/*
* This file is part of the sigrok project.
*
- * Copyright (C) 2010 Bert Vermeulen <bert@biot.com>
+ * 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
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
-#include <sigrok.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.
*/
-int filter_probes(int in_unitsize, int out_unitsize, int *probelist,
- const char *data_in, uint64_t length_in, char **data_out,
- uint64_t *length_out)
+SR_API 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)
{
unsigned int in_offset, out_offset;
int num_enabled_probes, out_bit, i;
uint64_t sample_in, sample_out;
- if (!(*data_out = malloc(length_in)))
- return SR_ERR_MALLOC;
+ 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);
projects / libsigrok.git / blobdiff