src/basic/strxcpyx.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2013 Kay Sievers
   6 ***/
   7
   8 /*
   9  * Concatenates/copies strings. In any case, terminates in all cases
  10  * with '\0' and moves the @dest pointer forward to the added '\0'.
  11  * Returns the remaining size, and 0 if the string was truncated.
  12  *
  13  * Due to the intended usage, these helpers silently noop invocations
  14  * having zero size.  This is technically an exception to the above
  15  * statement "terminates in all cases".  It's unexpected for such calls to
  16  * occur outside of a loop where this is the preferred behavior.
  17  */
  18
  19 #include <stdarg.h>
  20 #include <stdio.h>
  21 #include <string.h>
  22
  23 #include "strxcpyx.h"
  24
  25 size_t strpcpy(char **dest, size_t size, const char *src) {
  26         size_t len;
  27
  28         assert(dest);
  29         assert(src);
  30
  31         if (size == 0)
  32                 return 0;
  33
  34         len = strlen(src);
  35         if (len >= size) {
  36                 if (size > 1)
  37                         *dest = mempcpy(*dest, src, size-1);
  38                 size = 0;
  39         } else {
  40                 if (len > 0) {
  41                         *dest = mempcpy(*dest, src, len);
  42                         size -= len;
  43                 }
  44         }
  45         *dest[0] = '\0';
  46         return size;
  47 }
  48
  49 size_t strpcpyf(char **dest, size_t size, const char *src, ...) {
  50         va_list va;
  51         int i;
  52
  53         assert(dest);
  54         assert(src);
  55
  56         if (size == 0)
  57                 return 0;
  58
  59         va_start(va, src);
  60         i = vsnprintf(*dest, size, src, va);
  61         if (i < (int)size) {
  62                 *dest += i;
  63                 size -= i;
  64         } else {
  65                 size = 0;
  66         }
  67         va_end(va);
  68         return size;
  69 }
  70
  71 size_t strpcpyl(char **dest, size_t size, const char *src, ...) {
  72         va_list va;
  73
  74         assert(dest);
  75         assert(src);
  76
  77         va_start(va, src);
  78         do {
  79                 size = strpcpy(dest, size, src);
  80                 src = va_arg(va, char *);
  81         } while (src != NULL);
  82         va_end(va);
  83         return size;
  84 }
  85
  86 size_t strscpy(char *dest, size_t size, const char *src) {
  87         char *s;
  88
  89         assert(dest);
  90         assert(src);
  91
  92         s = dest;
  93         return strpcpy(&s, size, src);
  94 }
  95
  96 size_t strscpyl(char *dest, size_t size, const char *src, ...) {
  97         va_list va;
  98         char *s;
  99
 100         assert(dest);
 101         assert(src);
 102
 103         va_start(va, src);
 104         s = dest;
 105         do {
 106                 size = strpcpy(&s, size, src);
 107                 src = va_arg(va, char *);
 108         } while (src != NULL);
 109         va_end(va);
 110
 111         return size;
 112 }