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#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "csv.h"
#define MAX_LINE 2048
struct csv *
csv_create(void) {
struct csv *c;
c = malloc(sizeof c + sizeof(char *) + sizeof(float *));
if (c == NULL)
return NULL;
c->cols = 0;
c->rows = 0;
char **h = malloc(sizeof (char *) * MAX_LINE);
if (h == NULL)
return NULL;
c->headers = h;
float **d = malloc(sizeof (float *));
if (d == NULL)
return NULL;
c->data = d;
return c;
}
void
csv_destroy(struct csv *c) {
int i;
for (i = 0; i < c->cols; i++)
free(c->headers[i]);
for (i = 0; i < c->rows; i++)
free(c->data[i]);
free(c);
}
/* read_header reads each header field name from the first line of the file
* into *header, and returns the number of columns.
* This function mallocs the returned value of fields in *header[0..n-1]
*/
static int
read_header(FILE *f, char **header) {
char **headerp = header;
int c;
int ncols = 0;
char *n = malloc(MAX_LINE);
char *np = n;
while ((c = fgetc(f)) != EOF) {
if (c == ',' || c == '\n') {
*np++ = '\0';
*headerp = malloc(strlen(n));
strcpy(*headerp, n);
headerp++;
np = n;
ncols++;
if (c == '\n') break;
continue;
}
*np++ = c;
}
free(n);
return ncols;
}
/* read_data reads all the comma-separated values from f into *datap,
* and returns the number of rows.
* This function mallocs the number of rows in *header[0..n-1]
* -1 is returned on error.
*/
static int
read_data(FILE *f, float ***datap, int ncols) {
float **data = *datap;
int nrows = 0;
char *n = malloc(MAX_LINE);
if (n == NULL) {
perror("malloc");
return -1;
}
char *np = n;
data[0] = malloc(sizeof (float) * ncols);
if (data[0] == NULL) {
perror("malloc");
free(n);
return -1;
}
int c, x, y;
x = y = 0;
while ((c = fgetc(f)) != EOF) {
if (c == ',' || c == '\n') {
if (n == np) {
/* nothing in this column */
fprintf(stderr, "warning: no value in cell at row %d, col %d\n", y + 1, x + 1);
data[y][x] = 0.;
} else {
*np++ = '\0';
data[y][x] = (float)atof(n);
np = n;
}
x++;
if (x > ncols) {
/* extra cells in the row. eat up the rest of the row to avoid writing into
* unallocated memory */
fprintf(stderr, "warning: extra cells in row %d\n", y + 1);
while (c != '\n' && c != EOF)
c = fgetc(f);
if (c == EOF)
break;
}
if (c == '\n') {
if (x < ncols) {
fprintf(stderr, "warning: %d cells missing from row %d\n", ncols - x, y + 1);
for (; x < ncols; x++)
data[y][x] = 0.;
}
nrows++;
y++;
x = 0;
float **tmp = realloc(data, sizeof (float *) * (nrows + 1));
if (tmp == NULL) {
perror("malloc");
goto cleanup;
}
data = tmp;
data[y] = malloc(sizeof (float) * ncols);
if (data[y] == NULL) {
nrows--;
perror("malloc");
goto cleanup;
}
continue;
}
continue;
}
*np++ = c;
}
free(n);
*datap = data;
return nrows;
cleanup:
free(n);
for (int i = 0; i < nrows; i++)
free(data[i]);
return -1;
}
int
csv_read_file(FILE *f, struct csv *c, char hdr) {
int ch;
int ncols = 0;
if (hdr) {
/* read header */
ncols = read_header(f, c->headers);
} else {
/* scan the first line to get the value of ncols */
while ((ch = fgetc(f)) != EOF) {
if (ch == ',') ncols++;
if (ch == '\n') {
ncols++;
break;
}
}
/* ensure we can properly scan the first line when we come to it */
rewind(f);
}
c->cols = ncols;
/* read data */
int nrows = read_data(f, &c->data, ncols);
fclose(f);
if (nrows == -1) {
csv_destroy(c);
return 1;
}
c->rows = nrows;
return 0;
}
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