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Pascal/Delphi Source File | 1985-11-17 | 42.5 KB | 1,250 lines

.R: .R: .XT:4 .X:8 Boosters Users Guide by George F. Smith 609 Candlewick Lane Lilburn, GA 30247 (404) 923-6879 November, 1985 Version 1.0 (C) Copyright 1985 by George F. Smith All Rights Reserved .F: .F: .F:Boosters Users Guide...Page $$$... BOOSTERS USERS GUIDE Table of Contents Introduction What is Boosters? ............................. 3 Speed Without Snow ............................ 5 Section 1 Getting Started What's On the Distribution Disk ............... 6 What to Do First--BACKUP ...................... 7 Section 2 Ground Rules Some Notes On Video ........................... 8 Heap I/O ...................................... 10 Section 3 Descriptions of Boosters Routines ...... 12 BoDecl declares ............................... 13 BoxUL procedure ............................... 14 Calendar procedure ............................ 16 Center function ............................... 17 Copies function ............................... 18 CopyBlk procedure ............................. 19 CopyStr function .............................. 21 Cursor procedures ............................. 22 Dows function ................................. 23 Exec procedure ................................ 24 FillHeap procedure ............................ 26 FindStr procedure ............................. 27 GetStr procedure .............................. 29 Left function ................................. 30 MoveBg procedure .............................. 31 MoveBlk procedure ............................. 33 NsOrbit procedure ............................. 34 OverStr function .............................. 35 PutStr procedure .............................. 36 RemBlk procedure .............................. 37 RestoreScreen procedure ....................... 40 Right function ................................ 38 Rword function ................................ 39 SaveScreen procedure .......................... 40 SetAtt procedure .............................. 41 Space function ................................ 42 Stime procedure ............................... 45 Strip function ................................ 43 Timer function ................................ 44 TimeXY procedure .............................. 45 Upper function ................................ 47 Wait procedure ................................ 48 Word function ................................. 49 WordInd function .............................. 50 Words function ................................ 51 INTRODUCTION This book is a reference guide for Turbo Pascal (tm) programmers ì using the Boosters Utilities (C) in their work. It provides ì formats, descriptions, and tested coding examples for each Booster routine. Boosters is intended for students, software developers, hobbyists, ì or consultants who have at least a working knowledge of Turbo Pascal and who are targeting their products for IBM PC/compatible ì systems that run under MS-DOS 2.0 or higher. All Boosters routines will run under Turbo Pascal version 2.0 or 3.0, except the Exec procedure, which requires version 3.0. WHAT IS BOOSTERS? Boosters is a family of Turbo Pascal utilities tuned for speed of execution and ease of use. Their evolution is as follows: While developing a large program with Turbo Pascal, I found it ì convenient to write some string functions that had proved ì indispensible in my work with other languages. These are ì functions familiar to most programmers--routines to center or ì justify text, for example. Turbo Pascal's features made it ì extremely easy to write them in source code. As an example, the ì function Copies, which generates a string of length N of character ì C, can be expressed as: ì ì Function COPIES ( C : Char; N : LenType (* 1..255 *)ì ) : AnyString (* string[255] *) var S : AnyString; ì L : Integer absolute S; beginì L := N;ì FillChar ( S[1], N, C );ì Copies := Copy ( S, 1, N );ì end; ì ì With the function thus defined, you can wring a great deal of ì work from it, such as marking the length of a user input field ì with a particular character and attribute: ì GoToXY ( Xval, Yval ); (* Cursor at field beginning *)ì TextColor ( Yellow ); (* Brighten field *) Write ( Copies ( '_', Length(field) ); (* Mark field *)ì ì The preceding example works fine, but lacks the convenience and ì speed desired when used repeatedly. Seeking to combine the ì operations of those three procedures into one, and add a few ì enhancements, I wrote a routine called PutStr ("Put String") which has the following declaration: ì Procedure PUTSTR ( D : Char; (* Direction *) S : AnyString; (* string[255] *) X : ColumnType; (* 1..80 *) Y : RowType; (* 1..25 *) A : Integer ); ì ì PutStr writes string S directly to video memory beginning at ì location X,Y for length Length(S) with display attribute A. The ì value of 'D' tells PutStr whether to proceed horizontally or vertically. ì Since S is defined as a value parameter, it allows for the direct ì placement of function calls in the PutStr procedure statement. ì Applying PutStr to the last example, we get: PutStr ( h, Copie≤ ('_', length(field), Xval, Yval, 14);ì ì Because PutStr bypasses DOS and BIOS video I/O services and goes ì directly to screen memory, PutStr is faster than the standard ì procedure Write. ì Copies and PutStr became part of a growing collection of routines ì that performed frequently used string and video operations. For ì casual use, they were more than adequate in their source-level ì form. But for large programming efforts, especially ones that ì employed time-critical operations, I felt compelled to tighten ì every routine to its limit. Using the existing collection as ì prototypes, I began rewriting them in 8088 assembly language. ì The finished product--a collection of about 12 routines--was the original Boosters. SPEED WITHOUT SNOW From long association with the winters of Buffalo, New York, I ì have concluded that snow has very limited appeal. Unfortunately, ì on systems running with the IBM Color Graphics Adapter (tm), ì direct accesses to video memory will produce quick bursts of "snow." The IBM Technical Reference Manual (2.02) describes it this way: The processor and the display control unit have equal access to the display buffer during all the operating modes, except the high-resolution alphanumeric mode. During this mode, the processor should access the display buffer during the vertical retrace time. If it does not, the display will be affected with random patterns . . . (p 1-146) Programs that do direct video I/O only during vertical retrace will indeed avoid all snow affects. They will also avoid much of the speed gained from using the direct I/O technique, unless the amount of text written is slight. When reading or writing a full screen's worth of text, the loss of speed is painfully noticable if programs wait for vertical retrace before performing I/O operations. ì All is not grim, however. Boosters makes it easy for Turbo Pascal programmers to build screens on the heap, then display them almost instantly, without snow, on a color display (or, of course, a monochrome display). Please see the section on Heap I/O for details. The Boosters demo program, BoDemo, uses Heap I/O techniques to move large amounts of data to and from the screen. BOOSTERS PRODUCTION RELEASE Heap I/O support is a major component of Boosters' Special- Purpose section. Other notable members of this group include Exec, which allows programs to call other programs as if they were procedures, and Timer, which can add time-controlled processing to your programs. The addition of the special-purpose routines to the original string and video group make up the production release of Boosters--43 routines in all. As a supplement to the technical descriptions of Section 3, please refer to the Boosters demo program, BoDemo, and to the individual example programs included on the distribution diskette. SECTION 1 - GETTING STARTED WHAT'S ON THE DISTRIBUTION DISKETTE The diskette you received with your Boosters order contains ì files that are classified as follows:ì ì (A) The complete collection of the Boosters routines, ì contained in a file named Boosters.pas. (B) The above collection split into files for each Booster function and procedure. The Exec procedure, for example, resides on a file named Exec.pas; the Upper function can be found on Upper.pas--and so on. ì (C) A file of variable, type, and constant declarations that Boosters needs to run--named BoDecl.pas. (D) .COM files needed for the external procedures. ì (E) A program that demonstrates Boosters, BoDemo.pas and BoDemo.com. These programs perform the same exceptì for the Exec procedure, which will only run from BoDemo.com under Turbo Pascal Version 3.0. (The Exec call is commented out in the .pas version.) (F) Small programs illustrating how each Boosters routine works. All were tested, saved, then copied directly to the appropriate example sections of this Users Guide to ensure reproduction integrity. (G) Source files for the Boosters assembler routines. Due to directory space limitations, the assembler source files are stored in a subdirectory named BoAsm. There are over 115 files on the distribution diskette. SECTION 1 - GETTING STARTED WHAT TO DO FIRST--BACKUP The distribution diskette is not copy-protected, so either ì DiskCopy or Copy will work fine. Copy the original diskette and ì put it safely away. ì You will probably find it most convenient to keep Boosters right ì with Turbo Pascal--on the same diskette or subdirectory. At a minimum, copy Boosters.pas, BoDecl.pas, and the Boosters .com files. If there is sufficient disk space for the individual ì routines (category B above), we recommend you transfer those as well. ì ì Note: The Exec procedure requires that a copy of ì Command.com (version 2.0 or higher) be present on ì the default disk drive. The Command processor ì loads and passes control to the program you choose to execute. ì ì Having backed up your distribution diskette and copied Boosters to ì a convenient working location, fire up the demo program, ì BoDemo.com, and let it run for awhile. Working examples are a great benefit to understanding. You may find it convenient to clone parts of BoDemo.pas for your own programs. SECTION 2 - GROUND RULES SOME NOTES ON VIDEO Since Boosters addresses video memory frequently, it might be ì helpful to cover a few basics about the display area. 1. Boosters video operations assumes a screen size of 80 columns ì by 25 rows (80x25). In keeping with standard notational ì conventions, (1,1) refers to the upper left corner of the screen ì or current window, while (80,25) references the lower right. The variable X refers to the column, Y to the row, so that for X = 30 ì and Y = 10, for instance, we mean column 30, row 10 (30,10). 2. Boosters will run with the IBM Color/Graphics Adapter, theì the IBM Monochrome Adapter, the IBM Enhanced Graphics Adapter, and on most compatibles. It was developed on a 256K Compaq. 3. Each character in video memory has an attribute byte, located ì at the next higher address, that controls how the character will ì be displayed. For the Color/Graphics Adapter and compatibles, ì this attribute byte can blink, color, or intensify the character, and can color the character background. Blinking and intensity are available on the Monochrome Adapter, ì but color is interpreted as shown below: Attribute Byte Setting Monochrome Shows white-on-black normal black-on-white reverse video blue-on-black underlining black-on-black nothing The format of the attribute byte is presented below. A bit value ì of 1 activates a feature, while 0 turns it off. Bit Number 7 Blinking foreground 6 Red background 5 Green background 4 Blue background 3 Intensity foreground 2 Red foreground 1 Green foreground 0 Blue foreground A frequently used attribute setting is 14 (hex 0E), which ì produces an intensified yellow over a black background. Turbo ì Pascal includes a set of 16 predefined constants for designating ì colors, which you may find helpful. See page 161 of the version ì 3.0 manual for details. Boosters' Set Attribute (SetAtt) procedure gives you easy control ì over the character attributes. With SetAtt, you can set attributes ì in blocks as small as a single character or as large as the entire screen. SECTION 2 - GROUND RULES HEAP I/O Heap I/O describes a programming technique that consists of building or modifying screen displays on a page of the heap, then copying the page to video memory. For programs targeted to both monochrome and color monitor systems, this technique provides a common approach to fast screen output. The steps involved are: STEP TURBO/BOOSTERS EXAMPLE 1. Mark current top Mark ( HeapTop ); 2. Allocate pages For i := 1 to Npage do New ( Page[i] ); 3. Build screens a. Initially FillHeap ( page[1], ... ); BoxHeap ( page[1], ... ); (* and so on *) b. Modify existing SaveScreen ( page[1] ); screen MblkHeap ( page[1], ... ); (* perhaps more *) 4. Display any page RestoreScreen ( page[1] ); 5. Release heap memory Release ( HeapTop ); when finished Boosters has a number of routines that assist programmers in developing sophisticated screen displays on the heap. With one exception, each heap routine is a clone of some other Boosters routine. For example, procedure Calendar, which generates and displays a calendar for any month and year, has a corresponding heap routine called CalHeap. Both routines are identical except for the address of their output. Calendar sends its results to video memory, while CalHeap places its output on a specified page of the heap. NOTE: All heap routines have as their first argument the page of the heap to which output is sent. The remaining arguments match those of their corresponding video routine one-for-one. Thus, in the case of Calendar and CalHeap, their statements might appear as: Calendar ( 11, 1985, 30, 10 ); CalHeap ( page[1], 11, 1985, 30, 10 ); To view the results of CalHeap, of course, we must eventually copy page[1] to video memory, an operation which RestoreScreen performs almost instantly. The one heap routine that has no Boosters clone is FillHeap, which is useful for initializing a page of heap memory quickly. FillHeap is similar to Turbo Pascal's FillChar but differs in that it treats the heap as having the character/attribute nature of video memory. Please see section 3 for details on FillHeap. The following table pairs Boosters video routines with their corresponding heap routines. Please remember that heap memory must first be allocated (via New) before it can be used. Video Heap Purpose CopyBlk CblkHeap Copies a video block MoveBlk MblkHeap Moves a video block SetAtt HeapAt Set block attributes PutStr PutHeap Writes a string GetStr GetHeap Reads a string Calendar CalHeap Creates a calendar Boxul BoxHeap Draws a box FindStr FstrHeap Finds a string SECTION 3 DESCRIPTIONS OF BOOSTERS ROUTINES The examples in this section can be found on the Boosters distribution diskette. The file names begin with an X. The routine for PutStr, for instance, is named XPutStr. A SUGGESTION If you are new to Boosters, you might find it helpful to run the example programs as you read about them. Make sure BoDecl.pas and all the Boosters .pas files (PutStr.pas, GetStr.pas, etc.) are on the default drive and directory when you run the examples. Because the examples are generally simple, the routines they implement are easy to understand. Please pay particular attention to the uses of Heap I/O ( XBoxUl.pas, XFillHep.pas ). .E BODECL Purpose: Declarations for Boosters Utilities. Const H = 'H'; (* Code for horizontal PutStr & GetStr *) V = 'V'; (* " " vertical " " " *) StartElapsed : Boolean = FALSE; (* Initial value for timer function *) Npage = 2; (* Number of heap pages *) Type AnyString = string[255]; HeapBuf = ^AnyBuf; AnyBuf = Record Screen : array[1..4000] of byte; end; ColumnType = 1..80; (* With $R directive active, *) RowType = 1..25; (* keeps video routines in line *) result = Record AX,BX,CX,DX,BP,SI,DI,DS,ES,Flags : Integer; end; Var TimeElapsed, (* Used by Timer . . . *) SaveElapsed, (* " " " *) Ecode, (* " " Exec for error return *) I (* the ubiquitous index variable *) : Integer; SaveX (* handy for saving WhereX result *) : ColumnType; SaveY (* " " " WhereY " *) : RowType; Xheap : ColumnType; Yheap : RowType; HeapTop : ^Integer; (* for marking current top of heap *) Ch (* as in read(Kbd,ch) after KeyPressed *) : Char; Page (* screens for Heap I/O *) : array[1..Npage] of HeapBuf; VideoStatus : byte absolute $0000:$0449; MonoBuffer : AnyBuf absolute $B000:0000; GraphicsBuffer : AnyBuf absolute $B800:0000; Regs : Result; S, (* general string array *) FileDesc, (* File name and extension for EXEC *) ComLine (* Command Line setting for EXEC *) : AnyString; .E BOXUL Declaration: Procedure BoxUL ( X1 : ColumnType; Y1 : RowType; X2 : ColumnType; Y2 : RowType; Style, Attribute : Integer); Purpose: Draws a box (rectangle) in a given style with sides in specified attribute. Notes: 1. X1,Y1 and X2,Y2 designate the coordinates of the ì upper left and lower right corners, ì respectively, of the box to be drawn. ì 2. Style is a value from 1 to 4 that controls ì which set of box drawing characters to use. Style = 1 for single lines on all sides. Style = 2 for double lines on all sides. Style = 3 for double-lined vertical sides and single-lined horizontal sides. Style = 4 for single-lined vertical sides and double-lined horizontal sides. 3. The area enclosed by the box is not ì initialized. 4. A box must have at least 3 columns and 3 rows. Example: Draw concentric boxes with Boxul then with Heap I/O. (*$IBoDecl *) (*$IPutStr *) (*$ICopies *) (*$IFillHeap *) (*$IPutHeap *) (*$IRestores *) (*$IBoxHeap *) (*$IBoxul *) .E BEGIN ClrScr; PutStr ( h, 'USING BOXUL', 35, 12, 14 ); for i := 0 to 8 do boxul ( 5 + (3*i), 2+i, 75 - (3*i), 23-i , Random(4)+1, Yellow ); ClrScr; Mark ( HeapTop ); New ( Page[1] ); FillHeap ( Page[1], 1,1,80,25,#32,14 ); for i := 0 to 8 do boxHeap ( page[1], 5 + (3*i), 2+i, 75 - (3*i), 23-i , Random(4)+1, Yellow ); RestoreScreen ( page[1] ); PutStr ( h, 'USED BOXHEAP', 35, 12, 14 ); Release ( HeapTop ); END (* XBoxul *) . .E CALENDAR Declaration: Procedure Calendar ( MM, CCYY, X, Y : Integer ); Purpose: Generates a calendar for month MM of year CCYY, then displays it with upper-left coordinates X,Y. Notes: 1. The calendar size is 22 columns, 15 rows. 2. The calendar display includes trailing days from ì the previous month and the first days of the ì following month. 3. CALHEAP generates calendars on a page of the heap.ì Example: Display the U.S.A. Bicentennial month. (*$IBodecl *) (*$IPutStr *) (*$IStrip *) (*$ICopies *) (*$IBoxul *) (*$IDows *) (*$ICenter *) (*$ICalendar *) BEGIN ClrScr; Calendar ( 7, 1976, 29, 5 ); END (* XCalenda *) . CENTER Declaration: Function Center ( S : AnyString; N : Integer; Pad : Char ) : AnyString; Purpose: Returns a string of length N with S centered in it. Pad is added as necessary to fill out length. Notes: 1. AnyString is Type string[255]. 2. If length(S) > N, then the first N characters ì are returned. Example: Center numbers 1 through 8 within 10-byte fields on first line of screen. (*$IBoDecl *) (*$ICenter *) (*$IPutStr *) BEGIN for i := 1 to 8 do begin str ( i, S ); PutStr ( h, Center ( S, 10, ' '), 1 + (i-1) * 10, 1, 112 ); end; read; END (* XCenter *) . COPIES Declaration: Function Copies ( C : Char; N : Integer ) : AnyString; Purpose: Returns N concatenated copies of C. Notes: 1. AnyString is Type string[255]. 2. See CopyStr for concatenating strings. Example: Add vertical columns to the Center example. (*$IBoDecl *) (*$ICenter *) (*$IPutStr *) (*$ICopies *) BEGIN ClrScr; for i := 1 to 8 do begin str ( i, S ); PutStr ( h, Center ( S, 10, ' '), 1 + (i-1) * 10, 1, 112 ); PutStr ( v, Copies ( #179,24), 1 + (i-1) * 10, 2, 14 ); end; read; END (* XCenter *) . COPYBLK Declaration: Procedure CopyBlk ( X1 : ColumnType; Y1 : RowType; X2 : ColumnType; Y2 : RowType; X3 : ColumnType; Y3 : RowType ) ; Purpose: Copies block at screen location X1,Y1 (upper left) ì and X2,Y2 (lower right) to screen location beginning at upper left coordinates X3,Y3. Example: Create a box and copy it, first with CopyBlk, then with Heap I/O. (*$IBoDecl *) (*$IPutStr *) (*$ICopies *) (*$IBoxul *) (*$ICopyBlk *) (*$ICblkHeap *) (*$ISaves *) (*$IRestores *) BEGIN Mark ( HeapTop ); New ( page[1] ); ClrScr; Boxul ( 1, 1, 18, 10, 1, Yellow ); CopyBlk ( 1, 1, 18, 10, 1, 12 ); SaveScreen ( page[1] ); read; for i := 1 to 3 do begin CopyBlk ( 1, 1, 18, 10, 21+(i-1)*20, 1 ); CopyBlk ( 1, 1, 18, 10, 21+(i-1)*20, 12 ); end; read; ClrScr; read; .E for i := 1 to 3 do begin CblkHeap ( page[1], 1, 1, 18, 10, 21+(i-1)*20, 1 ); CblkHeap ( page[1], 1, 1, 18, 10, 21+(i-1)*20, 12 ); end; RestoreScreen ( page[1] ); Release ( HeapTop ); END (* XCopyBlk *) . .E COPYSTR Declaration: Function CopyStr ( S : AnyString; N : Integer ) : AnyString; Purpose: Returns N concatenated copies of S. Notes: 1. AnyString is Type string[255]. 2. See Copies for concatenating characters. Example: Section the screen. (*$IBoDecl *) (*$IPutStr *) (*$ICopies *) (*$ICopyStr *) Procedure BoCells ( y : RowType ); var Spacer : AnyString; N : Integer; begin S := Copies(#196,9)+#197; PutStr ( h, CopyStr ( S,8 ), 1, y, 14 ); Spacer := CopyStr ( ' '+#179, 8); for n := 1 to 5 do PutStr ( h, Spacer, 1, y+n, 14 ); end; BEGIN ClrScr; BoCells ( 1 ); BoCells ( 6 ); BoCells ( 11 ); BoCells ( 16 ); BoCells ( 21 ); Read; END (* XCopyStr *) . CURSOR ROUTINES Declaration: Procedure CursorOff; Procedure CursorOn; ì Purpose: CursorOff hides the cursor, CursorOn makes it ì visible. ì Example: Turn the cursor off, then turn it on when user ì strikes the Enter key. (*$IBoDecl *) (*$ICursor *) (*$IPutStr *) (*$ICopies *) (*$IBoxul *) BEGIN ClrScr; CursorOff; Boxul (30,8,50,16,3,14); PutStr (h, 'Press RETURN',34,10,14); PutStr (h, 'to get cursor',33,12,14); PutStr (h, 'BACK',38,14,14); read; CursorOn; END (* XCursor *) . DOWS Declaration: Function Dows ( MM, DD, CCYY : Integer) : AnyString; ì Purpose: Returns day of the week (Sunday, Monday, etc.) forì any valid date. ì Notes: 1. MM and DD must be within usual ranges for month ì and day. CCYY is 4-digit year (e.g., 1980, not ì 80). Example: Compute day of the week for user input. Pressing ì return at the prompt ends session. (*$IBoDecl *) (*$IDows *) (*$IPutStr *) (*$IStrip *) var mm, dd, ccyy, len : integer; BEGIN ClrScr; Repeat PutStr (h,'Enter the numeric value for any '+ 'month, day and year',1,1,14); PutStr (h,'separated by spaces: ',1,2,14); ClrEol; read ( s ); if length(s) > 0 then begin s := strip ( S, ' '); len := pos(' ',S) - 1; val (copy (s,1,len),mm,ecode); s := copy (s,len+2,50); len := pos(' ',s) - 1 ; val (copy (S,1,len),dd,ecode); len := length(s) - pos(' ',s); val (copy (S,length(s)-len+1,len),ccyy,ecode); if ccyy < 100 then ccyy := ccyy + 1900; PutStr (h,'Day of the week is '+ dows(mm,dd,ccyy),1,4,14); end; until length(s) = 0; END (* XDows *) . EXEC Declaration: Procedure Exec ( FileDescription, CommandLine : AnyString; Ecode : Integer); Purpose: Loads another program into memory and executes it, then returns control to the invoking program. Notes: 1. This is only available when issued from a .COM file under Turbo Pascal release 3.0. 2. FileDesc contains the drive, directory, file name and extension of the program to execute. 3. CommandLine specifies the DOS command line that Exec will pass to the command processor for execution. 4. Ecode = 0, execution was successful. Ecode = 1, improper parameters. Example 1: Format a disk on the B: drive (*$IBoDecl *) (*$IExec *) BEGIN FileDesc := 'COMMAND.COM'; ComLine := 'COMMAND /C FORMAT B:'; Exec (FileDesc, CommandLine, Ecode); END. Example 2: Execute the Norton Utilities' DiskLook (C). (*$IBoDecl *) (*$IExec *) BEGIN Filedesc := 'command.com'; ComLine := 'command /c DL B:'; Exec (FileDesc, ComLine, Ecode); Write(' Hello from Boosters'); END. Example 3: Execute Turbo Pascal (C). (*$IBoDecl *) (*$IExec *) BEGIN Filedesc := 'B:TURBO.COM'; Exec (FileDesc, ComLine, Ecode); Write(' Hello from Boosters'); END (* XExec *) . FILLHEAP Declaration: Procedure FillHeap ( Page : HeapBuf; X1 : ColumnType; Y1 : RowType; X2 : ColumnType; Y2 : RowType; C : Char; A : Integer); Purpose: Generates characters C with video attribute A on Page of the heap, from (X1,Y1) to (X2,Y2). Notes: 1. FillHeap is useful for initializing a page on the heap. Example: Generate and display alphabet screens A - Z. (*$IBoDecl *) (*$IRestores *) (*$IFillHeap *) BEGIN Mark ( HeapTop ); New ( Page[1] ); for i := 1 to 26 do begin FillHeap ( Page[1], 1, 1, 80, 25, Chr(64+i), 7 ); RestoreScreen ( Page[1] ); delay(150); end; Release ( HeapTop ); END (* XFillHep *) . FINDSTR Declaration: Procedure FindStr ( X : ColumnType; Y : RowType; VAR S : AnyString; N , Ecode : Integer); Purpose: Search for S in video memory, beginning at (X,Y). If S found, cursor is placed at offset N from S and Ecode is set to zero. Ecode is one when S is not found. Notes: 1. For N > 0, offset is calculated from end of S. Cursor will be positioned at length(S) + N. For instance, for N = 1, the cursor will be placed at S[length(S)+1]. 2. For N = 0, the cursor is placed at S[1]. 3. For N < 0, offset is calculated from beginning of S. Cursor will be placed at S[1] + (-N). Given N = -1, the cursor will be positioned at the display coordinate immediately preceding ì S[1]. 4. If the value of N is such that it would place the ì cursor offscreen, FindStr places the cursor at ì either the beginning of the display screen or at ì the end, whichever is closer to S. 5. FindStr's heap clone is FstrHeap. Procedure FstrHeap ( Page : HeapBuf; VAR S : AnyString; VAR Xheap : ColumnType; VAR Yheap : RowType; N , Ecode : Integer); external 'FstrHeap.com'; With FstrHeap, the search always begins at (1,1) on the heap. If S is found, Xheap and Yheap are set and ecode = 0. For S not found, ecode = 1. See BoDemo.pas for uses of FstrHeap. Example: Demonstrate string find capability. (*$IBoDecl *) (*$IFindStr *) (*$IGetStr *) (*$IPutStr *) BEGIN Randomize; ClrScr; PutStr (v,'I AM VERTICAL',Random(80)+1,1,7); FindStr (1,1,'I',0,Ecode); GetStr (v,S,0,0,13); read; insert ('NO LONGER ',S,6); PutStr (h,S,1,15,14); END (* XFindStr *) . GETSTR Declaration: Procedure GetStr ( HV : Char; VAR S : AnyString; X : ColumnType; Y : RowType; LEN : Integer); Purpose: Loads contents of video memory into S, beginning at coordinates X,Y for length LEN. Notes: 1. Direction of read operation is set by HV, which will be horizontal when HV = 'H', vertical when HV = 'V'. Constants H and V are set in Boosters Declaration File (BoDecl). 2. If X and Y are both zero, read operation begins at current position. 3. GETHEAP is the Heap I/O clone of GetStr. With GetHeap, X and Y cannot be zero, nor is there any positioning of the cursor. Example: Write and read a column of vertical text. (*$IBoDecl *) (*$IGetStr *) (*$IPutStr *) BEGIN ClrScr; PutStr (v,'I AM VERTICAL',1,1,7); GetStr (v,S,1,1,13); read; insert ('NO LONGER ',S,6); PutStr (h,S,1,15,14); END (* XGetStr *) . LEFT Declaration: Function Left ( S : AnyString; LEN : Integer; PAD : Char) : AnyString; Purpose: Left-justifies and pads (if necessary) S in theì result. ì Example: Create a sample input form. (*$IBoDecl *) (*$ILeft *) (*$IPutStr *) BEGIN ClrScr; PutStr (h,left('Name ',60,'_'),5,1,14); PutStr (h,left('Street ',60,'_'),5,2,14); PutStr (h,left('City, State, and Zip ',60,'_'), 5,3,14); read; END (* XLeft *) . MOVEBG Declaration: Procedure MoveBg ( Page : HeapBuf; X1 : ColumnType; Y1 : RowType; X2 : ColumnType; Y2 : RowType; X3 : ColumnType; Y3 : RowType); Purpose: Moves the block at X1,Y1 (upper left) and X2,Y2 (lower right) of the current screen to block beginning at X3,Y3 (upper left) on page. Notes: 1. When MoveBg is called, the block at X1,Y1,X2,Y2 is saved on the stack, the screen defined by ì page is copied to video memory, then the block ì on the stack is written to the screen. Example: Overlay some boxes, then move one from the other incrementally. (*$IBoDecl *) (*$IScreen *) (*$IPutStr *) (*$ICopies *) (*$IBoxul *) (*$ISetAtt *) (*$IMoveBg *) BEGIN Mark ( HeapTop ); New ( page[1] ); ClrScr; Boxul ( 20, 8, 37, 16, 1, 14); for i := 9 to 15 do PutStr ( h, Copies ( '▓',16),21, i, 14); SetAtt ( 38, 9, 40, 17, 30); SetAtt ( 21, 17, 40, 17, 30); Read; SaveScreen ( page[1] ); Boxul ( 20, 8, 37, 16, 1, 14); for i := 9 to 15 do PutStr ( h, Copies('▒',16),21, i, 7); Read; .E for i := 1 to 16 do begin Movebg ( page[1], 20+(i-1)*2, 8, 40+(i-1)*2, 17, 22+(i-1)*2, 8 ); delay(04); end; Release( HeapTop ); END (* XMoveBg *) . .E MOVEBLK Declaration: Procedure MoveBlk ( X1 : ColumnType; Y1 : RowType; X2 : ColumnType; Y2 : RowType; X3 : ColumnType; Y3 : RowType); Purpose: Moves the block defined by X1,Y1,X2,Y2 (upper- left and lower-right coordinates) to location X3,Y3 (upper-left). Notes: 1. The original block (X1,Y1,X2,Y2) is saved onì the stack, erased from video memory, then copied to (X3,Y3). By contrast, see CopyBlk description. 2. To move blocks on the heap, use MblkHeap. Example: Relocate three boxes. (*$IBoDecl *) (*$IMoveBlk *) (*$IPutStr *) (*$ICopies *) (*$IBoxul *) BEGIN ClrScr; BoxUl ( 1,1, 8, 7,3,14); BoxUl ( 10,1,17, 7,3,14); BoxUl ( 19,1,26, 7,3,14); PutStr (h,'Press enter to move boxes',1,9,14); read; MoveBlk (1,1,26,7,1,12); END (* XMoveBlk *) . .T:B:BoRef2.pas