dictionary handle

dictionary.c

@@ -0,0 +1,341 @@
+#include "dictionary.h"
+#include <memory.h>
+#include <string.h>
+
+#include "fast.memory.h"
+
+//#pragma debug -1
+
+typedef struct _Dictionary {
+  Word count;
+  Word offset;
+  Word table[16];
+} _Dictionary;
+
+typedef struct _DictionaryEntry {
+  Word hash;
+  Word next;
+  Word keySize;
+  Word dataSize;
+} _DictionaryEntry;
+
+#define SIZEOF_D sizeof(_Dictionary)
+#define SIZEOF_DE sizeof(_DictionaryEntry)
+#define H_TO_D(h) *((_Dictionary **)h)
+#define D_TO_DE(d,offset) (_DictionaryEntry *)((char *)d + offset)
+#define DE_TO_KEY(de) ((char *)de + SIZEOF_DE)
+#define DE_TO_DATA(de,keySize) ((char *)de + SIZEOF_DE + keySize)
+
+static Boolean keycmp(const char *key1, const char *key2, Word size)
+{
+	// key1 is guaranteed to be lowercase.
+	Word i;
+
+	for (i = 0; i < size; ++i)
+	{
+		char a, b;
+		a = key1[i];
+		b = key2[i];
+
+		if (b >= 'A' && b <= 'Z') b |= 0x20;
+		if (a != b) return 0;
+	}
+
+	return 1;
+
+}
+static Word findEntry(_Dictionary *d, const char *key, Word keySize, Word hash)
+{
+  Word offset;
+
+  offset = d->table[hash & 0x0f];
+
+  while (offset)
+  {
+	_DictionaryEntry *de;
+	de = D_TO_DE(d, offset);
+	if (de->hash == hash && de->keySize == keySize)
+	{
+	  char *tmp = DE_TO_KEY(de);
+	  if (keycmp(tmp, key, keySize)) return offset;
+	}
+	offset = de->next;
+  }
+
+  return offset;
+}
+
+void deleteEntry(_Dictionary *d, Word offset)
+{
+  // remove an entry, adjusting the hashtable and next pointers.
+
+  _DictionaryEntry *de;
+  Word size;
+  Word hash;
+  Word xoffset;
+  Word i;
+
+
+  de = D_TO_DE(d, offset);
+
+  size = SIZEOF_DE + de->keySize + de->dataSize;
+  hash = de->hash;
+
+  if (d->table[hash & 0x0f] == offset)
+	d->table[hash & 0x0f] = de->next;
+
+  for (i = 0; i < 16; ++i)
+  {
+	if (d->table[i] > offset) d->table[i] -= size;
+  }
+
+  // remove the entry.
+  memmove(de, de + size, d->offset - offset - size);
+
+  // de now points to the *next* entry.
+
+  d->count--;
+  d->offset -= size;
+
+  xoffset = offset;
+
+  while (xoffset < d->offset)
+  {
+	Word tmp = SIZEOF_DE + de->keySize + de->dataSize;
+
+	if (de->next >= offset) de->next -= size;
+	xoffset += tmp;
+	de = (_DictionaryEntry *)((char *)de + tmp);
+  }
+}
+
+// djb hash, modified to be case-insensitive 
+// and 16-bit.
+static Word hash(const char *key, Word keySize)
+{
+  Word h = 5381;
+  unsigned char c;
+  Word i;
+
+  for (i = 0; i < keySize; ++i)
+  {
+	c = key[i];
+	if (c >= 'A' && c <= 'Z') c |= 0x20;  // lowercase it.
+	h = ((h << 5) + h) ^ c;
+  }
+  return h;
+}
+
+Handle DictionaryCreate(Word MemID, Word initialSize)
+{
+	Word i;
+	Handle h;
+	_Dictionary *d;
+
+	if (initialSize < 2048) initialSize = 2048;
+
+	h = NewHandle(initialSize, MemID, attrNoSpec | attrLocked, NULL);
+	if (_toolErr) return NULL;
+
+	d = H_TO_D(h);
+
+	//bzero(d, SIZEOF_D);
+	d->count = 0;
+	for (i = 0; i < 16; ++i)
+		d->table[i] = 0;
+
+	d->offset = SIZEOF_D; // next entry.
+
+	return h;
+}
+
+
+Word DictionaryCount(Handle h)
+{
+  _Dictionary *d;
+
+  if (!h) return 0;
+
+  _HLock(h);
+
+  d = H_TO_D(h);
+
+  return d->count;
+}
+
+Boolean DictionaryContains(Handle h, const char *key, Word keySize)
+{
+  Word hh;
+  Word offset;
+  _Dictionary *d;
+
+  if (!h) return 0;
+
+  _HLock(h);
+
+  d = H_TO_D(h);
+
+  hh = hash(key, keySize);
+  offset = findEntry(d, key, keySize, hh);
+
+  return offset != 0;
+}
+void *DictionaryGet(Handle h, const char *key, Word keySize, Word *dataSize)
+{
+  Word hh;
+  Word offset;
+  _Dictionary *d;
+  _DictionaryEntry *de;
+
+  if (!h) return NULL;
+
+  _HLock(h);
+
+  d = H_TO_D(h);
+
+  hh = hash(key, keySize);
+  offset = findEntry(d, key, keySize, hh);
+
+  if (offset == 0)
+  {
+	if (dataSize) *dataSize = 0;
+	return NULL;
+  } 
+
+  de = D_TO_DE(d, offset);
+
+  if (dataSize) *dataSize = de->dataSize;
+
+  return DE_TO_DATA(de,keySize);
+}
+
+Word DictionaryAdd(Handle h, 
+  const char *key, Word keySize, 
+  const char *data, Word dataSize, 
+  Boolean replace)
+{
+  _Dictionary *d;
+  _DictionaryEntry *de;
+
+  Word hh;
+  Word offset;
+  Word size;
+  Word i;
+
+  LongWord hSize;
+  LongWord newSize;
+
+
+  if (!h) return 0;
+
+  _HLock(h);
+
+  d = H_TO_D(h);
+  hh = hash(key, keySize);
+
+  offset = findEntry(d, key, keySize, hh);
+
+  if (offset)
+  {
+	if (!replace) return 0;
+	// delete the previous entry iff datasize differs.
+	de = D_TO_DE(d, offset);
+	if (de->dataSize == dataSize)
+	{
+	  memcpy(DE_TO_DATA(de, keySize), data, dataSize);
+	  return 1;
+	}
+	//
+	deleteEntry(d, offset);
+  } 
+
+  // create and insert it.
+  offset = d->offset;
+
+  hSize = _GetHandleSize(h);
+
+  newSize = offset + SIZEOF_DE + keySize + dataSize;
+  if (newSize > 0xffff) return 0;
+
+  if (newSize > hSize)
+  {
+    _HUnlock(h);
+    newSize = (newSize + 4095) & ~4095;
+    SetHandleSize(newSize, h);
+    if (_toolErr) return 0;
+    _HLock(h);
+
+	d = H_TO_D(h);
+  }
+
+  de = D_TO_DE(d, offset);
+  de->hash = hh;
+  de->next = d->table[hh & 0x0f];
+  de->keySize = keySize;
+  de->dataSize = dataSize;
+
+  // copy the key (lowercase).
+  for (i = 0; i < keySize; ++i)
+  {
+	char c;
+	c = key[i];
+	if (c >= 'A' && c <= 'Z') c |= 0x020;
+	DE_TO_KEY(de)[i] = c;
+  }
+  memcpy(DE_TO_DATA(de, keySize), data, dataSize);
+
+  d->table[hh & 0x0f] = offset; 
+
+  d->count++;  
+  d->offset = newSize;
+
+  return 1;
+}
+
+void DictionaryRemove(Handle h, const char *key, Word keySize)
+{
+  _Dictionary *d;
+  Word offset;
+  Word hh;
+
+  if (!h) return;
+
+  _HLock(h);
+
+  d = H_TO_D(h);
+
+  hh = hash(key, keySize);
+
+  offset = findEntry(d, key, keySize, hh);
+  if (offset)
+  {
+	deleteEntry(d, offset);
+  }
+}
+
+Word DictionaryEnumerate(Handle h, DictionaryEnumerator *e, Word cookie)
+{
+  // returns the next offset;
+  _Dictionary *d;
+  _DictionaryEntry *de;
+
+  if (!h) return 0;
+
+  if (cookie == 0) cookie = SIZEOF_D;
+
+  _HLock(h);
+  d = H_TO_D(h);
+  if (cookie >= d->offset) return 0;
+
+  de = D_TO_DE(d, cookie);
+
+  if (e)
+  {
+	e->keySize = de->keySize;
+	e->valueSize = de->dataSize;
+	e->key = DE_TO_KEY(de);
+	e->value = DE_TO_DATA(de,de->keySize);
+  }
+
+  return cookie + SIZEOF_DE + de->keySize + de->dataSize;
+}

dictionary.h

@@ -0,0 +1,32 @@
+#ifndef __DICTIONARY_H__
+#define __DICTIONARY_H__
+
+#include <Types.h>
+
+typedef struct DictionaryEnumerator {
+  Word keySize;
+  Word valueSize;
+  void *key;
+  void *value;
+} DictionaryEnumerator;
+
+Handle DictionaryCreate(Word MemID, Word initialSize);
+
+Boolean DictionaryContains(Handle h, const void *key, Word keySize);
+
+void *DictionaryGet(Handle h, const char *key, Word keySize, Word *valueSize);
+
+Word DictionaryCount(handle h);
+
+Word DictionaryAdd(Handle h, const void *key, Word keySize, 
+  const void *value, Word valueSize, Boolean replace);
+
+// removal performance is awful.
+void DictionaryRemove(Handle h, const char *key, Word keySize);
+
+
+Word DictionaryEnumerate(Handle h, DictionaryEnumerator *e, Word cookie);
+
+
+
+#endif