update l-io

1 files changed, 77 insertions, 28 deletions

diff --git a/lualibs-io.lua b/lualibs-io.lua
index 66e2793..a9269ab 100644
--- a/lualibs-io.lua
+++ b/lualibs-io.lua
@@ -6,7 +6,10 @@ if not modules then modules = { } end modules ['l-io'] = {
     license   = "see context related readme files"
 }
 
-local byte, find, gsub = string.byte, string.find, string.gsub
+local io = io
+local byte, find, gsub, format = string.byte, string.find, string.gsub, string.format
+local concat = table.concat
+local type = type
 
 if string.find(os.getenv("PATH"),";") then
     io.fileseparator, io.pathseparator = "\\", ";"
@@ -14,16 +17,14 @@ else
     io.fileseparator, io.pathseparator = "/" , ":"
 end
 
-function io.loaddata(filename,textmode)
+function io.loaddata(filename,textmode) -- return nil if empty
     local f = io.open(filename,(textmode and 'r') or 'rb')
     if f then
-    --  collectgarbage("step") -- sometimes makes a big difference in mem consumption
         local data = f:read('*all')
-    --  garbagecollector.check(data)
         f:close()
-        return data
-    else
-        return nil
+        if #data > 0 then
+            return data
+        end
     end
 end
 
@@ -31,19 +32,59 @@ function io.savedata(filename,data,joiner)
     local f = io.open(filename,"wb")
     if f then
         if type(data) == "table" then
-            f:write(table.join(data,joiner or ""))
+            f:write(concat(data,joiner or ""))
         elseif type(data) == "function" then
             data(f)
         else
             f:write(data or "")
         end
         f:close()
+        io.flush()
         return true
     else
         return false
     end
 end
 
+function io.loadlines(filename,n) -- return nil if empty
+    local f = io.open(filename,'r')
+    if f then
+        if n then
+            local lines = { }
+            for i=1,n do
+                local line = f:read("*lines")
+                if line then
+                    lines[#lines+1] = line
+                else
+                    break
+                end
+            end
+            f:close()
+            lines = concat(lines,"\n")
+            if #lines > 0 then
+                return lines
+            end
+        else
+            local line = f:read("*line") or ""
+            assert(f:close())
+            if #line > 0 then
+                return line
+            end
+        end
+    end
+end
+
+function io.loadchunk(filename,n)
+    local f = io.open(filename,'rb')
+    if f then
+        local data = f:read(n or 1024)
+        f:close()
+        if #data > 0 then
+            return data
+        end
+    end
+end
+
 function io.exists(filename)
     local f = io.open(filename)
     if f == nil then
@@ -66,12 +107,19 @@ function io.size(filename)
 end
 
 function io.noflines(f)
-    local n = 0
-    for _ in f:lines() do
-        n = n + 1
+    if type(f) == "string" then
+        local f = io.open(filename)
+        local n = f and io.noflines(f) or 0
+        assert(f:close())
+        return n
+    else
+        local n = 0
+        for _ in f:lines() do
+            n = n + 1
+        end
+        f:seek('set',0)
+        return n
     end
-    f:seek('set',0)
-    return n
 end
 
 local nextchar = {
@@ -97,8 +145,6 @@ local nextchar = {
 function io.characters(f,n)
     if f then
         return nextchar[n or 1], f
-    else
-        return nil, nil
     end
 end
 
@@ -107,40 +153,42 @@ local nextbyte = {
         local a, b, c, d = f:read(1,1,1,1)
         if d then
             return byte(a), byte(b), byte(c), byte(d)
-        else
-            return nil, nil, nil, nil
+        end
+    end,
+    [3] = function(f)
+        local a, b, c = f:read(1,1,1)
+        if b then
+            return byte(a), byte(b), byte(c)
         end
     end,
     [2] = function(f)
         local a, b = f:read(1,1)
         if b then
             return byte(a), byte(b)
-        else
-            return nil, nil
         end
     end,
     [1] = function (f)
         local a = f:read(1)
         if a then
             return byte(a)
-        else
-            return nil
         end
     end,
     [-2] = function (f)
         local a, b = f:read(1,1)
         if b then
             return byte(b), byte(a)
-        else
-            return nil, nil
+        end
+    end,
+    [-3] = function(f)
+        local a, b, c = f:read(1,1,1)
+        if b then
+            return byte(c), byte(b), byte(a)
         end
     end,
     [-4] = function(f)
         local a, b, c, d = f:read(1,1,1,1)
         if d then
             return byte(d), byte(c), byte(b), byte(a)
-        else
-            return nil, nil, nil, nil
         end
     end
 }
@@ -157,12 +205,13 @@ function io.ask(question,default,options)
     while true do
         io.write(question)
         if options then
-            io.write(string.format(" [%s]",table.concat(options,"|")))
+            io.write(format(" [%s]",concat(options,"|")))
         end
         if default then
-            io.write(string.format(" [%s]",default))
+            io.write(format(" [%s]",default))
         end
-        io.write(string.format(" "))
+        io.write(format(" "))
+        io.flush()
         local answer = io.read()
         answer = gsub(answer,"^%s*(.*)%s*$","%1")
         if answer == "" and default then