that were extracted in order to -// resolve an undefined global (strong) symbol) - -# ifndef DMGL_NO_OPTS -# define FOLLY_DEFINED_DMGL 1 -# define DMGL_NO_OPTS 0 /* For readability... */ -# define DMGL_PARAMS (1 << 0) /* Include function args */ -# define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */ -# define DMGL_JAVA (1 << 2) /* Demangle as Java rather than C++. */ -# define DMGL_VERBOSE (1 << 3) /* Include implementation details. */ -# define DMGL_TYPES (1 << 4) /* Also try to demangle type encodings. */ -# define DMGL_RET_POSTFIX (1 << 5) /* Print function return types (when - present) after function signature */ -# endif - -extern "C" int cplus_demangle_v3_callback( - const char* mangled, - int options, // We use DMGL_PARAMS | DMGL_TYPES, aka 0x11 - void (*callback)(const char*, size_t, void*), - void* arg); - -#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()); - +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(), bytes_used); + return; } + + // Couldn't fit. Heap allocate a buffer, oh well. + std::unique_ptr heap_buffer(new char[bytes_used + 1]); + int final_bytes_used = + stringAppendfImplHelper(heap_buffer.get(), 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(), 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; } @@ -130,17 +105,31 @@ std::string stringPrintf(const char* format, ...) { 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 { @@ -214,6 +203,31 @@ const PrettySuffix kPrettyUnitsBinaryIECSuffixes[] = { { 0, 0 }, }; +const PrettySuffix kPrettySISuffixes[] = { + { "Y", 1e24L }, + { "Z", 1e21L }, + { "E", 1e18L }, + { "P", 1e15L }, + { "T", 1e12L }, + { "G", 1e9L }, + { "M", 1e6L }, + { "k", 1e3L }, + { "h", 1e2L }, + { "da", 1e1L }, + { "d", 1e-1L }, + { "c", 1e-2L }, + { "m", 1e-3L }, + { "u", 1e-6L }, + { "n", 1e-9L }, + { "p", 1e-12L }, + { "f", 1e-15L }, + { "a", 1e-18L }, + { "z", 1e-21L }, + { "y", 1e-24L }, + { " ", 0 }, + { 0, 0} +}; + const PrettySuffix* const kPrettySuffixes[PRETTY_NUM_TYPES] = { kPrettyTimeSuffixes, kPrettyBytesMetricSuffixes, @@ -222,6 +236,7 @@ const PrettySuffix* const kPrettySuffixes[PRETTY_NUM_TYPES] = { kPrettyUnitsMetricSuffixes, kPrettyUnitsBinarySuffixes, kPrettyUnitsBinaryIECSuffixes, + kPrettySISuffixes, }; } // namespace @@ -252,6 +267,50 @@ std::string prettyPrint(double val, PrettyType type, bool addSpace) { return std::string(buf); } +//TODO: +//1) Benchmark & optimize +double prettyToDouble(folly::StringPiece *const prettyString, + const PrettyType type) { + double value = folly::to(prettyString); + while (prettyString->size() > 0 && std::isspace(prettyString->front())) { + prettyString->advance(1); //Skipping spaces between number and suffix + } + const PrettySuffix* suffixes = kPrettySuffixes[type]; + int longestPrefixLen = -1; + int bestPrefixId = -1; + for (int j = 0 ; suffixes[j].suffix; ++j) { + if (suffixes[j].suffix[0] == ' '){//Checking for " " -> number rule. + if (longestPrefixLen == -1) { + longestPrefixLen = 0; //No characters to skip + bestPrefixId = j; + } + } else if (prettyString->startsWith(suffixes[j].suffix)) { + int suffixLen = 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) { + longestPrefixLen = suffixLen; + bestPrefixId = j; + } + } + } + if (bestPrefixId == -1) { //No valid suffix rule found + throw std::invalid_argument(folly::to( + "Unable to parse suffix \"", + prettyString->toString(), "\"")); + } + prettyString->advance(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()); + return result; +} + std::string hexDump(const void* ptr, size_t size) { std::ostringstream os; hexDump(ptr, size, std::ostream_iterator(os, "\n")); @@ -271,8 +330,20 @@ 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__) || \ - ((_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)); @@ -294,86 +365,145 @@ fbstring errnoStr(int err) { namespace { -// glibc doesn't have strlcpy -size_t my_strlcpy(char* dest, const char* src, size_t size) { - size_t len = strlen(src); - if (size != 0) { - size_t n = std::min(len, size - 1); // always null terminate! - memcpy(dest, src, n); - dest[n] = '\0'; - } - return len; +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. + unsigned char rotated = 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 += rotated; } -} // namespace - -#if FOLLY_HAVE_CPLUS_DEMANGLE_V3_CALLBACK - -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()); +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; } -namespace { - -struct DemangleBuf { - char* dest; - size_t remaining; - size_t total; -}; - -void demangleCallback(const char* str, size_t size, void* p) { - DemangleBuf* buf = static_cast(p); - size_t n = std::min(buf->remaining, size); - memcpy(buf->dest, str, n); - buf->dest += n; - buf->remaining -= n; - buf->total += size; +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; } -} // namespace - -size_t demangle(const char* name, char* out, size_t outSize) { - DemangleBuf dbuf; - dbuf.dest = out; - dbuf.remaining = outSize ? outSize - 1 : 0; // leave room for null term - dbuf.total = 0; - - // Unlike most library functions, this returns 1 on success and 0 on failure - int status = cplus_demangle_v3_callback( - name, - DMGL_PARAMS | DMGL_ANSI | DMGL_TYPES, - demangleCallback, - &dbuf); - if (status == 0) { // failed, return original - return my_strlcpy(out, name, outSize); +} // 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); } - if (outSize != 0) { - *dbuf.dest = '\0'; + + 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; } - return dbuf.total; -} -#else + // Convert 8 characters at a time + while (offset + 8 <= length) { + toLowerAscii64(*(uint64_t*)(str + offset)); + offset += 8; + } -fbstring demangle(const char* name) { - return name; -} + // Convert 4 characters at a time + while (offset + 4 <= length) { + toLowerAscii32(*(uint32_t*)(str + offset)); + offset += 4; + } -size_t demangle(const char* name, char* out, size_t outSize) { - return my_strlcpy(out, name, outSize); + // Convert any characters remaining after the last 4-byte aligned group + while (offset < length) { + toLowerAscii8(str[offset]); + offset++; + } } -#endif - namespace detail { size_t hexDumpLine(const void* ptr, size_t offset, size_t size, @@ -430,4 +560,3 @@ size_t hexDumpLine(const void* ptr, size_t offset, size_t size, # undef DMGL_TYPES # undef DMGL_RET_POSTFIX #endif -