FaceElement.cpp

//
// Created by rthier on 2016.04.11..
//

#include "FaceElement.h"
#include <cstring>    /* strtok_r */
#include "ObjCommon.h"
#include "wincompat.h" // msvc hax

namespace ObjMaster {
    bool FaceElement::isParsable(const char *fields) {
	// Not an empty string, the first character is an 'f' the second is a ' '
	return (fields != nullptr) && (fields[0] != 0) && (fields[0] == 'f') && (fields[1] == ' ');
    }

    FaceElement::FaceElement(const char *fields) {
	// The strtok_r changes the string so we need to duplicate it
	char copy[256];	// The line never should be longer than this anyways...
	copy[255] = 0;	// ensure terminator
	strncpy(copy, fields, 254);
	constructionHelper(copy);
	// Remark: The original code below makes very small malloc and free pairs and fragment memory!
	// char *copy = strdup(fields);
	// constructionHelper(copy);
	// free(copy);
    }

    // This variant modifies the provided 'string' but it is faster as it do this without the copy
    FaceElement::FaceElement(char *fields) {
	constructionHelper(fields);
    }

    // Common parts of constructors
    void FaceElement::constructionHelper(char* fields) {
	if (isParsable(fields)) {
	    // Count delimiters
	    // The first delimiter delimits the 'f' and the first FacePoint
	    // so to get the number of facePoints all we need to do is to count the delimiters!
	    int delimCount = 0;
	    for (int i = 0; (fields[i] != 0); ++i) {
		if (fields[i] == OBJ_DELIMITER[0]) {
		    ++delimCount;
		}
	    }

	    // Tokenization
	    char *savePtr;
	    // The 'f' is the first token...
	    char *key = strtok_r(fields, OBJ_DELIMITER, &savePtr);

	    // This both sets the facePointCount and fills in the face-points
	    // The facePointCount can be less than the delimCount when we handle only 3 points and
	    // there are more delimiters than that!
	    for (facePointCount = 0;
		 facePointCount < delimCount && facePointCount < MAX_FACEPOINT_COUNT;
		 ++facePointCount) {

		// Extract the currently latest FacePoint
		char *facePointStr = strtok_r(nullptr, OBJ_DELIMITER, &savePtr);
		// Parse the given facePoint and save it - with added extra check
		// in case of nasty errors that should never be there!
		if (facePointStr != nullptr) {
			facePoints[facePointCount] = FacePoint(facePointStr, true);
		}
	    }
	}
    }
}