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#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <errno.h>
#include "memfile.hpp"
#define INCREMENT 131072
#define INITIAL 256
struct memfile *memfile_open(int fd) {
if (ftruncate(fd, INITIAL) != 0) {
return NULL;
}
struct memfile *mf = new memfile;
if (mf == NULL) {
return NULL;
}
mf->fd = fd;
mf->tree = 0;
mf->off = 0;
return mf;
}
int memfile_close(struct memfile *file) {
// If it isn't full yet, flush out the string to the file now.
// If it is full, close out the buffered file writer.
if (file->fp == NULL) {
if (write(file->fd, file->map.c_str(), file->map.size()) != (ssize_t) file->map.size()) {
return -1;
}
if (file->fd >= 0) {
if (close(file->fd) != 0) {
return -1;
}
}
} else {
if (fclose(file->fp) != 0) {
return -1;
}
}
delete file;
return 0;
}
int memfile_write(struct memfile *file, void *s, long long len, bool &in_memory) {
// If it is full, append to the file.
// If it is not full yet, append to the string in memory.
in_memory = false;
if (file->fp != NULL) {
if (fwrite(s, sizeof(char), len, file->fp) != (size_t) len) {
return 0;
}
file->off += len;
} else {
file->map.append(std::string((char *) s, len));
file->off += len;
in_memory = true;
}
return len;
}
void memfile_full(struct memfile *file) {
// The file is full. Write out a copy of whatever has accumulated in memory
// to the file, and switch to appending to the file. Existing references
// into the memory still work.
if (file->fp != NULL) {
fprintf(stderr, "memfile marked full twice\n");
exit(EXIT_IMPOSSIBLE);
}
file->fp = fdopen(file->fd, "wb");
if (file->fp == NULL) {
fprintf(stderr, "fdopen memfile: %s\n", strerror(errno));
exit(EXIT_OPEN);
}
if (fwrite(file->map.c_str(), sizeof(char), file->map.size(), file->fp) != file->map.size()) {
fprintf(stderr, "memfile write: %s\n", strerror(errno));
exit(EXIT_WRITE);
}
}
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