add things around the actual hashing

Signed-off-by: Mattias Andrée <maandree@operamail.com>

7 files changed, 629 insertions, 0 deletions

diff --git a/src/libsha2.h b/src/libsha2.h
new file mode 100644
index 0000000..7fdee6b
--- /dev/null
+++ b/src/libsha2.h
@@ -0,0 +1,29 @@
+/**
+ * libsha2 – SHA-2-family hashing library
+ * 
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef LIBSHA2_H
+#define LIBSHA2_H  1
+
+
+#include "libsha2/digest.h"
+#include "libsha2/state.h"
+#include "libsha2/hex.h"
+
+
+#endif
+
diff --git a/src/libsha2/digest.c b/src/libsha2/digest.c
new file mode 100644
index 0000000..5cf0f03
--- /dev/null
+++ b/src/libsha2/digest.c
@@ -0,0 +1,46 @@
+/**
+ * libsha2 – SHA-2-family hashing library
+ * 
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "digest.h"
+
+
+
+/**
+ * Absorb more of the message
+ * 
+ * @param  state    The hashing state
+ * @param  message  The message
+ * @param  msglen   The length of the message
+ */
+void libsha2_update(libsha2_state_t* restrict state, const char* restrict message, size_t msglen)
+{
+}
+
+
+/**
+ * Absorb the last part of the message and output a hash
+ * 
+ * @param  state    The hashing state
+ * @param  message  The message
+ * @param  msglen   The length of the message, zero if there is nothing more to absorb
+ * @param  output   The output buffer for the hash
+ */
+void libsha2_digest(libsha2_state_t* restrict state, const char* restrict message, size_t msglen, char* output)
+{
+}
+
diff --git a/src/libsha2/digest.h b/src/libsha2/digest.h
new file mode 100644
index 0000000..47b3414
--- /dev/null
+++ b/src/libsha2/digest.h
@@ -0,0 +1,50 @@
+/**
+ * libsha2 – SHA-2-family hashing library
+ * 
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef LIBSHA2_DIGEST_H
+#define LIBSHA2_DIGEST_H  1
+
+
+#include "state.h"
+
+
+/**
+ * Absorb more of the message
+ * 
+ * @param  state    The hashing state
+ * @param  message  The message
+ * @param  msglen   The length of the message
+ */
+__attribute__((nonnull, nothrow))
+void libsha2_update(libsha2_state_t* restrict state, const char* restrict message, size_t msglen);
+
+/**
+ * Absorb the last part of the message and output a hash
+ * 
+ * @param  state    The hashing state
+ * @param  message  The message
+ * @param  msglen   The length of the message, zero if there is nothing more to absorb
+ * @param  output   The output buffer for the hash
+ */
+__attribute__((nonnull(1, 4), nothrow))
+void libsha2_digest(libsha2_state_t* restrict state, const char* restrict message, size_t msglen, char* output);
+
+
+
+#endif
+
diff --git a/src/libsha2/hex.c b/src/libsha2/hex.c
new file mode 100644
index 0000000..1f5c372
--- /dev/null
+++ b/src/libsha2/hex.c
@@ -0,0 +1,81 @@
+/**
+ * libsha2 – SHA-2-family hashing library
+ * 
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "hex.h"
+#include <string.h>
+
+
+
+/**
+ * Convert a binary hashsum to lower case hexadecimal representation
+ * 
+ * @param  output   Output array, should have an allocation size of at least `2 * n + 1`
+ * @param  hashsum  The hashsum to convert
+ * @param  n        The size of `hashsum`
+ */
+void libsha2_behex_lower(char* restrict output, const char* restrict hashsum, size_t n)
+{
+  output[2 * n] = '\0';
+  while (n--)
+    {
+      output[2 * n + 0] = "0123456789abcdef"[(hashsum[n] >> 4) & 15];
+      output[2 * n + 1] = "0123456789abcdef"[(hashsum[n] >> 0) & 15];
+    }
+}
+
+
+/**
+ * Convert a binary hashsum to upper case hexadecimal representation
+ * 
+ * @param  output   Output array, should have an allocation size of at least `2 * n + 1`
+ * @param  hashsum  The hashsum to convert
+ * @param  n        The size of `hashsum`
+ */
+void libsha2_behex_upper(char* restrict output, const char* restrict hashsum, size_t n)
+{
+  output[2 * n] = '\0';
+  while (n--)
+    {
+      output[2 * n + 0] = "0123456789ABCDEF"[(hashsum[n] >> 4) & 15];
+      output[2 * n + 1] = "0123456789ABCDEF"[(hashsum[n] >> 0) & 15];
+    }
+}
+
+
+/**
+ * Convert a hexadecimal hashsum (both lower case, upper
+ * case and mixed is supported) to binary representation
+ * 
+ * @param  output   Output array, should have an allocation size of at least `strlen(hashsum) / 2`
+ * @param  hashsum  The hashsum to convert
+ */
+void libsha2_unhex(char* restrict output, const char* restrict hashsum)
+{
+  size_t n = strlen(hashsum) / 2;
+  while (n--)
+    {
+      char a = hashsum[2 * n + 0];
+      char b = hashsum[2 * n + 1];
+      
+      a = (char)((a & 15) + (a > '9' ? 9 : 0));
+      b = (char)((b & 15) + (b > '9' ? 9 : 0));
+      
+      output[n] = (char)((a << 4) | b);
+    }
+}
+
diff --git a/src/libsha2/hex.h b/src/libsha2/hex.h
new file mode 100644
index 0000000..d9581b0
--- /dev/null
+++ b/src/libsha2/hex.h
@@ -0,0 +1,62 @@
+/**
+ * libsha2 – SHA-2-family hashing library
+ * 
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef LIBSHA2_HEX_H
+#define LIBSHA2_HEX_H  1
+
+
+#include <stddef.h>
+
+
+
+/**
+ * Convert a binary hashsum to lower case hexadecimal representation
+ * 
+ * @param  output   Output array, should have an allocation size of at least `2 * n + 1`
+ * @param  hashsum  The hashsum to convert
+ * @param  n        The size of `hashsum`
+ */
+__attribute__((leaf, nonnull, nothrow))
+void libsha2_behex_lower(char* restrict output, const char* restrict hashsum, size_t n);
+
+
+/**
+ * Convert a binary hashsum to upper case hexadecimal representation
+ * 
+ * @param  output   Output array, should have an allocation size of at least `2 * n + 1`
+ * @param  hashsum  The hashsum to convert
+ * @param  n        The size of `hashsum`
+ */
+__attribute__((leaf, nonnull, nothrow))
+void libsha2_behex_upper(char* restrict output, const char* restrict hashsum, size_t n);
+
+
+/**
+ * Convert a hexadecimal hashsum (both lower case, upper
+ * case and mixed is supported) to binary representation
+ * 
+ * @param  output   Output array, should have an allocation size of at least `strlen(hashsum) / 2`
+ * @param  hashsum  The hashsum to convert
+ */
+__attribute__((leaf, nonnull, nothrow))
+void libsha2_unhex(char* restrict output, const char* restrict hashsum);
+
+
+
+#endif
+
diff --git a/src/libsha2/state.c b/src/libsha2/state.c
new file mode 100644
index 0000000..0a7a5b1
--- /dev/null
+++ b/src/libsha2/state.c
@@ -0,0 +1,148 @@
+/**
+ * libsha2 – SHA-2-family hashing library
+ * 
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "state.h"
+#include <string.h>
+#include <errno.h>
+
+
+
+/**
+ * Round constants, SHA-256, should keep the 32 most significant bits of 64 first constants
+ */
+static const uint64_t ROUND_CONSTANTS[] = {
+  0x428A2F98D728AE22ULL, 0x7137449123EF65CDULL, 0xB5C0FBCFEC4D3B2FULL, 0xE9B5DBA58189DBBCULL,
+  0x3956C25BF348B538ULL, 0x59F111F1B605D019ULL, 0x923F82A4AF194F9BULL, 0xAB1C5ED5DA6D8118ULL,
+  0xD807AA98A3030242ULL, 0x12835B0145706FBEULL, 0x243185BE4EE4B28CULL, 0x550C7DC3D5FFB4E2ULL,
+  0x72BE5D74F27B896FULL, 0x80DEB1FE3B1696B1ULL, 0x9BDC06A725C71235ULL, 0xC19BF174CF692694ULL,
+  0xE49B69C19EF14AD2ULL, 0xEFBE4786384F25E3ULL, 0x0FC19DC68B8CD5B5ULL, 0x240CA1CC77AC9C65ULL,
+  0x2DE92C6F592B0275ULL, 0x4A7484AA6EA6E483ULL, 0x5CB0A9DCBD41FBD4ULL, 0x76F988DA831153B5ULL,
+  0x983E5152EE66DFABULL, 0xA831C66D2DB43210ULL, 0xB00327C898FB213FULL, 0xBF597FC7BEEF0EE4ULL,
+  0xC6E00BF33DA88FC2ULL, 0xD5A79147930AA725ULL, 0x06CA6351E003826FULL, 0x142929670A0E6E70ULL,
+  0x27B70A8546D22FFCULL, 0x2E1B21385C26C926ULL, 0x4D2C6DFC5AC42AEDULL, 0x53380D139D95B3DFULL,
+  0x650A73548BAF63DEULL, 0x766A0ABB3C77B2A8ULL, 0x81C2C92E47EDAEE6ULL, 0x92722C851482353BULL,
+  0xA2BFE8A14CF10364ULL, 0xA81A664BBC423001ULL, 0xC24B8B70D0F89791ULL, 0xC76C51A30654BE30ULL,
+  0xD192E819D6EF5218ULL, 0xD69906245565A910ULL, 0xF40E35855771202AULL, 0x106AA07032BBD1B8ULL,
+  0x19A4C116B8D2D0C8ULL, 0x1E376C085141AB53ULL, 0x2748774CDF8EEB99ULL, 0x34B0BCB5E19B48A8ULL,
+  0x391C0CB3C5C95A63ULL, 0x4ED8AA4AE3418ACBULL, 0x5B9CCA4F7763E373ULL, 0x682E6FF3D6B2B8A3ULL,
+  0x748F82EE5DEFB2FCULL, 0x78A5636F43172F60ULL, 0x84C87814A1F0AB72ULL, 0x8CC702081A6439ECULL,
+  0x90BEFFFA23631E28ULL, 0xA4506CEBDE82BDE9ULL, 0xBEF9A3F7B2C67915ULL, 0xC67178F2E372532BULL,
+  0xCA273ECEEA26619CULL, 0xD186B8C721C0C207ULL, 0xEADA7DD6CDE0EB1EULL, 0xF57D4F7FEE6ED178ULL,
+  0x06F067AA72176FBAULL, 0x0A637DC5A2C898A6ULL, 0x113F9804BEF90DAEULL, 0x1B710B35131C471BULL,
+  0x28DB77F523047D84ULL, 0x32CAAB7B40C72493ULL, 0x3C9EBE0A15C9BEBCULL, 0x431D67C49C100D4CULL,
+  0x4CC5D4BECB3E42B6ULL, 0x597F299CFC657E2AULL, 0x5FCB6FAB3AD6FAECULL, 0x6C44198C4A475817ULL};
+
+
+
+/**
+ * Initialise a state
+ * 
+ * @parma   state      The state that should be initialised
+ * @parma   algorithm  The hashing algorithm
+ * @return             Zero on success, -1 on error
+ */
+int libsha2_state_initialise(libsha2_state_t* restrict state, libsha2_algorithm_t algorithm)
+{
+  static const uint32_t H_224[] = {
+    0xC1059ED8UL, 0x367CD507UL, 0x3070DD17UL, 0xF70E5939UL,
+    0xFFC00B31UL, 0x68581511UL, 0x64F98FA7UL, 0xBEFA4FA4UL};
+  static const uint32_t H_256[] = {
+    0x6A09E667UL, 0xBB67AE85UL, 0x3C6EF372UL, 0xA54FF53AUL,
+    0x510E527FUL, 0x9B05688CUL, 0x1F83D9ABUL, 0x5BE0CD19UL};
+  static const uint64_t H_384[] = {
+    0xCBBB9D5DC1059ED8ULL, 0x629A292A367CD507ULL, 0x9159015A3070DD17ULL, 0x152FECD8F70E5939ULL,
+    0x67332667FFC00B31ULL, 0x8EB44A8768581511ULL, 0xDB0C2E0D64F98FA7ULL, 0x47B5481DBEFA4FA4ULL};
+  static const uint64_t H_512[] = {
+    0x6A09E667F3BCC908ULL, 0xBB67AE8584CAA73BULL, 0x3C6EF372FE94F82BULL, 0xA54FF53A5F1D36F1ULL,
+    0x510E527FADE682D1ULL, 0x9B05688C2B3E6C1FULL, 0x1F83D9ABFB41BD6BULL, 0x5BE0CD19137E2179ULL};
+  static const uint64_t H_512_224[] = {
+    0x8C3D37C819544DA2ULL, 0x73E1996689DCD4D6ULL, 0x1DFAB7AE32FF9C82ULL, 0x679DD514582F9FCFULL,
+    0x0F6D2B697BD44DA8ULL, 0x77E36F7304C48942ULL, 0x3F9D85A86A1D36C8ULL, 0x1112E6AD91D692A1ULL};
+  static const uint64_t H_512_256[] = {
+    0x22312194FC2BF72CULL, 0x9F555FA3C84C64C2ULL, 0x2393B86B6F53B151ULL, 0x963877195940EABDULL,
+    0x96283EE2A88EFFE3ULL, 0xBE5E1E2553863992ULL, 0x2B0199FC2C85B8AAULL, 0x0EB72DDC81C52CA2ULL};
+  
+  size_t i;
+  
+  state->message_size = 0;
+  state->algorithm = algorithm;
+  
+  /* Set initial hash values. */
+  switch (algorithm)
+    {
+    case LIBSHA2_224:      memcpy(state->h.b32, H_224,     sizeof(H_224));      break;
+    case LIBSHA2_256:      memcpy(state->h.b32, H_256,     sizeof(H_256));      break;
+    case LIBSHA2_384:      memcpy(state->h.b64, H_384,     sizeof(H_384));      break;
+    case LIBSHA2_512:      memcpy(state->h.b64, H_512,     sizeof(H_512));      break;
+    case LIBSHA2_512_224:  memcpy(state->h.b64, H_512_224, sizeof(H_512_224));  break;
+    case LIBSHA2_512_256:  memcpy(state->h.b64, H_512_256, sizeof(H_512_256));  break;
+    default:
+      return errno = EINVAL, -1;
+    }
+  
+  /* Set round constants. */
+  switch (algorithm)
+    {
+    case LIBSHA2_224:
+    case LIBSHA2_256:
+      for (i = 0; i < 64; i++)
+	state->k.b32[i] = (uint32_t)(ROUND_CONSTANTS[i] >> 32);
+      break;
+      
+    default:
+      memcpy(state->k.b64, ROUND_CONSTANTS, sizeof(ROUND_CONSTANTS));
+      break;
+    }
+  
+  return 0;
+}
+
+
+/**
+ * Get the output size of the algorithm specified for a state
+ * 
+ * @parma   state  The state
+ * @return         The number of bytes in the output, zero on error
+ */
+size_t libsha2_state_output_size(const libsha2_state_t* restrict state)
+{
+  return libsha2_algorithm_output_size(state->algorithm);
+}
+
+
+/**
+ * Get the output size of an algorithm
+ * 
+ * @parma   algorithm  The hashing algorithm
+ * @return             The number of bytes in the output, zero on error
+ */
+size_t libsha2_algorithm_output_size(libsha2_algorithm_t algorithm)
+{
+  switch (algorithm)
+    {
+    case LIBSHA2_224:     return 28;
+    case LIBSHA2_256:     return 32;
+    case LIBSHA2_384:     return 48;
+    case LIBSHA2_512:     return 64;
+    case LIBSHA2_512_224: return 28;
+    case LIBSHA2_512_256: return 32;
+    default:
+      return errno = EINVAL, 0;
+    }
+}
+
diff --git a/src/libsha2/state.h b/src/libsha2/state.h
new file mode 100644
index 0000000..c290186
--- /dev/null
+++ b/src/libsha2/state.h
@@ -0,0 +1,213 @@
+/**
+ * libsha2 – SHA-2-family hashing library
+ * 
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef LIBSHA2_STATE_H
+#define LIBSHA2_STATE_H  1
+
+
+#include <stdint.h>
+#include <stddef.h>
+
+
+
+/**
+ * Algorithms supported by libsha2
+ */
+typedef enum libsha2_algorithm
+  {
+    /**
+     * SHA-224, outputs 28 bytes
+     */
+    LIBSHA2_224 = 1,
+    
+    /**
+     * SHA-256, outputs 32 bytes
+     */
+    LIBSHA2_256 = 2,
+    
+    /**
+     * SHA-384, outputs 48 bytes
+     */
+    LIBSHA2_384 = 3,
+    
+    /**
+     * SHA-512, outputs 64 bytes
+     */
+    LIBSHA2_512 = 4,
+    
+    /**
+     * SHA-512/224, outputs 28 bytes
+     */
+    LIBSHA2_512_224 = 5,
+    
+    /**
+     * SHA-512/256, outputs 32 bytes
+     */
+    LIBSHA2_512_256 = 6,
+    
+  } libsha2_algorithm_t;
+
+
+/**
+ * Datastructure that describes the state of a hashing process
+ * 
+ * Data that could just as well be allocated (with `auto`) are
+ * allocated here so that is is easier to wipe the data without
+ * exposing two versions of each function: one to wipe data,
+ * and one not to wipe data to gain speed, now you can use use
+ * `explicit_bzero` (or `memset`) when you are done.
+ */
+typedef struct libsha2_state
+{
+  /**
+   * The size of the message, as far as processed, in bits;
+   */
+  size_t message_size;
+  
+  /**
+   * Round constants
+   */
+  union
+  {
+    /**
+     * For 32-bit algorithms
+     */
+    uint32_t b32[64];
+    
+    /**
+     * For 64-bit algorithms
+     */
+    uint64_t b64[80];
+    
+  } k;
+  
+  /**
+   * Words
+   */
+  union
+  {
+    /**
+     * For 32-bit algorithms
+     */
+    uint32_t b32[64];
+    
+    /**
+     * For 64-bit algorithms
+     */
+    uint64_t b64[80];
+    
+  } w;
+  
+  /**
+   * Hashing values
+   */
+  union
+  {
+    /**
+     * For 32-bit algorithms
+     */
+    uint32_t b32[8];
+    
+    /**
+     * For 64-bit algorithms
+     */
+    uint64_t b64[8];
+    
+  } h;
+  
+  /**
+   * Temporary hashing values
+   */
+  union
+  {
+    /**
+     * For 32-bit algorithms
+     */
+    uint32_t b32[8];
+    
+    /**
+     * For 64-bit algorithms
+     */
+    uint64_t b64[8];
+    
+  } work_h;
+  
+  /**
+   * Space for chunks to process
+   */
+  union
+  {
+    /**
+     * For 32-bit algorithms
+     */
+    unsigned char b32[64];
+    
+    /**
+     * For 64-bit algorithms
+     */
+    unsigned char b64[128];
+    
+  } chunk;
+  
+  /**
+   * Output buffer, required because
+   * some algorithms truncate the output
+   */
+  char output[64];
+  
+  /**
+   * The algorithm that is used
+   */
+  libsha2_algorithm_t algorithm;
+  
+} libsha2_state_t;
+
+
+
+/**
+ * Initialise a state
+ * 
+ * @parma   state      The state that should be initialised
+ * @parma   algorithm  The hashing algorithm
+ * @return             Zero on success, -1 on error
+ */
+__attribute__((leaf, nothrow, nonnull))
+int libsha2_state_initialise(libsha2_state_t* restrict state, libsha2_algorithm_t algorithm);
+
+/**
+ * Get the output size of the algorithm specified for a state
+ * 
+ * @parma   state  The state
+ * @return         The number of bytes in the output, zero on error
+ */
+__attribute__((nothrow, nonnull, pure))
+size_t libsha2_state_output_size(const libsha2_state_t* restrict state);
+
+/**
+ * Get the output size of an algorithm
+ * 
+ * @parma   algorithm  The hashing algorithm
+ * @return             The number of bytes in the output, zero on error
+ */
+__attribute__((leaf, nothrow, const))
+size_t libsha2_algorithm_output_size(libsha2_algorithm_t algorithm);
+
+
+
+#endif
+