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#include <fcntl.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include "read_file.h"
#define CHECK_OOM(ptr) \
if (ptr == NULL) { \
fprintf(stderr, "geheugen is op"); \
/* I think I should free the original memory here, but whatever */ \
return NULL; \
}
struct filebuf *stream_to_filebuf(FILE *restrict stream) {
size_t sz = 0;
size_t cap = 4096;
char *buf = malloc(cap);
CHECK_OOM(buf);
while (!feof(stream)) {
if (cap-sz == 0) {
cap *= 2;
buf = realloc(buf, cap);
CHECK_OOM(buf);
}
const size_t amount = cap-sz;
const size_t n = fread(buf+sz, 1, amount, stream);
sz += n;
if (n != amount && !feof(stream)) {
fprintf(stderr, "fout tijdens lezen van standaard invoer.\n");
free(buf);
return NULL;
}
}
buf = realloc(buf, sz);
struct filebuf *res = calloc(1, sizeof(struct filebuf));
res->buf = buf;
res->sz = sz;
res->mapping_type = MT_OWNED;
return res;
}
static void *fd_to_mmap(const int fd, struct stat sb) {
void *addr = mmap(NULL, sb.st_size, PROT_READ, MAP_SHARED, fd, 0);
if (addr == MAP_FAILED) {
return NULL;
}
close(fd);
return addr;
}
struct filebuf *file_to_filebuf(char *fname) {
const int fd = open(fname, O_RDONLY);
struct stat sb;
if (fstat(fd, &sb) == -1) {
goto stream;
}
void *addr;
if ((addr = fd_to_mmap(fd, sb)) != NULL) {
struct filebuf *res = calloc(1, sizeof(struct filebuf));
res->buf = addr;
res->sz = sb.st_size;
res->mapping_type = MT_MMAP;
return res;
}
stream: {
FILE *stream = fdopen(fd, "rb");
struct filebuf *res = stream_to_filebuf(stream);
fclose(stream);
return res;
}
}
void free_filebuf(struct filebuf *fb) {
switch (fb->mapping_type) {
case MT_MMAP:
munmap(fb->buf, fb->sz);
break;
case MT_OWNED:
free(fb->buf);
break;
}
free(fb);
}
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