Move base to DEPS

base/strings/safe_sprintf.h

-// Copyright 2013 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.
-
-#ifndef BASE_STRINGS_SAFE_SPRINTF_H_
-#define BASE_STRINGS_SAFE_SPRINTF_H_
-
-#include "build/build_config.h"
-
-#include <stddef.h>
-#include <stdint.h>
-#include <stdlib.h>
-
-#if defined(OS_POSIX)
-// For ssize_t
-#include <unistd.h>
-#endif
-
-#include "base/base_export.h"
-#include "base/basictypes.h"
-
-namespace base {
-namespace strings {
-
-#if defined(_MSC_VER)
-// Define ssize_t inside of our namespace.
-#if defined(_WIN64)
-typedef __int64 ssize_t;
-#else
-typedef long ssize_t;
-#endif
-#endif
-
-// SafeSPrintf() is a type-safe and completely self-contained version of
-// snprintf().
-//
-// SafeSNPrintf() is an alternative function signature that can be used when
-// not dealing with fixed-sized buffers. When possible, SafeSPrintf() should
-// always be used instead of SafeSNPrintf()
-//
-// These functions allow for formatting complicated messages from contexts that
-// require strict async-signal-safety. In fact, it is safe to call them from
-// any low-level execution context, as they are guaranteed to make no library
-// or system calls. It deliberately never touches "errno", either.
-//
-// The only exception to this rule is that in debug builds the code calls
-// RAW_CHECK() to help diagnose problems when the format string does not
-// match the rest of the arguments. In release builds, no CHECK()s are used,
-// and SafeSPrintf() instead returns an output string that expands only
-// those arguments that match their format characters. Mismatched arguments
-// are ignored.
-//
-// The code currently only supports a subset of format characters:
-//   %c, %o, %d, %x, %X, %p, and %s.
-//
-// SafeSPrintf() aims to be as liberal as reasonably possible. Integer-like
-// values of arbitrary width can be passed to all of the format characters
-// that expect integers. Thus, it is explicitly legal to pass an "int" to
-// "%c", and output will automatically look at the LSB only. It is also
-// explicitly legal to pass either signed or unsigned values, and the format
-// characters will automatically interpret the arguments accordingly.
-//
-// It is still not legal to mix-and-match integer-like values with pointer
-// values. For instance, you cannot pass a pointer to %x, nor can you pass an
-// integer to %p.
-//
-// The one exception is "0" zero being accepted by "%p". This works-around
-// the problem of C++ defining NULL as an integer-like value.
-//
-// All format characters take an optional width parameter. This must be a
-// positive integer. For %d, %o, %x, %X and %p, if the width starts with
-// a leading '0', padding is done with '0' instead of ' ' characters.
-//
-// There are a few features of snprintf()-style format strings, that
-// SafeSPrintf() does not support at this time.
-//
-// If an actual user showed up, there is no particularly strong reason they
-// couldn't be added. But that assumes that the trade-offs between complexity
-// and utility are favorable.
-//
-// For example, adding support for negative padding widths, and for %n are all
-// likely to be viewed positively. They are all clearly useful, low-risk, easy
-// to test, don't jeopardize the async-signal-safety of the code, and overall
-// have little impact on other parts of SafeSPrintf() function.
-//
-// On the other hands, adding support for alternate forms, positional
-// arguments, grouping, wide characters, localization or floating point numbers
-// are all unlikely to ever be added.
-//
-// SafeSPrintf() and SafeSNPrintf() mimic the behavior of snprintf() and they
-// return the number of bytes needed to store the untruncated output. This
-// does *not* include the terminating NUL byte.
-//
-// They return -1, iff a fatal error happened. This typically can only happen,
-// if the buffer size is a) negative, or b) zero (i.e. not even the NUL byte
-// can be written). The return value can never be larger than SSIZE_MAX-1.
-// This ensures that the caller can always add one to the signed return code
-// in order to determine the amount of storage that needs to be allocated.
-//
-// While the code supports type checking and while it is generally very careful
-// to avoid printing incorrect values, it tends to be conservative in printing
-// as much as possible, even when given incorrect parameters. Typically, in
-// case of an error, the format string will not be expanded. (i.e. something
-// like SafeSPrintf(buf, "%p %d", 1, 2) results in "%p 2"). See above for
-// the use of RAW_CHECK() in debug builds, though.
-//
-// Basic example:
-//   char buf[20];
-//   base::strings::SafeSPrintf(buf, "The answer: %2d", 42);
-//
-// Example with dynamically sized buffer (async-signal-safe). This code won't
-// work on Visual studio, as it requires dynamically allocating arrays on the
-// stack. Consider picking a smaller value for |kMaxSize| if stack size is
-// limited and known. On the other hand, if the parameters to SafeSNPrintf()
-// are trusted and not controllable by the user, you can consider eliminating
-// the check for |kMaxSize| altogether. The current value of SSIZE_MAX is
-// essentially a no-op that just illustrates how to implement an upper bound:
-//   const size_t kInitialSize = 128;
-//   const size_t kMaxSize = std::numeric_limits<ssize_t>::max();
-//   size_t size = kInitialSize;
-//   for (;;) {
-//     char buf[size];
-//     size = SafeSNPrintf(buf, size, "Error message \"%s\"\n", err) + 1;
-//     if (sizeof(buf) < kMaxSize && size > kMaxSize) {
-//       size = kMaxSize;
-//       continue;
-//     } else if (size > sizeof(buf))
-//       continue;
-//     write(2, buf, size-1);
-//     break;
-//   }
-
-namespace internal {
-// Helpers that use C++ overloading, templates, and specializations to deduce
-// and record type information from function arguments. This allows us to
-// later write a type-safe version of snprintf().
-
-struct Arg {
-  enum Type { INT, UINT, STRING, POINTER };
-
-  // Any integer-like value.
-  Arg(signed char c) : type(INT) {
-    integer.i = c;
-    integer.width = sizeof(char);
-  }
-  Arg(unsigned char c) : type(UINT) {
-    integer.i = c;
-    integer.width = sizeof(char);
-  }
-  Arg(signed short j) : type(INT) {
-    integer.i = j;
-    integer.width = sizeof(short);
-  }
-  Arg(unsigned short j) : type(UINT) {
-    integer.i = j;
-    integer.width = sizeof(short);
-  }
-  Arg(signed int j) : type(INT) {
-    integer.i = j;
-    integer.width = sizeof(int);
-  }
-  Arg(unsigned int j) : type(UINT) {
-    integer.i = j;
-    integer.width = sizeof(int);
-  }
-  Arg(signed long j) : type(INT) {
-    integer.i = j;
-    integer.width = sizeof(long);
-  }
-  Arg(unsigned long j) : type(UINT) {
-    integer.i = j;
-    integer.width = sizeof(long);
-  }
-  Arg(signed long long j) : type(INT) {
-    integer.i = j;
-    integer.width = sizeof(long long);
-  }
-  Arg(unsigned long long j) : type(UINT) {
-    integer.i = j;
-    integer.width = sizeof(long long);
-  }
-
-  // A C-style text string.
-  Arg(const char* s) : str(s), type(STRING) { }
-  Arg(char* s)       : str(s), type(STRING) { }
-
-  // Any pointer value that can be cast to a "void*".
-  template<class T> Arg(T* p) : ptr((void*)p), type(POINTER) { }
-
-  union {
-    // An integer-like value.
-    struct {
-      int64_t       i;
-      unsigned char width;
-    } integer;
-
-    // A C-style text string.
-    const char* str;
-
-    // A pointer to an arbitrary object.
-    const void* ptr;
-  };
-  const enum Type type;
-};
-
-// This is the internal function that performs the actual formatting of
-// an snprintf()-style format string.
-BASE_EXPORT ssize_t SafeSNPrintf(char* buf, size_t sz, const char* fmt,
-                                 const Arg* args, size_t max_args);
-
-#if !defined(NDEBUG)
-// In debug builds, allow unit tests to artificially lower the kSSizeMax
-// constant that is used as a hard upper-bound for all buffers. In normal
-// use, this constant should always be std::numeric_limits<ssize_t>::max().
-BASE_EXPORT void SetSafeSPrintfSSizeMaxForTest(size_t max);
-BASE_EXPORT size_t GetSafeSPrintfSSizeMaxForTest();
-#endif
-
-}  // namespace internal
-
-template<typename... Args>
-ssize_t SafeSNPrintf(char* buf, size_t N, const char* fmt, Args... args) {
-  // Use Arg() object to record type information and then copy arguments to an
-  // array to make it easier to iterate over them.
-  const internal::Arg arg_array[] = { args... };
-  return internal::SafeSNPrintf(buf, N, fmt, arg_array, sizeof...(args));
-}
-
-template<size_t N, typename... Args>
-ssize_t SafeSPrintf(char (&buf)[N], const char* fmt, Args... args) {
-  // Use Arg() object to record type information and then copy arguments to an
-  // array to make it easier to iterate over them.
-  const internal::Arg arg_array[] = { args... };
-  return internal::SafeSNPrintf(buf, N, fmt, arg_array, sizeof...(args));
-}
-
-// Fast-path when we don't actually need to substitute any arguments.
-BASE_EXPORT ssize_t SafeSNPrintf(char* buf, size_t N, const char* fmt);
-template<size_t N>
-inline ssize_t SafeSPrintf(char (&buf)[N], const char* fmt) {
-  return SafeSNPrintf(buf, N, fmt);
-}
-
-}  // namespace strings
-}  // namespace base
-
-#endif  // BASE_STRINGS_SAFE_SPRINTF_H_