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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include <cstdarg>
#ifdef _WIN32
#include <windows.h>
#else
#include <unistd.h>
#endif
#include <cstring>
#include "mozilla/Assertions.h"
#include "mozilla/Unused.h"
/* Template class allowing a limited number of increments on a value */
template <typename T>
class CheckedIncrement
{
public:
CheckedIncrement(T aValue, size_t aMaxIncrement)
: mValue(aValue), mMaxIncrement(aMaxIncrement)
{}
T operator ++(int)
{
if (!mMaxIncrement) {
MOZ_CRASH("overflow detected");
}
mMaxIncrement--;
return mValue++;
}
T& operator ++()
{
(*this)++;
return mValue;
}
operator T() { return mValue; }
private:
T mValue;
size_t mMaxIncrement;
};
void
FdPrintf(intptr_t aFd, const char* aFormat, ...)
{
if (aFd == 0) {
return;
}
char buf[256];
CheckedIncrement<char*> b(buf, sizeof(buf));
CheckedIncrement<const char*> f(aFormat, strlen(aFormat) + 1);
va_list ap;
va_start(ap, aFormat);
while (true) {
switch (*f) {
case '\0':
goto out;
case '%':
switch (*++f) {
case 'z': {
if (*(++f) == 'u') {
size_t i = va_arg(ap, size_t);
size_t x = 1;
// Compute the number of digits.
while (x <= i / 10) {
x *= 10;
}
// Write the digits into the buffer.
do {
*(b++) = "0123456789"[(i / x) % 10];
x /= 10;
} while (x > 0);
} else {
// Write out the format specifier if it's unknown.
*(b++) = '%';
*(b++) = 'z';
*(b++) = *f;
}
break;
}
case 'p': {
intptr_t ptr = va_arg(ap, intptr_t);
*(b++) = '0';
*(b++) = 'x';
int x = sizeof(intptr_t) * 8;
bool wrote_msb = false;
do {
x -= 4;
size_t hex_digit = ptr >> x & 0xf;
if (hex_digit || wrote_msb) {
*(b++) = "0123456789abcdef"[hex_digit];
wrote_msb = true;
}
} while (x > 0);
if (!wrote_msb) {
*(b++) = '0';
}
break;
}
default:
// Write out the format specifier if it's unknown.
*(b++) = '%';
*(b++) = *f;
break;
}
break;
default:
*(b++) = *f;
break;
}
f++;
}
out:
#ifdef _WIN32
// See comment in FdPrintf.h as to why WriteFile is used.
DWORD written;
WriteFile(reinterpret_cast<HANDLE>(aFd), buf, b - buf, &written, nullptr);
#else
MOZ_UNUSED(write(aFd, buf, b - buf));
#endif
va_end(ap);
}
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