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Save another byte per attribute by moving the type to the string pool

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This commit is contained in:
Eric Fischer
2015-06-18 12:12:20 -07:00
parent 1a44538bdf
commit a1d3ecf9bb
2 changed files with 23 additions and 19 deletions
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geojson.c
+15 -9
View File
@@ -395,17 +395,22 @@ static void merge(struct merge *merges, int nmerges, unsigned char *map, FILE *f
} }
struct stringpool { struct stringpool {
char *s; char *s; // first byte is type
struct stringpool *left; struct stringpool *left;
struct stringpool *right; struct stringpool *right;
long long off; long long off;
} *pooltree = NULL; } *pooltree = NULL;
long long addpool(FILE *poolfile, long long *poolpos, char *s) { long long addpool(FILE *poolfile, long long *poolpos, char *s, char type) {
struct stringpool **sp = &pooltree; struct stringpool **sp = &pooltree;
while (*sp != NULL) { while (*sp != NULL) {
int cmp = strcmp(s, (*sp)->s); int cmp = strcmp(s, (*sp)->s + 1);
if (cmp == 0) {
cmp = type - (*sp)->s[0];
}
if (cmp < 0) { if (cmp < 0) {
sp = &((*sp)->left); sp = &((*sp)->left);
} else if (cmp > 0) { } else if (cmp > 0) {
@@ -416,13 +421,15 @@ long long addpool(FILE *poolfile, long long *poolpos, char *s) {
} }
*sp = malloc(sizeof(struct stringpool)); *sp = malloc(sizeof(struct stringpool));
(*sp)->s = strdup(s); // XXX really should be mapped from the pool itself (*sp)->s = malloc(strlen(s) + 2);
(*sp)->s[0] = type;
strcpy((*sp)->s + 1, s); // XXX really should be mapped from the pool itself
(*sp)->left = NULL; (*sp)->left = NULL;
(*sp)->right = NULL; (*sp)->right = NULL;
(*sp)->off = *poolpos; (*sp)->off = *poolpos;
fwrite_check(s, strlen(s) + 1, sizeof(char), poolfile, "string pool"); fwrite_check((*sp)->s, strlen(s) + 2, sizeof(char), poolfile, "string pool");
*poolpos += strlen(s) + 1; *poolpos += strlen(s) + 2;
return (*sp)->off; return (*sp)->off;
} }
@@ -655,9 +662,8 @@ int read_json(int argc, char **argv, char *fname, const char *layername, int max
serialize_int(metafile, m, &metapos, fname); serialize_int(metafile, m, &metapos, fname);
for (i = 0; i < m; i++) { for (i = 0; i < m; i++) {
serialize_int(metafile, metatype[i], &metapos, fname); serialize_long_long(metafile, addpool(poolfile, &poolpos, metakey[i], VT_STRING), &metapos, fname);
serialize_long_long(metafile, addpool(poolfile, &poolpos, metakey[i]), &metapos, fname); serialize_long_long(metafile, addpool(poolfile, &poolpos, metaval[i], metatype[i]), &metapos, fname);
serialize_long_long(metafile, addpool(poolfile, &poolpos, metaval[i]), &metapos, fname);
} }
long long geomstart = geompos; long long geomstart = geompos;
tile.cc
+8 -10
View File
@@ -186,12 +186,12 @@ int coalindexcmp(const struct coalesce *c1, const struct coalesce *c2) {
return cmp; return cmp;
} }
struct pool_val *retrieve_string(char **f, struct pool *p, int type, char *stringpool) { struct pool_val *retrieve_string(char **f, struct pool *p, char *stringpool) {
struct pool_val *ret; struct pool_val *ret;
long long off; long long off;
deserialize_long_long(f, &off); deserialize_long_long(f, &off);
ret = pool(p, stringpool + off, type); ret = pool(p, stringpool + off + 1, stringpool[off]);
return ret; return ret;
} }
@@ -202,22 +202,20 @@ void decode_meta(char **meta, char *stringpool, struct pool *keys, struct pool *
int i; int i;
for (i = 0; i < m; i++) { for (i = 0; i < m; i++) {
int t; struct pool_val *key = retrieve_string(meta, keys, stringpool);
deserialize_int(meta, &t);
struct pool_val *key = retrieve_string(meta, keys, VT_STRING, stringpool);
if (only != NULL && (strcmp(key->s, only) != 0)) { if (only != NULL && (strcmp(key->s, only) != 0)) {
deserialize_int(meta, &t); // XXX if evaluate ever works again, check whether this is sufficient
*meta += t; (void) retrieve_string(meta, values, stringpool);
} else { } else {
struct pool_val *value = retrieve_string(meta, values, t, stringpool); struct pool_val *value = retrieve_string(meta, values, stringpool);
intmeta->push_back(key->n); intmeta->push_back(key->n);
intmeta->push_back(value->n); intmeta->push_back(value->n);
if (!is_pooled(file_keys, key->s, t)) { if (!is_pooled(file_keys, key->s, value->type)) {
// Dup to retain after munmap // Dup to retain after munmap
pool(file_keys, strdup(key->s), t); pool(file_keys, strdup(key->s), value->type);
} }
} }
} }