From e8a0a4b5acc5c5ac8debb1cc4be0a4a615314f2c Mon Sep 17 00:00:00 2001
From: Runxi Yu <me@runxiyu.org>
Date: Thu, 13 Mar 2025 22:57:59 +0800
Subject: [PATCH] Add del/get/put

---
 lmdb/items.ha | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++

diff --git a/lmdb/items.ha b/lmdb/items.ha
new file mode 100644
index 0000000000000000000000000000000000000000..38c1aaa85784574da61ea236b9099bb342f655f1
--- /dev/null
+++ b/lmdb/items.ha
@@ -0,0 +1,84 @@
+// Delete items from a database.
+//
+// This function removes key/data pairs from the database. If the database does not
+// support sorted duplicate data items ([[DUPSORT]]), the data parameter is ignored.
+// If the database supports sorted duplicates and the data parameter is NULL, all
+// of the duplicate data items for the key will be deleted. Otherwise, if the data
+// parameter is non-NULL, only the matching data item will be deleted. This function
+// will return [[NOTFOUND]] if the specified key/data pair is not in the database.
+//
+// Parameters:
+// - txn: A transaction handle returned by [[txn_begin]]
+// - dbi: A database handle returned by [[dbi_open]]
+// - key: The key to delete from the database
+// - data: The data to delete
+//
+// Return value: A non-zero error value on failure and 0 on success. Some possible errors are:
+// - EACCES: an attempt was made to write in a read-only transaction.
+// - EINVAL: an invalid parameter was specified.
+export @symbol("mdb_del") fn del(txn: *txn, dbi: *dbi, key: *val, data: *val) int;
+
+
+// Get items from a database.
+//
+// This function retrieves key/data pairs from the database. The address and length
+// of the data associated with the specified key are returned in the structure to
+// which data refers. If the database supports duplicate keys ([[DUPSORT]]), then
+// the first data item for the key will be returned. Retrieval of other items
+// requires the use of [[cursor_get]].
+//
+// The memory pointed to by the returned values is owned by the database. The caller
+// need not dispose of the memory, and may not modify it in any way. For values
+// returned in a read-only transaction, any modification attempts cause a SIGSEGV.
+// Values returned from the database are valid only until a subsequent update
+// operation, or the end of the transaction.
+//
+// Parameters:
+// - txn: A transaction handle returned by [[txn_begin]]
+// - dbi: A database handle returned by [[dbi_open]]
+// - key: The key to search for in the database
+// - data: The data corresponding to the key
+//
+// Return value: A non-zero error value on failure and 0 on success. Some possible errors are:
+// - [[NOTFOUND]]: the key was not in the database
+// - EINVAL: an invalid parameter was specified
+export @symbol("mdb_get") fn get(txn: *txn, dbi: *dbi, key: *val, data: *val) int;
+
+// Store items into a database.
+//
+// This function stores key/data pairs in the database. The default behavior
+// is to enter the new key/data pair, replacing any previously existing key
+// if duplicates are disallowed, or adding a duplicate data item if duplicates
+// are allowed ([[DUPSORT]]).
+//
+// Parameters:
+// - txn: A transaction handle returned by [[txn_begin]]
+// - dbi: A database handle returned by [[dbi_open]]
+// - key: The key to store in the database
+// - data: The data to store
+// - flags: Special options for this operation. Must be set to 0 or by bitwise
+//   OR'ing together one or more of the values described below.
+//
+// Flags:
+// - [[NODUPDATA]]: enter the new key/data pair only if it does not already appear
+//   in the database. Only valid if the database was opened with [[DUPSORT]].
+//   Returns [[KEYEXIST]] if the key/data pair already appears.
+// - [[NOOVERWRITE]]: enter the new key/data pair only if the key does not already
+//   appear in the database. Returns [[KEYEXIST]] if the key is present,
+//   even if the database supports duplicates. The data parameter will be set
+//   to the existing item.
+// - [[RESERVE]]: reserve space for data of the given size, but don't copy the
+//   given data. Instead, return a pointer to the reserved space, which the caller
+//   can fill later (before the next update or transaction end). This must not
+//   be specified if the database was opened with [[DUPSORT]].
+// - [[APPEND]]: append the given key/data pair to the end of the database for
+//   fast bulk loading when keys are already in correct order. Loading unsorted
+//   keys with this flag will cause a [[KEYEXIST]] error.
+// - [[APPENDDUP]]: same as [[APPEND]], but for sorted duplicate data.
+//
+// Return value: A non-zero error value on failure and 0 on success. Some possible errors are:
+// - [[MAP_FULL]]: the database is full (see [[env_set_mapsize]])
+// - [[TXN_FULL]]: the transaction has too many dirty pages
+// - EACCES: an attempt was made to write in a read-only transaction
+// - EINVAL: an invalid parameter was specified
+export @symbol("mdb_put") fn put(txn: *txn, dbi: *dbi, key: *val, data: *val, flags: uint) int;

-- 
2.48.1