170 lines
4 KiB
C
170 lines
4 KiB
C
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/*** line.c - Line stream related functions
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*
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* Copyright (c) 1996,1997 Microsoft Corporation
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* Author: Michael Tsang (MikeTs)
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* Created: 09/04/96
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*
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* This module implements the line stream layer so that it can
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* keep track of the information such as line number and line
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* position. This information is necessary for the scanner or
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* even the parser to accurately pin point the error location
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* in case of syntax or semantic errors.
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*
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* MODIFICATION HISTORY
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*/
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#include "pch.h"
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/***EP OpenLine - allocate and initialize line structure
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*
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* ENTRY
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* pfileSrc -> source file
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*
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* EXIT-SUCCESS
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* returns the pointer to the allocated line structure.
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* EXIT-FAILURE
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* returns NULL.
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*/
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PLINE EXPORT OpenLine(FILE *pfileSrc)
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{
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PLINE pline;
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ENTER((5, "OpenLine(pfileSrc=%p)\n", pfileSrc));
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if ((pline = malloc(sizeof(LINE))) == NULL)
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MSG(("OpenLine: failed to allocate line structure"))
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else
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{
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memset(pline, 0, sizeof(LINE));
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pline->pfileSrc = pfileSrc;
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}
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EXIT((5, "OpenLine=%p\n", pline));
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return pline;
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} //OpenLine
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/***EP CloseLine - free line structure
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*
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* ENTRY
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* pline->line structure
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*
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* EXIT
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* None
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*/
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VOID EXPORT CloseLine(PLINE pline)
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{
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ENTER((5, "CloseLine(pline=%p)\n", pline));
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free(pline);
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EXIT((5, "CloseLine!\n"));
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} //CloseLine
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/***EP LineGetC - get a character from the line stream
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*
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* This is equivalent to fgetc() except that it has the line
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* stream layer below it instead of directly from the file. It
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* is done this way to preserve the line number and line position
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* information for accurately pin pointing the error location
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* if necessary.
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*
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* ENTRY
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* pline -> line structure
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*
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* EXIT-SUCCESS
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* returns the character
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* EXIT-FAILURE
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* returns error code - EOF (end-of-file)
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*/
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int EXPORT LineGetC(PLINE pline)
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{
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int ch = 0;
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ENTER((5, "LineGetC(pline=%p)\n", pline));
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if (pline->wLinePos >= pline->wLineLen)
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{
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//
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// EOL is encountered
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//
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if (fgets(pline->szLineBuff, sizeof(pline->szLineBuff), pline->pfileSrc)
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!= NULL)
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{
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pline->wLinePos = 0;
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if (!(pline->wfLine & LINEF_LONGLINE))
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pline->wLineNum++;
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pline->wLineLen = (WORD)strlen(pline->szLineBuff);
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if (pline->szLineBuff[pline->wLineLen - 1] == '\n')
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pline->wfLine &= ~LINEF_LONGLINE;
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else
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pline->wfLine |= LINEF_LONGLINE;
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}
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else
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ch = EOF;
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}
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if (ch == 0)
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ch = (int)pline->szLineBuff[pline->wLinePos++];
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EXIT((5, "LineGetC=%x (ch=%c,Line=%u,NextPos=%u,LineLen=%u)\n",
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ch, ch, pline->wLineNum, pline->wLinePos, pline->wLineLen));
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return ch;
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} //LineGetC
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/***EP LineUnGetC - push a character back to the line stream
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*
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* This is equivalent to fungetc() except that it's source is
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* the line stream not the file stream. Refer to LineGetC for
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* explanation on this implementation.
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*
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* ENTRY
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* ch - character being pushed back
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* pline -> line structure
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*
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* EXIT-SUCCESS
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* returns the character being pushed
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* EXIT-FAILURE
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* returns -1
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*/
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int EXPORT LineUnGetC(int ch, PLINE pline)
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{
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ENTER((5, "LineUnGetC(ch=%c,pline=%p)\n", ch, pline));
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ASSERT(pline->wLinePos != 0);
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if (ch != EOF)
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{
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pline->wLinePos--;
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ASSERT((int)pline->szLineBuff[pline->wLinePos] == ch);
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}
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EXIT((5, "LineUnGetC=%x (ch=%c)\n", ch, ch));
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return ch;
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} //LineUnGetC
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/***EP LineFlush - flush a line
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*
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* The scanner may want to discard the rest of the line when it
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* detects an in-line comment symbol, for example.
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*
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* ENTRY
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* pline -> line structure
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*
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* EXIT
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* none
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*/
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VOID EXPORT LineFlush(PLINE pline)
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{
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ENTER((5, "LineFlush(pline=%p)\n", pline));
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pline->wLinePos = pline->wLineLen;
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EXIT((5, "LineFlush!\n"));
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} //LineFlush
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