/* * This file is part of the sigrok project. * * Copyright (C) 2010-2012 Bert Vermeulen * * 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 . */ #include #include #include #include #include "libsigrok.h" #include "libsigrok-internal.h" /* Message logging helpers with driver-specific prefix string. */ #define DRIVER_LOG_DOMAIN "filter: " #define sr_log(l, s, args...) sr_log(l, DRIVER_LOG_DOMAIN s, ## args) #define sr_spew(s, args...) sr_spew(DRIVER_LOG_DOMAIN s, ## args) #define sr_dbg(s, args...) sr_dbg(DRIVER_LOG_DOMAIN s, ## args) #define sr_info(s, args...) sr_info(DRIVER_LOG_DOMAIN s, ## args) #define sr_warn(s, args...) sr_warn(DRIVER_LOG_DOMAIN s, ## args) #define sr_err(s, args...) sr_err(DRIVER_LOG_DOMAIN s, ## args) /** * @file * * Helper functions to filter out unused probes from samples. */ /** * @defgroup grp_filter Probe filter * * Helper functions to filter out unused probes from samples. * * @{ */ /** * 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 probe_array Pointer to a list of probe 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 0.1.0 (but the API changed in 0.2.0) */ SR_API int sr_filter_probes(unsigned int in_unitsize, unsigned int out_unitsize, const GArray *probe_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 *probelist, out_bit; unsigned int i; uint64_t sample_in, sample_out; if (!probe_array) { sr_err("%s: probe_array was NULL", __func__); return SR_ERR_ARG; } probelist = (int *)probe_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 probes than the target unit size supports? */ if (probe_array->len > out_unitsize * 8) { sr_err("%s: too many probes (%d) for the target unit " "size (%d)", __func__, probe_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 (probe_array->len == 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; i < probe_array->len; i++) { if (sample_in & (1 << (probelist[i]))) 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; } /** @} */