text: // Copyright 2016 Google Inc.
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  #ifndef SECURITY_UTIL_LITE_HASH_INTERNAL_H__
  #define SECURITY_UTIL_LITE_HASH_INTERNAL_H__
  
  #include <stdint.h>
  #include <stddef.h>
  
  #ifdef __cplusplus
  extern "C" {
  #endif  // __cplusplus
  
  struct HASH_CTX;  // forward decl
  
  typedef struct HASH_VTAB {
    void (* const init)(struct HASH_CTX*);
    void (* const update)(struct HASH_CTX*, const void*, size_t);
    const uint8_t* (* const final)(struct HASH_CTX*);
    const uint8_t* (* const hash)(const void*, size_t, uint8_t*);
    unsigned int size;
  } HASH_VTAB;
  
  typedef struct HASH_CTX {
    const HASH_VTAB * f;
    uint64_t count;
  #ifndef SHA512_SUPPORT
    uint8_t buf[64];
    uint32_t state[8];  // upto SHA2-256
  #else
    uint8_t buf[128];
    uint64_t state[8];  // upto SHA2-512
  #endif
  } HASH_CTX;
  
  #define HASH_init(ctx) (ctx)->f->init(ctx)
  #define HASH_update(ctx, data, len) (ctx)->f->update(ctx, data, len)
  #define HASH_final(ctx) (ctx)->f->final(ctx)
  #define HASH_hash(data, len, digest) (ctx)->f->hash(data, len, digest)
  #define HASH_size(ctx) (ctx)->f->size
  
  #ifdef __cplusplus
  }
  #endif  // __cplusplus
  
  #endif  // SECURITY_UTIL_LITE_HASH_INTERNAL_H__
  