Update BaseLib according to code review comments.

[mirror_edk2.git] / MdePkg / Library / BaseLib / CheckSum.c

/** @file\r
  Utility functions to generate checksum based on 2's complement\r
  algorithm.\r
\r
  Copyright (c) 2007 - 2008, Intel Corporation<BR>\r
  All rights reserved. This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
\r
#include <BaseLibInternals.h>\r
\r
\r
/**\r
  Calculate the sum of all elements in a buffer in unit of UINT8. \r
  During calculation, the carry bits are dropped.\r
\r
  This function calculates the sum of all elements in a buffer \r
  in unit of UINT8. The carry bits in result of addition are dropped. \r
  The result is returned as UINT8. If Length is Zero, then Zero is \r
  returned.\r
  \r
  If Buffer is NULL, then ASSERT().\r
  If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT(). \r
\r
  @param  Buffer      Pointer to the buffer to carry out the sum operation.\r
  @param  Length      The size, in bytes, of Buffer .\r
\r
  @return Sum         The sum of Buffer with carry bits dropped during additions.\r
\r
**/\r
UINT8\r
EFIAPI\r
CalculateSum8 (\r
  IN      CONST UINT8        *Buffer,\r
  IN      UINTN              Length\r
  )\r
{\r
  UINT8     Sum;\r
  UINTN     Count;\r
\r
  ASSERT (Buffer != NULL);\r
  ASSERT (Length <= (MAX_ADDRESS - ((UINTN) Buffer) + 1));\r
\r
  for (Sum = 0, Count = 0; Count < Length; Count++) {\r
    Sum = (UINT8) (Sum + *(Buffer + Count));\r
  }\r
  \r
  return Sum;\r
}\r
\r
\r
/**\r
  Returns the two's complement checksum of all elements in a buffer \r
  of 8-bit values.\r
\r
  This function first calculates the sum of the 8-bit values in the \r
  buffer specified by Buffer and Length.  The carry bits in the result \r
  of addition are dropped. Then, the two's complement of the sum is \r
  returned.  If Length is 0, then 0 is returned.\r
  \r
  If Buffer is NULL, then ASSERT().\r
  If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT().\r
\r
  @param  Buffer      Pointer to the buffer to carry out the checksum operation.\r
  @param  Length      The size, in bytes, of Buffer.\r
\r
  @return Checksum    The 2's complement checksum of Buffer.\r
\r
**/\r
UINT8\r
EFIAPI\r
CalculateCheckSum8 (\r
  IN      CONST UINT8        *Buffer,\r
  IN      UINTN              Length\r
  )\r
{\r
  UINT8     CheckSum;\r
\r
  CheckSum = CalculateSum8 (Buffer, Length);\r
\r
  //\r
  // Return the checksum based on 2's complement.\r
  //\r
  return (UINT8) (0x100 - CheckSum);\r
}\r
\r
/**\r
  Returns the sum of all elements in a buffer of 16-bit values.  During \r
  calculation, the carry bits are dropped.\r
\r
  This function calculates the sum of the 16-bit values in the buffer \r
  specified by Buffer and Length. The carry bits in result of addition are dropped. \r
  The 16-bit result is returned.  If Length is 0, then 0 is returned.  \r
  \r
  If Buffer is NULL, then ASSERT().\r
  If Buffer is not aligned on a 16-bit boundary, then ASSERT().\r
  If Length is not aligned on a 16-bit boundary, then ASSERT().\r
  If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT().\r
\r
  @param  Buffer      Pointer to the buffer to carry out the sum operation.\r
  @param  Length      The size, in bytes, of Buffer.\r
\r
  @return Sum         The sum of Buffer with carry bits dropped during additions.\r
\r
**/\r
UINT16\r
EFIAPI\r
CalculateSum16 (\r
  IN      CONST UINT16       *Buffer,\r
  IN      UINTN              Length\r
  )\r
{\r
  UINT16    Sum;\r
  UINTN     Count;\r
  UINTN     Total;\r
\r
  ASSERT (Buffer != NULL);\r
  ASSERT (((UINTN) Buffer & 0x1) == 0);\r
  ASSERT ((Length & 0x1) == 0);\r
  ASSERT (Length <= (MAX_ADDRESS - ((UINTN) Buffer) + 1));\r
\r
  Total = Length / sizeof (*Buffer);\r
  for (Sum = 0, Count = 0; Count < Total; Count++) {\r
    Sum = (UINT16) (Sum + *(Buffer + Count));\r
  }\r
  \r
  return Sum;\r
}\r
\r
\r
/**\r
  Returns the two's complement checksum of all elements in a buffer of \r
  16-bit values.\r
\r
  This function first calculates the sum of the 16-bit values in the buffer \r
  specified by Buffer and Length.  The carry bits in the result of addition \r
  are dropped. Then, the two's complement of the sum is returned.  If Length \r
  is 0, then 0 is returned.\r
  \r
  If Buffer is NULL, then ASSERT().\r
  If Buffer is not aligned on a 16-bit boundary, then ASSERT().\r
  If Length is not aligned on a 16-bit boundary, then ASSERT().\r
  If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT(). \r
\r
  @param  Buffer      Pointer to the buffer to carry out the checksum operation.\r
  @param  Length      The size, in bytes, of Buffer.\r
\r
  @return Checksum    The 2's complement checksum of Buffer.\r
\r
**/\r
UINT16\r
EFIAPI\r
CalculateCheckSum16 (\r
  IN      CONST UINT16         *Buffer,\r
  IN      UINTN                Length\r
  )\r
{\r
  UINT16     CheckSum;\r
\r
  CheckSum = CalculateSum16 (Buffer, Length);\r
\r
  //\r
  // Return the checksum based on 2's complement.\r
  //\r
  return (UINT16) (0x10000 - CheckSum);\r
}\r
\r
\r
/**\r
  Returns the sum of all elements in a buffer of 32-bit values.  During \r
  calculation, the carry bits are dropped.\r
\r
  This function calculates the sum of the 32-bit values in the buffer \r
  specified by Buffer and Length. The carry bits in result of addition are dropped. \r
  The 32-bit result is returned.  If Length is 0, then 0 is returned.  \r
  \r
  If Buffer is NULL, then ASSERT().\r
  If Buffer is not aligned on a 32-bit boundary, then ASSERT().\r
  If Length is not aligned on a 32-bit boundary, then ASSERT().\r
  If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT().\r
\r
  @param  Buffer      Pointer to the buffer to carry out the sum operation.\r
  @param  Length      The size, in bytes, of Buffer.\r
\r
  @return Sum         The sum of Buffer with carry bits dropped during additions.\r
\r
**/\r
UINT32\r
EFIAPI\r
CalculateSum32 (\r
  IN      CONST UINT32         *Buffer,\r
  IN      UINTN                Length\r
  )\r
{\r
  UINT32    Sum;\r
  UINTN     Count;\r
  UINTN     Total;\r
\r
  ASSERT (Buffer != NULL);\r
  ASSERT (((UINTN) Buffer & 0x3) == 0);\r
  ASSERT ((Length & 0x3) == 0);\r
  ASSERT (Length <= (MAX_ADDRESS - ((UINTN) Buffer) + 1));\r
\r
  Total = Length / sizeof (*Buffer);\r
  for (Sum = 0, Count = 0; Count < Total; Count++) {\r
    Sum = Sum + *(Buffer + Count);\r
  }\r
  \r
  return Sum;\r
}\r
\r
\r
/**\r
  Returns the two's complement checksum of all elements in a buffer of \r
  32-bit values.\r
\r
  This function first calculates the sum of the 32-bit values in the buffer \r
  specified by Buffer and Length.  The carry bits in the result of addition \r
  are dropped. Then, the two's complement of the sum is returned.  If Length \r
  is 0, then 0 is returned.\r
  \r
  If Buffer is NULL, then ASSERT().\r
  If Buffer is not aligned on a 32-bit boundary, then ASSERT().\r
  If Length is not aligned on a 32-bit boundary, then ASSERT().\r
  If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT(). \r
\r
  @param  Buffer      Pointer to the buffer to carry out the checksum operation.\r
  @param  Length      The size, in bytes, of Buffer.\r
\r
  @return Checksum    The 2's complement checksum of Buffer.\r
\r
**/\r
UINT32\r
EFIAPI\r
CalculateCheckSum32 (\r
  IN      CONST UINT32         *Buffer,\r
  IN      UINTN                Length\r
  )\r
{\r
  UINT32     CheckSum;\r
\r
  CheckSum = CalculateSum32 (Buffer, Length);\r
\r
  //\r
  // Return the checksum based on 2's complement.\r
  //\r
  return (UINT32) ((UINT32)(-1) - CheckSum + 1);\r
}\r
\r
\r
/**\r
  Returns the sum of all elements in a buffer of 64-bit values.  During \r
  calculation, the carry bits are dropped.\r
\r
  This function calculates the sum of the 64-bit values in the buffer \r
  specified by Buffer and Length. The carry bits in result of addition are dropped. \r
  The 64-bit result is returned.  If Length is 0, then 0 is returned.  \r
  \r
  If Buffer is NULL, then ASSERT().\r
  If Buffer is not aligned on a 64-bit boundary, then ASSERT().\r
  If Length is not aligned on a 64-bit boundary, then ASSERT().\r
  If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT().\r
\r
  @param  Buffer      Pointer to the buffer to carry out the sum operation.\r
  @param  Length      The size, in bytes, of Buffer.\r
\r
  @return Sum         The sum of Buffer with carry bits dropped during additions.\r
\r
**/\r
UINT64\r
EFIAPI\r
CalculateSum64 (\r
  IN      CONST UINT64         *Buffer,\r
  IN      UINTN                Length\r
  )\r
{\r
  UINT64    Sum;\r
  UINTN     Count;\r
  UINTN     Total;\r
\r
  ASSERT (Buffer != NULL);\r
  ASSERT (((UINTN) Buffer & 0x7) == 0);\r
  ASSERT ((Length & 0x7) == 0);\r
  ASSERT (Length <= (MAX_ADDRESS - ((UINTN) Buffer) + 1));\r
\r
  Total = Length / sizeof (*Buffer);\r
  for (Sum = 0, Count = 0; Count < Total; Count++) {\r
    Sum = Sum + *(Buffer + Count);\r
  }\r
  \r
  return Sum;\r
}\r
\r
\r
/**\r
  Returns the two's complement checksum of all elements in a buffer of \r
  64-bit values.\r
\r
  This function first calculates the sum of the 64-bit values in the buffer \r
  specified by Buffer and Length.  The carry bits in the result of addition \r
  are dropped. Then, the two's complement of the sum is returned.  If Length \r
  is 0, then 0 is returned.\r
  \r
  If Buffer is NULL, then ASSERT().\r
  If Buffer is not aligned on a 64-bit boundary, then ASSERT().\r
  If Length is not aligned on a 64-bit boundary, then ASSERT().\r
  If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT(). \r
\r
  @param  Buffer      Pointer to the buffer to carry out the checksum operation.\r
  @param  Length      The size, in bytes, of Buffer.\r
\r
  @return Checksum    The 2's complement checksum of Buffer.\r
\r
**/\r
UINT64\r
EFIAPI\r
CalculateCheckSum64 (\r
  IN      CONST UINT64         *Buffer,\r
  IN      UINTN                Length\r
  )\r
{\r
  UINT64     CheckSum;\r
\r
  CheckSum = CalculateSum64 (Buffer, Length);\r
\r
  //\r
  // Return the checksum based on 2's complement.\r
  //\r
  return (UINT64) ((UINT64)(-1) - CheckSum + 1);\r
}\r
\r
\r