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1 files changed, 207 insertions, 0 deletions

diff --git a/src/luarocks/core/vers.lua b/src/luarocks/core/vers.lua
new file mode 100644
index 0000000..8e61798
--- /dev/null
+++ b/src/luarocks/core/vers.lua
@@ -0,0 +1,207 @@
+
+local vers = {}
+
+local util = require("luarocks.core.util")
+local require = nil
+--------------------------------------------------------------------------------
+
+local deltas = {
+   dev =    120000000,
+   scm =    110000000,
+   cvs =    100000000,
+   rc =    -1000,
+   pre =   -10000,
+   beta =  -100000,
+   alpha = -1000000
+}
+
+local version_mt = {
+   --- Equality comparison for versions.
+   -- All version numbers must be equal.
+   -- If both versions have revision numbers, they must be equal;
+   -- otherwise the revision number is ignored.
+   -- @param v1 table: version table to compare.
+   -- @param v2 table: version table to compare.
+   -- @return boolean: true if they are considered equivalent.
+   __eq = function(v1, v2)
+      if #v1 ~= #v2 then
+         return false
+      end
+      for i = 1, #v1 do
+         if v1[i] ~= v2[i] then
+            return false
+         end
+      end
+      if v1.revision and v2.revision then
+         return (v1.revision == v2.revision)
+      end
+      return true
+   end,
+   --- Size comparison for versions.
+   -- All version numbers are compared.
+   -- If both versions have revision numbers, they are compared;
+   -- otherwise the revision number is ignored.
+   -- @param v1 table: version table to compare.
+   -- @param v2 table: version table to compare.
+   -- @return boolean: true if v1 is considered lower than v2.
+   __lt = function(v1, v2)
+      for i = 1, math.max(#v1, #v2) do
+         local v1i, v2i = v1[i] or 0, v2[i] or 0
+         if v1i ~= v2i then
+            return (v1i < v2i)
+         end
+      end
+      if v1.revision and v2.revision then
+         return (v1.revision < v2.revision)
+      end
+      return false
+   end,
+   -- @param v1 table: version table to compare.
+   -- @param v2 table: version table to compare.
+   -- @return boolean: true if v1 is considered lower than or equal to v2.
+   __le = function(v1, v2)
+       return not (v2 < v1) -- luacheck: ignore
+   end,
+   --- Return version as a string.
+   -- @param v The version table.
+   -- @return The string representation.
+   __tostring = function(v)
+      return v.string
+   end,
+}
+
+local version_cache = {}
+setmetatable(version_cache, {
+   __mode = "kv"
+})
+
+--- Parse a version string, converting to table format.
+-- A version table contains all components of the version string
+-- converted to numeric format, stored in the array part of the table.
+-- If the version contains a revision, it is stored numerically
+-- in the 'revision' field. The original string representation of
+-- the string is preserved in the 'string' field.
+-- Returned version tables use a metatable
+-- allowing later comparison through relational operators.
+-- @param vstring string: A version number in string format.
+-- @return table or nil: A version table or nil
+-- if the input string contains invalid characters.
+function vers.parse_version(vstring)
+   if not vstring then return nil end
+   assert(type(vstring) == "string")
+
+   local cached = version_cache[vstring]
+   if cached then
+      return cached
+   end
+
+   local version = {}
+   local i = 1
+
+   local function add_token(number)
+      version[i] = version[i] and version[i] + number/100000 or number
+      i = i + 1
+   end
+
+   -- trim leading and trailing spaces
+   local v = vstring:match("^%s*(.*)%s*$")
+   version.string = v
+   -- store revision separately if any
+   local main, revision = v:match("(.*)%-(%d+)$")
+   if revision then
+      v = main
+      version.revision = tonumber(revision)
+   end
+   while #v > 0 do
+      -- extract a number
+      local token, rest = v:match("^(%d+)[%.%-%_]*(.*)")
+      if token then
+         add_token(tonumber(token))
+      else
+         -- extract a word
+         token, rest = v:match("^(%a+)[%.%-%_]*(.*)")
+         if not token then
+            util.warning("version number '"..v.."' could not be parsed.")
+            version[i] = 0
+            break
+         end
+         version[i] = deltas[token] or (token:byte() / 1000)
+      end
+      v = rest
+   end
+   setmetatable(version, version_mt)
+   version_cache[vstring] = version
+   return version
+end
+
+--- Utility function to compare version numbers given as strings.
+-- @param a string: one version.
+-- @param b string: another version.
+-- @return boolean: True if a > b.
+function vers.compare_versions(a, b)
+   if a == b then
+      return false
+   end
+   return vers.parse_version(a) > vers.parse_version(b)
+end
+
+--- A more lenient check for equivalence between versions.
+-- This returns true if the requested components of a version
+-- match and ignore the ones that were not given. For example,
+-- when requesting "2", then "2", "2.1", "2.3.5-9"... all match.
+-- When requesting "2.1", then "2.1", "2.1.3" match, but "2.2"
+-- doesn't.
+-- @param version string or table: Version to be tested; may be
+-- in string format or already parsed into a table.
+-- @param requested string or table: Version requested; may be
+-- in string format or already parsed into a table.
+-- @return boolean: True if the tested version matches the requested
+-- version, false otherwise.
+local function partial_match(version, requested)
+   assert(type(version) == "string" or type(version) == "table")
+   assert(type(requested) == "string" or type(version) == "table")
+
+   if type(version) ~= "table" then version = vers.parse_version(version) end
+   if type(requested) ~= "table" then requested = vers.parse_version(requested) end
+   if not version or not requested then return false end
+
+   for i, ri in ipairs(requested) do
+      local vi = version[i] or 0
+      if ri ~= vi then return false end
+   end
+   if requested.revision then
+      return requested.revision == version.revision
+   end
+   return true
+end
+
+--- Check if a version satisfies a set of constraints.
+-- @param version table: A version in table format
+-- @param constraints table: An array of constraints in table format.
+-- @return boolean: True if version satisfies all constraints,
+-- false otherwise.
+function vers.match_constraints(version, constraints)
+   assert(type(version) == "table")
+   assert(type(constraints) == "table")
+   local ok = true
+   setmetatable(version, version_mt)
+   for _, constr in pairs(constraints) do
+      if type(constr.version) == "string" then
+         constr.version = vers.parse_version(constr.version)
+      end
+      local constr_version, constr_op = constr.version, constr.op
+      setmetatable(constr_version, version_mt)
+      if     constr_op == "==" then ok = version == constr_version
+      elseif constr_op == "~=" then ok = version ~= constr_version
+      elseif constr_op == ">"  then ok = version >  constr_version
+      elseif constr_op == "<"  then ok = version <  constr_version
+      elseif constr_op == ">=" then ok = version >= constr_version
+      elseif constr_op == "<=" then ok = version <= constr_version
+      elseif constr_op == "~>" then ok = partial_match(version, constr_version)
+      end
+      if not ok then break end
+   end
+   return ok
+end
+
+return vers