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pacman/lib/libalpm/delta.c
Dan McGee 6cf8a5137e libalpm/delta: add const to most methods
Signed-off-by: Dan McGee <dan@archlinux.org>
2007-10-29 01:28:13 -05:00

267 lines
6.2 KiB
C

/*
* delta.c
*
* Copyright (c) 2007 by Judd Vinet <jvinet@zeroflux.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
#include "config.h"
#include <stdlib.h>
#include <string.h>
/* libalpm */
#include "delta.h"
#include "error.h"
#include "util.h"
#include "log.h"
#include "alpm_list.h"
#include "alpm.h"
/** \addtogroup alpm_deltas Delta Functions
* @brief Functions to manipulate libalpm deltas
* @{
*/
const char SYMEXPORT *alpm_delta_get_from(pmdelta_t *delta)
{
ALPM_LOG_FUNC;
/* Sanity checks */
ASSERT(delta != NULL, return(NULL));
return(delta->from);
}
const char SYMEXPORT *alpm_delta_get_to(pmdelta_t *delta)
{
ALPM_LOG_FUNC;
/* Sanity checks */
ASSERT(delta != NULL, return(NULL));
return(delta->to);
}
unsigned long SYMEXPORT alpm_delta_get_size(pmdelta_t *delta)
{
ALPM_LOG_FUNC;
/* Sanity checks */
ASSERT(delta != NULL, return(-1));
return(delta->size);
}
const char SYMEXPORT *alpm_delta_get_filename(pmdelta_t *delta)
{
ALPM_LOG_FUNC;
/* Sanity checks */
ASSERT(delta != NULL, return(NULL));
return(delta->filename);
}
const char SYMEXPORT *alpm_delta_get_md5sum(pmdelta_t *delta)
{
ALPM_LOG_FUNC;
/* Sanity checks */
ASSERT(delta != NULL, return(NULL));
return(delta->md5sum);
}
/** @} */
/** Calculates the combined size of a list of delta files.
*
* @param deltas the list of pmdelta_t * objects
*
* @return the combined size
*/
unsigned long _alpm_delta_path_size(alpm_list_t *deltas)
{
unsigned long sum = 0;
alpm_list_t *dlts = deltas;
while(dlts) {
pmdelta_t *d = (pmdelta_t *)alpm_list_getdata(dlts);
sum += d->size;
dlts = alpm_list_next(dlts);
}
return(sum);
}
/** Calculates the combined size of a list of delta files that are not
* in the cache.
*
* @param deltas the list of pmdelta_t * objects
*
* @return the combined size
*/
unsigned long _alpm_delta_path_size_uncached(alpm_list_t *deltas)
{
unsigned long sum = 0;
alpm_list_t *dlts = deltas;
while(dlts) {
pmdelta_t *d = (pmdelta_t *)alpm_list_getdata(dlts);
char *fname = _alpm_filecache_find(d->filename);
if(!fname) {
sum += d->size;
}
FREE(fname);
dlts = alpm_list_next(dlts);
}
return(sum);
}
/** Calculates the shortest path from one version to another.
*
* The shortest path is defined as the path with the smallest combined
* size, not the length of the path.
*
* The algorithm is based on Dijkstra's shortest path algorithm.
*
* @param deltas the list of pmdelta_t * objects that a package has
* @param from the version to start from
* @param to the version to end at
* @param path the current path
*
* @return the list of pmdelta_t * objects that has the smallest size.
* NULL (the empty list) is returned if there is no path between the
* versions.
*/
static alpm_list_t *shortest_delta_path(alpm_list_t *deltas,
const char *from, const char *to, alpm_list_t *path)
{
alpm_list_t *d;
alpm_list_t *shortest = NULL;
/* Found the 'to' version, this is a good path so return it. */
if(strcmp(from, to) == 0) {
return(path);
}
for(d = deltas; d; d = alpm_list_next(d)) {
pmdelta_t *v = alpm_list_getdata(d);
/* If this vertex has already been visited in the path, go to the
* next vertex. */
if(alpm_list_find(path, v))
continue;
/* Once we find a vertex that starts at the 'from' version,
* recursively find the shortest path using the 'to' version of this
* current vertex as the 'from' version in the function call. */
if(strcmp(v->from, from) == 0) {
alpm_list_t *newpath = alpm_list_copy(path);
alpm_list_free(path);
newpath = alpm_list_add(newpath, v);
newpath = shortest_delta_path(deltas, v->to, to, newpath);
if(newpath != NULL) {
/* The path returned works, now use it unless there is already a
* shorter path found. */
if(shortest == NULL) {
shortest = newpath;
} else if(_alpm_delta_path_size(shortest) > _alpm_delta_path_size(newpath)) {
alpm_list_free(shortest);
shortest = newpath;
} else {
alpm_list_free(newpath);
}
}
}
}
return(shortest);
}
/** Calculates the shortest path from one version to another.
*
* The shortest path is defined as the path with the smallest combined
* size, not the length of the path.
*
* @param deltas the list of pmdelta_t * objects that a package has
* @param from the version to start from
* @param to the version to end at
*
* @return the list of pmdelta_t * objects that has the smallest size.
* NULL (the empty list) is returned if there is no path between the
* versions.
*/
alpm_list_t *_alpm_shortest_delta_path(alpm_list_t *deltas, const char *from,
const char *to)
{
alpm_list_t *path = NULL;
path = shortest_delta_path(deltas, from, to, path);
return(path);
}
/** Parses the string representation of a pmdelta_t object.
*
* This function assumes that the string is in the correct format.
*
* @param line the string to parse
*
* @return A pointer to the new pmdelta_t object
*/
pmdelta_t *_alpm_delta_parse(char *line)
{
pmdelta_t *delta;
char *tmp = line, *tmp2;
CALLOC(delta, 1, sizeof(pmdelta_t), RET_ERR(PM_ERR_MEMORY, NULL));
tmp2 = tmp;
tmp = strchr(tmp, ' ');
*(tmp++) = '\0';
strncpy(delta->from, tmp2, DLT_VERSION_LEN);
tmp2 = tmp;
tmp = strchr(tmp, ' ');
*(tmp++) = '\0';
strncpy(delta->to, tmp2, DLT_VERSION_LEN);
tmp2 = tmp;
tmp = strchr(tmp, ' ');
*(tmp++) = '\0';
delta->size = atol(tmp2);
tmp2 = tmp;
tmp = strchr(tmp, ' ');
*(tmp++) = '\0';
strncpy(delta->filename, tmp2, DLT_FILENAME_LEN);
strncpy(delta->md5sum, tmp, DLT_MD5SUM_LEN);
return(delta);
}
/* vim: set ts=2 sw=2 noet: */