Merged core/ and stream/ -> src/. The split wasn't worth it.

1 files changed, 133 insertions, 0 deletions

diff --git a/src/upb_table.h b/src/upb_table.h
new file mode 100644
index 0000000..20dae92
--- /dev/null
+++ b/src/upb_table.h
@@ -0,0 +1,133 @@
+/*
+ * upb - a minimalist implementation of protocol buffers.
+ *
+ * Copyright (c) 2009 Joshua Haberman.  See LICENSE for details.
+ *
+ * This file defines very fast int->struct (inttable) and string->struct
+ * (strtable) hash tables.  The struct can be of any size, and it is stored
+ * in the table itself, for cache-friendly performance.
+ *
+ * The table uses internal chaining with Brent's variation (inspired by the
+ * Lua implementation of hash tables).  The hash function for strings is
+ * Austin Appleby's "MurmurHash."
+ */
+
+#ifndef UPB_TABLE_H_
+#define UPB_TABLE_H_
+
+#include <assert.h>
+#include "upb.h"
+#include "upb_string.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Note: the key cannot be zero!  Zero is used by the implementation. */
+typedef uint32_t upb_inttable_key_t;
+
+#define UPB_END_OF_CHAIN (uint32_t)0
+#define UPB_EMPTY_ENTRY (uint32_t)0
+
+typedef struct {
+  upb_inttable_key_t key;
+  uint32_t next;  /* Internal chaining. */
+} upb_inttable_entry;
+
+// TODO: consider storing the hash in the entry.  This would avoid the need to
+// rehash on table resizes, but more importantly could possibly improve lookup
+// performance by letting us compare hashes before comparing lengths or the
+// strings themselves.
+typedef struct {
+  upb_string *key;         // We own a ref.
+  uint32_t next;           // Internal chaining.
+} upb_strtable_entry;
+
+typedef struct {
+  void *entries;
+  uint32_t count;       /* How many elements are currently in the table? */
+  uint16_t entry_size;  /* How big is each entry? */
+  uint8_t size_lg2;     /* The table is 2^size_lg2 in size. */
+  uint32_t mask;
+} upb_table;
+
+typedef struct {
+  upb_table t;
+} upb_strtable;
+
+typedef struct {
+  upb_table t;
+} upb_inttable;
+
+/* Initialize and free a table, respectively.  Specify the initial size
+ * with 'size' (the size will be increased as necessary).  Entry size
+ * specifies how many bytes each entry in the table is. */
+void upb_inttable_init(upb_inttable *table, uint32_t size, uint16_t entry_size);
+void upb_inttable_free(upb_inttable *table);
+void upb_strtable_init(upb_strtable *table, uint32_t size, uint16_t entry_size);
+void upb_strtable_free(upb_strtable *table);
+
+INLINE uint32_t upb_table_size(upb_table *t) { return 1 << t->size_lg2; }
+INLINE uint32_t upb_inttable_size(upb_inttable *t) {
+  return upb_table_size(&t->t);
+}
+INLINE uint32_t upb_strtable_size(upb_strtable *t) {
+  return upb_table_size(&t->t);
+}
+
+INLINE uint32_t upb_table_count(upb_table *t) { return t->count; }
+INLINE uint32_t upb_inttable_count(upb_inttable *t) {
+  return upb_table_count(&t->t);
+}
+INLINE uint32_t upb_strtable_count(upb_strtable *t) {
+  return upb_table_count(&t->t);
+}
+
+/* Inserts the given key into the hashtable with the given value.  The key must
+ * not already exist in the hash table.  The data will be copied from e into
+ * the hashtable (the amount of data copied comes from entry_size when the
+ * table was constructed).  Therefore the data at val may be freed once the
+ * call returns. */
+void upb_inttable_insert(upb_inttable *t, upb_inttable_entry *e);
+void upb_strtable_insert(upb_strtable *t, upb_strtable_entry *e);
+
+INLINE uint32_t upb_inttable_bucket(upb_inttable *t, upb_inttable_key_t k) {
+  return (k & t->t.mask) + 1;  /* Identity hash for ints. */
+}
+
+/* Looks up key in this table.  Inlined because this is in the critical path of
+ * decoding.  We have the caller specify the entry_size because fixing this as
+ * a literal (instead of reading table->entry_size) gives the compiler more
+ * ability to optimize. */
+INLINE void *upb_inttable_fastlookup(upb_inttable *t, uint32_t key,
+                                     uint32_t entry_size) {
+  assert(key != 0);
+  uint32_t bucket = upb_inttable_bucket(t, key);
+  upb_inttable_entry *e;
+  do {
+    e = (upb_inttable_entry*)UPB_INDEX(t->t.entries, bucket-1, entry_size);
+    if(e->key == key) return e;
+  } while((bucket = e->next) != UPB_END_OF_CHAIN);
+  return NULL;  /* Not found. */
+}
+
+INLINE void *upb_inttable_lookup(upb_inttable *t, uint32_t key) {
+  return upb_inttable_fastlookup(t, key, t->t.entry_size);
+}
+
+void *upb_strtable_lookup(upb_strtable *t, upb_string *key);
+
+/* Provides iteration over the table.  The order in which the entries are
+ * returned is undefined.  Insertions invalidate iterators.  The _next
+ * functions return NULL when the end has been reached. */
+void *upb_inttable_begin(upb_inttable *t);
+void *upb_inttable_next(upb_inttable *t, upb_inttable_entry *cur);
+
+void *upb_strtable_begin(upb_strtable *t);
+void *upb_strtable_next(upb_strtable *t, upb_strtable_entry *cur);
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif  /* UPB_TABLE_H_ */