third_party/tcmalloc/vendor/src/raw_printer.cc

// Copyright (c) 2008, Google Inc.
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// ---
// Author: sanjay@google.com (Sanjay Ghemawat)

#include <config.h>
#include <stdarg.h>
#include <stdio.h>
#include "raw_printer.h"
#include "base/logging.h"

namespace base {

RawPrinter::RawPrinter(char* buf, int length)
    : base_(buf),
      ptr_(buf),
      limit_(buf + length - 1) {
  RAW_DCHECK(length > 0, "");
  *ptr_ = '\0';
  *limit_ = '\0';
}

void RawPrinter::Printf(const char* format, ...) {
  if (limit_ > ptr_) {
    va_list ap;
    va_start(ap, format);
    int avail = limit_ - ptr_;
    // We pass avail+1 to vsnprintf() since that routine needs room
    // to store the trailing \0.
    const int r = perftools_vsnprintf(ptr_, avail+1, format, ap);
    va_end(ap);
    if (r < 0) {
      // Perhaps an old glibc that returns -1 on truncation?
      ptr_ = limit_;
    } else if (r > avail) {
      // Truncation
      ptr_ = limit_;
    } else {
      ptr_ += r;
    }
  }
}

}