tor-browser

string_util.cc (23266B)

---

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/string_util.h"

#include <ctype.h>
#include <errno.h>
#include <math.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <wchar.h>
#include <wctype.h>

#include <vector>

#include "base/basictypes.h"
#include "base/logging.h"

namespace {

// Hack to convert any char-like type to its unsigned counterpart.
// For example, it will convert char, signed char and unsigned char to unsigned
// char.
template <typename T>
struct ToUnsigned {
 typedef T Unsigned;
};

template <>
struct ToUnsigned<char> {
 typedef unsigned char Unsigned;
};
template <>
struct ToUnsigned<signed char> {
 typedef unsigned char Unsigned;
};
template <>
struct ToUnsigned<wchar_t> {
#if defined(XP_WIN)
 typedef unsigned short Unsigned;
#else
 typedef uint32_t Unsigned;
#endif
};
template <>
struct ToUnsigned<short> {
 typedef unsigned short Unsigned;
};

// Generalized string-to-number conversion.
//
// StringToNumberTraits should provide:
//  - a typedef for string_type, the STL string type used as input.
//  - a typedef for value_type, the target numeric type.
//  - a static function, convert_func, which dispatches to an appropriate
//    strtol-like function and returns type value_type.
//  - a static function, valid_func, which validates |input| and returns a bool
//    indicating whether it is in proper form.  This is used to check for
//    conditions that convert_func tolerates but should result in
//    StringToNumber returning false.  For strtol-like funtions, valid_func
//    should check for leading whitespace.
template <typename StringToNumberTraits>
bool StringToNumber(const typename StringToNumberTraits::string_type& input,
                   typename StringToNumberTraits::value_type* output) {
 typedef StringToNumberTraits traits;

 errno = 0;  // Thread-safe?  It is on at least Mac, Linux, and Windows.
 typename traits::string_type::value_type* endptr = NULL;
 typename traits::value_type value =
     traits::convert_func(input.c_str(), &endptr);
 *output = value;

 // Cases to return false:
 //  - If errno is ERANGE, there was an overflow or underflow.
 //  - If the input string is empty, there was nothing to parse.
 //  - If endptr does not point to the end of the string, there are either
 //    characters remaining in the string after a parsed number, or the string
 //    does not begin with a parseable number.  endptr is compared to the
 //    expected end given the string's stated length to correctly catch cases
 //    where the string contains embedded NUL characters.
 //  - valid_func determines that the input is not in preferred form.
 return errno == 0 && !input.empty() &&
        input.c_str() + input.length() == endptr && traits::valid_func(input);
}

class StringToLongTraits {
public:
 typedef std::string string_type;
 typedef long value_type;
 static const int kBase = 10;
 static inline value_type convert_func(const string_type::value_type* str,
                                       string_type::value_type** endptr) {
   return strtol(str, endptr, kBase);
 }
 static inline bool valid_func(const string_type& str) {
   return !str.empty() && !isspace(str[0]);
 }
};

class String16ToLongTraits {
public:
 typedef string16 string_type;
 typedef long value_type;
 static const int kBase = 10;
 static inline value_type convert_func(const string_type::value_type* str,
                                       string_type::value_type** endptr) {
#if defined(XP_WIN)
   return wcstol(str, endptr, kBase);
#else
   std::string ascii_string = UTF16ToASCII(string16(str));
   char* ascii_end = NULL;
   value_type ret = strtol(ascii_string.c_str(), &ascii_end, kBase);
   if (ascii_string.c_str() + ascii_string.length() == ascii_end) {
     *endptr =
         const_cast<string_type::value_type*>(str) + ascii_string.length();
   }
   return ret;
#endif
 }
 static inline bool valid_func(const string_type& str) {
   return !str.empty() && !iswspace(str[0]);
 }
};

class StringToInt64Traits {
public:
 typedef std::string string_type;
 typedef int64_t value_type;
 static const int kBase = 10;
 static inline value_type convert_func(const string_type::value_type* str,
                                       string_type::value_type** endptr) {
#ifdef XP_WIN
   return _strtoi64(str, endptr, kBase);
#else  // assume XP_UNIX
   return strtoll(str, endptr, kBase);
#endif
 }
 static inline bool valid_func(const string_type& str) {
   return !str.empty() && !isspace(str[0]);
 }
};

class String16ToInt64Traits {
public:
 typedef string16 string_type;
 typedef int64_t value_type;
 static const int kBase = 10;
 static inline value_type convert_func(const string_type::value_type* str,
                                       string_type::value_type** endptr) {
#ifdef XP_WIN
   return _wcstoi64(str, endptr, kBase);
#else  // assume XP_UNIX
   std::string ascii_string = UTF16ToASCII(string16(str));
   char* ascii_end = NULL;
   value_type ret = strtoll(ascii_string.c_str(), &ascii_end, kBase);
   if (ascii_string.c_str() + ascii_string.length() == ascii_end) {
     *endptr =
         const_cast<string_type::value_type*>(str) + ascii_string.length();
   }
   return ret;
#endif
 }
 static inline bool valid_func(const string_type& str) {
   return !str.empty() && !iswspace(str[0]);
 }
};

}  // namespace

namespace base {

bool IsWprintfFormatPortable(const wchar_t* format) {
 for (const wchar_t* position = format; *position != '\0'; ++position) {
   if (*position == '%') {
     bool in_specification = true;
     bool modifier_l = false;
     while (in_specification) {
       // Eat up characters until reaching a known specifier.
       if (*++position == '\0') {
         // The format string ended in the middle of a specification.  Call
         // it portable because no unportable specifications were found.  The
         // string is equally broken on all platforms.
         return true;
       }

       if (*position == 'l') {
         // 'l' is the only thing that can save the 's' and 'c' specifiers.
         modifier_l = true;
       } else if (((*position == 's' || *position == 'c') && !modifier_l) ||
                  *position == 'S' || *position == 'C' || *position == 'F' ||
                  *position == 'D' || *position == 'O' || *position == 'U') {
         // Not portable.
         return false;
       }

       if (wcschr(L"diouxXeEfgGaAcspn%", *position)) {
         // Portable, keep scanning the rest of the format string.
         in_specification = false;
       }
     }
   }
 }

 return true;
}

}  // namespace base

static const wchar_t kWhitespaceWide[] = {
   0x0009,  // <control-0009> to <control-000D>
   0x000A, 0x000B, 0x000C, 0x000D,
   0x0020,  // Space
   0x0085,  // <control-0085>
   0x00A0,  // No-Break Space
   0x1680,  // Ogham Space Mark
   0x180E,  // Mongolian Vowel Separator
   0x2000,  // En Quad to Hair Space
   0x2001, 0x2002, 0x2003, 0x2004, 0x2005,
   0x2006, 0x2007, 0x2008, 0x2009, 0x200A,
   0x200C,  // Zero Width Non-Joiner
   0x2028,  // Line Separator
   0x2029,  // Paragraph Separator
   0x202F,  // Narrow No-Break Space
   0x205F,  // Medium Mathematical Space
   0x3000,  // Ideographic Space
   0};
static const char kWhitespaceASCII[] = {
   0x09,  // <control-0009> to <control-000D>
   0x0A, 0x0B, 0x0C, 0x0D,
   0x20,  // Space
   0};

template <typename STR>
TrimPositions TrimStringT(const STR& input,
                         const typename STR::value_type trim_chars[],
                         TrimPositions positions, STR* output) {
 // Find the edges of leading/trailing whitespace as desired.
 const typename STR::size_type last_char = input.length() - 1;
 const typename STR::size_type first_good_char =
     (positions & TRIM_LEADING) ? input.find_first_not_of(trim_chars) : 0;
 const typename STR::size_type last_good_char =
     (positions & TRIM_TRAILING) ? input.find_last_not_of(trim_chars)
                                 : last_char;

 // When the string was all whitespace, report that we stripped off whitespace
 // from whichever position the caller was interested in.  For empty input, we
 // stripped no whitespace, but we still need to clear |output|.
 if (input.empty() || (first_good_char == STR::npos) ||
     (last_good_char == STR::npos)) {
   bool input_was_empty = input.empty();  // in case output == &input
   output->clear();
   return input_was_empty ? TRIM_NONE : positions;
 }

 // Trim the whitespace.
 *output = input.substr(first_good_char, last_good_char - first_good_char + 1);

 // Return where we trimmed from.
 return static_cast<TrimPositions>(
     ((first_good_char == 0) ? TRIM_NONE : TRIM_LEADING) |
     ((last_good_char == last_char) ? TRIM_NONE : TRIM_TRAILING));
}

TrimPositions TrimWhitespace(const std::wstring& input, TrimPositions positions,
                            std::wstring* output) {
 return TrimStringT(input, kWhitespaceWide, positions, output);
}

TrimPositions TrimWhitespaceASCII(const std::string& input,
                                 TrimPositions positions,
                                 std::string* output) {
 return TrimStringT(input, kWhitespaceASCII, positions, output);
}

// This function is only for backward-compatibility.
// To be removed when all callers are updated.
TrimPositions TrimWhitespace(const std::string& input, TrimPositions positions,
                            std::string* output) {
 return TrimWhitespaceASCII(input, positions, output);
}

std::string WideToASCII(const std::wstring& wide) {
 DCHECK(IsStringASCII(wide));
 return std::string(wide.begin(), wide.end());
}

std::wstring ASCIIToWide(const std::string& ascii) {
 DCHECK(IsStringASCII(ascii));
 return std::wstring(ascii.begin(), ascii.end());
}

std::string UTF16ToASCII(const string16& utf16) {
 DCHECK(IsStringASCII(utf16));
 return std::string(utf16.begin(), utf16.end());
}

string16 ASCIIToUTF16(const std::string& ascii) {
 DCHECK(IsStringASCII(ascii));
 return string16(ascii.begin(), ascii.end());
}

template <class STR>
static bool DoIsStringASCII(const STR& str) {
 for (size_t i = 0; i < str.length(); i++) {
   typename ToUnsigned<typename STR::value_type>::Unsigned c = str[i];
   if (c > 0x7F) return false;
 }
 return true;
}

bool IsStringASCII(const std::wstring& str) { return DoIsStringASCII(str); }

#if !defined(XP_WIN)
bool IsStringASCII(const string16& str) { return DoIsStringASCII(str); }
#endif

bool IsStringASCII(const std::string& str) { return DoIsStringASCII(str); }

// Overloaded wrappers around vsnprintf and vswprintf. The buf_size parameter
// is the size of the buffer. These return the number of characters in the
// formatted string excluding the NUL terminator. If the buffer is not
// large enough to accommodate the formatted string without truncation, they
// return the number of characters that would be in the fully-formatted string
// (vsnprintf, and vswprintf on Windows), or -1 (vswprintf on POSIX platforms).
inline int vsnprintfT(char* buffer, size_t buf_size, const char* format,
                     va_list argptr) {
 return base::vsnprintf(buffer, buf_size, format, argptr);
}

inline int vsnprintfT(wchar_t* buffer, size_t buf_size, const wchar_t* format,
                     va_list argptr) {
 return base::vswprintf(buffer, buf_size, format, argptr);
}

// Templatized backend for StringPrintF/StringAppendF. This does not finalize
// the va_list, the caller is expected to do that.
template <class StringType>
static void StringAppendVT(StringType* dst,
                          const typename StringType::value_type* format,
                          va_list ap) {
 // First try with a small fixed size buffer.
 // This buffer size should be kept in sync with StringUtilTest.GrowBoundary
 // and StringUtilTest.StringPrintfBounds.
 typename StringType::value_type stack_buf[1024];

 va_list backup_ap;
 base_va_copy(backup_ap, ap);

#if !defined(XP_WIN)
 errno = 0;
#endif
 int result = vsnprintfT(stack_buf, arraysize(stack_buf), format, backup_ap);
 va_end(backup_ap);

 if (result >= 0 && result < static_cast<int>(arraysize(stack_buf))) {
   // It fit.
   dst->append(stack_buf, result);
   return;
 }

 // Repeatedly increase buffer size until it fits.
 int mem_length = arraysize(stack_buf);
 while (true) {
   if (result < 0) {
#if !defined(XP_WIN)
     // On Windows, vsnprintfT always returns the number of characters in a
     // fully-formatted string, so if we reach this point, something else is
     // wrong and no amount of buffer-doubling is going to fix it.
     if (errno != 0 && errno != EOVERFLOW)
#endif
     {
       // If an error other than overflow occurred, it's never going to work.
       DLOG(WARNING) << "Unable to printf the requested string due to error.";
       return;
     }
     // Try doubling the buffer size.
     mem_length *= 2;
   } else {
     // We need exactly "result + 1" characters.
     mem_length = result + 1;
   }

   if (mem_length > 32 * 1024 * 1024) {
     // That should be plenty, don't try anything larger.  This protects
     // against huge allocations when using vsnprintfT implementations that
     // return -1 for reasons other than overflow without setting errno.
     DLOG(WARNING) << "Unable to printf the requested string due to size.";
     return;
   }

   std::vector<typename StringType::value_type> mem_buf(mem_length);

   // Restore the va_list before we use it again.
   base_va_copy(backup_ap, ap);

   result = vsnprintfT(&mem_buf[0], mem_length, format, ap);
   va_end(backup_ap);

   if ((result >= 0) && (result < mem_length)) {
     // It fit.
     dst->append(&mem_buf[0], result);
     return;
   }
 }
}

namespace {

template <typename STR, typename INT, typename UINT, bool NEG>
struct IntToStringT {
 // This is to avoid a compiler warning about unary minus on unsigned type.
 // For example, say you had the following code:
 //   template <typename INT>
 //   INT abs(INT value) { return value < 0 ? -value : value; }
 // Even though if INT is unsigned, it's impossible for value < 0, so the
 // unary minus will never be taken, the compiler will still generate a
 // warning.  We do a little specialization dance...
 template <typename INT2, typename UINT2, bool NEG2>
 struct ToUnsignedT {};

 template <typename INT2, typename UINT2>
 struct ToUnsignedT<INT2, UINT2, false> {
   static UINT2 ToUnsigned(INT2 value) { return static_cast<UINT2>(value); }
 };

 template <typename INT2, typename UINT2>
 struct ToUnsignedT<INT2, UINT2, true> {
   static UINT2 ToUnsigned(INT2 value) {
     return static_cast<UINT2>(value < 0 ? -value : value);
   }
 };

 // This set of templates is very similar to the above templates, but
 // for testing whether an integer is negative.
 template <typename INT2, bool NEG2>
 struct TestNegT {};
 template <typename INT2>
 struct TestNegT<INT2, false> {
   static bool TestNeg(INT2 value) {
     // value is unsigned, and can never be negative.
     return false;
   }
 };
 template <typename INT2>
 struct TestNegT<INT2, true> {
   static bool TestNeg(INT2 value) { return value < 0; }
 };

 static STR IntToString(INT value) {
   // log10(2) ~= 0.3 bytes needed per bit or per byte log10(2**8) ~= 2.4.
   // So round up to allocate 3 output characters per byte, plus 1 for '-'.
   const int kOutputBufSize = 3 * sizeof(INT) + 1;

   // Allocate the whole string right away, we will right back to front, and
   // then return the substr of what we ended up using.
   STR outbuf(kOutputBufSize, 0);

   bool is_neg = TestNegT<INT, NEG>::TestNeg(value);
   // Even though is_neg will never be true when INT is parameterized as
   // unsigned, even the presence of the unary operation causes a warning.
   UINT res = ToUnsignedT<INT, UINT, NEG>::ToUnsigned(value);

   for (typename STR::iterator it = outbuf.end();;) {
     --it;
     DCHECK(it != outbuf.begin());
     *it = static_cast<typename STR::value_type>((res % 10) + '0');
     res /= 10;

     // We're done..
     if (res == 0) {
       if (is_neg) {
         --it;
         DCHECK(it != outbuf.begin());
         *it = static_cast<typename STR::value_type>('-');
       }
       return STR(it, outbuf.end());
     }
   }
   NOTREACHED();
   return STR();
 }
};

}  // namespace

std::string IntToString(int value) {
 return IntToStringT<std::string, int, unsigned int, true>::IntToString(value);
}
std::wstring IntToWString(int value) {
 return IntToStringT<std::wstring, int, unsigned int, true>::IntToString(
     value);
}
std::string UintToString(unsigned int value) {
 return IntToStringT<std::string, unsigned int, unsigned int,
                     false>::IntToString(value);
}
std::wstring UintToWString(unsigned int value) {
 return IntToStringT<std::wstring, unsigned int, unsigned int,
                     false>::IntToString(value);
}
std::string Int64ToString(int64_t value) {
 return IntToStringT<std::string, int64_t, uint64_t, true>::IntToString(value);
}
std::wstring Int64ToWString(int64_t value) {
 return IntToStringT<std::wstring, int64_t, uint64_t, true>::IntToString(
     value);
}
std::string Uint64ToString(uint64_t value) {
 return IntToStringT<std::string, uint64_t, uint64_t, false>::IntToString(
     value);
}
std::wstring Uint64ToWString(uint64_t value) {
 return IntToStringT<std::wstring, uint64_t, uint64_t, false>::IntToString(
     value);
}

// Lower-level routine that takes a va_list and appends to a specified
// string.  All other routines are just convenience wrappers around it.
static void StringAppendV(std::string* dst, const char* format, va_list ap) {
 StringAppendVT(dst, format, ap);
}

static void StringAppendV(std::wstring* dst, const wchar_t* format,
                         va_list ap) {
 StringAppendVT(dst, format, ap);
}

std::string StringPrintf(const char* format, ...) {
 va_list ap;
 va_start(ap, format);
 std::string result;
 StringAppendV(&result, format, ap);
 va_end(ap);
 return result;
}

std::wstring StringPrintf(const wchar_t* format, ...) {
 va_list ap;
 va_start(ap, format);
 std::wstring result;
 StringAppendV(&result, format, ap);
 va_end(ap);
 return result;
}

const std::string& SStringPrintf(std::string* dst, const char* format, ...) {
 va_list ap;
 va_start(ap, format);
 dst->clear();
 StringAppendV(dst, format, ap);
 va_end(ap);
 return *dst;
}

const std::wstring& SStringPrintf(std::wstring* dst, const wchar_t* format,
                                 ...) {
 va_list ap;
 va_start(ap, format);
 dst->clear();
 StringAppendV(dst, format, ap);
 va_end(ap);
 return *dst;
}

void StringAppendF(std::string* dst, const char* format, ...) {
 va_list ap;
 va_start(ap, format);
 StringAppendV(dst, format, ap);
 va_end(ap);
}

void StringAppendF(std::wstring* dst, const wchar_t* format, ...) {
 va_list ap;
 va_start(ap, format);
 StringAppendV(dst, format, ap);
 va_end(ap);
}

template <typename STR>
static void SplitStringT(const STR& str, const typename STR::value_type s,
                        bool trim_whitespace, std::vector<STR>* r) {
 size_t last = 0;
 size_t i;
 size_t c = str.size();
 for (i = 0; i <= c; ++i) {
   if (i == c || str[i] == s) {
     size_t len = i - last;
     STR tmp = str.substr(last, len);
     if (trim_whitespace) {
       STR t_tmp;
       TrimWhitespace(tmp, TRIM_ALL, &t_tmp);
       r->push_back(t_tmp);
     } else {
       r->push_back(tmp);
     }
     last = i + 1;
   }
 }
}

void SplitString(const std::wstring& str, wchar_t s,
                std::vector<std::wstring>* r) {
 SplitStringT(str, s, true, r);
}

void SplitString(const std::string& str, char s, std::vector<std::string>* r) {
 SplitStringT(str, s, true, r);
}

// For the various *ToInt conversions, there are no *ToIntTraits classes to use
// because there's no such thing as strtoi.  Use *ToLongTraits through a cast
// instead, requiring that long and int are compatible and equal-width.  They
// are on our target platforms.

// XXX Sigh.

#if !defined(HAVE_64BIT_BUILD)
bool StringToInt(const std::string& input, int* output) {
 COMPILE_ASSERT(sizeof(int) == sizeof(long), cannot_strtol_to_int);
 return StringToNumber<StringToLongTraits>(input,
                                           reinterpret_cast<long*>(output));
}

bool StringToInt(const string16& input, int* output) {
 COMPILE_ASSERT(sizeof(int) == sizeof(long), cannot_wcstol_to_int);
 return StringToNumber<String16ToLongTraits>(input,
                                             reinterpret_cast<long*>(output));
}

#else
bool StringToInt(const std::string& input, int* output) {
 long tmp;
 bool ok = StringToNumber<StringToLongTraits>(input, &tmp);
 if (!ok || tmp > kint32max) {
   return false;
 }
 *output = static_cast<int>(tmp);
 return true;
}

bool StringToInt(const string16& input, int* output) {
 long tmp;
 bool ok = StringToNumber<String16ToLongTraits>(input, &tmp);
 if (!ok || tmp > kint32max) {
   return false;
 }
 *output = static_cast<int>(tmp);
 return true;
}
#endif  //  !defined(HAVE_64BIT_BUILD)

bool StringToInt64(const std::string& input, int64_t* output) {
 return StringToNumber<StringToInt64Traits>(input, output);
}

bool StringToInt64(const string16& input, int64_t* output) {
 return StringToNumber<String16ToInt64Traits>(input, output);
}

int StringToInt(const std::string& value) {
 int result;
 StringToInt(value, &result);
 return result;
}

int StringToInt(const string16& value) {
 int result;
 StringToInt(value, &result);
 return result;
}

int64_t StringToInt64(const std::string& value) {
 int64_t result;
 StringToInt64(value, &result);
 return result;
}

int64_t StringToInt64(const string16& value) {
 int64_t result;
 StringToInt64(value, &result);
 return result;
}

// The following code is compatible with the OpenBSD lcpy interface.  See:
//   http://www.gratisoft.us/todd/papers/strlcpy.html
//   ftp://ftp.openbsd.org/pub/OpenBSD/src/lib/libc/string/{wcs,str}lcpy.c

namespace {

template <typename CHAR>
size_t lcpyT(CHAR* dst, const CHAR* src, size_t dst_size) {
 for (size_t i = 0; i < dst_size; ++i) {
   if ((dst[i] = src[i]) == 0)  // We hit and copied the terminating NULL.
     return i;
 }

 // We were left off at dst_size.  We over copied 1 byte.  Null terminate.
 if (dst_size != 0) dst[dst_size - 1] = 0;

 // Count the rest of the |src|, and return it's length in characters.
 while (src[dst_size]) ++dst_size;
 return dst_size;
}

}  // namespace

size_t base::strlcpy(char* dst, const char* src, size_t dst_size) {
 return lcpyT<char>(dst, src, dst_size);
}
size_t base::wcslcpy(wchar_t* dst, const wchar_t* src, size_t dst_size) {
 return lcpyT<wchar_t>(dst, src, dst_size);
}