protobuf/upb/lex/atoi.c

// Protocol Buffers - Google's data interchange format
// Copyright 2023 Google LLC.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google LLC nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "upb/lex/atoi.h"

// Must be last.
#include "upb/port/def.inc"

const char* upb_BufToUint64(const char* ptr, const char* end, uint64_t* val) {
  uint64_t u64 = 0;
  while (ptr < end) {
    unsigned ch = *ptr - '0';
    if (ch >= 10) break;
    if (u64 > UINT64_MAX / 10 || u64 * 10 > UINT64_MAX - ch) {
      return NULL;  // integer overflow
    }
    u64 *= 10;
    u64 += ch;
    ptr++;
  }

  *val = u64;
  return ptr;
}

const char* upb_BufToInt64(const char* ptr, const char* end, int64_t* val,
                           bool* is_neg) {
  bool neg = false;
  uint64_t u64;

  if (ptr != end && *ptr == '-') {
    ptr++;
    neg = true;
  }

  ptr = upb_BufToUint64(ptr, end, &u64);
  if (!ptr || u64 > (uint64_t)INT64_MAX + neg) {
    return NULL;  // integer overflow
  }

  *val = neg ? -u64 : u64;
  if (is_neg) *is_neg = neg;
  return ptr;
}