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-rw-r--r--src/basic/string-util.c1099
1 files changed, 1099 insertions, 0 deletions
diff --git a/src/basic/string-util.c b/src/basic/string-util.c
new file mode 100644
index 0000000..93917bc
--- /dev/null
+++ b/src/basic/string-util.c
@@ -0,0 +1,1099 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <errno.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdio_ext.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "alloc-util.h"
+#include "escape.h"
+#include "gunicode.h"
+#include "locale-util.h"
+#include "macro.h"
+#include "string-util.h"
+#include "terminal-util.h"
+#include "utf8.h"
+#include "util.h"
+#include "fileio.h"
+
+int strcmp_ptr(const char *a, const char *b) {
+
+ /* Like strcmp(), but tries to make sense of NULL pointers */
+ if (a && b)
+ return strcmp(a, b);
+
+ if (!a && b)
+ return -1;
+
+ if (a && !b)
+ return 1;
+
+ return 0;
+}
+
+char* endswith(const char *s, const char *postfix) {
+ size_t sl, pl;
+
+ assert(s);
+ assert(postfix);
+
+ sl = strlen(s);
+ pl = strlen(postfix);
+
+ if (pl == 0)
+ return (char*) s + sl;
+
+ if (sl < pl)
+ return NULL;
+
+ if (memcmp(s + sl - pl, postfix, pl) != 0)
+ return NULL;
+
+ return (char*) s + sl - pl;
+}
+
+char* endswith_no_case(const char *s, const char *postfix) {
+ size_t sl, pl;
+
+ assert(s);
+ assert(postfix);
+
+ sl = strlen(s);
+ pl = strlen(postfix);
+
+ if (pl == 0)
+ return (char*) s + sl;
+
+ if (sl < pl)
+ return NULL;
+
+ if (strcasecmp(s + sl - pl, postfix) != 0)
+ return NULL;
+
+ return (char*) s + sl - pl;
+}
+
+char* first_word(const char *s, const char *word) {
+ size_t sl, wl;
+ const char *p;
+
+ assert(s);
+ assert(word);
+
+ /* Checks if the string starts with the specified word, either
+ * followed by NUL or by whitespace. Returns a pointer to the
+ * NUL or the first character after the whitespace. */
+
+ sl = strlen(s);
+ wl = strlen(word);
+
+ if (sl < wl)
+ return NULL;
+
+ if (wl == 0)
+ return (char*) s;
+
+ if (memcmp(s, word, wl) != 0)
+ return NULL;
+
+ p = s + wl;
+ if (*p == 0)
+ return (char*) p;
+
+ if (!strchr(WHITESPACE, *p))
+ return NULL;
+
+ p += strspn(p, WHITESPACE);
+ return (char*) p;
+}
+
+static size_t strcspn_escaped(const char *s, const char *reject) {
+ bool escaped = false;
+ int n;
+
+ for (n=0; s[n]; n++) {
+ if (escaped)
+ escaped = false;
+ else if (s[n] == '\\')
+ escaped = true;
+ else if (strchr(reject, s[n]))
+ break;
+ }
+
+ /* if s ends in \, return index of previous char */
+ return n - escaped;
+}
+
+/* Split a string into words. */
+const char* split(const char **state, size_t *l, const char *separator, SplitFlags flags) {
+ const char *current;
+
+ current = *state;
+
+ if (!*current) {
+ assert(**state == '\0');
+ return NULL;
+ }
+
+ current += strspn(current, separator);
+ if (!*current) {
+ *state = current;
+ return NULL;
+ }
+
+ if (flags & SPLIT_QUOTES && strchr("\'\"", *current)) {
+ char quotechars[2] = {*current, '\0'};
+
+ *l = strcspn_escaped(current + 1, quotechars);
+ if (current[*l + 1] == '\0' || current[*l + 1] != quotechars[0] ||
+ (current[*l + 2] && !strchr(separator, current[*l + 2]))) {
+ /* right quote missing or garbage at the end */
+ if (flags & SPLIT_RELAX) {
+ *state = current + *l + 1 + (current[*l + 1] != '\0');
+ return current + 1;
+ }
+ *state = current;
+ return NULL;
+ }
+ *state = current++ + *l + 2;
+ } else if (flags & SPLIT_QUOTES) {
+ *l = strcspn_escaped(current, separator);
+ if (current[*l] && !strchr(separator, current[*l]) && !(flags & SPLIT_RELAX)) {
+ /* unfinished escape */
+ *state = current;
+ return NULL;
+ }
+ *state = current + *l;
+ } else {
+ *l = strcspn(current, separator);
+ *state = current + *l;
+ }
+
+ return current;
+}
+
+char *strnappend(const char *s, const char *suffix, size_t b) {
+ size_t a;
+ char *r;
+
+ if (!s && !suffix)
+ return strdup("");
+
+ if (!s)
+ return strndup(suffix, b);
+
+ if (!suffix)
+ return strdup(s);
+
+ assert(s);
+ assert(suffix);
+
+ a = strlen(s);
+ if (b > ((size_t) -1) - a)
+ return NULL;
+
+ r = new(char, a+b+1);
+ if (!r)
+ return NULL;
+
+ memcpy(r, s, a);
+ memcpy(r+a, suffix, b);
+ r[a+b] = 0;
+
+ return r;
+}
+
+char *strappend(const char *s, const char *suffix) {
+ return strnappend(s, suffix, strlen_ptr(suffix));
+}
+
+char *strjoin_real(const char *x, ...) {
+ va_list ap;
+ size_t l;
+ char *r, *p;
+
+ va_start(ap, x);
+
+ if (x) {
+ l = strlen(x);
+
+ for (;;) {
+ const char *t;
+ size_t n;
+
+ t = va_arg(ap, const char *);
+ if (!t)
+ break;
+
+ n = strlen(t);
+ if (n > ((size_t) -1) - l) {
+ va_end(ap);
+ return NULL;
+ }
+
+ l += n;
+ }
+ } else
+ l = 0;
+
+ va_end(ap);
+
+ r = new(char, l+1);
+ if (!r)
+ return NULL;
+
+ if (x) {
+ p = stpcpy(r, x);
+
+ va_start(ap, x);
+
+ for (;;) {
+ const char *t;
+
+ t = va_arg(ap, const char *);
+ if (!t)
+ break;
+
+ p = stpcpy(p, t);
+ }
+
+ va_end(ap);
+ } else
+ r[0] = 0;
+
+ return r;
+}
+
+char *strstrip(char *s) {
+ if (!s)
+ return NULL;
+
+ /* Drops trailing whitespace. Modifies the string in place. Returns pointer to first non-space character */
+
+ return delete_trailing_chars(skip_leading_chars(s, WHITESPACE), WHITESPACE);
+}
+
+char *delete_chars(char *s, const char *bad) {
+ char *f, *t;
+
+ /* Drops all specified bad characters, regardless where in the string */
+
+ if (!s)
+ return NULL;
+
+ if (!bad)
+ bad = WHITESPACE;
+
+ for (f = s, t = s; *f; f++) {
+ if (strchr(bad, *f))
+ continue;
+
+ *(t++) = *f;
+ }
+
+ *t = 0;
+
+ return s;
+}
+
+char *delete_trailing_chars(char *s, const char *bad) {
+ char *p, *c = s;
+
+ /* Drops all specified bad characters, at the end of the string */
+
+ if (!s)
+ return NULL;
+
+ if (!bad)
+ bad = WHITESPACE;
+
+ for (p = s; *p; p++)
+ if (!strchr(bad, *p))
+ c = p + 1;
+
+ *c = 0;
+
+ return s;
+}
+
+char *truncate_nl(char *s) {
+ assert(s);
+
+ s[strcspn(s, NEWLINE)] = 0;
+ return s;
+}
+
+char ascii_tolower(char x) {
+
+ if (x >= 'A' && x <= 'Z')
+ return x - 'A' + 'a';
+
+ return x;
+}
+
+char ascii_toupper(char x) {
+
+ if (x >= 'a' && x <= 'z')
+ return x - 'a' + 'A';
+
+ return x;
+}
+
+char *ascii_strlower(char *t) {
+ char *p;
+
+ assert(t);
+
+ for (p = t; *p; p++)
+ *p = ascii_tolower(*p);
+
+ return t;
+}
+
+char *ascii_strupper(char *t) {
+ char *p;
+
+ assert(t);
+
+ for (p = t; *p; p++)
+ *p = ascii_toupper(*p);
+
+ return t;
+}
+
+char *ascii_strlower_n(char *t, size_t n) {
+ size_t i;
+
+ if (n <= 0)
+ return t;
+
+ for (i = 0; i < n; i++)
+ t[i] = ascii_tolower(t[i]);
+
+ return t;
+}
+
+int ascii_strcasecmp_n(const char *a, const char *b, size_t n) {
+
+ for (; n > 0; a++, b++, n--) {
+ int x, y;
+
+ x = (int) (uint8_t) ascii_tolower(*a);
+ y = (int) (uint8_t) ascii_tolower(*b);
+
+ if (x != y)
+ return x - y;
+ }
+
+ return 0;
+}
+
+int ascii_strcasecmp_nn(const char *a, size_t n, const char *b, size_t m) {
+ int r;
+
+ r = ascii_strcasecmp_n(a, b, MIN(n, m));
+ if (r != 0)
+ return r;
+
+ return CMP(n, m);
+}
+
+bool chars_intersect(const char *a, const char *b) {
+ const char *p;
+
+ /* Returns true if any of the chars in a are in b. */
+ for (p = a; *p; p++)
+ if (strchr(b, *p))
+ return true;
+
+ return false;
+}
+
+bool string_has_cc(const char *p, const char *ok) {
+ const char *t;
+
+ assert(p);
+
+ /*
+ * Check if a string contains control characters. If 'ok' is
+ * non-NULL it may be a string containing additional CCs to be
+ * considered OK.
+ */
+
+ for (t = p; *t; t++) {
+ if (ok && strchr(ok, *t))
+ continue;
+
+ if (*t > 0 && *t < ' ')
+ return true;
+
+ if (*t == 127)
+ return true;
+ }
+
+ return false;
+}
+
+static int write_ellipsis(char *buf, bool unicode) {
+ if (unicode || is_locale_utf8()) {
+ buf[0] = 0xe2; /* tri-dot ellipsis: … */
+ buf[1] = 0x80;
+ buf[2] = 0xa6;
+ } else {
+ buf[0] = '.';
+ buf[1] = '.';
+ buf[2] = '.';
+ }
+
+ return 3;
+}
+
+static char *ascii_ellipsize_mem(const char *s, size_t old_length, size_t new_length, unsigned percent) {
+ size_t x, need_space, suffix_len;
+ char *t;
+
+ assert(s);
+ assert(percent <= 100);
+ assert(new_length != (size_t) -1);
+
+ if (old_length <= new_length)
+ return strndup(s, old_length);
+
+ /* Special case short ellipsations */
+ switch (new_length) {
+
+ case 0:
+ return strdup("");
+
+ case 1:
+ if (is_locale_utf8())
+ return strdup("…");
+ else
+ return strdup(".");
+
+ case 2:
+ if (!is_locale_utf8())
+ return strdup("..");
+
+ break;
+
+ default:
+ break;
+ }
+
+ /* Calculate how much space the ellipsis will take up. If we are in UTF-8 mode we only need space for one
+ * character ("…"), otherwise for three characters ("..."). Note that in both cases we need 3 bytes of storage,
+ * either for the UTF-8 encoded character or for three ASCII characters. */
+ need_space = is_locale_utf8() ? 1 : 3;
+
+ t = new(char, new_length+3);
+ if (!t)
+ return NULL;
+
+ assert(new_length >= need_space);
+
+ x = ((new_length - need_space) * percent + 50) / 100;
+ assert(x <= new_length - need_space);
+
+ memcpy(t, s, x);
+ write_ellipsis(t + x, false);
+ suffix_len = new_length - x - need_space;
+ memcpy(t + x + 3, s + old_length - suffix_len, suffix_len);
+ *(t + x + 3 + suffix_len) = '\0';
+
+ return t;
+}
+
+char *ellipsize_mem(const char *s, size_t old_length, size_t new_length, unsigned percent) {
+ size_t x, k, len, len2;
+ const char *i, *j;
+ char *e;
+ int r;
+
+ /* Note that 'old_length' refers to bytes in the string, while 'new_length' refers to character cells taken up
+ * on screen. This distinction doesn't matter for ASCII strings, but it does matter for non-ASCII UTF-8
+ * strings.
+ *
+ * Ellipsation is done in a locale-dependent way:
+ * 1. If the string passed in is fully ASCII and the current locale is not UTF-8, three dots are used ("...")
+ * 2. Otherwise, a unicode ellipsis is used ("…")
+ *
+ * In other words: you'll get a unicode ellipsis as soon as either the string contains non-ASCII characters or
+ * the current locale is UTF-8.
+ */
+
+ assert(s);
+ assert(percent <= 100);
+
+ if (new_length == (size_t) -1)
+ return strndup(s, old_length);
+
+ if (new_length == 0)
+ return strdup("");
+
+ /* If no multibyte characters use ascii_ellipsize_mem for speed */
+ if (ascii_is_valid_n(s, old_length))
+ return ascii_ellipsize_mem(s, old_length, new_length, percent);
+
+ x = ((new_length - 1) * percent) / 100;
+ assert(x <= new_length - 1);
+
+ k = 0;
+ for (i = s; i < s + old_length; i = utf8_next_char(i)) {
+ char32_t c;
+ int w;
+
+ r = utf8_encoded_to_unichar(i, &c);
+ if (r < 0)
+ return NULL;
+
+ w = unichar_iswide(c) ? 2 : 1;
+ if (k + w <= x)
+ k += w;
+ else
+ break;
+ }
+
+ for (j = s + old_length; j > i; ) {
+ char32_t c;
+ int w;
+ const char *jj;
+
+ jj = utf8_prev_char(j);
+ r = utf8_encoded_to_unichar(jj, &c);
+ if (r < 0)
+ return NULL;
+
+ w = unichar_iswide(c) ? 2 : 1;
+ if (k + w <= new_length) {
+ k += w;
+ j = jj;
+ } else
+ break;
+ }
+ assert(i <= j);
+
+ /* we don't actually need to ellipsize */
+ if (i == j)
+ return memdup_suffix0(s, old_length);
+
+ /* make space for ellipsis, if possible */
+ if (j < s + old_length)
+ j = utf8_next_char(j);
+ else if (i > s)
+ i = utf8_prev_char(i);
+
+ len = i - s;
+ len2 = s + old_length - j;
+ e = new(char, len + 3 + len2 + 1);
+ if (!e)
+ return NULL;
+
+ /*
+ printf("old_length=%zu new_length=%zu x=%zu len=%u len2=%u k=%u\n",
+ old_length, new_length, x, len, len2, k);
+ */
+
+ memcpy(e, s, len);
+ write_ellipsis(e + len, true);
+ memcpy(e + len + 3, j, len2);
+ *(e + len + 3 + len2) = '\0';
+
+ return e;
+}
+
+char *cellescape(char *buf, size_t len, const char *s) {
+ /* Escape and ellipsize s into buffer buf of size len. Only non-control ASCII
+ * characters are copied as they are, everything else is escaped. The result
+ * is different then if escaping and ellipsization was performed in two
+ * separate steps, because each sequence is either stored in full or skipped.
+ *
+ * This function should be used for logging about strings which expected to
+ * be plain ASCII in a safe way.
+ *
+ * An ellipsis will be used if s is too long. It was always placed at the
+ * very end.
+ */
+
+ size_t i = 0, last_char_width[4] = {}, k = 0, j;
+
+ assert(len > 0); /* at least a terminating NUL */
+
+ for (;;) {
+ char four[4];
+ int w;
+
+ if (*s == 0) /* terminating NUL detected? then we are done! */
+ goto done;
+
+ w = cescape_char(*s, four);
+ if (i + w + 1 > len) /* This character doesn't fit into the buffer anymore? In that case let's
+ * ellipsize at the previous location */
+ break;
+
+ /* OK, there was space, let's add this escaped character to the buffer */
+ memcpy(buf + i, four, w);
+ i += w;
+
+ /* And remember its width in the ring buffer */
+ last_char_width[k] = w;
+ k = (k + 1) % 4;
+
+ s++;
+ }
+
+ /* Ellipsation is necessary. This means we might need to truncate the string again to make space for 4
+ * characters ideally, but the buffer is shorter than that in the first place take what we can get */
+ for (j = 0; j < ELEMENTSOF(last_char_width); j++) {
+
+ if (i + 4 <= len) /* nice, we reached our space goal */
+ break;
+
+ k = k == 0 ? 3 : k - 1;
+ if (last_char_width[k] == 0) /* bummer, we reached the beginning of the strings */
+ break;
+
+ assert(i >= last_char_width[k]);
+ i -= last_char_width[k];
+ }
+
+ if (i + 4 <= len) /* yay, enough space */
+ i += write_ellipsis(buf + i, false);
+ else if (i + 3 <= len) { /* only space for ".." */
+ buf[i++] = '.';
+ buf[i++] = '.';
+ } else if (i + 2 <= len) /* only space for a single "." */
+ buf[i++] = '.';
+ else
+ assert(i + 1 <= len);
+
+ done:
+ buf[i] = '\0';
+ return buf;
+}
+
+bool nulstr_contains(const char *nulstr, const char *needle) {
+ const char *i;
+
+ if (!nulstr)
+ return false;
+
+ NULSTR_FOREACH(i, nulstr)
+ if (streq(i, needle))
+ return true;
+
+ return false;
+}
+
+char* strshorten(char *s, size_t l) {
+ assert(s);
+
+ if (strnlen(s, l+1) > l)
+ s[l] = 0;
+
+ return s;
+}
+
+char *strreplace(const char *text, const char *old_string, const char *new_string) {
+ size_t l, old_len, new_len, allocated = 0;
+ char *t, *ret = NULL;
+ const char *f;
+
+ assert(old_string);
+ assert(new_string);
+
+ if (!text)
+ return NULL;
+
+ old_len = strlen(old_string);
+ new_len = strlen(new_string);
+
+ l = strlen(text);
+ if (!GREEDY_REALLOC(ret, allocated, l+1))
+ return NULL;
+
+ f = text;
+ t = ret;
+ while (*f) {
+ size_t d, nl;
+
+ if (!startswith(f, old_string)) {
+ *(t++) = *(f++);
+ continue;
+ }
+
+ d = t - ret;
+ nl = l - old_len + new_len;
+
+ if (!GREEDY_REALLOC(ret, allocated, nl + 1))
+ return mfree(ret);
+
+ l = nl;
+ t = ret + d;
+
+ t = stpcpy(t, new_string);
+ f += old_len;
+ }
+
+ *t = 0;
+ return ret;
+}
+
+static void advance_offsets(ssize_t diff, size_t offsets[static 2], size_t shift[static 2], size_t size) {
+ if (!offsets)
+ return;
+
+ if ((size_t) diff < offsets[0])
+ shift[0] += size;
+ if ((size_t) diff < offsets[1])
+ shift[1] += size;
+}
+
+char *strip_tab_ansi(char **ibuf, size_t *_isz, size_t highlight[2]) {
+ const char *i, *begin = NULL;
+ enum {
+ STATE_OTHER,
+ STATE_ESCAPE,
+ STATE_CSI,
+ STATE_CSO,
+ } state = STATE_OTHER;
+ char *obuf = NULL;
+ size_t osz = 0, isz, shift[2] = {};
+ FILE *f;
+
+ assert(ibuf);
+ assert(*ibuf);
+
+ /* This does three things:
+ *
+ * 1. Replaces TABs by 8 spaces
+ * 2. Strips ANSI color sequences (a subset of CSI), i.e. ESC '[' … 'm' sequences
+ * 3. Strips ANSI operating system sequences (CSO), i.e. ESC ']' … BEL sequences
+ *
+ * Everything else will be left as it is. In particular other ANSI sequences are left as they are, as are any
+ * other special characters. Truncated ANSI sequences are left-as is too. This call is supposed to suppress the
+ * most basic formatting noise, but nothing else.
+ *
+ * Why care for CSO sequences? Well, to undo what terminal_urlify() and friends generate. */
+
+ isz = _isz ? *_isz : strlen(*ibuf);
+
+ f = open_memstream(&obuf, &osz);
+ if (!f)
+ return NULL;
+
+ /* Note we turn off internal locking on f for performance reasons. It's safe to do so since we created f here
+ * and it doesn't leave our scope. */
+
+ (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+
+ for (i = *ibuf; i < *ibuf + isz + 1; i++) {
+
+ switch (state) {
+
+ case STATE_OTHER:
+ if (i >= *ibuf + isz) /* EOT */
+ break;
+ else if (*i == '\x1B')
+ state = STATE_ESCAPE;
+ else if (*i == '\t') {
+ fputs(" ", f);
+ advance_offsets(i - *ibuf, highlight, shift, 7);
+ } else
+ fputc(*i, f);
+
+ break;
+
+ case STATE_ESCAPE:
+ if (i >= *ibuf + isz) { /* EOT */
+ fputc('\x1B', f);
+ advance_offsets(i - *ibuf, highlight, shift, 1);
+ break;
+ } else if (*i == '[') { /* ANSI CSI */
+ state = STATE_CSI;
+ begin = i + 1;
+ } else if (*i == ']') { /* ANSI CSO */
+ state = STATE_CSO;
+ begin = i + 1;
+ } else {
+ fputc('\x1B', f);
+ fputc(*i, f);
+ advance_offsets(i - *ibuf, highlight, shift, 1);
+ state = STATE_OTHER;
+ }
+
+ break;
+
+ case STATE_CSI:
+
+ if (i >= *ibuf + isz || /* EOT … */
+ !strchr("01234567890;m", *i)) { /* … or invalid chars in sequence */
+ fputc('\x1B', f);
+ fputc('[', f);
+ advance_offsets(i - *ibuf, highlight, shift, 2);
+ state = STATE_OTHER;
+ i = begin-1;
+ } else if (*i == 'm')
+ state = STATE_OTHER;
+
+ break;
+
+ case STATE_CSO:
+
+ if (i >= *ibuf + isz || /* EOT … */
+ (*i != '\a' && (uint8_t) *i < 32U) || (uint8_t) *i > 126U) { /* … or invalid chars in sequence */
+ fputc('\x1B', f);
+ fputc(']', f);
+ advance_offsets(i - *ibuf, highlight, shift, 2);
+ state = STATE_OTHER;
+ i = begin-1;
+ } else if (*i == '\a')
+ state = STATE_OTHER;
+
+ break;
+ }
+ }
+
+ if (fflush_and_check(f) < 0) {
+ fclose(f);
+ return mfree(obuf);
+ }
+
+ fclose(f);
+
+ free(*ibuf);
+ *ibuf = obuf;
+
+ if (_isz)
+ *_isz = osz;
+
+ if (highlight) {
+ highlight[0] += shift[0];
+ highlight[1] += shift[1];
+ }
+
+ return obuf;
+}
+
+char *strextend_with_separator(char **x, const char *separator, ...) {
+ bool need_separator;
+ size_t f, l, l_separator;
+ char *r, *p;
+ va_list ap;
+
+ assert(x);
+
+ l = f = strlen_ptr(*x);
+
+ need_separator = !isempty(*x);
+ l_separator = strlen_ptr(separator);
+
+ va_start(ap, separator);
+ for (;;) {
+ const char *t;
+ size_t n;
+
+ t = va_arg(ap, const char *);
+ if (!t)
+ break;
+
+ n = strlen(t);
+
+ if (need_separator)
+ n += l_separator;
+
+ if (n > ((size_t) -1) - l) {
+ va_end(ap);
+ return NULL;
+ }
+
+ l += n;
+ need_separator = true;
+ }
+ va_end(ap);
+
+ need_separator = !isempty(*x);
+
+ r = realloc(*x, l+1);
+ if (!r)
+ return NULL;
+
+ p = r + f;
+
+ va_start(ap, separator);
+ for (;;) {
+ const char *t;
+
+ t = va_arg(ap, const char *);
+ if (!t)
+ break;
+
+ if (need_separator && separator)
+ p = stpcpy(p, separator);
+
+ p = stpcpy(p, t);
+
+ need_separator = true;
+ }
+ va_end(ap);
+
+ assert(p == r + l);
+
+ *p = 0;
+ *x = r;
+
+ return r + l;
+}
+
+char *strrep(const char *s, unsigned n) {
+ size_t l;
+ char *r, *p;
+ unsigned i;
+
+ assert(s);
+
+ l = strlen(s);
+ p = r = malloc(l * n + 1);
+ if (!r)
+ return NULL;
+
+ for (i = 0; i < n; i++)
+ p = stpcpy(p, s);
+
+ *p = 0;
+ return r;
+}
+
+int split_pair(const char *s, const char *sep, char **l, char **r) {
+ char *x, *a, *b;
+
+ assert(s);
+ assert(sep);
+ assert(l);
+ assert(r);
+
+ if (isempty(sep))
+ return -EINVAL;
+
+ x = strstr(s, sep);
+ if (!x)
+ return -EINVAL;
+
+ a = strndup(s, x - s);
+ if (!a)
+ return -ENOMEM;
+
+ b = strdup(x + strlen(sep));
+ if (!b) {
+ free(a);
+ return -ENOMEM;
+ }
+
+ *l = a;
+ *r = b;
+
+ return 0;
+}
+
+int free_and_strdup(char **p, const char *s) {
+ char *t;
+
+ assert(p);
+
+ /* Replaces a string pointer with a strdup()ed new string,
+ * possibly freeing the old one. */
+
+ if (streq_ptr(*p, s))
+ return 0;
+
+ if (s) {
+ t = strdup(s);
+ if (!t)
+ return -ENOMEM;
+ } else
+ t = NULL;
+
+ free(*p);
+ *p = t;
+
+ return 1;
+}
+
+int free_and_strndup(char **p, const char *s, size_t l) {
+ char *t;
+
+ assert(p);
+ assert(s || l == 0);
+
+ /* Replaces a string pointer with a strndup()ed new string,
+ * freeing the old one. */
+
+ if (!*p && !s)
+ return 0;
+
+ if (*p && s && strneq(*p, s, l) && (l > strlen(*p) || (*p)[l] == '\0'))
+ return 0;
+
+ if (s) {
+ t = strndup(s, l);
+ if (!t)
+ return -ENOMEM;
+ } else
+ t = NULL;
+
+ free_and_replace(*p, t);
+ return 1;
+}
+
+#if !HAVE_EXPLICIT_BZERO
+/*
+ * Pointer to memset is volatile so that compiler must de-reference
+ * the pointer and can't assume that it points to any function in
+ * particular (such as memset, which it then might further "optimize")
+ * This approach is inspired by openssl's crypto/mem_clr.c.
+ */
+typedef void *(*memset_t)(void *,int,size_t);
+
+static volatile memset_t memset_func = memset;
+
+void* explicit_bzero_safe(void *p, size_t l) {
+ if (l > 0)
+ memset_func(p, '\0', l);
+
+ return p;
+}
+#endif
+
+char* string_erase(char *x) {
+ if (!x)
+ return NULL;
+
+ /* A delicious drop of snake-oil! To be called on memory where
+ * we stored passphrases or so, after we used them. */
+ explicit_bzero_safe(x, strlen(x));
+ return x;
+}
+
+char *string_free_erase(char *s) {
+ return mfree(string_erase(s));
+}
+
+bool string_is_safe(const char *p) {
+ const char *t;
+
+ if (!p)
+ return false;
+
+ for (t = p; *t; t++) {
+ if (*t > 0 && *t < ' ') /* no control characters */
+ return false;
+
+ if (strchr(QUOTES "\\\x7f", *t))
+ return false;
+ }
+
+ return true;
+}