src/basic/strxcpyx.c

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