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Implement function to compute the size needed for RR field.

This commit is contained in:
Vreixo Formoso 2007-12-24 04:31:15 +01:00
parent 9de0be2602
commit d48c553f40
3 changed files with 241 additions and 1 deletions
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4
Makefile.am
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@ -37,7 +37,9 @@ src_libisofs_la_SOURCES = \
src/ecma119_tree.h \ src/ecma119_tree.h \
src/ecma119_tree.c \ src/ecma119_tree.c \
src/writer.h \ src/writer.h \
src/buffer.c src/buffer.c \
src/rockridge.h \
src/rockridge.c
libinclude_HEADERS = \ libinclude_HEADERS = \
src/libisofs.h src/libisofs.h

199
src/rockridge.c Normal file
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@ -0,0 +1,199 @@
/*
* Copyright (c) 2007 Vreixo Formoso
* Copyright (c) 2007 Mario Danic
*
* This file is part of the libisofs project; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation. See COPYING file for details.
*/
#include "rockridge.h"
#include "node.h"
#include "ecma119_tree.h"
#include "error.h"
#include <string.h>
/**
* Compute the length needed for write all RR and SUSP entries for a given
* node.
*
* @param type
* 0 normal entry, 1 "." entry for that node (it is a dir), 2 ".."
* for that node (i.e., it will refer to the parent)
* @param space
* Available space in the System Use Area for the directory record.
* @param ce
* Will be filled with the space needed in a CE
* @return
* The size needed for the RR entries in the System Use Area
*/
size_t rrip_calc_len(Ecma119Image *t, Ecma119Node *n, int type,
size_t space, size_t *ce)
{
size_t su_size;
/* space min is 255 - 33 - 37 = 185 */
/* PX and TF, we are sure they always fit in SUA */
su_size = 44 + 26;
if (n->type == ECMA119_DIR) {
if (n->info.dir.real_parent != NULL) {
/* it is a reallocated entry */
if (type == 2) {
/* we need to add a PL entry */
su_size += 12;
} else if (type == 0) {
/* we need to add a RE entry */
su_size += 4;
}
}
} else if (n->type == ECMA119_SPECIAL) {
if (S_ISBLK(n->node->mode) || S_ISCHR(n->node->mode)) {
/* block or char device, we need a PN entry */
su_size += 20;
}
} else if (n->type == ECMA119_PLACEHOLDER) {
/* we need the CL entry */
su_size += 12;
}
if (type == 0) {
size_t namelen = strlen(n->node->name);
/* NM entry */
if (su_size + 5 + namelen <= space) {
/* ok, it fits in System Use Area */
su_size += 5 + namelen;
} else {
/* the NM will be divided in a CE */
namelen = namelen - (space - su_size - 5 - 28);
*ce = 5 + namelen;
su_size = space;
}
if (n->type == ECMA119_SYMLINK) {
/*
* for symlinks, we also need to write the SL
*/
char *cur, *prev;
size_t sl_len = 5;
int cew = (*ce != 0); /* are we writing to CE? */
prev = ((IsoSymlink*)n->node)->dest;
cur = strchr(prev, '/');
while (1) {
size_t clen;
if (cur) {
clen = cur - prev;
} else {
/* last component */
clen = strlen(prev);
}
if (clen == 1 && prev[0] == '.') {
clen = 0;
} else if (clen == 2 && prev[0] == '.' && prev[1] == '.') {
clen = 0;
}
/* flags and len for each component record (RRIP, 4.1.3.1) */
clen += 2;
if (!cew) {
/* we are still writing to the SUA */
if (su_size + sl_len + clen > space) {
/*
* ok, we need a Continuation Area anyway
* TODO this can be handled better, but for now SL
* will be completelly moved into the CA
*/
if (su_size + 28 <= space) {
/* the CE entry fills without reducing NM */
su_size += 28;
cew = 1;
} else {
/* we need to reduce NM */
*ce = (28 - (space - su_size)) + 5;
su_size = space;
cew = 1;
}
}
} else {
if (sl_len + clen > 255) {
/* we need an addition SL entry */
if (clen > 250) {
/*
* case 1, component too large to fit in a
* single SL entry. Thus, the component need
* to be divided anyway.
* Note than clen can be up to 255 + 2 = 257.
*
* First, we check how many bytes fit in current
* SL field
*/
int fit = 255 - sl_len - 2;
if (clen - 250 <= fit) {
/*
* the component can be divided between this
* and another SL entry
*/
*ce += 255; /* this SL, full */
sl_len = 5 + (clen - fit);
} else {
/*
* the component will need a 2rd SL entry in
* any case, so we prefer to don't write
* anything in this SL
*/
*ce += sl_len + 255;
sl_len = 5 + (clen - 250);
}
} else {
/* case 2, create a new SL entry */
*ce += sl_len;
sl_len = 5 + clen;
}
} else {
sl_len += clen;
}
}
if (!cur || cur[1] == '\0') {
/* cur[1] can be \0 if dest ends with '/' */
break;
}
prev = cur + 1;
cur = strchr(prev, '/');
}
/* and finally write the pending SL field */
if (!cew) {
/* the whole SL fits into the SUA */
su_size += sl_len;
} else {
*ce += sl_len;
}
}
} else {
/* "." or ".." entry */
su_size += 5; /* NM field */
if (type == 1 && n->parent == NULL) {
/*
* "." for root directory
* we need to write SP and ER entries. The first fits in SUA,
* ER needs a Continuation Area, thus we also need a CE entry
*/
su_size += 7 + 28; /* SP + CE */
*ce = 182; /* ER */
}
}
return su_size;
}

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src/rockridge.h Normal file
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/*
* Copyright (c) 2007 Vreixo Formoso
* Copyright (c) 2007 Mario Danic
*
* This file is part of the libisofs project; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation. See COPYING file for details.
*/
/**
* Functions and structures used for Rock Ridge support.
*
* See IEEE P1282, Rock Ridge Interchange Protocol, Draft Standard version
* 1.12 for further details.
*/
#ifndef LIBISO_ROCKRIDGE_H
#define LIBISO_ROCKRIDGE_H
#include "ecma119.h"
/**
* Compute the length needed for write all RR and SUSP entries for a given
* node.
*
* @param type
* 0 normal entry, 1 "." entry for that node (it is a dir), 2 ".."
* for that node (i.e., it will refer to the parent)
* @param space
* Available space in the System Use Area for the directory record.
* @param ce
* Will be filled with the space needed in a CE
* @return
* The size needed for the RR entries in the System Use Area
*/
size_t rrip_calc_len(Ecma119Image *t, Ecma119Node *n, int type,
size_t space, size_t *ce);
#endif /* LIBISO_ROCKRIDGE_H */