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authorSverker Eriksson <[email protected]>2017-04-28 14:54:42 +0200
committerGitHub <[email protected]>2017-04-28 14:54:42 +0200
commit61e55780e2800e340e8ff16b5414f08373f89ef3 (patch)
treec584727c8695ac4c72c4fae9deff18931a8c54d4 /erts/doc/src
parent2e2526b58f74c6c3209b3feca34866772be65335 (diff)
parente40ec046a2a1037b2f87b657503c5f21c5de4e2a (diff)
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Merge PR1413 from g-andrade/feature/phash2_nif
Support hashing terms from NIF code
Diffstat (limited to 'erts/doc/src')
-rw-r--r--erts/doc/src/erl_nif.xml36
1 files changed, 36 insertions, 0 deletions
diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml
index 6bb1109415..05b519fe7d 100644
--- a/erts/doc/src/erl_nif.xml
+++ b/erts/doc/src/erl_nif.xml
@@ -813,6 +813,29 @@ typedef enum {
</item>
</taglist>
</item>
+ <tag><marker id="ErlNifHash"/><c>ErlNifHash</c></tag>
+ <item>
+ <p>An enumeration of the supported hash types that can be generated
+ using <seealso marker="#enif_hash"><c>enif_hash</c></seealso>.
+ </p>
+ <taglist>
+ <tag><c>ERL_NIF_INTERNAL_HASH</c></tag>
+ <item>
+ <p>Non-portable hash function that only guarantees the same hash
+ for the same term within one Erlang VM instance.</p>
+ <p>It takes 32-bit salt values and generates hashes within <c>0..2^32-1</c>.</p>
+ </item>
+ <tag><c>ERL_NIF_PHASH2</c></tag>
+ <item>
+ <p>Portable hash function that gives the same hash for the
+ same Erlang term regardless of machine architecture and ERTS version.</p>
+ <p><em>It ignores salt values</em> and generates hashes within <c>0..2^27-1</c>.</p>
+ <p>Slower than <c>ERL_NIF_INTERNAL_HASH.</c>
+ It corresponds to <seealso marker="erlang#phash2-1"><c>erlang:phash2/1</c></seealso>.
+ </p>
+ </item>
+ </taglist>
+ </item>
</taglist>
</section>
@@ -1387,6 +1410,19 @@ typedef enum {
</func>
<func>
+ <name>
+ <ret>ErlNifUInt64</ret>
+ <nametext>enif_hash(ErlNifHash type, ERL_NIF_TERM term, ErlNifUInt64 salt)</nametext>
+ </name>
+ <fsummary>Hash terms.</fsummary>
+ <desc>
+ <p>Hashes <c>term</c> according to the specified
+ <seealso marker="#ErlNifHash"><c>ErlNifHash</c></seealso> <c>type</c>.</p>
+ <p>Ranges of taken salt (if any) and returned value depend on the hash type.</p>
+ </desc>
+ </func>
+
+ <func>
<name><ret>int</ret><nametext>enif_inspect_binary(ErlNifEnv* env,
ERL_NIF_TERM bin_term, ErlNifBinary* bin)</nametext></name>
<fsummary>Inspect the content of a binary.</fsummary>