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