Initial import from SVN

scripts/lua/modules/json.lua

@@ -0,0 +1,187 @@
+--
+-- (C) 2013-15 - ntop.org
+--
+
+--- Simple class for JSON parsing
+
+dirs = ntop.getDirs()
+package.path = dirs.installdir .. "/scripts/lua/modules/?.lua;" .. package.path
+
+local parseElement
+
+local function skipWhitespaces(content, pos)
+  local _,nend = content:find("^[ \n\r\t]+", pos)
+  if (nend ~= nil) then
+     return nend+1
+  else
+     return pos
+  end
+end
+
+local function parseNumber(content, pos)
+  -- Integer part
+  local integer_part = content:match('^-?[1-9]%d*', pos)
+                       or content:match("^-?0", pos)
+
+  if not integer_part then
+    return nil
+  end
+
+  -- Decimal part
+  local lstart = pos + integer_part:len()
+  local decimal_part = content:match('^%.%d+', i) or ""
+  lstart = lstart + decimal_part:len()
+
+  -- Exponential
+  local exponent_part = content:match('^[eE][-+]?%d+', i) or ""
+  lstart = lstart + exponent_part:len()
+  local full_number_text = integer_part .. decimal_part .. exponent_part
+  local cnumber = tonumber(full_number_text)
+
+  if not cnumber then
+    return nil
+  end
+
+  return cnumber, lstart
+end
+
+local function parseString(content, pos)
+  if (content:sub(pos, pos) ~= '"') then
+    return ""
+  end
+  local i = pos + 1
+  local clen = content:len()
+  local val = ""
+
+  while (i <= clen) do
+    local c = content:sub(i, i)
+    if (c == '"') then
+      return val, i+1
+    end
+    val = val..c
+    i = i + 1
+  end
+
+  return ""
+end
+
+local function parseObject(content, pos)
+  if (content:sub(pos, pos) ~= '{') then
+    return {}, pos
+  end
+  local lstart = skipWhitespaces(content, pos+1)
+  local val = {}
+
+  -- Handle empty array
+  if (content:sub(lstart, lstart) == '}') then
+    return val, lstart+1
+  end
+
+  local clen = content:len()
+  while (lstart <= clen) do
+    local key, nstart = parseString(content, lstart)
+    lstart = skipWhitespaces(content, nstart)
+    if (content == nil or lstart == nil or
+        content:sub(lstart, lstart) ~= ':') then
+      return {}, lstart
+    end
+    lstart = skipWhitespaces(content, lstart+1)
+    local nval, nstart = parseElement(content, lstart)
+    val[key] = nval
+    -- We have key and value, must have a } or a ,
+    lstart = skipWhitespaces(content, nstart)
+    if (content == nil or lstart == nil) then
+      return {}, clen
+    end
+    if (content:sub(lstart, lstart) == '}') then
+      return val, lstart+1
+    end
+    if (content:sub(lstart, lstart) ~= ',') then
+      return {}, lstart
+    end
+    lstart = skipWhitespaces(content, lstart+1) -- skip comma
+  end
+
+  return {}, lstart
+end
+
+local function parseArray(content, pos)
+  if (content:sub(pos, pos) ~= '[') then
+    return {}, pos
+  end
+
+  local lstart = skipWhitespaces(content, pos+1)
+  local val = {}
+  -- Handle empty array
+  if (content:sub(lstart, lstart) == ']') then
+    return val, lstart+1
+  end
+  local idx = 1 -- keep 1 to n convention
+  local clen = content:len()
+
+  while (lstart <= clen) do
+    local nval, nstart = parseElement(content, lstart)
+    val[idx] = nval
+    idx = idx + 1
+    lstart = skipWhitespaces(content, nstart)
+    -- Need a ] or a , now
+    if (content == nil or lstart == nil) then
+      return {}, clen
+    end
+    if (content:sub(lstart, lstart) == ']') then
+      return val, lstart+1
+    end
+    if (content:sub(lstart, lstart) ~= ',') then
+      return {}, lstart
+    end
+    lstart = skipWhitespaces(content, lstart+1)
+  end
+  return {}, lstart
+end
+
+parseElement = function(content, pos)
+  pos = skipWhitespaces(content, pos)
+
+  if (pos > content:len()) then
+    return {}, pos
+  end
+
+  if (content:find('^"', pos)) then
+    return parseString(content, pos)
+  elseif (content:find('^[-0123456789 ]', pos)) then
+    return parseNumber(content, pos)
+  elseif (content:find('^%{', pos)) then
+    return parseObject(content, pos)
+  elseif (content:find('^%[', pos)) then
+    return parseArray(content, pos)
+  else
+    return {}, pos
+  end
+end
+
+-- Exposed methods:
+-- printTable: prints an indented version of a JSON parsing table
+-- parseJSON: creates a table from a JSON
+
+function printTable(tbl, indent)
+  if (tbl == nil) then return end
+  if not indent then indent = 0 end
+  for k, v in pairs(tbl) do
+    formatting = string.rep("  ", indent) .. k .. ": "
+    if type(v) == "table" then
+      io.write(formatting)
+      printTable(v, indent+1)
+    elseif type(v) == 'boolean' then
+      io.write(formatting .. tostring(v).."\n")
+    else
+      io.write(formatting .. v.."\n")
+    end
+  end
+end
+
+function parseJSON(content)
+  if (content == nil) then return {} end
+  local table = parseElement(content, 1)
+  --printTable(table)
+  return table
+end