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#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define MAX_LINE 2048
/* 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]
*/
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(sizeof n * sizeof *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.
*/
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 (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; y++)
free(data[i]);
free(data);
return -1;
}
int
main(int argc, char **argv) {
int c;
int flag_H = 0;
while ((c = getopt(argc, argv, "H")) != -1) {
switch (c) {
case 'H':
flag_H = 1;
break;
}
}
if (argc - optind > 1) {
fprintf(stderr,
"usage: %s [-H] [file]\n if no filename given, data is \
read from stdin\n"
" -H\tread data headers from first line\n", argv[0]);
return 1;
}
FILE *f;
if (argc - optind == 0) {
f = stdin;
} else {
f = fopen(argv[optind], "r");
if (f == NULL) {
perror(argv[optind]);
return 1;
}
}
int ncols = 0;
if (flag_H) {
/* read header */
char **header = malloc(sizeof (char *) * MAX_LINE);
ncols = read_header(f, &header);
for (int i = 0; i < ncols; i++) {
printf("%s\t", header[i]);
free(header[i]);
}
printf("\n");
free(header);
} else {
/* scan the first line to get the value of ncols */
while ((c = fgetc(f)) != EOF) {
if (c == ',') ncols++;
if (c == '\n') {
ncols++;
break;
}
}
/* ensure we can properly scan the first line when we come to it */
rewind(f);
}
/* read data */
float **data = malloc(sizeof (float *) * 1);
if (data == NULL) {
perror("malloc");
return 1;
}
int nrows = read_data(f, &data, ncols);
if (nrows == -1) {
free(data);
fclose(f);
return 1;
}
for (int i = 0; i < nrows; i++) {
for (int j = 0; j < ncols; j++)
printf("%g\t", data[i][j]);
printf("\n");
}
fprintf(stderr, "table has %d rows of %d columns\n", nrows, ncols);
for (int i = 0; i < nrows; i++)
free(data[i]);
free(data);
fclose(f);
return 0;
}
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