| /* |
| * This file is part of the sigrok 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 "sigrok.h" |
| #include "sigrok-internal.h" |
| |
| /** |
| * Remove unused probes from samples. |
| * |
| * Convert sample from maximum probes -- the way the hardware driver sent |
| * it -- to a sample taking up only as much space as required, with |
| * unused probes removed. |
| * |
| * The "unit size" is the number of bytes used to store probe values. |
| * For example, a unit size of 1 means one byte is used (which can store |
| * 8 probe values, each of them is 1 bit). A unit size of 2 means we can |
| * store 16 probe values, 3 means we can store 24 probe 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 probes), 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 probe values in the order specified via the |
| * probelist. For example, if in_unitsize = 4, probelist = [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 probe 5, bit 1 = value |
| * of probe 16, bit 2 = value of probe 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 |
| * probes in 'probelist'. |
| * @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. |
| * @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. |
| */ |
| SR_API int sr_filter_probes(int in_unitsize, int out_unitsize, |
| const int *probelist, const uint8_t *data_in, |
| uint64_t length_in, uint8_t **data_out, |
| uint64_t *length_out) |
| { |
| unsigned int in_offset, out_offset; |
| int num_enabled_probes, out_bit, i; |
| uint64_t sample_in, sample_out; |
| |
| if (!probelist) { |
| sr_err("filter: %s: probelist was NULL", __func__); |
| return SR_ERR_ARG; |
| } |
| |
| if (!data_in) { |
| sr_err("filter: %s: data_in was NULL", __func__); |
| return SR_ERR_ARG; |
| } |
| |
| if (!data_out) { |
| sr_err("filter: %s: data_out was NULL", __func__); |
| return SR_ERR_ARG; |
| } |
| |
| if (!length_out) { |
| sr_err("filter: %s: length_out was NULL", __func__); |
| return SR_ERR_ARG; |
| } |
| |
| num_enabled_probes = 0; |
| for (i = 0; probelist[i]; i++) |
| num_enabled_probes++; |
| |
| /* Are there more probes than the target unit size supports? */ |
| if (num_enabled_probes > out_unitsize * 8) { |
| sr_err("filter: %s: too many probes (%d) for the target unit " |
| "size (%d)", num_enabled_probes, out_unitsize, __func__); |
| return SR_ERR_ARG; |
| } |
| |
| if (!(*data_out = g_try_malloc(length_in))) { |
| sr_err("filter: %s: data_out malloc failed", __func__); |
| return SR_ERR_MALLOC; |
| } |
| |
| if (num_enabled_probes == in_unitsize * 8) { |
| /* All probes 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 probes are used, so "compress". */ |
| in_offset = out_offset = 0; |
| while (in_offset <= length_in - in_unitsize) { |
| memcpy(&sample_in, data_in + in_offset, in_unitsize); |
| sample_out = out_bit = 0; |
| for (i = 0; probelist[i]; i++) { |
| if (sample_in & (1 << (probelist[i] - 1))) |
| sample_out |= (1 << out_bit); |
| out_bit++; |
| } |
| memcpy((*data_out) + out_offset, &sample_out, out_unitsize); |
| in_offset += in_unitsize; |
| out_offset += out_unitsize; |
| } |
| *length_out = out_offset; |
| |
| return SR_OK; |
| } |