cii: Add hash

cii/CMakeLists.txt

@@ -5,9 +5,11 @@ set(CMAKE_C_STANDARD 11)
 
 set(SOURCE_FILES
     src/atom.c
+    src/hash.c
     )
 set(HEADER_FILES
     include/cii/atom.h
+    include/cii/hash.h
     )
 
 add_library(cii STATIC

cii/include/cii/hash.h

@@ -0,0 +1,12 @@
+// Copyright (c) 2023 Xu Shaohua <[email protected]>. All rights reserved.
+// Use of this source is governed by GNU General Public License
+// that can be found in the LICENSE file.
+
+#ifndef CII_HASH_H_
+#define CII_HASH_H_
+
+#include <stddef.h>
+
+size_t str_hash(const char* str, size_t len);
+
+#endif  // CII_HASH_H_

cii/src/atom.c

@@ -7,6 +7,9 @@
 #include <assert.h>
 #include <limits.h>
 #include <string.h>
+#include <stdlib.h>
+
+#include "cii/hash.h"
 
 struct atom_s {
   struct atom_s* link;
@@ -16,8 +19,41 @@ struct atom_s {
 
 typedef struct atom_s atom_t;
 
-const size_t kBucketCap = 2048;
-static atom_t g_buckets[kBucketCap];
+#define ATOM_BUCKET_LEN 2048
+static atom_t* g_buckets[ATOM_BUCKET_LEN];
+
+atom_t* atom_new_node(const char* str, size_t len) {
+  const size_t total_len = sizeof(atom_t) + len + 1;
+  atom_t* p = malloc(total_len);
+  assert(p != NULL);
+  p->len = len;
+  p->str = (char*)(p + 1);
+  if (len > 0) {
+    memcpy(p->str, str, len);
+  }
+  p->str[len] = '\0';
+  return p;
+}
+
+const char* atom_new(const char* str, size_t len) {
+  assert(str != NULL);
+  size_t hash = str_hash(str, len);
+  hash %= ATOM_BUCKET_LEN;
+
+  atom_t* p;
+  for (p = g_buckets[hash]; p != NULL; p = p->link) {
+    if (len == p->len && strncmp(p->str, str, len) == 0) {
+      return p->str;
+    }
+  }
+
+  // create new entry
+  p = atom_new_node(str, len);
+  p->link = g_buckets[hash];
+  g_buckets[hash] = p;
+
+  return p->str;
+}
 
 const char* atom_string(const char* str) {
   assert(str != NULL);

cii/src/hash.c

@@ -0,0 +1,59 @@
+// Copyright (c) 2023 Xu Shaohua <[email protected]>. All rights reserved.
+// Use of this source is governed by GNU General Public License
+// that can be found in the LICENSE file.
+
+#include "cii/hash.h"
+
+static size_t scatter[] = {
+    2078917053, 143302914, 1027100827, 1953210302, 755253631, 2002600785,
+    1405390230, 45248011, 1099951567, 433832350, 2018585307, 438263339,
+    813528929, 1703199216, 618906479, 573714703, 766270699, 275680090,
+    1510320440, 1583583926, 1723401032, 1965443329, 1098183682, 1636505764,
+    980071615, 1011597961, 643279273, 1315461275, 157584038, 1069844923,
+    471560540, 89017443, 1213147837, 1498661368, 2042227746, 1968401469,
+    1353778505, 1300134328, 2013649480, 306246424, 1733966678, 1884751139,
+    744509763, 400011959, 1440466707, 1363416242, 973726663, 59253759,
+    1639096332, 336563455, 1642837685, 1215013716, 154523136, 593537720,
+    704035832, 1134594751, 1605135681, 1347315106, 302572379, 1762719719,
+    269676381, 774132919, 1851737163, 1482824219, 125310639, 1746481261,
+    1303742040, 1479089144, 899131941, 1169907872, 1785335569, 485614972,
+    907175364, 382361684, 885626931, 200158423, 1745777927, 1859353594,
+    259412182, 1237390611, 48433401, 1902249868, 304920680, 202956538,
+    348303940, 1008956512, 1337551289, 1953439621, 208787970, 1640123668,
+    1568675693, 478464352, 266772940, 1272929208, 1961288571, 392083579,
+    871926821, 1117546963, 1871172724, 1771058762, 139971187, 1509024645,
+    109190086, 1047146551, 1891386329, 994817018, 1247304975, 1489680608,
+    706686964, 1506717157, 579587572, 755120366, 1261483377, 884508252,
+    958076904, 1609787317, 1893464764, 148144545, 1415743291, 2102252735,
+    1788268214, 836935336, 433233439, 2055041154, 2109864544, 247038362,
+    299641085, 834307717, 1364585325, 23330161, 457882831, 1504556512,
+    1532354806, 567072918, 404219416, 1276257488, 1561889936, 1651524391,
+    618454448, 121093252, 1010757900, 1198042020, 876213618, 124757630,
+    2082550272, 1834290522, 1734544947, 1828531389, 1982435068, 1002804590,
+    1783300476, 1623219634, 1839739926, 69050267, 1530777140, 1802120822,
+    316088629, 1830418225, 488944891, 1680673954, 1853748387, 946827723,
+    1037746818, 1238619545, 1513900641, 1441966234, 367393385, 928306929,
+    946006977, 985847834, 1049400181, 1956764878, 36406206, 1925613800,
+    2081522508, 2118956479, 1612420674, 1668583807, 1800004220, 1447372094,
+    523904750, 1435821048, 923108080, 216161028, 1504871315, 306401572,
+    2018281851, 1820959944, 2136819798, 359743094, 1354150250, 1843084537,
+    1306570817, 244413420, 934220434, 672987810, 1686379655, 1301613820,
+    1601294739, 484902984, 139978006, 503211273, 294184214, 176384212,
+    281341425, 228223074, 147857043, 1893762099, 1896806882, 1947861263,
+    1193650546, 273227984, 1236198663, 2116758626, 489389012, 593586330,
+    275676551, 360187215, 267062626, 265012701, 719930310, 1621212876,
+    2108097238, 2026501127, 1865626297, 894834024, 552005290, 1404522304,
+    48964196, 5816381, 1889425288, 188942202, 509027654, 36125855,
+    365326415, 790369079, 264348929, 513183458, 536647531, 13672163,
+    313561074, 1730298077, 286900147, 1549759737, 1699573055, 776289160,
+    2143346068, 1975249606, 1136476375, 262925046, 92778659, 1856406685,
+    1884137923, 53392249, 1735424165, 1602280572
+};
+
+size_t str_hash(const char* str, size_t len) {
+  size_t h = 0;
+  for (size_t i = 0; i < len; ++i) {
+    h = (h << 1) + scatter[(unsigned char)str[i]];
+  }
+  return h;
+}