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	tcsv.c - ploot - simple plotting tools
	git clone git://bitreich.org/ploot git://enlrupgkhuxnvlhsf6lc3fziv5h2hhfrinws65…
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	tcsv.c (2343B)
	---
	1 #include "csv.h"
	2
	3 #include <errno.h>
	4 #include <assert.h>
	5 #include <string.h>
	6 #include <time.h>
	7 #include <stdlib.h>
	8 #include <limits.h>
	9 #include <time.h>
	10
	11 #include "log.h"
	12 #include "util.h"
	13
	14 /*
	15 * Read CSV data onto a set of (struct csv).
	16 */
	17
	18 static void
	19 csv_addtime(struct csv *vl, time_t epoch)
	20 {
	21 assert(vl->t = realloc(vl->t, (vl->n + 1) * sizeof(*vl->t)));
	22 vl->t[vl->n] = epoch;
	23 }
	24
	25 static void
	26 csv_addval(struct csv *vl, double field)
	27 {
	28 assert(vl->v = realloc(vl->v, (vl->n + 1) * sizeof(*vl->v)));
	29 vl->v[vl->n] = field;
	30 }
	31
	32 /*
	33 * Add to each column the value on the current row. The time_t
	34 * buffer is shared among all fields.
	35 */
	36 void
	37 csv_addrow(struct csv vl, size_t ncol, char line)
	38 {
	39 char *field;
	40 time_t *tbuf;
	41 long l;
	42 double d;
	43
	44 field = strsep(&line, ",");
	45 if (!field)
	46 die(1, "missing epoch at row %zu", vl->n);
	47
	48 l = strtol(field, NULL, 10);
	49 if (errno)
	50 die(100, "parsing number '%s'", field);
	51 csv_addtime(vl, l);
	52 tbuf = vl[0].t;
	53 for (; (field = strsep(&line, ",")); ncol--, vl->n++, vl++) {
	54 if (ncol == 0)
	55 die(1, "too many fields at line %zu", vl->n);
	56 d = strtod(field, NULL);
	57 if (errno)
	58 die(100, "parsing double '%s'", field);
	59 csv_addval(vl, d);
	60 vl->t = tbuf;
	61 }
	62 if (ncol > 0)
	63 die(1, "too few fields at line %zu", vl->n);
	64 }
	65
	66 /*
	67 * < *ncol >
	68 * epoch,label1,label2,label3
	69 */
	70 void
	71 csv_labels(FILE fp, struct csv vl, size_t ncol)
	72 {
	73 char field, line, *cp;
	74 struct csv *col;
	75 size_t sz;
	76 ssize_t r;
	77
	78 sz = 0, line = NULL;
	79 r = getline(&line, &sz, fp);
	80 if (ferror(fp))
	81 die(111, "error while reading from file");
	82 if (r == -1)
	83 die(100, "missing label line");
	84 strchomp(line);
	85
	86 cp = line;
	87 if (strcmp(strsep(&cp, ","), "epoch") != 0)
	88 die(1, "first label must be 'epoch'");
	89
	90 *vl = NULL;
	91 *ncol = 0;
	92 while ((field = strsep(&cp, ","))) {
	93 assert(vl = realloc(vl, sz += sizeof(**vl)));
	94 col = (vl) + (ncol)++;
	95 strlcpy(col->label, field, sizeof(col->label));
	96 }
	97
	98 free(line);
	99 }
	100
	101 /*
	102 * < ncol >
	103 * epoch,a1,b1,c1 ^
	104 * epoch,a2,b2,c2 vl->n
	105 * epoch,a3,b3,c3 v
	106 */
	107 void
	108 csv_values(FILE fp, struct csv vl, size_t ncol)
	109 {
	110 char *line;
	111 size_t sz;
	112
	113 sz = 0, line = NULL;
	114 while (getline(&line, &sz, fp) > -1)
	115 csv_addrow(vl, ncol, line);
	116 if (vl->n == 0)
	117 die(1, "no value could be read");
	118 if (vl->n == 1)
	119 die(1, "only one value could be read");
	120
	121 free(line);
	122 }