[thirdparty/systemd.git] / src / basic / replace-var.c

/* SPDX-License-Identifier: LGPL-2.1+ */

#include <errno.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>

#include "alloc-util.h"
#include "macro.h"
#include "replace-var.h"
#include "string-util.h"

/*
 * Generic infrastructure for replacing @FOO@ style variables in
 * strings. Will call a callback for each replacement.
 */

static int get_variable(const char *b, char **r) {
        size_t k;
        char *t;

        assert(b);
        assert(r);

        if (*b != '@')
                return 0;

        k = strspn(b + 1, UPPERCASE_LETTERS "_");
        if (k <= 0 || b[k+1] != '@')
                return 0;

        t = strndup(b + 1, k);
        if (!t)
                return -ENOMEM;

        *r = t;
        return 1;
}

char *replace_var(const char *text, char *(*lookup)(const char *variable, void *userdata), void *userdata) {
        char *r, *t;
        const char *f;
        size_t l;

        assert(text);
        assert(lookup);

        l = strlen(text);
        r = new(char, l+1);
        if (!r)
                return NULL;

        f = text;
        t = r;
        while (*f) {
                _cleanup_free_ char *v = NULL, *n = NULL;
                char *a;
                int k;
                size_t skip, d, nl;

                k = get_variable(f, &v);
                if (k < 0)
                        goto oom;
                if (k == 0) {
                        *(t++) = *(f++);
                        continue;
                }

                n = lookup(v, userdata);
                if (!n)
                        goto oom;

                skip = strlen(v) + 2;

                d = t - r;
                nl = l - skip + strlen(n);
                a = realloc(r, nl + 1);
                if (!a)
                        goto oom;

                l = nl;
                r = a;
                t = r + d;

                t = stpcpy(t, n);
                f += skip;
        }

        *t = 0;
        return r;

oom:
        return mfree(r);
}
Commit	Line	Data
53e1b683	1	/* SPDX-License-Identifier: LGPL-2.1+ */
6e6fb527	2
11c3a366 TA	3	#include <errno.h>
	4	#include <stddef.h>
	5	#include <stdlib.h>
6e6fb527 LP	6	#include <string.h>
6e6fb527 LP	7
b5efdb8a	8	#include "alloc-util.h"
6e6fb527	9	#include "macro.h"
6e6fb527	10	#include "replace-var.h"
b11d6a7b	11	#include "string-util.h"
6e6fb527 LP	12
	13	/*
	14	* Generic infrastructure for replacing @FOO@ style variables in
	15	* strings. Will call a callback for each replacement.
	16	*/
	17
	18	static int get_variable(const char b, char *r) {
	19	size_t k;
	20	char *t;
	21
	22	assert(b);
	23	assert(r);
	24
	25	if (*b != '@')
	26	return 0;
	27
4b549144	28	k = strspn(b + 1, UPPERCASE_LETTERS "_");
6e6fb527 LP	29	if (k <= 0 \|\| b[k+1] != '@')
	30	return 0;
	31
	32	t = strndup(b + 1, k);
	33	if (!t)
	34	return -ENOMEM;
	35
	36	*r = t;
	37	return 1;
	38	}
	39
2d5dece8	40	char replace_var(const char text, char (lookup)(const char variable, void userdata), void *userdata) {
6e6fb527 LP	41	char r, t;
	42	const char *f;
	43	size_t l;
	44
	45	assert(text);
	46	assert(lookup);
	47
	48	l = strlen(text);
	49	r = new(char, l+1);
	50	if (!r)
	51	return NULL;
	52
	53	f = text;
	54	t = r;
	55	while (*f) {
	56	_cleanup_free_ char v = NULL, n = NULL;
	57	char *a;
	58	int k;
	59	size_t skip, d, nl;
	60
	61	k = get_variable(f, &v);
	62	if (k < 0)
	63	goto oom;
	64	if (k == 0) {
	65	(t++) = (f++);
	66	continue;
	67	}
	68
	69	n = lookup(v, userdata);
	70	if (!n)
	71	goto oom;
	72
	73	skip = strlen(v) + 2;
	74
	75	d = t - r;
	76	nl = l - skip + strlen(n);
	77	a = realloc(r, nl + 1);
	78	if (!a)
	79	goto oom;
	80
	81	l = nl;
	82	r = a;
	83	t = r + d;
	84
	85	t = stpcpy(t, n);
	86	f += skip;
	87	}
	88
	89	*t = 0;
	90	return r;
	91
	92	oom:
6b430fdb	93	return mfree(r);
6e6fb527	94	}