csv

commit 1f76650300e3a22379f84779f0763967907ebc53
parent 5cd26a74f359f4b33ac0a133fc041a0f49afdaee
Author: phoebos <ben@bvnf.space>
Date:   Sat,  2 Oct 2021 11:59:05 +0000

move header reading into its own function

Diffstat:
M
csv.c
 | 
63
+++++++++++++++++++++++++++++++++++++++------------------------

1 file changed, 39 insertions(+), 24 deletions(-)
diff --git a/csv.c b/csv.c
@@ -6,6 +6,34 @@
 
 #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;
+}
+
 int
 main(int argc, char **argv) {
 	if (argc > 2) {
@@ -24,34 +52,21 @@ read from stdin\n", argv[0]);
 		}
 	}
 
-	char **header = malloc(sizeof (char *) * MAX_LINE);
-	char **headerp = header;
+	int ncols;
 
 	/* read 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;
+	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]);
 	}
-	do {
-		printf("%s ", *header);
-		free(*header);
-	} while (*++header);
-	puts("");
+	printf("\n");
+	free(header);
 
 	/* read data */
+	char *n = malloc(MAX_LINE);
+	char *np = n;
 	int nrows = 0;
 	float **data;
 	data = malloc(sizeof (float *) * (nrows + 1));
@@ -65,7 +80,7 @@ read from stdin\n", argv[0]);
 		goto fail;
 	}
 	np = n;
-	int x, y;
+	int c, x, y;
 	x = y = 0;
 	while ((c = fgetc(f)) != EOF) {
 		if (c == ',' || c == '\n') {