Using memcpy to compress blanks out of an array

This program will compress out the blanks from a simple array. It uses memcpy() to shift entries around. This is intended as a demonstration of concept, and lacks practical application as a standalone entity. By D. Lovelady H OPTION(*NOSHOWCPY:*NOEXPDDS:*NODEBUGIO:*SRCSTMT) H DATFMT(*ISO) TIMFMT(*ISO) H BndDir('QC2LE') H DFTACTGRP(*NO) D ARRMEMCPY PR ExtPgm('ARRMEMCPY') D ARRMEMCPY PI D MemCpy PR * ExtProc('__memcpy') D ToAddr * value D FromAddr * value D copyLen 10I 0 value D compressArray PR ExtProc('compressArray') D MAX_DIM C 6 D line S 30 DIM(6) Inz(*Blanks) /Free line(2) = ' data 1' ; line(5) = ' data here' ; line(6) = ' f=data 2' ; compressArray() ; *INLR = *On ; /End-free P compressArray B D compressArray PI D pSrc S * D pTgt S * D len S 10I 0 D i S 3U 0 D j S 3U 0 D skipped S 3U 0 Inz(*Zero) D nextEnt S 3U 0 /Free i = 1 ; nextEnt = MAX_DIM + 1 ; DoU i = *Zero or i >= nextEnt ; // Essentially forever. i = %Lookup(*Blanks: line: i) ; If i > *Zero and i < nextEnt ; // We found a target skipped = *Zero ; pTgt = %Addr(line(i)) ; // We'll copy TO here... For j = i+1 to nextEnt - 1 ; // Find our source (FROM) addr skipped += 1 ; // Number skipped (blank) lines If line(j) <> *Blank ; // We found our source pSrc = %Addr(line(j)) ; // Set our FROM addreess // Length is number of elements // from j to end of array * // length of each element len = %Size(LINE) * (nextEnt - j) ; memcpy(pTgt: pSrc: len) ; nextEnt -= skipped ; // Last possible nonblank + 1 // Now we need to overlay blank lines at the end // Number of lines to clear is the value in SKIPPED.) line(nextEnt) = *Blanks ; If skipped > 1 ; pSrc = %Addr(line(nextEnt)) ; // Blank line pTgt = pSrc + %Size(line) ; // Next entry len = %Size(line) * (skipped - 1) ; memcpy(pTgt: pSrc: len) ; EndIF ; Leave ; // Out of inner FOR loop EndIF ; // Found non-blank after blank EndFOR ; // Find next blank If j >= nextEnt ; // No more non-blank entries Leave ; // We're done! EndIF ; EndIF ; // End: found a target EndDO ; Return ; /End-free P compressArray E

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