data.c

/* data.c - data/read routines 
 *
 * part of dbasic
 * (C) k theis <theis.kurt@gmail.com> 2022
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "dbasic.h"

/* scan the buffer for data statements
 * first scan, get a count of records,
 * then create the memory space to hold
 * these records. Scan from beginning again
 * but this time populate the newly created
 * memory space with the data in the statements.
 */

extern float *DataStorage;
extern int DataStorageMax;
extern int DataPosition;
extern int GARBAGE;

int scanData(char *buffer, int lastpos) {

	int position=0;		// current position in the buffer;
	int n=0;
	char ln[6]={'\0'} ,keyword[12]={'\0'},line[80]={'\0'};
	int x=0;;
	char *testline;
	char numstr[12]={'\0'};

bufscan:
	/* scan the buffer */
	memset(line,0,sizeof(line));
	n = 0;
	while (1) {
		line[n] = buffer[position+n];
		/* NOTE: \n here not stripped off so it needs to be tested */
		if (line[n] == '\n' || line[n] == '\0') break;
		n++;
		if (n+position >= lastpos) break;
	}
	if (n+position >= lastpos) goto step2;
	line[n] = '\0';
	position += (n+1);

	/* test the line for a data statement */
	sscanf(line,"%s %s",ln,keyword);
	if (strcmp(keyword,"data")!=0) goto bufscan;

	/* keyword = data, count the elements in the line */
	/* format: 10 data 1,2,3,4,5\n\0  has 4 commas and 5 elements  */
	for (x=0; x<strlen(line); x++) 
		if (line[x] == ',') DataStorageMax++;
	DataStorageMax++;		// the final element
	goto bufscan;			// done with line

step2:
	
	/* define storage space for the data elements */
	if (GARBAGE)
		free(DataStorage);
	DataStorage = malloc((DataStorageMax+1)*sizeof(float));
	if (DataStorage == NULL) {
		printf("Error - memory allocation error in data elements\n");
		return -1;
	}

	/* now rescan the buffer, reading each data statement 
	 * and filling DataStorage with values 
	 */
	position=0;
	n=0;
bufload:
	memset(line,0,sizeof(line));
	n = 0;
	while (1) {
		line[n] = buffer[position+n];
		if (line[n] == '\n' || line[n] == '\0') break;
		n++;
		if (n+position >= lastpos) break;
	}
	if (n+position >= lastpos) goto step3;
	line[n] = '\0';
	position += (n+1);

	/* test the line for a data statement */
    sscanf(line,"%s %s",ln,keyword);
    if (strcmp(keyword,"data")!=0) goto bufload;

	/* keyword = data, read and load elements */
	/* format: 10 data 1,2,3,4,5\n\0 */
	testline = line;
	if (isdigit(*testline)) while (isdigit(*testline)) testline++;	// skip line #
	if (isblank(*testline)) while (isblank(*testline)) testline++;	// and spaces
	if (isalpha(*testline)) while (isalpha(*testline)) testline++;	// and DATA statement
	if (isblank(*testline)) while (isblank(*testline)) testline++;	// final space

	/* the rest of the line holds a bunch of floats and commas */
bufload2:
	n = 0;
	memset(numstr,0,sizeof(numstr));
	while (1) {
		if (*testline == '\n' || *testline == '\0') break;
		if (*testline == ',') break;
		numstr[n] = *testline;
		n++; testline++;
	}
	
	/* value in intval */
	numstr[n+1] = '\0';
	DataStorage[DataPosition] = atof(numstr);
	DataPosition++;
	testline += 1;		// skip the comma
	//if (*testline == '\n' || *testline == '\0') goto bufload;	// done with this line
	if (*testline == '\0') goto bufload;	// done with this line
	goto bufload2;		// finish the line


step3:
	/* finished loading */
	DataStorageMax = DataPosition-1;		// max number of data elements
	
	return 0;
}

	
int run_read(char *line) {		// load variables with data values
	extern float *NumVar[26];
	extern float *DataStorage;
	extern int DataStorageMax;
	extern int DataPosition;
	float eval(char *);

	if (isdigit(*line)) while (isdigit(*line)) line++;  // skip line #
    if (isblank(*line)) while (isblank(*line)) line++;  // and spaces
    if (isalpha(*line)) while (isalpha(*line)) line++;  // and READ statement
    if (isblank(*line)) while (isblank(*line)) line++;  // final space

	/* format: 1000 read a,b,c,d,e\n\0  */
	while (1) {
		if (*line == ',' || *line == ' ') {							// ignore spaces, commas
			line++;
			continue;
		}
		if (*line == '\n' || *line == '\0') return 0;				// normal end
		if (*line >= 'a' && *line <= 'z' && *(line+1) != '$') {		// just numeric vars
			if (DataPosition > DataStorageMax) {
				printf("Out Of Data\n");
				return -1;
			}
			// get subscript (if used)
			int subscript = 0;
			char charvar = *line;
			line++;
			if (*line == '(') {		// using subscripts
				line++;
				char SUBNUM[LINESIZE]={'\0'};
				int n=0;
				while (1) {
					if (*line == ')') break;
					SUBNUM[n] = *line;
					line++; n++;
				}
				subscript = eval(SUBNUM);
				line++;
			}
			NumVar[charvar-'a'][subscript] = DataStorage[DataPosition];
			DataPosition++;
			line++;
			continue;
		}
		printf("Unknown character in read statement\n");
		return -1;
	}

	return -1;
}