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/*

 * JFFS2 -- Journalling Flash File System, Version 2.

 *

 * Copyright (C) 2001-2003 Red Hat, Inc.

 * Created by Arjan van de Ven <arjanv@redhat.com>

 *

 * Copyright (C) 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>,

 *                    University of Szeged, Hungary

 *

 * For licensing information, see the file 'LICENCE' in this directory.

 *

 * $Id: compr.c,v 1.45 2005/07/26 13:24:40 havasi Exp $

 *

 */

#include "compr.h"

static DEFINE_SPINLOCK(jffs2_compressor_list_lock);

/* Available compressors are on this list */

static LIST_HEAD(jffs2_compressor_list);

/* Actual compression mode */

static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;

/* Statistics for blocks stored without compression */

static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;

/* jffs2_compress:

 * @data: Pointer to uncompressed data

 * @cdata: Pointer to returned pointer to buffer for compressed data

 * @datalen: On entry, holds the amount of data available for compression.

 *      On exit, expected to hold the amount of data actually compressed.

 * @cdatalen: On entry, holds the amount of space available for compressed

 *      data. On exit, expected to hold the actual size of the compressed

 *      data.

 *

 * Returns: Lower byte to be stored with data indicating compression type used.

 * Zero is used to show that the data could not be compressed - the

 * compressed version was actually larger than the original.

 * Upper byte will be used later. (soon)

 *

 * If the cdata buffer isn't large enough to hold all the uncompressed data,

 * jffs2_compress should compress as much as will fit, and should set

 * *datalen accordingly to show the amount of data which were compressed.

 */

uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,

                             unsigned char *data_in, unsigned char **cpage_out,

                             uint32_t *datalen, uint32_t *cdatalen)

{

        int ret = JFFS2_COMPR_NONE;

        int compr_ret;

        struct jffs2_compressor *this, *best=NULL;

        unsigned char *output_buf = NULL, *tmp_buf;

        uint32_t orig_slen, orig_dlen;

        uint32_t best_slen=0, best_dlen=0;

        switch (jffs2_compression_mode) {

        case JFFS2_COMPR_MODE_NONE:

                break;

        case JFFS2_COMPR_MODE_PRIORITY:

                output_buf = kmalloc(*cdatalen,GFP_KERNEL);

                if (!output_buf) {

                        printk(KERN_WARNING "JFFS2: No memory for compressor allocation. Compression failed.\n");

                        goto out;

                }

                orig_slen = *datalen;

                orig_dlen = *cdatalen;

                spin_lock(&jffs2_compressor_list_lock);

                list_for_each_entry(this, &jffs2_compressor_list, list) {

                        /* Skip decompress-only backwards-compatibility and disabled modules */

                        if ((!this->compress)||(this->disabled))

                                continue;

                        this->usecount++;

                        spin_unlock(&jffs2_compressor_list_lock);

                        *datalen  = orig_slen;

                        *cdatalen = orig_dlen;

                        compr_ret = this->compress(data_in, output_buf, datalen, cdatalen, NULL);

                        spin_lock(&jffs2_compressor_list_lock);

                        this->usecount--;

                        if (!compr_ret) {

                                ret = this->compr;

                                this->stat_compr_blocks++;

                                this->stat_compr_orig_size += *datalen;

                                this->stat_compr_new_size  += *cdatalen;

                                break;

                        }

                }

                spin_unlock(&jffs2_compressor_list_lock);

                if (ret == JFFS2_COMPR_NONE) kfree(output_buf);

                break;

        case JFFS2_COMPR_MODE_SIZE:

                orig_slen = *datalen;

                orig_dlen = *cdatalen;

                spin_lock(&jffs2_compressor_list_lock);

                list_for_each_entry(this, &jffs2_compressor_list, list) {

                        /* Skip decompress-only backwards-compatibility and disabled modules */

                        if ((!this->compress)||(this->disabled))

                                continue;

                        /* Allocating memory for output buffer if necessary */

                        if ((this->compr_buf_size<orig_dlen)&&(this->compr_buf)) {

                                spin_unlock(&jffs2_compressor_list_lock);

                                kfree(this->compr_buf);

                                spin_lock(&jffs2_compressor_list_lock);

                                this->compr_buf_size=0;

                                this->compr_buf=NULL;

                        }

                        if (!this->compr_buf) {

                                spin_unlock(&jffs2_compressor_list_lock);

                                tmp_buf = kmalloc(orig_dlen,GFP_KERNEL);

                                spin_lock(&jffs2_compressor_list_lock);

                                if (!tmp_buf) {

                                        printk(KERN_WARNING "JFFS2: No memory for compressor allocation. (%d bytes)\n",orig_dlen);

                                        continue;

                                }

                                else {

                                        this->compr_buf = tmp_buf;

                                        this->compr_buf_size = orig_dlen;

                                }

                        }

                        this->usecount++;

                        spin_unlock(&jffs2_compressor_list_lock);

                        *datalen  = orig_slen;

                        *cdatalen = orig_dlen;

                        compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen, NULL);

                        spin_lock(&jffs2_compressor_list_lock);

                        this->usecount--;

                        if (!compr_ret) {

                                if ((!best_dlen)||(best_dlen>*cdatalen)) {

                                        best_dlen = *cdatalen;

                                        best_slen = *datalen;

                                        best = this;

                                }

                        }

                }

                if (best_dlen) {

                        *cdatalen = best_dlen;

                        *datalen  = best_slen;

                        output_buf = best->compr_buf;

                        best->compr_buf = NULL;

                        best->compr_buf_size = 0;

                        best->stat_compr_blocks++;

                        best->stat_compr_orig_size += best_slen;

                        best->stat_compr_new_size  += best_dlen;

                        ret = best->compr;

                }

                spin_unlock(&jffs2_compressor_list_lock);

                break;

        default:

                printk(KERN_ERR "JFFS2: unknow compression mode.\n");

        }

 out:

        if (ret == JFFS2_COMPR_NONE) {

                *cpage_out = data_in;

                *datalen = *cdatalen;

                none_stat_compr_blocks++;

                none_stat_compr_size += *datalen;

        }

        else {

                *cpage_out = output_buf;

        }

        return ret;

}

int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,

                     uint16_t comprtype, unsigned char *cdata_in,

                     unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)

{

        struct jffs2_compressor *this;

        int ret;

        /* Older code had a bug where it would write non-zero 'usercompr'

           fields. Deal with it. */

        if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)

                comprtype &= 0xff;

        switch (comprtype & 0xff) {

        case JFFS2_COMPR_NONE:

                /* This should be special-cased elsewhere, but we might as well deal with it */

                memcpy(data_out, cdata_in, datalen);

                none_stat_decompr_blocks++;

                break;

        case JFFS2_COMPR_ZERO:

                memset(data_out, 0, datalen);

                break;

        default:

                spin_lock(&jffs2_compressor_list_lock);

                list_for_each_entry(this, &jffs2_compressor_list, list) {

                        if (comprtype == this->compr) {

                                this->usecount++;

                                spin_unlock(&jffs2_compressor_list_lock);

                                ret = this->decompress(cdata_in, data_out, cdatalen, datalen, NULL);

                                spin_lock(&jffs2_compressor_list_lock);

                                if (ret) {

                                        printk(KERN_WARNING "Decompressor \"%s\" returned %d\n", this->name, ret);

                                }

                                else {

                                        this->stat_decompr_blocks++;

                                }

                                this->usecount--;

                                spin_unlock(&jffs2_compressor_list_lock);

                                return ret;

                        }

                }

                printk(KERN_WARNING "JFFS2 compression type 0x%02x not available.\n", comprtype);

                spin_unlock(&jffs2_compressor_list_lock);

                return -EIO;

        }

        return 0;

}

int jffs2_register_compressor(struct jffs2_compressor *comp)

{

        struct jffs2_compressor *this;

        if (!comp->name) {

                printk(KERN_WARNING "NULL compressor name at registering JFFS2 compressor. Failed.\n");

                return -1;

        }

        comp->compr_buf_size=0;

        comp->compr_buf=NULL;

        comp->usecount=0;

        comp->stat_compr_orig_size=0;

        comp->stat_compr_new_size=0;

        comp->stat_compr_blocks=0;

        comp->stat_decompr_blocks=0;

        D1(printk(KERN_DEBUG "Registering JFFS2 compressor \"%s\"\n", comp->name));

        spin_lock(&jffs2_compressor_list_lock);

        list_for_each_entry(this, &jffs2_compressor_list, list) {

                if (this->priority < comp->priority) {

                        list_add(&comp->list, this->list.prev);

                        goto out;

                }

        }

        list_add_tail(&comp->list, &jffs2_compressor_list);

out:

        D2(list_for_each_entry(this, &jffs2_compressor_list, list) {

                printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);

        })

        spin_unlock(&jffs2_compressor_list_lock);

        return 0;

}

int jffs2_unregister_compressor(struct jffs2_compressor *comp)

{

        D2(struct jffs2_compressor *this;)

        D1(printk(KERN_DEBUG "Unregistering JFFS2 compressor \"%s\"\n", comp->name));

        spin_lock(&jffs2_compressor_list_lock);

        if (comp->usecount) {

                spin_unlock(&jffs2_compressor_list_lock);

                printk(KERN_WARNING "JFFS2: Compressor modul is in use. Unregister failed.\n");

                return -1;

        }

        list_del(&comp->list);

        D2(list_for_each_entry(this, &jffs2_compressor_list, list) {

                printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);

        })

        spin_unlock(&jffs2_compressor_list_lock);

        return 0;

}

#ifdef CONFIG_JFFS2_PROC

#define JFFS2_STAT_BUF_SIZE 16000

char *jffs2_list_compressors(void)

{

        struct jffs2_compressor *this;

        char *buf, *act_buf;

        act_buf = buf = kmalloc(JFFS2_STAT_BUF_SIZE,GFP_KERNEL);

        list_for_each_entry(this, &jffs2_compressor_list, list) {

                act_buf += sprintf(act_buf, "%10s priority:%d ", this->name, this->priority);

                if ((this->disabled)||(!this->compress))

                        act_buf += sprintf(act_buf,"disabled");

                else

                        act_buf += sprintf(act_buf,"enabled");

                act_buf += sprintf(act_buf,"\n");

        }

        return buf;

}

char *jffs2_stats(void)

{

        struct jffs2_compressor *this;

        char *buf, *act_buf;

        act_buf = buf = kmalloc(JFFS2_STAT_BUF_SIZE,GFP_KERNEL);

        act_buf += sprintf(act_buf,"JFFS2 compressor statistics:\n");

        act_buf += sprintf(act_buf,"%10s   ","none");

        act_buf += sprintf(act_buf,"compr: %d blocks (%d)  decompr: %d blocks\n", none_stat_compr_blocks,

                           none_stat_compr_size, none_stat_decompr_blocks);

        spin_lock(&jffs2_compressor_list_lock);

        list_for_each_entry(this, &jffs2_compressor_list, list) {

                act_buf += sprintf(act_buf,"%10s ",this->name);

                if ((this->disabled)||(!this->compress))

                        act_buf += sprintf(act_buf,"- ");

                else

                        act_buf += sprintf(act_buf,"+ ");

                act_buf += sprintf(act_buf,"compr: %d blocks (%d/%d)  decompr: %d blocks ", this->stat_compr_blocks,

                                   this->stat_compr_new_size, this->stat_compr_orig_size,

                                   this->stat_decompr_blocks);

                act_buf += sprintf(act_buf,"\n");

        }

        spin_unlock(&jffs2_compressor_list_lock);

        return buf;

}

char *jffs2_get_compression_mode_name(void)

{

        switch (jffs2_compression_mode) {

        case JFFS2_COMPR_MODE_NONE:

                return "none";

        case JFFS2_COMPR_MODE_PRIORITY:

                return "priority";

        case JFFS2_COMPR_MODE_SIZE:

                return "size";

        }

        return "unkown";

}

int jffs2_set_compression_mode_name(const char *name)

{

        if (!strcmp("none",name)) {

                jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;

                return 0;

        }

        if (!strcmp("priority",name)) {

                jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;

                return 0;

        }

        if (!strcmp("size",name)) {

                jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;

                return 0;

        }

        return 1;

}

static int jffs2_compressor_Xable(const char *name, int disabled)

{

        struct jffs2_compressor *this;

        spin_lock(&jffs2_compressor_list_lock);

        list_for_each_entry(this, &jffs2_compressor_list, list) {

                if (!strcmp(this->name, name)) {

                        this->disabled = disabled;

                        spin_unlock(&jffs2_compressor_list_lock);

                        return 0;

                }

        }

        spin_unlock(&jffs2_compressor_list_lock);

        printk(KERN_WARNING "JFFS2: compressor %s not found.\n",name);

        return 1;

}

int jffs2_enable_compressor_name(const char *name)

{

        return jffs2_compressor_Xable(name, 0);

}

int jffs2_disable_compressor_name(const char *name)

{

        return jffs2_compressor_Xable(name, 1);

}

int jffs2_set_compressor_priority(const char *name, int priority)

{

        struct jffs2_compressor *this,*comp;

        spin_lock(&jffs2_compressor_list_lock);

        list_for_each_entry(this, &jffs2_compressor_list, list) {

                if (!strcmp(this->name, name)) {

                        this->priority = priority;

                        comp = this;

                        goto reinsert;

                }

        }

        spin_unlock(&jffs2_compressor_list_lock);

        printk(KERN_WARNING "JFFS2: compressor %s not found.\n",name);

        return 1;

reinsert:

        /* list is sorted in the order of priority, so if

           we change it we have to reinsert it into the

           good place */

        list_del(&comp->list);

        list_for_each_entry(this, &jffs2_compressor_list, list) {

                if (this->priority < comp->priority) {

                        list_add(&comp->list, this->list.prev);

                        spin_unlock(&jffs2_compressor_list_lock);

                        return 0;

                }

        }

        list_add_tail(&comp->list, &jffs2_compressor_list);

        spin_unlock(&jffs2_compressor_list_lock);

        return 0;

}

#endif

void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig)

{

        if (orig != comprbuf)

                kfree(comprbuf);

}

int jffs2_compressors_init(void)

{

/* Registering compressors */

#ifdef CONFIG_JFFS2_ZLIB

        jffs2_zlib_init();

#endif

#ifdef CONFIG_JFFS2_RTIME

        jffs2_rtime_init();

#endif

#ifdef CONFIG_JFFS2_RUBIN

        jffs2_rubinmips_init();

        jffs2_dynrubin_init();

#endif

/* Setting default compression mode */

#ifdef CONFIG_JFFS2_CMODE_NONE

        jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;

        D1(printk(KERN_INFO "JFFS2: default compression mode: none\n");)

#else

#ifdef CONFIG_JFFS2_CMODE_SIZE

        jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;

        D1(printk(KERN_INFO "JFFS2: default compression mode: size\n");)

#else

        D1(printk(KERN_INFO "JFFS2: default compression mode: priority\n");)

#endif

#endif

        return 0;

}

int jffs2_compressors_exit(void)

{

/* Unregistering compressors */

#ifdef CONFIG_JFFS2_RUBIN

        jffs2_dynrubin_exit();

        jffs2_rubinmips_exit();

#endif

#ifdef CONFIG_JFFS2_RTIME

        jffs2_rtime_exit();

#endif

#ifdef CONFIG_JFFS2_ZLIB

        jffs2_zlib_exit();

#endif

        return 0;

}