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x2utils/X2UtStrings.pas
2007-06-08 14:10:03 +00:00

426 lines
12 KiB
ObjectPascal

{** Provides various string-related functions.
*
* Last changed: $Date$ <br />
* Revision: $Rev$ <br />
* Author: $Author$ <br />
*}
unit X2UtStrings;
interface
uses
Types;
type
{** Backwards compatibility }
TSplitArray = TStringDynArray;
{** Formats the specified size.
*
* @param ABytes the size to format in bytes.
* @param AKeepBytes if true, only decimal separators will be added and
* the text 'bytes' appended. If False, a suitable unit
* will be chosen (KB, MB, GB).
* @param AFormat the format used for the output, see the Delphi Help for
* FormatFloat.
* @result the formatted size.
*}
function FormatSize(const ABytes: Int64; AKeepBytes: Boolean = False;
const AFormat: String = ',0.##'): String;
{** Compares two strings without case sensitivity.
*
* @param AMatch the string to match.
* @param AAgainst the string to match against.
* @param ALength the maximum length to compare.
* @result -1 if AMatch is lower by ordinal value than AAgainst,
* 0 if the two are equal, 1 if AMatch is higher.
*}
function CompareTextL(const AMatch, AAgainst: String;
const ALength: Integer): Integer;
{** Compares two strings without case sensitivity.
*
* @param AMatch the string to match.
* @param AAgainst the string to match against.
* @param ALength the maximum length to compare.
* @result True if the comparison is a match, False otherwise.
*}
function SameTextL(const AMatch, AAgainst: String;
const ALength: Integer): Boolean;
{** Compares two strings without case sensitivity.
*
* The length of AAgainst is used as the maximum length to check.
*
* @param AMatch the string to match
* @param AAgainst the string to match against
* @result -1 if AMatch is lower by ordinal value than AAgainst,
* 0 if the two are equal, 1 if AMatch is higher.
*}
function CompareTextS(const AMatch, AAgainst: String): Integer;
{** Compares two strings without case sensitivity.
*
* The length of AAgainst is used as the maximum length to check.
*
* @param AMatch the string to match.
* @param AAgainst the string to match against.
* @result True if the comparison is a match, False otherwise.
*}
function SameTextS(const AMatch, AAgainst: String): Boolean;
{** Splits a string on a specified delimiter.
*
* @param ASource the source string.
* @param ADelimiter the delimiter to split on.
* @param ADest the array which will receive the split parts.
* @todo though optimized, it now fails on #0 characters, need
* to determine the end by checking the AnsiString length.
*}
procedure Split(const ASource, ADelimiter: String; out ADest: TStringDynArray);
{** Appends string parts with a specified glue value.
*
* @param ASource the source parts
* @param AGlue the string added between the parts
* @result the composed parts
*}
function Join(const ASource: TStringDynArray; const AGlue: String): String;
{** Determines if one path is the child of another path.
*
* Matches the start of two normalized paths. Either of the path may contain
* parent-references (ex. 'some\..\..\path\'). Note that the file system is
* not actually accessed, all checks are performed on the strings only.
*
* @param AChild the path to check
* @param AParent the path which is supposed to be the parent
* @param AFailIfSame if True, fails if the child path is the parent path
* @result True if the child is indeed a child of the parent,
* False otherwise.
*}
function ChildPath(const AChild, AParent: String;
const AFailIfSame: Boolean = False): Boolean;
{** Determines if one path is the child of another path.
*
* Matches the start of two normalized paths. Either of the path may contain
* parent-references (ex. 'some\..\..\path\'). Note that the file system is
* not actually accessed, all checks are performed on the strings only.
*
* The parameters are modified to return the expanded file names, stripped
* of any trailing path delimiter.
*
* @param AChild the path to check
* @param AParent the path which is supposed to be the parent
* @param AFailIfSame if True, fails if the child path is the parent path
* @result True if the child is indeed a child of the parent,
* False otherwise.
*}
function ChildPathEx(var AChild, AParent: String;
const AFailIfSame: Boolean = False): Boolean;
function ReplacePart(const ASource: String; const AStart, ALength: Integer;
const AReplace: String): String;
implementation
uses
SysUtils,
Windows;
function FormatSize(const ABytes: Int64; AKeepBytes: Boolean;
const AFormat: String): String;
const
KB = 1024;
MB = KB * 1024;
GB = MB * 1024;
var
dSize: Double;
sExt: String;
begin
sExt := ' bytes';
dSize := ABytes;
if (not AKeepBytes) and (ABytes >= KB) then
if (ABytes >= KB) and (ABytes < MB) then begin
// 1 kB ~ 1 MB
dSize := ABytes / KB;
sExt := ' KB';
end else if (ABytes >= MB) and (ABytes < GB) then begin
// 1 MB ~ 1 GB
dSize := ABytes / MB;
sExt := ' MB';
end else begin
// 1 GB ~ x
dSize := ABytes / GB;
sExt := ' GB';
end;
Result := FormatFloat(AFormat, dSize) + sExt;
end;
function CompareTextL(const AMatch, AAgainst: String;
const ALength: Integer): Integer;
var
sMatch: String;
sAgainst: String;
begin
// If there is no reason to copy; don't.
if Length(AMatch) <= ALength then
sMatch := AMatch
else
sMatch := Copy(AMatch, 1, ALength);
if Length(AAgainst) <= ALength then
sAgainst := AAgainst
else
sAgainst := Copy(AAgainst, 1, ALength);
Result := CompareText(sMatch, sAgainst);
end;
function SameTextL(const AMatch, AAgainst: String;
const ALength: Integer): Boolean;
begin
Result := (CompareTextL(AMatch, AAgainst, ALength) = 0);
end;
function CompareTextS(const AMatch, AAgainst: String): Integer;
begin
Result := CompareTextL(AMatch, AAgainst, Length(AAgainst));
end;
function SameTextS(const AMatch, AAgainst: String): Boolean;
begin
Result := SameTextL(AMatch, AAgainst, Length(AAgainst));
end;
procedure Split(const ASource, ADelimiter: String; out ADest: TStringDynArray);
// StrPos is slow. Sloooooow slow. This function may not be advanced or
// the fastest one around, but it sure kicks StrPos' ass.
// 11.5 vs 1.7 seconds on a 2.4 Ghz for 10.000 iterations, baby!
function StrPosEx(const ASource, ASearch: PChar): PChar;
var
pPos: PChar;
pSub: PChar;
begin
Result := nil;
// Search for the first character
pPos := ASource;
while pPos^ <> #0 do
begin
if pPos^ = ASearch^ then
begin
// Found the first character, match the rest
pSub := ASearch;
Result := pPos;
Inc(pSub);
Inc(pPos);
while pSub^ <> #0 do
begin
if pPos^ <> pSub^ then
begin
// No match, resume as normal
Result := nil;
break;
end;
Inc(pSub);
Inc(pPos);
end;
// If still assigned, all characters matched
if Assigned(Result) then
exit;
end else
Inc(pPos);
end;
end;
const
GrowStart = 32;
GrowMax = 256;
var
iCapacity: Integer;
iCount: Integer;
iDelimLen: Integer;
iLength: Integer;
iPos: Integer;
iSize: Integer;
pDelimiter: PChar;
pLast: PChar;
pPos: PChar;
begin
// Reserve some space
iCapacity := GrowStart;
iCount := 0;
SetLength(ADest, iCapacity);
iDelimLen := Length(ADelimiter);
iLength := Length(ASource);
iPos := -1;
pDelimiter := PChar(ADelimiter);
pPos := PChar(ASource);
repeat
// Find delimiter
pLast := pPos;
pPos := StrPosEx(pPos, pDelimiter);
if pPos <> nil then
begin
// Make space
Inc(iCount);
if iCount > iCapacity then
begin
if iCapacity < GrowMax then
Inc(iCapacity, iCapacity)
else
Inc(iCapacity, GrowMax);
SetLength(ADest, iCapacity);
end;
// Copy substring
iSize := Integer(pPos) - Integer(pLast);
SetString(ADest[iCount - 1], pLast, iSize);
// Move pointer
Inc(pPos, iDelimLen);
Inc(iPos, iSize + iDelimLen);
end else
begin
if iPos < iLength then
begin
// Copy what's left
Inc(iCount);
if iCount > iCapacity then
SetLength(ADest, iCount);
ADest[iCount - 1] := pLast;
end;
if iCount <> iCapacity then
// Shrink array
SetLength(ADest, iCount);
break;
end;
until False;
end;
function Join(const ASource: TStringDynArray; const AGlue: String): String;
var
iGlue: Integer;
iHigh: Integer;
iItem: Integer;
iLength: Integer;
pGlue: PChar;
pPos: PChar;
begin
if High(ASource) = -1 then
begin
Result := '';
exit;
end;
iGlue := Length(AGlue);
pGlue := PChar(AGlue);
iLength := -iGlue;
// First run: calculate the size we need to reserve (two loops should
// generally be more efficient than a lot of memory resizing)
iHigh := High(ASource);
for iItem := iHigh downto 0 do
Inc(iLength, Length(ASource[iItem]) + iGlue);
SetLength(Result, iLength);
pPos := PChar(Result);
Inc(pPos, Length(Result));
// Copy last item
iLength := Length(ASource[iHigh]);
Dec(pPos, iLength);
Move(PChar(ASource[iHigh])^, pPos^, iLength);
// Copy remaining items and glue strings
for iItem := iHigh - 1 downto 0 do
begin
Dec(pPos, iGlue);
Move(pGlue^, pPos^, iGlue);
iLength := Length(ASource[iItem]);
Dec(pPos, iLength);
Move(PChar(ASource[iItem])^, pPos^, iLength);
end;
end;
function ChildPath(const AChild, AParent: String;
const AFailIfSame: Boolean): Boolean;
var
sChild: String;
sParent: String;
begin
sChild := AChild;
sParent := AParent;
Result := ChildPathEx(sChild, sParent, AFailIfSame);
end;
function ChildPathEx(var AChild, AParent: String;
const AFailIfSame: Boolean): Boolean;
begin
AChild := ExcludeTrailingPathDelimiter(ExpandFileName(AChild));
AParent := ExcludeTrailingPathDelimiter(ExpandFileName(AParent));
Result := SameTextS(AChild, AParent) and
((not AFailIfSame) or
(Length(AChild) > Length(AParent)));
end;
function ReplacePart(const ASource: String; const AStart, ALength: Integer;
const AReplace: String): String;
var
iSrcLength: Integer;
iLength: Integer;
iDiff: Integer;
iDest: Integer;
begin
iSrcLength := Length(ASource);
iLength := Length(AReplace);
iDiff := iLength - ALength;
iDest := 1;
SetLength(Result, iSrcLength + iDiff);
// Write first part
CopyMemory(@Result[iDest], @ASource[1], AStart - 1);
Inc(iDest, AStart - 1);
// Write replacement
CopyMemory(@Result[iDest], @AReplace[1], iLength);
Inc(iDest, iLength);
// Write last part
CopyMemory(@Result[iDest], @ASource[AStart + ALength],
iSrcLength - AStart - (ALength - 1));
end;
end.