db23 - simple in-memory key-value DB api

diff --git a/db23.sh b/db23.sh
new file mode 100755 (executable)
index 0000000..a3a25bb
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+++ b/db23.sh
@@ -0,0 +1,114 @@
+#!/bin/sh
+
+# Copyright 2023, 2024 Paul Hänsch
+# 
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+# 
+# THE SOFTWARE IS PROVIDED “AS IS” AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+# IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+[ -n "$include_db23" ] && return 0
+include_db23="$0"
+
+. "$_EXEC/cgilite/storage.sh"
+
+DB2() {
+  local call data file key val seq
+  data="${BR}${1}${BR}" call="$2"
+  shift 2
+
+  case $call in
+    new|discard)
+      printf ''
+      ;;
+    open|load) file="$1"
+      cat "$file" || return 1
+      ;;
+    check|contains) key="$(STRING "$1")" val=''
+      val="${data##*"${BR}${key}"      }" val="${val%%"${BR}"*}"
+      [ "$val" = '' ] && return 1
+      ;;
+    count) key="$(STRING "$1")" val='' seq=0
+      val="${data##*"${BR}${key}"      }" val="${val%%"${BR}"*}"
+      [ "$val" = '' ] || val="${val}   "
+      while [ "$val" != '' ]; do
+        seq=$((seq + 1)) val="${val#*  }"
+      done
+      printf "%i\n" "$seq"
+      [ $seq = 0 ] && return 1
+      ;;
+    get) key="$(STRING "$1")" seq="${2:-1}"
+      val="${data##*"${BR}${key}"      }" val="${val%%"${BR}"*}"
+      [ "$val" = '' ] && return 1 || val="${val}       "
+      while [ $seq -gt 1 ]; do
+        seq=$((seq - 1)) val="${val#*  }"
+      done
+      [ "$val" = '' ] && return 1
+      UNSTRING "${val%%        *}"
+      ;;
+    iterate|raw) key="$(STRING "$1")"
+      val="${data##*"${BR}${key}"      }" val="${val%%"${BR}"*}"
+      [ "$val" = '' ] && return 1
+      printf '%s\n' $val
+      ;;
+    delete|remove) key="$(STRING "$1")"
+      val="${data#*"${BR}${key}"       *"${BR}"}"
+      key="${data%"${BR}${key}"        *"${BR}"*}"
+      [ "${key}${BR}${val}" = "${data}" ] && return 1
+      printf '%s' "${key#"${BR}"}${BR}${val%"${BR}"}"
+      ;;
+    set|store) key="$(STRING "$1")" val=""
+      shift 1
+      val="$(for v in "$@"; do STRING "$v"; printf \\t; done)"
+      if [ "${data#*"${BR}${key}"      *}" != "$data" ]; then
+        data="${data%"${BR}${key}"     *"${BR}"*}${BR}${key}   ${val%  }${BR}${data#*"${BR}${key}"     *"${BR}"}"
+        data="${data#"${BR}"}" data="${data%"${BR}"}"
+      else
+        data="${data#"${BR}"}${key}    ${val%  }${BR}"
+        data="${data#"${BR}"}"
+      fi
+      printf %s\\n "${data}"
+      ;;
+    append) key="$(STRING "$1")" val=""
+      val="${data##*"${BR}${key}"      }" val="${val%%"${BR}"*}"
+      if [ "$val" = '' ]; then
+        printf %s\\n "${data}"
+        return 1
+      else
+        shift 1
+        val="${val}$(for v in "$@"; do printf \\t; STRING "$v"; done)"
+        data="${data%"${BR}${key}"     *"${BR}"*}${BR}${key}   ${val%  }${BR}${data#*"${BR}${key}"     *"${BR}"}"
+        data="${data#"${BR}"}" data="${data%"${BR}"}"
+        printf %s\\n "${data}"
+      fi
+      ;;
+    flush|save|write) file="$1"
+      data="${data#"${BR}"}" data="${data%"${BR}"}"
+      printf '%s\n' "$data" >"$file" || return 1
+      ;;
+  esac
+  return 0
+}
+
+DB3() {
+  # wrapper function that allows easyer use of DB2
+  # by always keeping file data in $db3_data
+
+  case "$1" in
+    new|discard|open|load|delete|remove|set|store|append)
+      db3_data="$(DB2 "$db3_data" "$@")"
+      return "$?"
+      ;;
+    get|count|check|contains|iterate|raw|flush|save|write)
+      DB2 "$db3_data" "$@"
+      return "$?"
+      ;;
+  esac
+}