From 3da34a5fa70a51f0cf06d677a4f07b470693260c Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Wed, 24 Apr 2019 14:01:20 -0300
Subject: Revamp of 'lua_pushfstring' / 'luaO_pushvfstring'

The function 'luaO_pushvfstring' now uses an internal buffer to
concatenate small strings, instead of pushing all pieces on the
stack. This avoids the creation of several small Lua strings for each
piece of the result. (For instance, a format like "n: '%d'" used to
create three intermediate strings: "n: '", the numeral, and "'".
Now it creates none.)
---
 testes/strings.lua | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

(limited to 'testes')

diff --git a/testes/strings.lua b/testes/strings.lua
index 8bcbb391..66c1176d 100644
--- a/testes/strings.lua
+++ b/testes/strings.lua
@@ -400,5 +400,66 @@ do
   assert(co() == "2")
 end
 
+
+if T==nil then
+  (Message or print)
+     ("\n >>> testC not active: skipping 'pushfstring' tests <<<\n")
+else
+
+  print"testing 'pushfstring'"
+
+  -- formats %U, %f, %I already tested elsewhere
+
+  local blen = 400    -- internal buffer length in 'luaO_pushfstring'
+
+  local function callpfs (op, fmt, n)
+    local x = {T.testC("pushfstring" .. op .. "; return *", fmt, n)}
+    -- stack has code, 'fmt', 'n', and result from operation
+    assert(#x == 4)  -- make sure nothing else was left in the stack
+    return x[4]
+  end
+
+  local function testpfs (op, fmt, n)
+    assert(callpfs(op, fmt, n) == string.format(fmt, n))
+  end
+
+  testpfs("I", "", 0)
+  testpfs("I", string.rep("a", blen - 1), 0)
+  testpfs("I", string.rep("a", blen), 0)
+  testpfs("I", string.rep("a", blen + 1), 0)
+
+  local str = string.rep("ab", blen) .. "%d" .. string.rep("d", blen / 2)
+  testpfs("I", str, 2^14)
+  testpfs("I", str, -2^15)
+
+  str = "%d" .. string.rep("cd", blen)
+  testpfs("I", str, 2^14)
+  testpfs("I", str, -2^15)
+
+  str = string.rep("c", blen - 2) .. "%d"
+  testpfs("I", str, 2^14)
+  testpfs("I", str, -2^15)
+
+  for l = 12, 14 do
+    local str1 = string.rep("a", l)
+    for i = 0, 500, 13 do
+      for j = 0, 500, 13 do
+        str = string.rep("a", i) .. "%s" .. string.rep("d", j)
+        testpfs("S", str, str1)
+        testpfs("S", str, str)
+      end
+    end
+  end
+
+  str = "abc %c def"
+  testpfs("I", str, string.byte("A"))
+  -- non-printable character
+  assert(callpfs("I", str, 255) == "abc <\\255> def")
+
+  str = string.rep("a", blen - 1) .. "%p" .. string.rep("cd", blen)
+  testpfs("P", str, {})
+end
+
+
 print('OK')
 
-- 
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