File queuing service (rev. 1)

fload1.c

#include <stdio.h>
#include <stdlib.h>
#include "fload.h"

#define MAX_FILE_COUNT 256
static FILE *files[MAX_FILE_COUNT] = {0};
static int fcount = 0;


//Queues specific file for loading
int floadQueue( const char *fname )
{
	if ( fname == NULL ) return 1; //Check the file name
	if ( fcount >= MAX_FILE_COUNT ) return 1; //Check for file stack overflow
	if ( ( files[fcount] = fopen( fname, "rt" ) ) == NULL ) return 1; //Attempt to open the file
	fcount++; //Update stack counter
	return 0;
}

//Reads single line from file queue (returned string must be freed by user)
char *floadRead( )
{
	const int buflen = 4096;
	char *buf = NULL;
	FILE *f = NULL;
	
	if ( fcount <= 0 ) return NULL; //Check file count (recursion lock)
	if ( ( buf = calloc( buflen, sizeof( char ) ) ) == NULL ) return NULL; //Allocate memory for the new line
	f = files[fcount - 1];

	//Check if another line can be read
	if ( fgets( buf, buflen, f ) == NULL )
	{
		//If not, attempt to read from another file
		free( buf );
		fclose( f );
		fcount--;
		return floadRead( );
	}

	return buf;
}

//Skip reading current file
void floadSkip( )
{
	FILE *f = files[fcount - 1];
	if ( fcount <= 0 ) return;
	fclose( f );
	fcount--;
}

//Close all queued files
void floadEnd( )
{
	while ( fcount )
		fclose( files[--fcount] );
}