Merge pull request #31 from phi-gamma/masterHEADmaster

v2.5

1 files changed, 110 insertions, 16 deletions

diff --git a/lualibs-util-fil.lua b/lualibs-util-fil.lua
index 28c92c7..0f9731a 100644
--- a/lualibs-util-fil.lua
+++ b/lualibs-util-fil.lua
@@ -6,8 +6,10 @@ if not modules then modules = { } end modules ['util-fil'] = {
     license   = "see context related readme files"
 }
 
-local byte = string.byte
-local extract = bit32.extract
+local byte    = string.byte
+local char    = string.char
+local extract = bit32 and bit32.extract
+local floor   = math.floor
 
 -- Here are a few helpers (the starting point were old ones I used for parsing
 -- flac files). In Lua 5.3 we can probably do this better. Some code will move
@@ -36,6 +38,8 @@ function files.size(f)
     return f:seek("end")
 end
 
+files.getsize = files.size
+
 function files.setposition(f,n)
     if zerobased[f] then
         f:seek("set",n)
@@ -90,7 +94,8 @@ end
 function files.readinteger1(f)  -- one byte
     local n = byte(f:read(1))
     if n  >= 0x80 then
-        return n - 0xFF - 1
+     -- return n - 0xFF - 1
+        return n - 0x100
     else
         return n
     end
@@ -104,12 +109,27 @@ function files.readcardinal2(f)
     local a, b = byte(f:read(2),1,2)
     return 0x100 * a + b
 end
+function files.readcardinal2le(f)
+    local b, a = byte(f:read(2),1,2)
+    return 0x100 * a + b
+end
 
 function files.readinteger2(f)
     local a, b = byte(f:read(2),1,2)
     local n = 0x100 * a + b
     if n >= 0x8000 then
-        return n - 0xFFFF - 1
+     -- return n - 0xFFFF - 1
+        return n - 0x10000
+    else
+        return n
+    end
+end
+function files.readinteger2le(f)
+    local b, a = byte(f:read(2),1,2)
+    local n = 0x100 * a + b
+    if n >= 0x8000 then
+     -- return n - 0xFFFF - 1
+        return n - 0x10000
     else
         return n
     end
@@ -119,17 +139,57 @@ function files.readcardinal3(f)
     local a, b, c = byte(f:read(3),1,3)
     return 0x10000 * a + 0x100 * b + c
 end
+function files.readcardinal3le(f)
+    local c, b, a = byte(f:read(3),1,3)
+    return 0x10000 * a + 0x100 * b + c
+end
+
+function files.readinteger3(f)
+    local a, b, c = byte(f:read(3),1,3)
+    local n = 0x10000 * a + 0x100 * b + c
+    if n >= 0x80000 then
+     -- return n - 0xFFFFFF - 1
+        return n - 0x1000000
+    else
+        return n
+    end
+end
+function files.readinteger3le(f)
+    local c, b, a = byte(f:read(3),1,3)
+    local n = 0x10000 * a + 0x100 * b + c
+    if n >= 0x80000 then
+     -- return n - 0xFFFFFF - 1
+        return n - 0x1000000
+    else
+        return n
+    end
+end
 
 function files.readcardinal4(f)
     local a, b, c, d = byte(f:read(4),1,4)
     return 0x1000000 * a + 0x10000 * b + 0x100 * c + d
 end
+function files.readcardinal4le(f)
+    local d, c, b, a = byte(f:read(4),1,4)
+    return 0x1000000 * a + 0x10000 * b + 0x100 * c + d
+end
 
 function files.readinteger4(f)
     local a, b, c, d = byte(f:read(4),1,4)
     local n = 0x1000000 * a + 0x10000 * b + 0x100 * c + d
     if n >= 0x8000000 then
-        return n - 0xFFFFFFFF - 1
+     -- return n - 0xFFFFFFFF - 1
+        return n - 0x100000000
+    else
+        return n
+    end
+end
+function files.readinteger4le(f)
+    local d, c, b, a = byte(f:read(4),1,4)
+    local n = 0x1000000 * a + 0x10000 * b + 0x100 * c + d
+    if n >= 0x8000000 then
+     -- return n - 0xFFFFFFFF - 1
+        return n - 0x100000000
     else
         return n
     end
@@ -139,23 +199,28 @@ function files.readfixed4(f)
     local a, b, c, d = byte(f:read(4),1,4)
     local n = 0x100 * a + b
     if n >= 0x8000 then
-        return n - 0xFFFF - 1 + (0x100 * c + d)/0xFFFF
+     -- return n - 0xFFFF - 1 + (0x100 * c + d)/0xFFFF
+        return n - 0x10000    + (0x100 * c + d)/0xFFFF
     else
         return n              + (0x100 * c + d)/0xFFFF
     end
 end
 
-function files.read2dot14(f)
-    local a, b = byte(f:read(2),1,2)
-    local n = 0x100 * a + b
-    local m = extract(n,0,30)
-    if n > 0x7FFF then
-        n = extract(n,30,2)
-        return m/0x4000 - 4
-    else
-        n = extract(n,30,2)
-        return n + m/0x4000
+if extract then
+
+    function files.read2dot14(f)
+        local a, b = byte(f:read(2),1,2)
+        local n = 0x100 * a + b
+        local m = extract(n,0,30)
+        if n > 0x7FFF then
+            n = extract(n,30,2)
+            return m/0x4000 - 4
+        else
+            n = extract(n,30,2)
+            return n + m/0x4000
+        end
     end
+
 end
 
 function files.skipshort(f,n)
@@ -165,3 +230,32 @@ end
 function files.skiplong(f,n)
     f:read(4*(n or 1))
 end
+
+-- writers (kind of slow)
+
+function files.writecardinal2(f,n)
+    local a = char(n % 256)
+    n = floor(n/256)
+    local b = char(n % 256)
+    f:write(b,a)
+end
+
+function files.writecardinal4(f,n)
+    local a = char(n % 256)
+    n = floor(n/256)
+    local b = char(n % 256)
+    n = floor(n/256)
+    local c = char(n % 256)
+    n = floor(n/256)
+    local d = char(n % 256)
+    f:write(d,c,b,a)
+end
+
+function files.writestring(f,s)
+    f:write(char(byte(s,1,#s)))
+end
+
+function files.writebyte(f,b)
+    f:write(char(b))
+end
+