/*

 * dict.c: dictionary of reusable strings, just used to avoid allocation

 *         and freeing operations.

 *

 * Copyright (C) 2003 Daniel Veillard.

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED

 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF

 * MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE AUTHORS AND

 * CONTRIBUTORS ACCEPT NO RESPONSIBILITY IN ANY CONCEIVABLE MANNER.

 *

 * Author: daniel@veillard.com

 */

#define IN_LIBXML

#include "XmlEnglibxml.h"

#include <string.h>

#include "Libxml2_globals.h"

#define MAX_HASH_LEN 4

// TODO: Optimize: "Magic number" -- make it configurable global parameter

//       1 entry is 16 bytes

#define MIN_DICT_SIZE 128

#define MAX_DICT_HASH 8 * 2048

/* #define ALLOW_REMOVAL */

/* #define DEBUG_GROW */

/*

 * xmlDictAddString:

 * @dict: the dictionnary

 * @name: the name of the userdata

 * @len: the length of the name, if -1 it is recomputed

 *

 * Add the string to the array[s]

 *

 * Returns the pointer of the local string, or NULL in case of error.

 *

 * OOM: possible --> NULL is returned, OOM flag is set

 */

static const xmlChar*

xmlDictAddString(xmlDictPtr dict, const xmlChar *name, int namelen) {

    xmlDictStringsPtr pool;

    const xmlChar *ret;

    int size = 0; /* + sizeof(_xmlDictStrings) == 1024 */

    pool = dict->strings;

    while (pool != NULL) {

        if (pool->end - pool->free > namelen)

            goto found_pool;

        if (pool->size > size) size = pool->size;

            pool = pool->next;

    }

    /*

     * Not found, need to allocate

     */

    if (pool == NULL) {

        if (size == 0) 

            size = 1000;

        else 

            size *= 4; /* exponential growth */

        if (size < 4 * namelen)

            size = 4 * namelen; /* just in case ! */

        pool = (xmlDictStringsPtr) xmlMalloc(sizeof(xmlDictStrings) + size);

        if (pool == NULL)

            return(NULL);

        pool->size = size;

        pool->nbStrings = 0;

        pool->free = &pool->array[0];

        pool->end = &pool->array[size];

        pool->next = dict->strings;

        dict->strings = pool;

    }

found_pool:

    ret = pool->free;

    memcpy(pool->free, name, namelen);

    pool->free += namelen;

    *(pool->free++) = 0;

    return(ret);

}

/*

 * xmlDictAddQString:

 * @dict: the dictionnary

 * @prefix: the prefix of the userdata

 * @name: the name of the userdata

 * @len: the length of the name, if -1 it is recomputed

 *

 * Add the QName to the array[s]

 *

 * Returns the pointer of the local string, or NULL in case of error.

 */

static const xmlChar *

xmlDictAddQString(xmlDictPtr dict, const xmlChar *prefix,

                 const xmlChar *name, int namelen)

{

    xmlDictStringsPtr pool;

    const xmlChar *ret;

    int size = 0; /* + sizeof(_xmlDictStrings) == 1024 */

    int plen;

    if (prefix == NULL) return(xmlDictAddString(dict, name, namelen));

    plen = xmlStrlen(prefix);

    pool = dict->strings;

    while (pool != NULL) {

    if (pool->end - pool->free > namelen)

        goto found_pool;

    if (pool->size > size) size = pool->size;

    pool = pool->next;

    }

    /*

     * Not found, need to allocate

     */

    if (pool == NULL) {

        if (size == 0) size = 1000;

    else size *= 4; /* exponential growth */

        if (size < 4 * namelen)

        size = 4 * namelen; /* just in case ! */

    pool = (xmlDictStringsPtr) xmlMalloc(sizeof(xmlDictStrings) + size);

    if (pool == NULL)

        return(NULL);

    pool->size = size;

    pool->nbStrings = 0;

    pool->free = &pool->array[0];

    pool->end = &pool->array[size];

    pool->next = dict->strings;

    dict->strings = pool;

    }

found_pool:

    ret = pool->free;

    memcpy(pool->free, prefix, plen);

    pool->free += plen;

    *(pool->free++) = ':';

    namelen -= plen + 1;

    memcpy(pool->free, name, namelen);

    pool->free += namelen;

    *(pool->free++) = 0;

    return(ret);

}

/*

 * xmlDictComputeKey:

 * Calculate the hash key

 *

 * OOM: never

 */

static unsigned long

xmlDictComputeKey(const xmlChar *name, int namelen) {

    unsigned long value = 0L;

    if (name == NULL) return(0);

    value = *name;

    value <<= 5;

    if (namelen > 10) {

        value += name[namelen - 1];

        namelen = 10;

    }

    switch (namelen) {

        case 10: value += name[9];

        case 9: value += name[8];

        case 8: value += name[7];

        case 7: value += name[6];

        case 6: value += name[5];

        case 5: value += name[4];

        case 4: value += name[3];

        case 3: value += name[2];

        case 2: value += name[1];

        default: break;

    }

    return(value);

}

/*

 * xmlDictComputeQKey:

 * Calculate the hash key

 */

static unsigned long

xmlDictComputeQKey(const xmlChar *prefix, const xmlChar *name, int len)

{

    unsigned long value = 0L;

    int plen;

    if (prefix == NULL)

        return(xmlDictComputeKey(name, len));

    plen = xmlStrlen(prefix);

    if (plen == 0)

    value += 30 * (unsigned long) ':';

    else

    value += 30 * (*prefix);

    if (len > 10) {

        value += name[len - (plen + 1 + 1)];

        len = 10;

    if (plen > 10)

        plen = 10;

    }

    switch (plen) {

        case 10: value += prefix[9];

        case 9: value += prefix[8];

        case 8: value += prefix[7];

        case 7: value += prefix[6];

        case 6: value += prefix[5];

        case 5: value += prefix[4];

        case 4: value += prefix[3];

        case 3: value += prefix[2];

        case 2: value += prefix[1];

        case 1: value += prefix[0];

        default: break;

    }

    len -= plen;

    if (len > 0) {

        value += (unsigned long) ':';

    len--;

    }

    switch (len) {

        case 10: value += name[9];

        case 9: value += name[8];

        case 8: value += name[7];

        case 7: value += name[6];

        case 6: value += name[5];

        case 5: value += name[4];

        case 4: value += name[3];

        case 3: value += name[2];

        case 2: value += name[1];

        case 1: value += name[0];

        default: break;

    }

    return(value);

}

/**

 * xmlDictCreate:

 *

 * Create a new dictionary

 *

 * Returns the newly created dictionnary, or NULL if an error occured.

 *

 * OOM: possible --> NULL is returned; OOM flag is set

 */

xmlDictPtr

xmlDictCreate(void) {

    xmlDictPtr dict;

    dict = (xmlDictPtr)xmlMalloc(sizeof(xmlDict));

    if (dict) {

        dict->ref_counter = 1;

        dict->size = MIN_DICT_SIZE;

        dict->nbElems = 0;

        dict->dict = (xmlDictEntryPtr)xmlMalloc(MIN_DICT_SIZE * sizeof(xmlDictEntry));

        dict->strings = NULL;

        dict->subdict = NULL;

        if (dict->dict) {

            memset(dict->dict, 0, MIN_DICT_SIZE * sizeof(xmlDictEntry));

            return(dict);

        }

        xmlFree(dict); // OOM

    }

    return(NULL); // OOM

}

/**

 * xmlDictCreateSub:

 * @sub: an existing dictionnary

 *

 * Create a new dictionary, inheriting strings from the read-only

 * dictionnary @sub. On lookup, strings are first searched in the

 * new dictionnary, then in @sub, and if not found are created in the

 * new dictionnary.

 *

 * Returns the newly created dictionnary, or NULL if an error occured.

 */

xmlDictPtr

xmlDictCreateSub(xmlDictPtr sub) {

    xmlDictPtr dict = xmlDictCreate();

    if ((dict != NULL) && (sub != NULL)) {

        dict->subdict = sub;

    xmlDictReference(dict->subdict);

    }

    return(dict);

}

/**

 * xmlDictReference:

 * @dict: the dictionnary

 *

 * Increment the reference counter of a dictionary

 *

 * Returns 0 in case of success and -1 in case of error

 *

 * OOM: never

 */

int

xmlDictReference(xmlDictPtr dict) {

    if (dict == NULL) return -1;

    dict->ref_counter++;

    return(0);

}

/**

 * xmlDictGrow:

 * @dict: the dictionnary

 * @size: the new size of the dictionnary

 *

 * resize the dictionnary

 *

 * Returns 0 in case of success, -1 in case of failure

 *

 * OOM: possible --> returns -1, OOM is set

 */

static int

xmlDictGrow(xmlDictPtr dict, int size) {

    unsigned long key;

    int oldsize, i;

    xmlDictEntryPtr iter, next;

    struct _xmlDictEntry *olddict;

#ifdef DEBUG_GROW

    unsigned long nbElem = 0;

#endif

    if (dict == NULL)

        return(-1);

    if (size < 8)

        return(-1);

    if (size > 8 * 2048)

        return(-1);

    oldsize = dict->size;

    olddict = dict->dict;

    if (olddict == NULL)

        return(-1);

    dict->dict = (xmlDictEntryPtr)xmlMalloc(size * sizeof(xmlDictEntry));

    if (dict->dict == NULL) {

        dict->dict = olddict;

        return(-1);

    }

    memset(dict->dict, 0, size * sizeof(xmlDictEntry));

    dict->size = size;

    /*  If the two loops are merged, there would be situations where

    a new entry needs to allocated and data copied into it from

    the main dict. So instead, we run through the array twice, first

    copying all the elements in the main array (where we can't get

    conflicts) and then the rest, so we only free (and don't allocate)

    */

    for (i = 0; i < oldsize; i++) {

        if (olddict[i].valid == 0)

            continue;

        key = xmlDictComputeKey(olddict[i].name, olddict[i].len) % dict->size;

        memcpy(&(dict->dict[key]), &(olddict[i]), sizeof(xmlDictEntry));

        dict->dict[key].next = NULL;

#ifdef DEBUG_GROW

        nbElem++;

#endif

    }

    for (i = 0; i < oldsize; i++) {

        iter = olddict[i].next;

        while (iter) {

            next = iter->next;

            /*

            * put back the entry in the new dict

            */

            key = xmlDictComputeKey(iter->name, iter->len) % dict->size;

            if (dict->dict[key].valid == 0) {

                memcpy(&(dict->dict[key]), iter, sizeof(xmlDictEntry));

                dict->dict[key].next = NULL;

                dict->dict[key].valid = 1;

                xmlFree(iter);

            } else {

                iter->next = dict->dict[key].next;

                dict->dict[key].next = iter;

            }

#ifdef DEBUG_GROW

            nbElem++;

#endif

            iter = next;

        } // while (iter)

    } // for (i = 0; i < oldsize; i++)

    xmlFree(olddict);

#ifdef DEBUG_GROW

    xmlGenericError(xmlGenericErrorContext,

        "xmlDictGrow : from %d to %d, %d elems\n", oldsize, size, nbElem);

#endif

    return(0);

}

/**

 * xmlDictFree:

 * @dict: the dictionnary

 *

 * Free the hash @dict and its contents. The userdata is

 * deallocated with @f if provided.

 */

void

xmlDictFree(xmlDictPtr dict) {

    int i;

    xmlDictEntryPtr iter;

    xmlDictEntryPtr next;

    int inside_dict = 0;

    xmlDictStringsPtr pool, nextp;

    if (dict == NULL)

        return;

    /* decrement the counter, it may be shared by a parser and docs */

    dict->ref_counter--;

    if (dict->ref_counter > 0)

        return;

    if (dict->subdict != NULL) {

        xmlDictFree(dict->subdict);

    }

    if (dict->dict) {

        for(i = 0; ((i < dict->size) && (dict->nbElems > 0)); i++)

        {

            iter = &(dict->dict[i]);

            if (iter->valid == 0)

                continue;

            inside_dict = 1;

            while (iter)

            {

                next = iter->next;

                if (!inside_dict)

                    xmlFree(iter);

                dict->nbElems--;

                inside_dict = 0;

                iter = next;

            }

            inside_dict = 0;

        }

        xmlFree(dict->dict);

    }

    pool = dict->strings;

    while (pool != NULL) {

        nextp = pool->next;

        xmlFree(pool);

        pool = nextp;

    }

    xmlFree(dict);

}

/**

 * xmlDictLookup:

 * @dict: the dictionnary

 * @name: the name of the userdata

 * @len: the length of the name, if -1 it is recomputed

 *

 * Add the @name to the hash @dict if not present.

 *

 * Returns the internal copy of the name or NULL in case of internal error

 *

 * OOM: possible --> returns NULL and OOM flag is set

 */

const xmlChar*

xmlDictLookup(xmlDictPtr dict, const xmlChar *name, int len) {

    unsigned long key, okey, nbi = 0;

    xmlDictEntryPtr entry;

    xmlDictEntryPtr insert;

    const xmlChar *ret;

    if ((dict == NULL) || (name == NULL))

        return(NULL);

    if (len < 0)

        len = xmlStrlen(name);

    /*

     * Check for duplicate and insertion location.

     */

    okey = xmlDictComputeKey(name, len);

    key = okey % dict->size;

    if (dict->dict[key].valid == 0) {

        insert = NULL;

    } else {

        for (insert = &(dict->dict[key]); 

             insert->next != NULL; 

             insert = insert->next)

        {

#ifdef __GNUC__

            if (insert->len == len) {

                if (!memcmp(insert->name, name, len))

                    return(insert->name);

            }

#else

            if ((insert->len == len) && (!xmlStrncmp(insert->name, name, len)))

                return(insert->name);

#endif

            nbi++;

        }

#ifdef __GNUC__

        if (insert->len == len) {

            if (!memcmp(insert->name, name, len))

                return(insert->name);

        }

#else

        if ((insert->len == len) && (!xmlStrncmp(insert->name, name, len)))

            return(insert->name);

#endif

    }

    if (dict->subdict) {

        key = okey % dict->subdict->size;

        if (dict->subdict->dict[key].valid != 0) {

            xmlDictEntryPtr tmp;

            for (tmp = &(dict->subdict->dict[key]); tmp->next != NULL; tmp = tmp->next)

            {

#ifdef __GNUC__

                if (tmp->len == len) {

                    if (!memcmp(tmp->name, name, len))

                        return(tmp->name);