X-Git-Url: https://sigrok.org/gitweb/?p=libsigrok.git;a=blobdiff_plain;f=filter.c;h=8e74b10d0f0f4ae8742b1ea3bba77243eaefc924;hp=5698d333f0eea57de70aa97c5ca5277a1c2f4312;hb=fca75cbb741ae756bf50eaf1cdc6d4d53fcc60cd;hpb=488a13b110d3563194dd63e087e295a4aa114002 diff --git a/filter.c b/filter.c index 5698d333..8e74b10d 100644 --- a/filter.c +++ b/filter.c @@ -1,7 +1,7 @@ /* - * This file is part of the sigrok project. + * This file is part of the libsigrok project. * - * Copyright (C) 2010 Bert Vermeulen + * 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 @@ -20,31 +20,48 @@ #include #include #include -#include -#include "sigrok-internal.h" +#include +#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 probes from samples. + * Remove unused channels from samples. * - * Convert sample from maximum probes -- the way the hardware driver sent + * 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 probes removed. + * unused channels removed. * - * The "unit size" is the number of bytes used to store probe values. + * 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 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. + * 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 probes), but only 2 of them are actually + * 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 probe values in the order specified via the - * probelist. For example, if in_unitsize = 4, probelist = [5, 16, 30], and + * 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 probe 5, bit 1 = value - * of probe 16, bit 2 = value of probe 30. Unused bit(s) in the output byte(s) + * 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 @@ -53,9 +70,11 @@ * * @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). - * @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. + * 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 @@ -69,62 +88,71 @@ * 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 */ -int sr_filter_probes(int in_unitsize, int out_unitsize, const int *probelist, - const unsigned char *data_in, uint64_t length_in, - char **data_out, uint64_t *length_out) +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 num_enabled_probes, out_bit, i; - uint64_t sample_in, sample_out; + int *channellist, out_bit; + unsigned int i; + uint8_t *sample_in, *sample_out; - if (!probelist) { - sr_err("filter: %s: probelist was NULL", __func__); + 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("filter: %s: data_in was NULL", __func__); + sr_err("%s: data_in was NULL", __func__); return SR_ERR_ARG; } if (!data_out) { - sr_err("filter: %s: data_out was NULL", __func__); + sr_err("%s: data_out was NULL", __func__); return SR_ERR_ARG; } if (!length_out) { - sr_err("filter: %s: length_out was NULL", __func__); + 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("filter: %s: data_out malloc failed", __func__); + sr_err("%s: data_out malloc failed", __func__); return SR_ERR_MALLOC; } - num_enabled_probes = 0; - for (i = 0; probelist[i]; i++) - num_enabled_probes++; - - if (num_enabled_probes == in_unitsize * 8) { - /* All probes are used -- no need to compress anything. */ + 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 probes are used, so "compress". */ + /* If we reached this point, not all channels 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); + 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++; } - memcpy((*data_out) + out_offset, &sample_out, out_unitsize); in_offset += in_unitsize; out_offset += out_unitsize; } @@ -132,3 +160,5 @@ int sr_filter_probes(int in_unitsize, int out_unitsize, const int *probelist, return SR_OK; } + +/** @} */