--- /dev/null
+// Copyright (c) 2016 Ryan Prichard
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+
+// Efficient integer->string conversion and string concatenation. The
+// hexadecimal conversion may optionally have leading zeros. Other ways to
+// convert integers to strings in C++ suffer these drawbacks:
+//
+// * std::stringstream: Inefficient, even more so than stdio.
+//
+// * std::to_string: No hexadecimal output, tends to use heap allocation, not
+// supported on Cygwin.
+//
+// * stdio routines: Requires parsing a format string (inefficient). The
+// caller *must* know how large the content is for correctness. The
+// string-printf functions are extremely inconsistent on Windows. In
+// particular, 64-bit integers, wide strings, and return values are
+// problem areas.
+//
+// StringBuilderTest.cc is a standalone program that tests this header.
+
+#ifndef WINPTY_STRING_BUILDER_H
+#define WINPTY_STRING_BUILDER_H
+
+#include <array>
+#include <string>
+#include <type_traits>
+
+#ifdef STRING_BUILDER_TESTING
+#include <assert.h>
+#define STRING_BUILDER_CHECK(cond) assert(cond)
+#else
+#define STRING_BUILDER_CHECK(cond)
+#endif // STRING_BUILDER_TESTING
+
+#include "WinptyAssert.h"
+
+template <typename C, size_t sz>
+struct ValueString {
+ std::array<C, sz> m_array;
+ size_t m_offset;
+ size_t m_size;
+
+ const C *c_str() const { return m_array.data() + m_offset; }
+ const C *data() const { return m_array.data() + m_offset; }
+ size_t size() const { return m_size; }
+ std::basic_string<C> str() const {
+ return std::basic_string<C>(data(), m_size);
+ }
+};
+
+#ifdef _MSC_VER
+// Disable an MSVC /SDL error that forbids unsigned negation. Signed negation
+// invokes undefined behavior for INTxx_MIN, so unsigned negation is simpler to
+// reason about. (We assume twos-complement in any case.)
+#define STRING_BUILDER_ALLOW_UNSIGNED_NEGATE(x) \
+ ( \
+ __pragma(warning(push)) \
+ __pragma(warning(disable:4146)) \
+ (x) \
+ __pragma(warning(pop)) \
+ )
+#else
+#define STRING_BUILDER_ALLOW_UNSIGNED_NEGATE(x) (x)
+#endif
+
+// Formats an integer as decimal without leading zeros.
+template <typename C, typename I>
+ValueString<C, sizeof(I) * 3 + 1 + 1> gdecOfInt(const I value) {
+ typedef typename std::make_unsigned<I>::type U;
+ auto unsValue = static_cast<U>(value);
+ const bool isNegative = (value < 0);
+ if (isNegative) {
+ unsValue = STRING_BUILDER_ALLOW_UNSIGNED_NEGATE(-unsValue);
+ }
+ decltype(gdecOfInt<C, I>(value)) out;
+ auto &arr = out.m_array;
+ C *const endp = arr.data() + arr.size();
+ C *outp = endp;
+ *(--outp) = '\0';
+ STRING_BUILDER_CHECK(outp >= arr.data());
+ do {
+ const int digit = unsValue % 10;
+ unsValue /= 10;
+ *(--outp) = '0' + digit;
+ STRING_BUILDER_CHECK(outp >= arr.data());
+ } while (unsValue != 0);
+ if (isNegative) {
+ *(--outp) = '-';
+ STRING_BUILDER_CHECK(outp >= arr.data());
+ }
+ out.m_offset = outp - arr.data();
+ out.m_size = endp - outp - 1;
+ return out;
+}
+
+template <typename I> decltype(gdecOfInt<char, I>(0)) decOfInt(I i) {
+ return gdecOfInt<char>(i);
+}
+
+template <typename I> decltype(gdecOfInt<wchar_t, I>(0)) wdecOfInt(I i) {
+ return gdecOfInt<wchar_t>(i);
+}
+
+// Formats an integer as hexadecimal, with or without leading zeros.
+template <typename C, bool leadingZeros=false, typename I>
+ValueString<C, sizeof(I) * 2 + 1> ghexOfInt(const I value) {
+ typedef typename std::make_unsigned<I>::type U;
+ const auto unsValue = static_cast<U>(value);
+ static const C hex[16] = {'0','1','2','3','4','5','6','7',
+ '8','9','a','b','c','d','e','f'};
+ decltype(ghexOfInt<C, leadingZeros, I>(value)) out;
+ auto &arr = out.m_array;
+ C *outp = arr.data();
+ int inIndex = 0;
+ int shift = sizeof(I) * 8 - 4;
+ const int len = sizeof(I) * 2;
+ if (!leadingZeros) {
+ for (; inIndex < len - 1; ++inIndex, shift -= 4) {
+ STRING_BUILDER_CHECK(shift >= 0 && shift < sizeof(unsValue) * 8);
+ const int digit = (unsValue >> shift) & 0xF;
+ if (digit != 0) {
+ break;
+ }
+ }
+ }
+ for (; inIndex < len; ++inIndex, shift -= 4) {
+ const int digit = (unsValue >> shift) & 0xF;
+ *(outp++) = hex[digit];
+ STRING_BUILDER_CHECK(outp <= arr.data() + arr.size());
+ }
+ *(outp++) = '\0';
+ STRING_BUILDER_CHECK(outp <= arr.data() + arr.size());
+ out.m_offset = 0;
+ out.m_size = outp - arr.data() - 1;
+ return out;
+}
+
+template <bool leadingZeros=false, typename I>
+decltype(ghexOfInt<char, leadingZeros, I>(0)) hexOfInt(I i) {
+ return ghexOfInt<char, leadingZeros, I>(i);
+}
+
+template <bool leadingZeros=false, typename I>
+decltype(ghexOfInt<wchar_t, leadingZeros, I>(0)) whexOfInt(I i) {
+ return ghexOfInt<wchar_t, leadingZeros, I>(i);
+}
+
+template <typename C>
+class GStringBuilder {
+public:
+ typedef std::basic_string<C> StringType;
+
+ GStringBuilder() {}
+ GStringBuilder(size_t capacity) {
+ m_out.reserve(capacity);
+ }
+
+ GStringBuilder &operator<<(C ch) { m_out.push_back(ch); return *this; }
+ GStringBuilder &operator<<(const C *str) { m_out.append(str); return *this; }
+ GStringBuilder &operator<<(const StringType &str) { m_out.append(str); return *this; }
+
+ template <size_t sz>
+ GStringBuilder &operator<<(const ValueString<C, sz> &str) {
+ m_out.append(str.data(), str.size());
+ return *this;
+ }
+
+private:
+ // Forbid output of char/wchar_t for GStringBuilder if the type doesn't
+ // exactly match the builder element type. The code still allows
+ // signed char and unsigned char, but I'm a little worried about what
+ // happens if a user tries to output int8_t or uint8_t.
+ template <typename P>
+ typename std::enable_if<
+ (std::is_same<P, char>::value || std::is_same<P, wchar_t>::value) &&
+ !std::is_same<C, P>::value, GStringBuilder&>::type
+ operator<<(P ch) {
+ ASSERT(false && "Method was not supposed to be reachable.");
+ return *this;
+ }
+
+public:
+ GStringBuilder &operator<<(short i) { return *this << gdecOfInt<C>(i); }
+ GStringBuilder &operator<<(unsigned short i) { return *this << gdecOfInt<C>(i); }
+ GStringBuilder &operator<<(int i) { return *this << gdecOfInt<C>(i); }
+ GStringBuilder &operator<<(unsigned int i) { return *this << gdecOfInt<C>(i); }
+ GStringBuilder &operator<<(long i) { return *this << gdecOfInt<C>(i); }
+ GStringBuilder &operator<<(unsigned long i) { return *this << gdecOfInt<C>(i); }
+ GStringBuilder &operator<<(long long i) { return *this << gdecOfInt<C>(i); }
+ GStringBuilder &operator<<(unsigned long long i) { return *this << gdecOfInt<C>(i); }
+
+ GStringBuilder &operator<<(const void *p) {
+ m_out.push_back(static_cast<C>('0'));
+ m_out.push_back(static_cast<C>('x'));
+ *this << ghexOfInt<C>(reinterpret_cast<uintptr_t>(p));
+ return *this;
+ }
+
+ StringType str() { return m_out; }
+ StringType str_moved() { return std::move(m_out); }
+ const C *c_str() const { return m_out.c_str(); }
+
+private:
+ StringType m_out;
+};
+
+typedef GStringBuilder<char> StringBuilder;
+typedef GStringBuilder<wchar_t> WStringBuilder;
+
+#endif // WINPTY_STRING_BUILDER_H
projects / VSoRC / .git / blobdiff