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| author | Pascal Obry <obry@adacore.com> | 2005-06-16 10:31:41 +0200 |
|---|---|---|
| committer | Arnaud Charlet <charlet@gcc.gnu.org> | 2005-06-16 10:31:41 +0200 |
| commit | 0ba5b393544f89748b24bd522b56ce62d38e2a13 (patch) | |
| tree | 98b90457f8da442292245fa317ed89f4c9975189 /gcc/ada/a-strunb.adb | |
| parent | 00109226ca019e0e67fc12872afe1a2a7a68115b (diff) | |
| download | gcc-0ba5b393544f89748b24bd522b56ce62d38e2a13.tar.gz | |
a-stzunb.adb, [...] (Realloc_For_Chunk): New implementation which is slightly more efficient.
2005-06-14 Pascal Obry <obry@adacore.com>
* a-stzunb.adb, a-stwiun.adb, a-strunb.adb (Realloc_For_Chunk): New
implementation which is slightly more efficient.
From-SVN: r101023
Diffstat (limited to 'gcc/ada/a-strunb.adb')
| -rw-r--r-- | gcc/ada/a-strunb.adb | 36 |
1 files changed, 27 insertions, 9 deletions
diff --git a/gcc/ada/a-strunb.adb b/gcc/ada/a-strunb.adb index bf492ebedd0..026cb3bd712 100644 --- a/gcc/ada/a-strunb.adb +++ b/gcc/ada/a-strunb.adb @@ -1,8 +1,8 @@ ------------------------------------------------------------------------------ -- -- --- GNAT RUNTIME COMPONENTS -- +-- GNAT RUN-TIME COMPONENTS -- -- -- --- A D A . S T R I N G S . U N B O U N D E D -- +-- A D A . S T R I N G S . U N B O U N D E D -- -- -- -- B o d y -- -- -- @@ -623,7 +623,6 @@ package body Ada.Strings.Unbounded is (Source.Reference (1 .. Source.Last), Pattern, From, Going, Mapping); end Index; - function Index (Source : Unbounded_String; Set : Maps.Character_Set; @@ -755,17 +754,36 @@ package body Ada.Strings.Unbounded is (Source : in out Unbounded_String; Chunk_Size : Natural) is - Growth_Factor : constant := 50; - S_Length : constant Natural := Source.Reference'Length; + Growth_Factor : constant := 32; + -- The growth factor controls how much extra space is allocated when + -- we have to increase the size of an allocated unbounded string. By + -- allocating extra space, we avoid the need to reallocate on every + -- append, particularly important when a string is built up by repeated + -- append operations of small pieces. This is expressed as a factor so + -- 32 means add 1/32 of the length of the string as growth space. + + Min_Mul_Alloc : constant := Standard'Maximum_Alignment; + -- Allocation will be done by a multiple of Min_Mul_Alloc This causes + -- no memory loss as most (all?) malloc implementations are obliged to + -- align the returned memory on the maximum alignment as malloc does not + -- know the target alignment. + + S_Length : constant Natural := Source.Reference'Length; begin if Chunk_Size > S_Length - Source.Last then declare - Alloc_Chunk_Size : constant Positive := - Chunk_Size + (S_Length / Growth_Factor); - Tmp : String_Access; + New_Size : constant Positive := + S_Length + Chunk_Size + (S_Length / Growth_Factor); + + New_Rounded_Up_Size : constant Positive := + ((New_Size - 1) / Min_Mul_Alloc + 1) * + Min_Mul_Alloc; + + Tmp : constant String_Access := + new String (1 .. New_Rounded_Up_Size); + begin - Tmp := new String (1 .. S_Length + Alloc_Chunk_Size); Tmp (1 .. Source.Last) := Source.Reference (1 .. Source.Last); Free (Source.Reference); Source.Reference := Tmp; |