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/*
* A helper routine to copy the strings between differing structures.
*/
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include "mph.h"
#define MAX_OFFSETS 10
#define OFFSET_SHIFT 1
#define lstr_at(p, n) (*(char**)(((char*)(p))+(n >> OFFSET_SHIFT)))
#define str_at(p, n) ( \
(((n) & MPH_STRING_OFFSET_MASK) == MPH_STRING_OFFSET_ARRAY) \
? (char*)(p) + (n >> OFFSET_SHIFT) \
: lstr_at(p, n) \
)
char*
_mph_copy_structure_strings (
void *to, const mph_string_offset_t *to_offsets,
const void *from, const mph_string_offset_t *from_offsets,
size_t num_strings)
{
int i;
size_t buflen;
int len[MAX_OFFSETS];
char *buf, *cur = NULL;
g_assert (num_strings < MAX_OFFSETS);
for (i = 0; i < num_strings; ++i) {
lstr_at (to, to_offsets[i]) = NULL;
}
buflen = num_strings;
for (i = 0; i < num_strings; ++i) {
const char* s = str_at(from, from_offsets[i]);
len [i] = s ? strlen (s) : 0;
if (len[i] < INT_MAX - buflen)
buflen += len[i];
else
len[i] = -1;
}
cur = buf = malloc (buflen);
if (buf == NULL) {
return NULL;
}
for (i = 0; i < num_strings; ++i) {
if (len[i] > 0) {
lstr_at (to, to_offsets[i]) =
strcpy (cur, str_at (from, from_offsets[i]));
cur += (len[i] +1);
}
}
return buf;
}
#ifdef TEST
/*
* To run the tests:
* $ gcc -DTEST -I.. `pkg-config --cflags --libs glib-2.0` x-struct-str.c
* $ ./a.out
*/
#include <stdio.h>
struct foo {
char *a;
int b;
char *c;
char d[10];
};
struct bar {
int b;
char *a;
double d;
char *c;
char *e;
};
int
main ()
{
/* test copying foo to bar */
struct foo f = {"hello", 42, "world", "!!"};
struct bar b;
mph_string_offset_t foo_offsets[] = {
MPH_STRING_OFFSET(struct foo, a, MPH_STRING_OFFSET_PTR),
MPH_STRING_OFFSET(struct foo, c, MPH_STRING_OFFSET_PTR),
MPH_STRING_OFFSET(struct foo, d, MPH_STRING_OFFSET_ARRAY)
};
mph_string_offset_t bar_offsets[] = {
MPH_STRING_OFFSET(struct bar, a, MPH_STRING_OFFSET_PTR),
MPH_STRING_OFFSET(struct bar, c, MPH_STRING_OFFSET_PTR),
MPH_STRING_OFFSET(struct bar, e, MPH_STRING_OFFSET_PTR)
};
char *buf;
buf = _mph_copy_structure_strings (&b, bar_offsets,
&f, foo_offsets, 3);
printf ("b.a=%s\n", b.a);
printf ("b.c=%s\n", b.c);
printf ("b.e=%s\n", b.e);
f.c = NULL;
buf = _mph_copy_structure_strings (&b, bar_offsets,
&f, foo_offsets, 3);
printf ("b.a=%s\n", b.a);
printf ("b.c=%s\n", b.c);
printf ("b.e=%s\n", b.e);
return 0;
}
#endif
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