/*
- * Copyright 2012 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.
* limitations under the License.
*/
-#ifndef FOLLY_STRING_INL_H_
-#define FOLLY_STRING_INL_H_
+#pragma once
#include <stdexcept>
+#include <iterator>
-#ifndef FOLLY_BASE_STRING_H_
+#include <folly/CppAttributes.h>
+
+#ifndef FOLLY_STRING_H_
#error This file may only be included from String.h
#endif
if (e == 'P') { // printable
++p;
} else if (e == 'O') { // octal
- out.append(&*last, p - last);
+ out.append(&*last, size_t(p - last));
esc[1] = '0' + ((v >> 6) & 7);
esc[2] = '0' + ((v >> 3) & 7);
esc[3] = '0' + (v & 7);
++p;
last = p;
} else { // special 1-character escape
- out.append(&*last, p - last);
+ out.append(&*last, size_t(p - last));
esc[1] = e;
out.append(esc, 2);
++p;
last = p;
}
}
- out.append(&*last, p - last);
+ out.append(&*last, size_t(p - last));
}
namespace detail {
out.append(&*last, p - last);
}
+namespace detail {
+// Map from character code to escape mode:
+// 0 = pass through
+// 1 = unused
+// 2 = pass through in PATH mode
+// 3 = space, replace with '+' in QUERY mode
+// 4 = percent-encode
+extern const unsigned char uriEscapeTable[];
+} // namespace detail
+
+template <class String>
+void uriEscape(StringPiece str, String& out, UriEscapeMode mode) {
+ static const char hexValues[] = "0123456789abcdef";
+ char esc[3];
+ esc[0] = '%';
+ // Preallocate assuming that 25% of the input string will be escaped
+ out.reserve(out.size() + str.size() + 3 * (str.size() / 4));
+ auto p = str.begin();
+ auto last = p; // last regular character
+ // We advance over runs of passthrough characters and copy them in one go;
+ // this is faster than calling push_back repeatedly.
+ unsigned char minEncode = static_cast<unsigned char>(mode);
+ while (p != str.end()) {
+ char c = *p;
+ unsigned char v = static_cast<unsigned char>(c);
+ unsigned char discriminator = detail::uriEscapeTable[v];
+ if (LIKELY(discriminator <= minEncode)) {
+ ++p;
+ } else if (mode == UriEscapeMode::QUERY && discriminator == 3) {
+ out.append(&*last, size_t(p - last));
+ out.push_back('+');
+ ++p;
+ last = p;
+ } else {
+ out.append(&*last, size_t(p - last));
+ esc[1] = hexValues[v >> 4];
+ esc[2] = hexValues[v & 0x0f];
+ out.append(esc, 3);
+ ++p;
+ last = p;
+ }
+ }
+ out.append(&*last, size_t(p - last));
+}
+
+template <class String>
+void uriUnescape(StringPiece str, String& out, UriEscapeMode mode) {
+ out.reserve(out.size() + str.size());
+ auto p = str.begin();
+ auto last = p;
+ // We advance over runs of passthrough characters and copy them in one go;
+ // this is faster than calling push_back repeatedly.
+ while (p != str.end()) {
+ char c = *p;
+ switch (c) {
+ case '%':
+ {
+ if (UNLIKELY(std::distance(p, str.end()) < 3)) {
+ throw std::invalid_argument("incomplete percent encode sequence");
+ }
+ auto h1 = detail::hexTable[static_cast<unsigned char>(p[1])];
+ auto h2 = detail::hexTable[static_cast<unsigned char>(p[2])];
+ if (UNLIKELY(h1 == 16 || h2 == 16)) {
+ throw std::invalid_argument("invalid percent encode sequence");
+ }
+ out.append(&*last, size_t(p - last));
+ out.push_back((h1 << 4) | h2);
+ p += 3;
+ last = p;
+ break;
+ }
+ case '+':
+ if (mode == UriEscapeMode::QUERY) {
+ out.append(&*last, size_t(p - last));
+ out.push_back(' ');
+ ++p;
+ last = p;
+ break;
+ }
+ // else fallthrough
+ FOLLY_FALLTHROUGH;
+ default:
+ ++p;
+ break;
+ }
+ }
+ out.append(&*last, size_t(p - last));
+}
+
namespace detail {
/*
return *s.start();
}
-/*
- * These output conversion templates allow us to support multiple
- * output string types, even when we are using an arbitrary
- * OutputIterator.
- */
-template<class OutStringT> struct OutputConverter {};
-
-template<> struct OutputConverter<std::string> {
- std::string operator()(StringPiece sp) const {
- return sp.toString();
- }
-};
-
-template<> struct OutputConverter<fbstring> {
- fbstring operator()(StringPiece sp) const {
- return sp.toFbstring();
- }
-};
-
-template<> struct OutputConverter<StringPiece> {
- StringPiece operator()(StringPiece sp) const { return sp; }
-};
-
/*
* Shared implementation for all the split() overloads.
*
template<class OutStringT, class DelimT, class OutputIterator>
void internalSplit(DelimT delim, StringPiece sp, OutputIterator out,
bool ignoreEmpty) {
- assert(sp.start() != nullptr);
+ assert(sp.empty() || sp.start() != nullptr);
const char* s = sp.start();
const size_t strSize = sp.size();
const size_t dSize = delimSize(delim);
- OutputConverter<OutStringT> conv;
-
if (dSize > strSize || dSize == 0) {
if (!ignoreEmpty || strSize > 0) {
- *out++ = conv(sp);
+ *out++ = to<OutStringT>(sp);
}
return;
}
ignoreEmpty);
}
- int tokenStartPos = 0;
- int tokenSize = 0;
- for (int i = 0; i <= strSize - dSize; ++i) {
+ size_t tokenStartPos = 0;
+ size_t tokenSize = 0;
+ for (size_t i = 0; i <= strSize - dSize; ++i) {
if (atDelim(&s[i], delim)) {
if (!ignoreEmpty || tokenSize > 0) {
- *out++ = conv(StringPiece(&s[tokenStartPos], tokenSize));
+ *out++ = to<OutStringT>(sp.subpiece(tokenStartPos, tokenSize));
}
tokenStartPos = i + dSize;
++tokenSize;
}
}
-
+ tokenSize = strSize - tokenStartPos;
if (!ignoreEmpty || tokenSize > 0) {
- tokenSize = strSize - tokenStartPos;
- *out++ = conv(StringPiece(&s[tokenStartPos], tokenSize));
+ *out++ = to<OutStringT>(sp.subpiece(tokenStartPos, tokenSize));
}
}
}
inline char prepareDelim(char c) { return c; }
+template <bool exact, class Delim, class OutputType>
+bool splitFixed(const Delim& delimiter, StringPiece input, OutputType& output) {
+ static_assert(
+ exact || std::is_same<OutputType, StringPiece>::value ||
+ IsSomeString<OutputType>::value,
+ "split<false>() requires that the last argument be a string type");
+ if (exact && UNLIKELY(std::string::npos != input.find(delimiter))) {
+ return false;
+ }
+ output = folly::to<OutputType>(input);
+ return true;
+}
+
+template <bool exact, class Delim, class OutputType, class... OutputTypes>
+bool splitFixed(
+ const Delim& delimiter,
+ StringPiece input,
+ OutputType& outHead,
+ OutputTypes&... outTail) {
+ size_t cut = input.find(delimiter);
+ if (UNLIKELY(cut == std::string::npos)) {
+ return false;
+ }
+ StringPiece head(input.begin(), input.begin() + cut);
+ StringPiece tail(input.begin() + cut + detail::delimSize(delimiter),
+ input.end());
+ if (LIKELY(splitFixed<exact>(delimiter, tail, outTail...))) {
+ outHead = folly::to<OutputType>(head);
+ return true;
+ }
+ return false;
+}
+
}
//////////////////////////////////////////////////////////////////////
void split(const Delim& delimiter,
const String& input,
fbvector<OutputType>& out,
- bool ignoreEmpty = false) {
+ bool ignoreEmpty) {
detail::internalSplit<OutputType>(
detail::prepareDelim(delimiter),
StringPiece(input),
ignoreEmpty);
}
+template <bool exact, class Delim, class... OutputTypes>
+typename std::enable_if<
+ AllConvertible<OutputTypes...>::value && sizeof...(OutputTypes) >= 1,
+ bool>::type
+split(const Delim& delimiter, StringPiece input, OutputTypes&... outputs) {
+ return detail::splitFixed<exact>(
+ detail::prepareDelim(delimiter), input, outputs...);
+}
+
+namespace detail {
+
+/*
+ * If a type can have its string size determined cheaply, we can more
+ * efficiently append it in a loop (see internalJoinAppend). Note that the
+ * struct need not conform to the std::string api completely (ex. does not need
+ * to implement append()).
+ */
+template <class T> struct IsSizableString {
+ enum { value = IsSomeString<T>::value
+ || std::is_same<T, StringPiece>::value };
+};
+
+template <class Iterator>
+struct IsSizableStringContainerIterator :
+ IsSizableString<typename std::iterator_traits<Iterator>::value_type> {
+};
+
+template <class Delim, class Iterator, class String>
+void internalJoinAppend(Delim delimiter,
+ Iterator begin,
+ Iterator end,
+ String& output) {
+ assert(begin != end);
+ if (std::is_same<Delim, StringPiece>::value &&
+ delimSize(delimiter) == 1) {
+ internalJoinAppend(delimFront(delimiter), begin, end, output);
+ return;
+ }
+ toAppend(*begin, &output);
+ while (++begin != end) {
+ toAppend(delimiter, *begin, &output);
+ }
+}
+
+template <class Delim, class Iterator, class String>
+typename std::enable_if<IsSizableStringContainerIterator<Iterator>::value>::type
+internalJoin(Delim delimiter,
+ Iterator begin,
+ Iterator end,
+ String& output) {
+ output.clear();
+ if (begin == end) {
+ return;
+ }
+ const size_t dsize = delimSize(delimiter);
+ Iterator it = begin;
+ size_t size = it->size();
+ while (++it != end) {
+ size += dsize + it->size();
+ }
+ output.reserve(size);
+ internalJoinAppend(delimiter, begin, end, output);
+}
+
+template <class Delim, class Iterator, class String>
+typename
+std::enable_if<!IsSizableStringContainerIterator<Iterator>::value>::type
+internalJoin(Delim delimiter,
+ Iterator begin,
+ Iterator end,
+ String& output) {
+ output.clear();
+ if (begin == end) {
+ return;
+ }
+ internalJoinAppend(delimiter, begin, end, output);
+}
+
+} // namespace detail
+
+template <class Delim, class Iterator, class String>
+void join(const Delim& delimiter,
+ Iterator begin,
+ Iterator end,
+ String& output) {
+ detail::internalJoin(
+ detail::prepareDelim(delimiter),
+ begin,
+ end,
+ output);
+}
+
+template <class String1, class String2>
+void backslashify(const String1& input, String2& output, bool hex_style) {
+ static const char hexValues[] = "0123456789abcdef";
+ output.clear();
+ output.reserve(3 * input.size());
+ for (unsigned char c : input) {
+ // less than space or greater than '~' are considered unprintable
+ if (c < 0x20 || c > 0x7e || c == '\\') {
+ bool hex_append = false;
+ output.push_back('\\');
+ if (hex_style) {
+ hex_append = true;
+ } else {
+ if (c == '\r') output += 'r';
+ else if (c == '\n') output += 'n';
+ else if (c == '\t') output += 't';
+ else if (c == '\a') output += 'a';
+ else if (c == '\b') output += 'b';
+ else if (c == '\0') output += '0';
+ else if (c == '\\') output += '\\';
+ else {
+ hex_append = true;
+ }
+ }
+ if (hex_append) {
+ output.push_back('x');
+ output.push_back(hexValues[(c >> 4) & 0xf]);
+ output.push_back(hexValues[c & 0xf]);
+ }
+ } else {
+ output += c;
+ }
+ }
+}
+
+template <class String1, class String2>
+void humanify(const String1& input, String2& output) {
+ size_t numUnprintable = 0;
+ size_t numPrintablePrefix = 0;
+ for (unsigned char c : input) {
+ if (c < 0x20 || c > 0x7e || c == '\\') {
+ ++numUnprintable;
+ }
+ if (numUnprintable == 0) {
+ ++numPrintablePrefix;
+ }
+ }
+
+ // hexlify doubles a string's size; backslashify can potentially
+ // explode it by 4x. Now, the printable range of the ascii
+ // "spectrum" is around 95 out of 256 values, so a "random" binary
+ // string should be around 60% unprintable. We use a 50% hueristic
+ // here, so if a string is 60% unprintable, then we just use hex
+ // output. Otherwise we backslash.
+ //
+ // UTF8 is completely ignored; as a result, utf8 characters will
+ // likely be \x escaped (since most common glyphs fit in two bytes).
+ // This is a tradeoff of complexity/speed instead of a convenience
+ // that likely would rarely matter. Moreover, this function is more
+ // about displaying underlying bytes, not about displaying glyphs
+ // from languages.
+ if (numUnprintable == 0) {
+ output = input;
+ } else if (5 * numUnprintable >= 3 * input.size()) {
+ // However! If we have a "meaningful" prefix of printable
+ // characters, say 20% of the string, we backslashify under the
+ // assumption viewing the prefix as ascii is worth blowing the
+ // output size up a bit.
+ if (5 * numPrintablePrefix >= input.size()) {
+ backslashify(input, output);
+ } else {
+ output = "0x";
+ hexlify(input, output, true /* append output */);
+ }
+ } else {
+ backslashify(input, output);
+ }
+}
+
+template<class InputString, class OutputString>
+bool hexlify(const InputString& input, OutputString& output,
+ bool append_output) {
+ if (!append_output) output.clear();
+
+ static char hexValues[] = "0123456789abcdef";
+ auto j = output.size();
+ output.resize(2 * input.size() + output.size());
+ for (size_t i = 0; i < input.size(); ++i) {
+ int ch = input[i];
+ output[j++] = hexValues[(ch >> 4) & 0xf];
+ output[j++] = hexValues[ch & 0xf];
+ }
+ return true;
+}
+
+template<class InputString, class OutputString>
+bool unhexlify(const InputString& input, OutputString& output) {
+ if (input.size() % 2 != 0) {
+ return false;
+ }
+ output.resize(input.size() / 2);
+ int j = 0;
+
+ for (size_t i = 0; i < input.size(); i += 2) {
+ int highBits = detail::hexTable[static_cast<uint8_t>(input[i])];
+ int lowBits = detail::hexTable[static_cast<uint8_t>(input[i + 1])];
+ if ((highBits | lowBits) & 0x10) {
+ // One of the characters wasn't a hex digit
+ return false;
+ }
+ output[j++] = (highBits << 4) + lowBits;
+ }
+ return true;
+}
+
namespace detail {
/**
* Hex-dump at most 16 bytes starting at offset from a memory area of size
}
} // namespace folly
-
-#endif /* FOLLY_STRING_INL_H_ */
-
projects / folly.git / blobdiff