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New strpool module

git-svn-id: svn://svn.cc65.org/cc65/trunk@2167 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz 2003-05-24 20:51:41 +00:00
parent 8b279cf126
commit 9421bf0e70
2 changed files with 389 additions and 0 deletions

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src/common/strpool.c Normal file
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/*****************************************************************************/
/* */
/* strpool.c */
/* */
/* A string pool */
/* */
/* */
/* */
/* (C) 2003 Ullrich von Bassewitz */
/* Römerstrasse 52 */
/* D-70794 Filderstadt */
/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
/* A string pool is used to store identifiers and other strings. Each string
* stored in the pool has a unique id, which may be used to access the string
* in the pool. Identical strings are only stored once in the pool and have
* identical ids. This means that instead of comparing strings, just the
* string pool ids must be compared.
*/
#include <string.h>
/* common */
#include "coll.h"
#include "hashstr.h"
#include "strbuf.h"
#include "strpool.h"
#include "xmalloc.h"
/*****************************************************************************/
/* Data */
/*****************************************************************************/
/* A string pool entry */
struct StrPoolEntry {
StrPoolEntry* Next; /* Pointer to next entry in hash chain */
unsigned Hash; /* Full hash value */
unsigned Id; /* The numeric string id */
unsigned Len; /* Length of the string (excluding terminator) */
char S[1]; /* The string itself */
};
/*****************************************************************************/
/* struct StrPoolEntry */
/*****************************************************************************/
static StrPoolEntry* NewStrPoolEntry (const char* S, unsigned Hash, unsigned Id)
/* Create a new string pool entry and return it. */
{
/* Get the length of the string */
unsigned Len = strlen (S);
/* Allocate memory */
StrPoolEntry* E = xmalloc (sizeof (StrPoolEntry) + Len);
/* Initialize the fields */
E->Next = 0;
E->Hash = Hash;
E->Id = Id;
E->Len = Len;
memcpy (E->S, S, Len+1);
/* Return the new entry */
return E;
}
/*****************************************************************************/
/* Code */
/*****************************************************************************/
StrPool* InitStrPool (StrPool* P)
/* Initialize a string pool */
{
unsigned I;
/* Initialize the fields */
for (I = 0; I < sizeof (P->Tab) / sizeof (P->Tab[0]); ++I) {
P->Tab[I] = 0;
}
P->Entries = EmptyCollection;
P->TotalSize = 0;
/* Return a pointer to the initialized pool */
return P;
}
void DoneStrPool (StrPool* P)
/* Free the data of a string pool (but not the data itself) */
{
unsigned I;
/* Free all entries and clear the entry collection */
for (I = 0; I < CollCount (&P->Entries); ++I) {
xfree (CollAtUnchecked (&P->Entries, I));
}
CollDeleteAll (&P->Entries);
/* Clear the hash table */
for (I = 0; I < sizeof (P->Tab) / sizeof (P->Tab[0]); ++I) {
P->Tab[I] = 0;
}
/* Reset the size */
P->TotalSize = 0;
}
StrPool* NewStrPool (void)
/* Allocate, initialize and return a new string pool */
{
/* Allocate memory, initialize and return it */
return InitStrPool (xmalloc (sizeof (StrPool)));
}
void FreeStrPool (StrPool* P)
/* Free a string pool */
{
/* Free all entries */
DoneStrPool (P);
/* Free the string pool itself */
xfree (P);
}
const char* SP_Get (const StrPool* P, unsigned Index)
/* Return a string from the pool. Index must exist, otherwise FAIL is called. */
{
/* Get the collection entry */
const StrPoolEntry* E = CollConstAt (&P->Entries, Index);
/* Return the string from the entry */
return E->S;
}
unsigned SP_Add (StrPool* P, const char* S)
/* Add a string to the buffer and return the index. If the string does already
* exist in the pool, SP_Add will just return the index of the existing string.
*/
{
/* Calculate the string hash */
unsigned Hash = HashStr (S);
/* Calculate the reduced string hash */
unsigned RHash = Hash % (sizeof (P->Tab)/sizeof (P->Tab[0]));
/* Search for an existing entry */
StrPoolEntry* E = P->Tab[RHash];
while (E) {
if (E->Hash == Hash && strcmp (E->S, S) == 0) {
/* Found, return the id of the existing string */
return E->Id;
}
E = E->Next;
}
/* We didn't find the entry, so create a new one */
E = NewStrPoolEntry (S, Hash, CollCount (&P->Entries));
/* Insert the new entry into the entry collection */
CollAppend (&P->Entries, E);
/* Insert the new entry into the hash table */
E->Next = P->Tab[RHash];
P->Tab[RHash] = E;
/* Add up the string size (plus terminator) */
P->TotalSize += E->Len + 1;
/* Return the id of the entry */
return E->Id;
}
unsigned SP_AddBuf (StrPool* P, const void* Buffer, unsigned Size)
/* Add strings from a string buffer. Buffer must contain a list of zero
* terminated strings. These strings are added to the pool, starting with
* the current index. The number of strings added is returned.
* Beware: The function will do only loose range checking for the buffer
* limits, so a SEGV may occur if the last string in the buffer is not
* correctly terminated.
*/
{
/* Cast the buffer pointer to something useful */
const char* Buf = Buffer;
/* Remember the current number of strings in the buffer. */
unsigned OldCount = SB_GetCount (P);
/* Add all strings from the buffer */
while (Size) {
/* Add the next entry */
unsigned Id = SP_Add (P, Buf);
/* Get the entry from the id */
const StrPoolEntry* E = CollConstAt (&P->Entries, Id);
/* Skip this string */
Buf += E->Len + 1;
Size -= E->Len + 1;
}
/* Return the number of strings added */
return SB_GetCount (P) - OldCount;
}
void SP_Build (StrPool* P, const void* Buffer, unsigned Size)
/* Delete existing data and use the data from Buffer instead. */
{
/* Delete old data */
DoneStrPool (P);
/* Add the buffer data */
SP_AddBuf (P, Buffer, Size);
}

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src/common/strpool.h Normal file
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/*****************************************************************************/
/* */
/* strpool.h */
/* */
/* A string pool */
/* */
/* */
/* */
/* (C) 2003 Ullrich von Bassewitz */
/* Römerstrasse 52 */
/* D-70794 Filderstadt */
/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
/* A string pool is used to store identifiers and other strings. Each string
* stored in the pool has a unique id, which may be used to access the string
* in the pool. Identical strings are only stored once in the pool and have
* identical ids. This means that instead of comparing strings, just the
* string pool ids must be compared.
*/
#ifndef STRPOOL_H
#define STRPOOL_H
/* common */
#include "coll.h"
#include "inline.h"
#include "strbuf.h"
/*****************************************************************************/
/* Data */
/*****************************************************************************/
/* Opaque entry */
typedef struct StrPoolEntry StrPoolEntry;
typedef struct StrPool StrPool;
struct StrPool {
StrPoolEntry* Tab[211]; /* Entry hash table */
Collection Entries; /* Entries sorted by number */
unsigned TotalSize; /* Total size of all string data */
};
/*****************************************************************************/
/* Code */
/*****************************************************************************/
StrPool* InitStrPool (StrPool* P);
/* Initialize a string pool */
void DoneStrPool (StrPool* P);
/* Free the data of a string pool (but not the data itself) */
StrPool* NewStrPool (void);
/* Allocate, initialize and return a new string pool */
void FreeStrPool (StrPool* P);
/* Free a string pool */
void SP_Use (char* Buffer, unsigned Size);
/* Delete existing data and use the data from Buffer instead. Buffer must be
* allocated on the heap and will be freed using xfree() if necessary.
*/
const char* SP_Get (const StrPool* P, unsigned Index);
/* Return a string from the pool. Index must exist, otherwise FAIL is called. */
unsigned SP_Add (StrPool* P, const char* S);
/* Add a string to the buffer and return the index. If the string does already
* exist in the pool, SP_Add will just return the index of the existing string.
*/
#if defined(HAVE_INLINE)
INLINE unsigned SB_GetCount (const StrPool* P)
/* Return the number of strings in the pool */
{
return CollCount (&P->Entries);
}
#else
# define SB_GetCount(P) CollCount (&(P)->Entries)
#endif
/* End of strpool.h */
#endif