+++ /dev/null
-/*
- * This file is part of the libsigrok project.
- *
- * 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"
-
-#define LOG_PREFIX "filter"
-
-/**
- * @file
- *
- * Helper functions to filter out unused channels from samples.
- */
-
-/**
- * @defgroup grp_filter Channel filter
- *
- * Helper functions to filter out unused channels from samples.
- *
- * @{
- */
-
-/**
- * Remove unused channels from samples.
- *
- * Convert sample from maximum channels -- the way the hardware driver sent
- * it -- to a sample taking up only as much space as required, with
- * unused channels removed.
- *
- * The "unit size" is the number of bytes used to store channel values.
- * For example, a unit size of 1 means one byte is used (which can store
- * 8 channel values, each of them is 1 bit). A unit size of 2 means we can
- * store 16 channel values, 3 means we can store 24 channel values, and so on.
- *
- * If the data coming from the logic analyzer has a unit size of 4 for
- * example (as the device has 32 channels), but only 2 of them are actually
- * used in an acquisition, this function can convert the samples to only
- * use up 1 byte per sample (unit size = 1) instead of 4 bytes per sample.
- *
- * The output will contain the channel values in the order specified via the
- * channellist. For example, if in_unitsize = 4, channellist = [5, 16, 30], and
- * out_unitsize = 1, then the output samples (each of them one byte in size)
- * will have the following format: bit 0 = value of channel 5, bit 1 = value
- * of channel 16, bit 2 = value of channel 30. Unused bit(s) in the output byte(s)
- * are zero.
- *
- * The caller must make sure that length_in is not bigger than the memory
- * actually allocated for the input data (data_in), as this function does
- * not check that.
- *
- * @param in_unitsize The unit size (>= 1) of the input (data_in).
- * @param out_unitsize The unit size (>= 1) the output shall have (data_out).
- * The requested unit size must be big enough to hold as
- * much data as is specified by the number of enabled
- * channels in 'channellist'.
- * @param channel_array Pointer to a list of channel numbers, numbered starting
- * from 0. The list is terminated with -1.
- * @param data_in Pointer to the input data buffer. Must not be NULL.
- * @param length_in The input data length (>= 1), in number of bytes.
- * @param data_out Variable which will point to the newly allocated buffer
- * of output data. The caller is responsible for g_free()'ing
- * the buffer when it's no longer needed. Must not be NULL.
- * @param length_out Pointer to the variable which will contain the output
- * data length (in number of bytes) when the function
- * returns SR_OK. 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 values of
- * out_unitsize, data_out, and length_out are undefined.
- *
- * @since 0.2.0
- */
-SR_API int sr_filter_channels(unsigned int in_unitsize, unsigned int out_unitsize,
- const GArray *channel_array, const uint8_t *data_in,
- uint64_t length_in, uint8_t **data_out,
- uint64_t *length_out)
-{
- unsigned int in_offset, out_offset;
- int *channellist, out_bit;
- unsigned int i;
- uint8_t *sample_in, *sample_out;
-
- if (!channel_array) {
- sr_err("%s: channel_array was NULL", __func__);
- return SR_ERR_ARG;
- }
- channellist = (int *)channel_array->data;
-
- if (!data_in) {
- sr_err("%s: data_in was NULL", __func__);
- return SR_ERR_ARG;
- }
-
- if (!data_out) {
- sr_err("%s: data_out was NULL", __func__);
- return SR_ERR_ARG;
- }
-
- if (!length_out) {
- sr_err("%s: length_out was NULL", __func__);
- return SR_ERR_ARG;
- }
-
- /* Are there more channels than the target unit size supports? */
- if (channel_array->len > out_unitsize * 8) {
- sr_err("%s: too many channels (%d) for the target unit "
- "size (%d)", __func__, channel_array->len, out_unitsize);
- return SR_ERR_ARG;
- }
-
- if (!(*data_out = g_try_malloc(length_in))) {
- sr_err("%s: data_out malloc failed", __func__);
- return SR_ERR_MALLOC;
- }
-
- if (channel_array->len == in_unitsize * 8) {
- /* All channels are used -- no need to compress anything. */
- memcpy(*data_out, data_in, length_in);
- *length_out = length_in;
- return SR_OK;
- }
-
- /* If we reached this point, not all channels are used, so "compress". */
- in_offset = out_offset = 0;
- while (in_offset <= length_in - in_unitsize) {
- sample_in = (uint8_t *)data_in + in_offset;
- sample_out = (*data_out) + out_offset;
- memset(sample_out, 0, out_unitsize);
- out_bit = 0;
- for (i = 0; i < channel_array->len; i++) {
- if (sample_in[channellist[i]>>3] & (1 << (channellist[i]&7)))
- sample_out[out_bit>>3] |= (1 << (out_bit&7));
- out_bit++;
- }
- in_offset += in_unitsize;
- out_offset += out_unitsize;
- }
- *length_out = out_offset;
-
- return SR_OK;
-}
-
-/** @} */
projects / libsigrok.git / commitdiff