libsigrok/datastore.c

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/*
* This file is part of the sigrok project.
*
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* Copyright (C) 2010-2012 Bert Vermeulen <bert@biot.com>
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <glib.h>
#include "libsigrok.h"
#include "libsigrok-internal.h"
/**
* @file
*
* Creating, using, or destroying libsigrok datastores.
*/
/**
* @defgroup grp_datastore Datastore
*
* Creating, using, or destroying libsigrok datastores.
*
* @{
*/
static gpointer new_chunk(struct sr_datastore **ds);
/**
* Create a new datastore with the specified unit size.
*
* The unit size is fixed once the datastore is created, and cannot be
* changed later on, neither can data be added to the datastore with
* different unit sizes later.
*
* It is the caller's responsibility to free the allocated memory of the
* datastore via the sr_datastore_destroy() function, if no longer needed.
*
* @todo Unitsize should probably be unsigned int or uint32_t or similar.
* @todo This function should have a 'chunksize' parameter, and
* struct sr_datastore a 'chunksize' field.
*
* @param unitsize The unit size (>= 1) to be used for this datastore.
* @param ds Pointer to a variable which will hold the newly created
* datastore structure.
*
* @return SR_OK upon success, SR_ERR_MALLOC upon memory allocation errors,
* or SR_ERR_ARG upon invalid arguments. If something other than SR_OK
* is returned, the value of 'ds' is undefined.
*/
SR_API int sr_datastore_new(int unitsize, struct sr_datastore **ds)
{
if (!ds) {
sr_err("ds: %s: ds was NULL", __func__);
return SR_ERR_ARG;
}
if (unitsize <= 0) {
sr_err("ds: %s: unitsize was %d, but it must be >= 1",
__func__, unitsize);
return SR_ERR_ARG;
}
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if (!(*ds = g_try_malloc(sizeof(struct sr_datastore)))) {
sr_err("ds: %s: ds malloc failed", __func__);
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return SR_ERR_MALLOC;
}
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(*ds)->ds_unitsize = unitsize;
(*ds)->num_units = 0;
(*ds)->chunklist = NULL;
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return SR_OK;
}
/**
* Destroy the specified datastore and free the memory used by it.
*
* This will free the memory used by the data in the datastore's 'chunklist',
* by the chunklist data structure itself, and by the datastore struct.
*
* @param ds The datastore to destroy.
*
* @return SR_OK upon success, SR_ERR_ARG upon invalid arguments.
*/
SR_API int sr_datastore_destroy(struct sr_datastore *ds)
{
GSList *chunk;
if (!ds) {
sr_err("ds: %s: ds was NULL", __func__);
return SR_ERR_ARG;
}
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for (chunk = ds->chunklist; chunk; chunk = chunk->next)
g_free(chunk->data);
g_slist_free(ds->chunklist);
g_free(ds);
ds = NULL;
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return SR_OK;
}
/**
* Append some data to the specified datastore.
*
* @todo More elaborate function description.
* @todo This function should use the (not yet available) 'chunksize' field
* of struct sr_datastore (instead of hardcoding DATASTORE_CHUNKSIZE).
* @todo in_unitsize and probelist are unused?
* @todo A few of the parameters can be const.
* @todo Ideally, 'ds' should be unmodified upon errors.
* @todo Should 0 be allowed as length?
* @todo Specify/document the data format of the 'data' parameter.
*
* @param ds Pointer to the datastore which shall receive the data.
* Must not be NULL.
* @param data Pointer to the memory buffer containing the data to add.
* Must not be NULL.
* @param length Length of the data to add (in number of bytes).
* @param in_unitsize The unit size (>= 1) of the input data.
* @param probelist Pointer to a list of integers (probe numbers). The probe
* numbers in this list are 1-based, i.e. the first probe
* is expected to be numbered 1 (not 0!). Must not be NULL.
*
* @return SR_OK upon success, SR_ERR_MALLOC upon memory allocation errors,
* or SR_ERR_ARG upon invalid arguments. If something other than SR_OK
* is returned, the value/state of 'ds' is undefined.
*/
SR_API int sr_datastore_put(struct sr_datastore *ds, void *data,
unsigned int length, int in_unitsize, const int *probelist)
{
unsigned int stored;
int capacity, size, num_chunks, chunk_bytes_free, chunk_offset;
gpointer chunk;
if (!ds) {
sr_err("ds: %s: ds was NULL", __func__);
return SR_ERR_ARG;
}
/* Unitsize must not be 0, we'll divide by 0 otherwise. */
if (ds->ds_unitsize == 0) {
sr_err("ds: %s: ds->ds_unitsize was 0", __func__);
return SR_ERR_ARG;
}
if (!data) {
sr_err("ds: %s: data was NULL", __func__);
return SR_ERR_ARG;
}
if (in_unitsize < 1) {
sr_err("ds: %s: in_unitsize was %d, but it must be >= 1",
__func__, in_unitsize);
return SR_ERR_ARG;
}
if (!probelist) {
sr_err("ds: %s: probelist was NULL", __func__);
return SR_ERR_ARG;
}
/* Get the last chunk in the list, or create a new one if needed. */
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if (ds->chunklist == NULL) {
if (!(chunk = new_chunk(&ds))) {
sr_err("ds: %s: couldn't allocate new chunk", __func__);
return SR_ERR_MALLOC;
}
} else {
chunk = g_slist_last(ds->chunklist)->data;
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}
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/* Get/calculate number of chunks, free space, etc. */
num_chunks = g_slist_length(ds->chunklist);
capacity = (num_chunks * DATASTORE_CHUNKSIZE);
chunk_bytes_free = capacity - (ds->ds_unitsize * ds->num_units);
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chunk_offset = capacity - (DATASTORE_CHUNKSIZE * (num_chunks - 1))
- chunk_bytes_free;
stored = 0;
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while (stored < length) {
/* No more free space left, allocate a new chunk. */
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if (chunk_bytes_free == 0) {
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if (!(chunk = new_chunk(&ds))) {
sr_err("ds: %s: couldn't allocate new chunk",
__func__);
return SR_ERR_MALLOC;
}
chunk_bytes_free = DATASTORE_CHUNKSIZE;
chunk_offset = 0;
}
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if (length - stored > (unsigned int)chunk_bytes_free)
size = chunk_bytes_free;
else
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/* Last part, won't fill up this chunk. */
size = length - stored;
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memcpy(chunk + chunk_offset, data + stored, size);
chunk_bytes_free -= size;
stored += size;
}
ds->num_units += stored / ds->ds_unitsize;
return SR_OK;
}
/**
* Allocate a new memory chunk, append it to the datastore's chunklist.
*
* The newly allocated chunk is added to the datastore's chunklist by this
* function, and the return value additionally points to the new chunk.
*
* The allocated memory is guaranteed to be cleared.
*
* @todo This function should use the datastore's 'chunksize' field instead
* of hardcoding DATASTORE_CHUNKSIZE.
* @todo Return int, so we can return SR_OK / SR_ERR_ARG / SR_ERR_MALLOC?
*
* @param ds Pointer to a variable which holds the datastore structure.
* Must not be NULL. The contents of 'ds' are modified in-place.
*
* @return Pointer to the newly allocated chunk, or NULL upon failure.
*/
static gpointer new_chunk(struct sr_datastore **ds)
{
gpointer chunk;
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/* Note: Caller checked that ds != NULL. */
chunk = g_try_malloc0(DATASTORE_CHUNKSIZE * (*ds)->ds_unitsize);
if (!chunk) {
sr_err("ds: %s: chunk malloc failed (ds_unitsize was %u)",
__func__, (*ds)->ds_unitsize);
return NULL; /* TODO: SR_ERR_MALLOC later? */
}
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(*ds)->chunklist = g_slist_append((*ds)->chunklist, chunk);
return chunk; /* TODO: SR_OK later? */
}
/** @} */