unroff/src/insert.c

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/* $Revision: 1.6 $
*/
/* The implementation of the Scheme primitive `file-insertions'.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "unroff.h"
static int cmp(const void *p1, const void *p2) {
struct S_String *s1, *s2;
Object o1, o2;
int tmp;
o1 = *(Object *)p1, s1 = STRING(Car(o1));
o2 = *(Object *)p2, s2 = STRING(Car(o2));
if ((tmp = memcmp(s1->data, s2->data,
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s1->size < s2->size ? s1->size : s2->size)) == 0) {
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if (s1->size == s2->size)
return Get_Integer(Car(Cdr(o1))) - Get_Integer(Car(Cdr(o2)));
else
return s1->size - s2->size;
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}
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return tmp;
}
#define Finish_File {\
if (fromfn) {\
copy_rest(from, to, fromfn, tofn);\
close(from);\
close(to);\
if (rename(tofn, fromfn) == -1) {\
Saved_Errno = errno;\
Primitive_Error("cannot rename ~s to ~s: ~E", tofn, fromfn);\
}\
free(tofn);\
}\
}
static void copy(int from, int to, char *fromfn, char *tofn,
int len, int off) {
char buf[8192];
int n;
while (len > 0) {
if ((n = read(from, buf, len > 8192 ? 8192 : len)) == -1)
read_error(fromfn);
if (n == 0)
fatal_error("file `%s' too short for insertion at offset %d",
fromfn, off);
if (write(to, buf, n) != n)
write_error(tofn);
len -= n;
}
}
static void copy_rest(int from, int to, char *fromfn, char *tofn) {
char buf[8192];
int n;
while ((n = read(from, buf, 8192)) > 0)
if (write(to, buf, n) != n)
write_error(tofn);
if (n == -1)
read_error(fromfn);
}
static Object p_file_insertions(Object spec) {
Object v, x;
int i, t, from = 0, to = 0; /* make gcc -Wuninitialized happy */
char *currfn, *fromfn, *tofn = 0; /* ditto */
struct stat st;
int off = 0, nextoff; /* ditto for `off' */
struct S_String *ins;
v = P_List_To_Vector(spec);
for (i = VECTOR(v)->size; --i >= 0; ) {
x = VECTOR(v)->data[i];
Check_List(x);
if (Fast_Length(x) < 3 || TYPE(Car(x)) != T_String ||
((t = TYPE(Car(Cdr(x)))) != T_Fixnum && t != T_Bignum) ||
TYPE(Car(Cdr(Cdr(x)))) != T_String)
Primitive_Error("invalid file insertion specification");
}
qsort(VECTOR(v)->data, VECTOR(v)->size, sizeof(Object), cmp);
for (fromfn = 0, i = 0; i < VECTOR(v)->size; i++) {
x = VECTOR(v)->data[i];
currfn = Get_String(Car(x));
if (!fromfn || strcmp(fromfn, currfn) != 0) {
Finish_File;
fromfn = currfn;
if ((from = open(fromfn, O_RDONLY)) == -1)
open_error(fromfn);
(void)fstat(from, &st);
if (st.st_nlink > 1) {
warn("links to `%s' exist; insertion skipped", fromfn);
close(from);
fromfn = 0;
continue;
}
tofn = safe_malloc(strlen(fromfn) + 1 + 4);
sprintf(tofn, "%s.new", fromfn);
if ((to = open(tofn, O_WRONLY|O_CREAT|O_TRUNC, st.st_mode)) == -1)
open_error(tofn);
off = 0;
}
x = Cdr(x);
nextoff = Get_Integer(Car(x));
if (nextoff < 0)
Primitive_Error("invalid insertion offset ~a", Car(x));
x = Cdr(x);
ins = STRING(Car(x));
copy(from, to, fromfn, tofn, nextoff-off, nextoff);
if (write(to, ins->data, ins->size) != ins->size)
write_error(tofn);
off = nextoff;
}
Finish_File;
return Void;
}
void init_insert(void) {
Define_Primitive(p_file_insertions, "file-insertions", 1, 1, EVAL);
}