/*
*   $Id: read.c,v 1.6 2002/06/19 05:27:17 darren Exp $
*
*   Copyright (c) 1996-2002, Darren Hiebert
*
*   This source code is released for free distribution under the terms of the
*   GNU General Public License.
*
*   This module contains low level source and tag file read functions (newline
*   conversion for source files are performed at this level).
*/

/*
*   INCLUDE FILES
*/
#include "general.h"	/* must always come first */

#include <string.h>
#include <ctype.h>

#define FILE_WRITE
#include "read.h"
#include "debug.h"
#include "entry.h"
#include "main.h"
#include "routines.h"
#include "options.h"

/*
*   DATA DEFINITIONS
*/
inputFile File;			/* globally read through macros */
static fpos_t StartOfLine;	/* holds deferred position of start of line */

/*
*   FUNCTION DEFINITIONS
*/

extern void freeSourceFileResources (void)
{
    vStringDelete (File.name);
    vStringDelete (File.path);
    vStringDelete (File.source.name);
    vStringDelete (File.line);
}

/*
 *   Source file access functions
 */

static void setInputFileName (const char *const fileName)
{
    const char *const head = fileName;
    const char *const tail = baseFilename (head);

    if (File.name != NULL)
	vStringDelete (File.name);
    File.name = vStringNewInit (fileName);

    if (File.path != NULL)
	vStringDelete (File.path);
    if (tail == head)
	File.path = NULL;
    else
    {
	const size_t length = tail - head - 1;
	File.path = vStringNew ();
	vStringNCopyS (File.path, fileName, length);
    }
}

static void setSourceFileParameters (vString *const fileName)
{
    if (File.source.name != NULL)
	vStringDelete (File.source.name);
    File.source.name = fileName;

    if (File.source.tagPath != NULL)
	eFree (File.source.tagPath);
    if (! Option.tagRelative || isAbsolutePath (vStringValue (fileName)))
	File.source.tagPath = eStrdup (vStringValue (fileName));
    else
	File.source.tagPath =
		relativeFilename (vStringValue (fileName), TagFile.directory);

    if (vStringLength (fileName) > TagFile.max.file)
	TagFile.max.file = vStringLength (fileName);

    File.source.isHeader = isIncludeFile (vStringValue (fileName));
    File.source.language = getFileLanguage (vStringValue (fileName));
}

static boolean setSourceFileName (vString *const fileName)
{
    boolean result = FALSE;
    if (getFileLanguage (vStringValue (fileName)) != LANG_IGNORE)
    {
	vString *pathName;
	if (isAbsolutePath (vStringValue (fileName)) || File.path == NULL)
	    pathName = vStringNewCopy (fileName);
	else
	    pathName = combinePathAndFile (vStringValue (File.path),
					vStringValue (fileName));
	setSourceFileParameters (pathName);
	result = TRUE;
    }
    return result;
}

/*
 *   Line directive parsing
 */

static int skipWhite (void)
{
    int c;
    do
	c = getc (File.fp);
    while (c == ' '  ||  c == '\t');
    return c;
}

static unsigned long readLineNumber (void)
{
    unsigned long lNum = 0;
    int c = skipWhite ();
    while (c != EOF  &&  isdigit (c))
    {
	lNum = (lNum * 10) + (c - '0');
	c = getc (File.fp);
    }
    ungetc (c, File.fp);
    if (c != ' '  &&  c != '\t')
	lNum = 0;

    return lNum;
}

/* While ANSI only permits lines of the form:
 *   # line n "filename"
 * Earlier compilers generated lines of the form
 *   # n filename
 * GNU C will output lines of the form:
 *   # n "filename"
 * So we need to be fairly flexible in what we accept.
 */
static vString *readFileName (void)
{
    vString *const fileName = vStringNew ();
    boolean quoteDelimited = FALSE;
    int c = skipWhite ();

    if (c == '"')
    {
	c = getc (File.fp);		/* skip double-quote */
	quoteDelimited = TRUE;
    }
    while (c != EOF  &&  c != '\n'  &&
	    (quoteDelimited ? (c != '"') : (c != ' '  &&  c != '\t')))
    {
	vStringPut (fileName, c);
	c = getc (File.fp);
    }
    if (c == '\n')
	ungetc (c, File.fp);
    vStringPut (fileName, '\0');

    return fileName;
}

static boolean parseLineDirective (void)
{
    boolean result = FALSE;
    int c = skipWhite ();
    DebugStatement ( const char* lineStr = ""; )

    if (isdigit (c))
    {
	ungetc (c, File.fp);
	result = TRUE;
    }
    else if (c == 'l'  &&  getc (File.fp) == 'i'  &&
	     getc (File.fp) == 'n'  &&  getc (File.fp) == 'e')
    {
	c = getc (File.fp);
	if (c == ' '  ||  c == '\t')
	{
	    DebugStatement ( lineStr = "line"; )
	    result = TRUE;
	}
    }
    if (result)
    {
	const unsigned long lNum = readLineNumber ();
	if (lNum == 0)
	    result = FALSE;
	else
	{
	    vString *const fileName = readFileName ();
	    if (vStringLength (fileName) == 0)
	    {
		File.source.lineNumber = lNum - 1;  /* applies to NEXT line */
		DebugStatement ( debugPrintf (DEBUG_RAW, "#%s %ld", lineStr, lNum); )
	    }
	    else if (setSourceFileName (fileName))
	    {
		File.source.lineNumber = lNum - 1;  /* applies to NEXT line */
		DebugStatement ( debugPrintf (DEBUG_RAW, "#%s %ld \"%s\"",
				lineStr, lNum, vStringValue (fileName)); )
	    }

	    if (Option.include.fileNames && vStringLength (fileName) > 0 &&
		lNum == 1)
	    {
		tagEntryInfo tag;
		initTagEntry (&tag, baseFilename (vStringValue (fileName)));

		tag.isFileEntry     = TRUE;
		tag.lineNumberEntry = TRUE;
		tag.lineNumber      = 1;
		tag.kindName        = "file";
		tag.kind            = 'F';

		makeTagEntry (&tag);
	    }
	    vStringDelete (fileName);
	    result = TRUE;
	}
    }
    return result;
}

/*
 *   Source file I/O operations
 */

/*  This function opens a source file, and resets the line counter.  If it
 *  fails, it will display an error message and leave the File.fp set to NULL.
 */
extern boolean fileOpen (const char *const fileName, const langType language)
{
#ifdef VMS
    const char *const openMode = "r";
#else
    const char *const openMode = "rb";
#endif
    boolean opened = FALSE;

    /*	If another file was already open, then close it.
     */
    if (File.fp != NULL)
    {
	fclose (File.fp);		/* close any open source file */
	File.fp = NULL;
    }

    File.fp = fopen (fileName, openMode);
    if (File.fp == NULL)
	error (WARNING | PERROR, "cannot open \"%s\"", fileName);
    else
    {
	opened = TRUE;

	setInputFileName (fileName);
	fgetpos (File.fp, &StartOfLine);
	fgetpos (File.fp, &File.filePosition);
	File.currentLine  = NULL;
	File.language     = language;
	File.lineNumber   = 0L;
	File.eof          = FALSE;
	File.newLine      = TRUE;

	if (File.line != NULL)
	    vStringClear (File.line);

	setSourceFileParameters (vStringNewInit (fileName));
	File.source.lineNumber = 0L;

	verbose ("OPENING %s as %s language %sfile\n", fileName,
		getLanguageName (language),
		File.source.isHeader ? "include " : "");
    }
    return opened;
}

extern void fileClose (void)
{
    if (File.fp != NULL)
    {
	/*  The line count of the file is 1 too big, since it is one-based
	 *  and is incremented upon each newline.
	 */
	if (Option.printTotals)
	{
	    fileStatus *status = eStat (vStringValue (File.name));
	    addTotals (0, File.lineNumber - 1L, status->size);
	}
	fclose (File.fp);
	File.fp = NULL;
    }
}

extern boolean fileEOF (void)
{
    return File.eof;
}

/*  Action to take for each encountered source newline.
 */
static void fileNewline (void)
{
    File.filePosition = StartOfLine;
    File.newLine = FALSE;
    File.lineNumber++;
    File.source.lineNumber++;
    DebugStatement ( if (Option.breakLine == File.lineNumber) lineBreak (); )
    DebugStatement ( debugPrintf (DEBUG_RAW, "%6ld: ", File.lineNumber); )
}

/*  This function reads a single character from the stream, performing newline
 *  canonicalization.
 */
static int iFileGetc (void)
{
    int	c;
readnext:
    c = getc (File.fp);

    /*	If previous character was a newline, then we're starting a line.
     */
    if (File.newLine  &&  c != EOF)
    {
	fileNewline ();
	if (c == '#'  &&  Option.lineDirectives)
	{
	    if (parseLineDirective ())
		goto readnext;
	    else
	    {
		fsetpos (File.fp, &StartOfLine);
		c = getc (File.fp);
	    }
	}
    }

    if (c == EOF)
	File.eof = TRUE;
    else if (c == NEWLINE)
    {
	File.newLine = TRUE;
	fgetpos (File.fp, &StartOfLine);
    }
    else if (c == CRETURN)
    {
	/*  Turn line breaks into a canonical form. The three commonly
	 *  used forms if line breaks: LF (UNIX), CR (MacIntosh), and
	 *  CR-LF (MS-DOS) are converted into a generic newline.
	 */
	const int next = getc (File.fp);	/* is CR followed by LF? */

	if (next != NEWLINE)
	    ungetc (next, File.fp);

	c = NEWLINE;				/* convert CR into newline */
	File.newLine = TRUE;
	fgetpos (File.fp, &StartOfLine);
    }
    DebugStatement ( debugPutc (DEBUG_RAW, c); )
    return c;
}

extern void fileUngetc (int c)
{
    File.ungetch = c;
}

static vString *iFileGetLine (void)
{
    vString *result = NULL;
    int c;
    if (File.line == NULL)
	File.line = vStringNew ();
    vStringClear (File.line);
    do
    {
	c = iFileGetc ();
	if (c != EOF)
	    vStringPut (File.line, c);
	if (c == '\n'  ||  (c == EOF  &&  vStringLength (File.line) > 0))
	{
	    vStringTerminate (File.line);
#ifdef HAVE_REGEX
	    if (vStringLength (File.line) > 0)
		matchRegex (File.line, File.source.language);
#endif
	    result = File.line;
	    break;
	}
    } while (c != EOF);
    Assert (result != NULL  ||  File.eof);
    return result;
}

/*  Do not mix use of fileReadLine () and fileGetc () for the same file.
 */
extern int fileGetc (void)
{
    int c;

    /*	If there is an ungotten character, then return it.  Don't do any
     *	other processing on it, though, because we already did that the
     *	first time it was read through fileGetc ().
     */
    if (File.ungetch != '\0')
    {
	c = File.ungetch;
	File.ungetch = '\0';
	return c;	    /* return here to avoid re-calling debugPutc () */
    }
    do
    {
	if (File.currentLine != NULL)
	{
	    c = *File.currentLine++;
	    if (c == '\0')
		File.currentLine = NULL;
	}
	else
	{
	    vString* const line = iFileGetLine ();
	    if (line != NULL)
		File.currentLine = (unsigned char*) vStringValue (line);
	    if (File.currentLine == NULL)
		c = EOF;
	    else
		c = '\0';
	}
    } while (c == '\0');
    DebugStatement ( debugPutc (DEBUG_READ, c); )
    return c;
}

/*  An alternative interface to fileGetc (). Do not mix use of fileReadLine()
 *  and fileGetc() for the same file. The returned string does not contain
 *  the terminating newline. A NULL return value means that all lines in the
 *  file have been read and we are at the end of file.
 */
extern const unsigned char *fileReadLine (void)
{
    vString* const line = iFileGetLine ();
    const unsigned char* result = NULL;
    if (line != NULL)
    {
	result = (const unsigned char*) vStringValue (line);
	vStringStripNewline (line);
	DebugStatement ( debugPrintf (DEBUG_READ, "%s\n", result); )
    }
    return result;
}

/*
 *   Source file line reading with automatic buffer sizing
 */
extern char *readLine (vString *const vLine, FILE *const fp)
{
    char *result = NULL;

    vStringClear (vLine);
    if (fp == NULL)		/* to free memory allocated to buffer */
	error (FATAL, "NULL file pointer");
    else
    {
	boolean reReadLine;

	/*  If reading the line places any character other than a null or a
	 *  newline at the last character position in the buffer (one less
	 *  than the buffer size), then we must resize the buffer and
	 *  reattempt to read the line.
	 */
	do
	{
	    char *const pLastChar = vStringValue (vLine) + vStringSize (vLine) -2;
	    fpos_t startOfLine;

	    fgetpos (fp, &startOfLine);
	    reReadLine = FALSE;
	    *pLastChar = '\0';
	    result = fgets (vStringValue (vLine), (int) vStringSize (vLine), fp);
	    if (result == NULL)
	    {
		if (! feof (fp))
		    error (FATAL | PERROR, "Failure on attempt to read file");
	    }
	    else if (*pLastChar != '\0'  &&
		     *pLastChar != '\n'  &&  *pLastChar != '\r')
	    {
		/*  buffer overflow */
		reReadLine = vStringAutoResize (vLine);
		if (reReadLine)
		    fsetpos (fp, &startOfLine);
		else
		    error (FATAL | PERROR, "input line too big; out of memory");
	    }
	    else
	    {
		char* eol;
		vStringSetLength (vLine);
		/* canonicalize new line */
		eol = vStringValue (vLine) + vStringLength (vLine) - 1;
		if (*eol == '\r')
		    *eol = '\n';
		else if (*(eol - 1) == '\r'  &&  *eol == '\n')
		{
		    *(eol - 1) = '\n';
		    *eol = '\0';
		    --vLine->length;
		}
	    }
	} while (reReadLine);
    }
    return result;
}

/*  Places into the line buffer the contents of the line referenced by
 *  "location".
 */
extern char *readSourceLine (vString *const vLine, fpos_t location,
			     long *const pSeekValue)
{
    fpos_t orignalPosition;
    char *result;

    fgetpos (File.fp, &orignalPosition);
    fsetpos (File.fp, &location);
    if (pSeekValue != NULL)
	*pSeekValue = ftell (File.fp);
    result = readLine (vLine, File.fp);
    if (result == NULL)
	error (FATAL, "Unexpected end of file: %s", vStringValue (File.name));
    fsetpos (File.fp, &orignalPosition);

    return result;
}

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