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Write the index to a file and then memory map it

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This commit is contained in:
Eric Fischer 2014-09-17 15:44:07 -07:00
parent ee8c23b010
commit 6613246554
1 changed files with 33 additions and 21 deletions
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54
geojson.c
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@ -216,11 +216,12 @@ void deserialize_string(FILE *f) {
printf("%s", s);
}
void check(struct index *ix) {
void check(struct index *ix, long long n) {
FILE *f = fopen("meta.out", "rb");
int i;
for (; ix != NULL; ix = ix->next) {
off_t pos = ix->fpos;
for (i = 0; i < n; i++) {
off_t pos = ix[i].fpos;
fseeko(f, pos, SEEK_SET);
int m;
@ -264,8 +265,8 @@ void check(struct index *ix) {
void read_json(FILE *f) {
json_pull *jp = json_begin_file(f);
struct index *index = NULL;
FILE *out = fopen("meta.out", "wb");
FILE *metafile = fopen("meta.out", "wb");
FILE *indexfile = fopen("index.out", "wb");
long long fpos = 0;
while (1) {
@ -346,33 +347,31 @@ void read_json(FILE *f) {
metaval[m] = properties->values[i]->string;
m++;
} else {
fprintf(stderr, "%d: Unsupported meta type\n", jp->line);
fprintf(stderr, "%d: Unsupported metafile type\n", jp->line);
goto next_feature;
}
}
}
serialize_int(out, m, &fpos);
serialize_int(metafile, m, &fpos);
for (i = 0; i < m; i++) {
serialize_int(out, metatype[i], &fpos);
serialize_string(out, metakey[i], &fpos);
serialize_string(out, metaval[i], &fpos);
serialize_int(metafile, metatype[i], &fpos);
serialize_string(metafile, metakey[i], &fpos);
serialize_string(metafile, metaval[i], &fpos);
}
unsigned bbox[] = { UINT_MAX, UINT_MAX, 0, 0 };
serialize_int(out, t, &fpos);
parse_geometry(t, coordinates, bbox, &fpos, out, VT_MOVETO);
serialize_int(out, VT_END, &fpos);
serialize_int(metafile, t, &fpos);
parse_geometry(t, coordinates, bbox, &fpos, metafile, VT_MOVETO);
serialize_int(metafile, VT_END, &fpos);
// printf("bbox %x %x %x %x\n", bbox[0], bbox[1], bbox[2], bbox[3]);
struct index *ix = malloc(sizeof(struct index));
ix->index = encode_bbox(bbox[0], bbox[1], bbox[2], bbox[3], 0);
ix->fpos = start;
ix->next = index;
index = ix;
struct index ix;
ix.index = encode_bbox(bbox[0], bbox[1], bbox[2], bbox[3], 0);
ix.fpos = start;
fwrite(&ix, sizeof(struct index), 1, indexfile);
}
next_feature:
@ -382,9 +381,22 @@ next_feature:
}
json_end(jp);
fclose(out);
fclose(metafile);
fclose(indexfile);
check(index);
int fd = open("index.out", O_RDWR);
struct stat st;
fstat(fd, &st);
struct index *index = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
if (index == MAP_FAILED) {
perror("mmap index");
exit(EXIT_FAILURE);
}
check(index, st.st_size / sizeof(struct index));
munmap(index, st.st_size);
close(fd);
}
int main(int argc, char **argv) {