half-edge/filereader.c
hasufell 1218778145
Restructure files
filereader: file operation, reading files, reading .obj
parser: parses a string representing obj structure, converting
        to HE_obj
print: various helper functions for printing the structures
2014-05-08 17:39:23 +02:00

97 lines
2.3 KiB
C

/*
* Copyright 2011-2014 hasufell
*
* This file is part of a hasufell project.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation version 2 of the License only.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "err.h"
#include "filereader.h"
#include "parser.h"
#include "types.h"
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
/**
* Read an obj file and return a HE_obj
* if parsing worked.
*
* @param filename file to open
* @return the HE_obj or NULL for failure
*/
HE_obj *read_obj_file(char const * const filename)
{
char *string = NULL; /* file content */
HE_obj *obj = NULL;
/* read the whole file into string */
string = read_file(filename);
if (!filename || !*filename || !string || !*string)
return NULL;
obj = parse_obj(string);
free(string);
return obj;
}
/**
* Reads a file and returns a newly allocated string.
*
* @param filename file to open
* @return newly allocated string, must be freed by the caller
*/
char *read_file(char const * const filename)
{
char buf[STD_FILE_BUF],
*string = NULL;
int objfile = 0;
size_t str_size = 0;
ssize_t n;
objfile = open(filename, O_RDONLY);
if (objfile) {
/* read and copy chunks */
while ((n = read(objfile, buf, STD_FILE_BUF)) > 0) {
char *tmp_ptr = NULL;
str_size += n; /* count total bytes read */
tmp_ptr = (char*) realloc( /* allocate correct size */
string, /* pointer to realloc */
str_size /* total bytes read */
+ 1); /* space for trailing NULL byte */
CHECK_PTR_VAL(tmp_ptr);
string = tmp_ptr;
/* append buffer to string */
memcpy(string + (str_size - n), buf, n);
}
/* add trailing NULL byte */
string[str_size] = '\0';
close(objfile);
return string;
} else {
return NULL;
}
}