input.c

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/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2014 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 <config.h>
#include <string.h>
#include <errno.h>
#include <glib.h>
#include <glib/gstdio.h>
#include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h"

/** @cond PRIVATE */
#define LOG_PREFIX "input"
/** @endcond */

/** @cond PRIVATE */
#define CHUNK_SIZE      (4 * 1024 * 1024)
/** @endcond */

/**
 * @file
 *
 * Input module handling.
 */

/**
 * @defgroup grp_input Input modules
 *
 * Input file/data module handling.
 *
 * libsigrok can process acquisition data in several different ways.
 * Aside from acquiring data from a hardware device, it can also take it
 * from a file in various formats (binary, CSV, VCD, and so on).
 *
 * Like all libsigrok data handling, processing is done in a streaming
 * manner: input should be supplied a chunk at a time. This way anything
 * that processes data can do so in real time, without the user having
 * to wait for the whole thing to be finished.
 *
 * Every input module is "pluggable", meaning it's handled as being separate
 * from the main libsigrok, but linked in to it statically. To keep things
 * modular and separate like this, functions within an input module should be
 * declared static, with only the respective 'struct sr_input_module' being
 * exported for use into the wider libsigrok namespace.
 *
 * @{
 */

/** @cond PRIVATE */
extern SR_PRIV struct sr_input_module input_binary;
extern SR_PRIV struct sr_input_module input_chronovu_la8;
extern SR_PRIV struct sr_input_module input_csv;
extern SR_PRIV struct sr_input_module input_logicport;
extern SR_PRIV struct sr_input_module input_null;
extern SR_PRIV struct sr_input_module input_protocoldata;
extern SR_PRIV struct sr_input_module input_raw_analog;
extern SR_PRIV struct sr_input_module input_saleae;
extern SR_PRIV struct sr_input_module input_stf;
extern SR_PRIV struct sr_input_module input_trace32_ad;
extern SR_PRIV struct sr_input_module input_vcd;
extern SR_PRIV struct sr_input_module input_wav;
/** @endcond */

static const struct sr_input_module *input_module_list[] = {
        &input_binary,
        &input_chronovu_la8,
        &input_csv,
        &input_logicport,
        &input_null,
        &input_protocoldata,
        &input_raw_analog,
        &input_saleae,
#if defined HAVE_INPUT_STF && HAVE_INPUT_STF
        &input_stf,
#endif
        &input_trace32_ad,
        &input_vcd,
        &input_wav,
        NULL,
};

/**
 * Returns a NULL-terminated list of all available input modules.
 *
 * @since 0.4.0
 */
SR_API const struct sr_input_module **sr_input_list(void)
{
        return input_module_list;
}

/**
 * Returns the specified input module's ID.
 *
 * @since 0.4.0
 */
SR_API const char *sr_input_id_get(const struct sr_input_module *imod)
{
        if (!imod) {
                sr_err("Invalid input module NULL!");
                return NULL;
        }

        return imod->id;
}

/**
 * Returns the specified input module's name.
 *
 * @since 0.4.0
 */
SR_API const char *sr_input_name_get(const struct sr_input_module *imod)
{
        if (!imod) {
                sr_err("Invalid input module NULL!");
                return NULL;
        }

        return imod->name;
}

/**
 * Returns the specified input module's description.
 *
 * @since 0.4.0
 */
SR_API const char *sr_input_description_get(const struct sr_input_module *imod)
{
        if (!imod) {
                sr_err("Invalid input module NULL!");
                return NULL;
        }

        return imod->desc;
}

/**
 * Returns the specified input module's file extensions typical for the file
 * format, as a NULL terminated array, or returns a NULL pointer if there is
 * no preferred extension.
 * @note these are a suggestions only.
 *
 * @since 0.4.0
 */
SR_API const char *const *sr_input_extensions_get(
                const struct sr_input_module *imod)
{
        if (!imod) {
                sr_err("Invalid input module NULL!");
                return NULL;
        }

        return imod->exts;
}

/**
 * Return the input module with the specified ID, or NULL if no module
 * with that id is found.
 *
 * @since 0.4.0
 */
SR_API const struct sr_input_module *sr_input_find(const char *id)
{
        int i;

        for (i = 0; input_module_list[i]; i++) {
                if (!strcmp(input_module_list[i]->id, id))
                        return input_module_list[i];
        }

        return NULL;
}

/**
 * Returns a NULL-terminated array of struct sr_option, or NULL if the
 * module takes no options.
 *
 * Each call to this function must be followed by a call to
 * sr_input_options_free().
 *
 * @since 0.4.0
 */
SR_API const struct sr_option **sr_input_options_get(const struct sr_input_module *imod)
{
        const struct sr_option *mod_opts, **opts;
        int size, i;

        if (!imod || !imod->options)
                return NULL;

        mod_opts = imod->options();

        for (size = 0; mod_opts[size].id; size++)
                ;
        opts = g_malloc((size + 1) * sizeof(struct sr_option *));

        for (i = 0; i < size; i++)
                opts[i] = &mod_opts[i];
        opts[i] = NULL;

        return opts;
}

/**
 * After a call to sr_input_options_get(), this function cleans up all
 * resources returned by that call.
 *
 * @since 0.4.0
 */
SR_API void sr_input_options_free(const struct sr_option **options)
{
        int i;

        if (!options)
                return;

        for (i = 0; options[i]; i++) {
                if (options[i]->def) {
                        g_variant_unref(options[i]->def);
                        ((struct sr_option *)options[i])->def = NULL;
                }

                if (options[i]->values) {
                        g_slist_free_full(options[i]->values, (GDestroyNotify)g_variant_unref);
                        ((struct sr_option *)options[i])->values = NULL;
                }
        }
        g_free(options);
}

/**
 * Create a new input instance using the specified input module.
 *
 * This function is used when a client wants to use a specific input
 * module to parse a stream. No effort is made to identify the format.
 *
 * @param imod The input module to use. Must not be NULL.
 * @param options GHashTable consisting of keys corresponding with
 * the module options @c id field. The values should be GVariant
 * pointers with sunk references, of the same GVariantType as the option's
 * default value.
 *
 * @since 0.4.0
 */
SR_API struct sr_input *sr_input_new(const struct sr_input_module *imod,
                GHashTable *options)
{
        struct sr_input *in;
        const struct sr_option *mod_opts;
        const GVariantType *gvt;
        GHashTable *new_opts;
        GHashTableIter iter;
        gpointer key, value;
        int i;

        in = g_malloc0(sizeof(struct sr_input));
        in->module = imod;

        new_opts = g_hash_table_new_full(g_str_hash, g_str_equal, g_free,
                        (GDestroyNotify)g_variant_unref);
        if (imod->options) {
                mod_opts = imod->options();
                for (i = 0; mod_opts[i].id; i++) {
                        if (options && g_hash_table_lookup_extended(options,
                                        mod_opts[i].id, &key, &value)) {
                                /* Option not given: insert the default value. */
                                gvt = g_variant_get_type(mod_opts[i].def);
                                if (!g_variant_is_of_type(value, gvt)) {
                                        sr_err("Invalid type for '%s' option.",
                                                (char *)key);
                                        g_free(in);
                                        return NULL;
                                }
                                g_hash_table_insert(new_opts, g_strdup(mod_opts[i].id),
                                                g_variant_ref(value));
                        } else {
                                /* Pass option along. */
                                g_hash_table_insert(new_opts, g_strdup(mod_opts[i].id),
                                                g_variant_ref(mod_opts[i].def));
                        }
                }

                /* Make sure no invalid options were given. */
                if (options) {
                        g_hash_table_iter_init(&iter, options);
                        while (g_hash_table_iter_next(&iter, &key, &value)) {
                                if (!g_hash_table_lookup(new_opts, key)) {
                                        sr_err("Input module '%s' has no option '%s'",
                                                imod->id, (char *)key);
                                        g_hash_table_destroy(new_opts);
                                        g_free(in);
                                        return NULL;
                                }
                        }
                }
        }

        if (in->module->init && in->module->init(in, new_opts) != SR_OK) {
                g_free(in);
                in = NULL;
        } else {
                in->buf = g_string_sized_new(128);
        }

        if (new_opts)
                g_hash_table_destroy(new_opts);

        return in;
}

/* Returns TRUE if all required meta items are available. */
static gboolean check_required_metadata(const uint8_t *metadata, uint8_t *avail)
{
        int m, a;
        uint8_t reqd;

        for (m = 0; metadata[m]; m++) {
                if (!(metadata[m] & SR_INPUT_META_REQUIRED))
                        continue;
                reqd = metadata[m] & ~SR_INPUT_META_REQUIRED;
                for (a = 0; avail[a]; a++) {
                        if (avail[a] == reqd)
                                break;
                }
                if (!avail[a])
                        /* Found a required meta item that isn't available. */
                        return FALSE;
        }

        return TRUE;
}

/**
 * Try to find an input module that can parse the given buffer.
 *
 * The buffer must contain enough of the beginning of the file for
 * the input modules to find a match. This is format-dependent. When
 * magic strings get checked, 128 bytes normally could be enough. Note
 * that some formats try to parse larger header sections, and benefit
 * from seeing a larger scope.
 *
 * If an input module is found, an instance is created into *in.
 * Otherwise, *in contains NULL. When multiple input moduless claim
 * support for the format, the one with highest confidence takes
 * precedence. Applications will see at most one input module spec.
 *
 * If an instance is created, it has the given buffer used for scanning
 * already submitted to it, to be processed before more data is sent.
 * This allows a frontend to submit an initial chunk of a non-seekable
 * stream, such as stdin, without having to keep it around and submit
 * it again later.
 *
 */
SR_API int sr_input_scan_buffer(GString *buf, const struct sr_input **in)
{
        const struct sr_input_module *imod, *best_imod;
        GHashTable *meta;
        unsigned int m, i;
        unsigned int conf, best_conf;
        int ret;
        uint8_t mitem, avail_metadata[8];

        /* No more metadata to be had from a buffer. */
        avail_metadata[0] = SR_INPUT_META_HEADER;
        avail_metadata[1] = 0;

        *in = NULL;
        best_imod = NULL;
        best_conf = ~0;
        for (i = 0; input_module_list[i]; i++) {
                imod = input_module_list[i];
                if (!imod->metadata[0]) {
                        /* Module has no metadata for matching so will take
                         * any input. No point in letting it try to match. */
                        continue;
                }
                if (!check_required_metadata(imod->metadata, avail_metadata))
                        /* Cannot satisfy this module's requirements. */
                        continue;

                meta = g_hash_table_new(NULL, NULL);
                for (m = 0; m < sizeof(imod->metadata); m++) {
                        mitem = imod->metadata[m] & ~SR_INPUT_META_REQUIRED;
                        if (mitem == SR_INPUT_META_HEADER)
                                g_hash_table_insert(meta, GINT_TO_POINTER(mitem), buf);
                }
                if (g_hash_table_size(meta) == 0) {
                        /* No metadata for this module, so nothing to match. */
                        g_hash_table_destroy(meta);
                        continue;
                }
                sr_spew("Trying module %s.", imod->id);
                ret = imod->format_match(meta, &conf);
                g_hash_table_destroy(meta);
                if (ret == SR_ERR_DATA) {
                        /* Module recognized this buffer, but cannot handle it. */
                        continue;
                } else if (ret == SR_ERR) {
                        /* Module didn't recognize this buffer. */
                        continue;
                } else if (ret != SR_OK) {
                        /* Can be SR_ERR_NA. */
                        continue;
                }

                /* Found a matching module. */
                sr_spew("Module %s matched, confidence %u.", imod->id, conf);
                if (conf >= best_conf)
                        continue;
                best_imod = imod;
                best_conf = conf;
        }

        if (best_imod) {
                *in = sr_input_new(best_imod, NULL);
                g_string_insert_len((*in)->buf, 0, buf->str, buf->len);
                return SR_OK;
        }

        return SR_ERR;
}

/**
 * Try to find an input module that can parse the given file.
 *
 * If an input module is found, an instance is created into *in.
 * Otherwise, *in contains NULL. When multiple input moduless claim
 * support for the format, the one with highest confidence takes
 * precedence. Applications will see at most one input module spec.
 *
 */
SR_API int sr_input_scan_file(const char *filename, const struct sr_input **in)
{
        int64_t filesize;
        FILE *stream;
        const struct sr_input_module *imod, *best_imod;
        GHashTable *meta;
        GString *header;
        size_t count;
        unsigned int midx, i;
        unsigned int conf, best_conf;
        int ret;
        uint8_t avail_metadata[8];

        *in = NULL;

        if (!filename || !filename[0]) {
                sr_err("Invalid filename.");
                return SR_ERR_ARG;
        }
        stream = g_fopen(filename, "rb");
        if (!stream) {
                sr_err("Failed to open %s: %s", filename, g_strerror(errno));
                return SR_ERR;
        }
        filesize = sr_file_get_size(stream);
        if (filesize < 0) {
                sr_err("Failed to get size of %s: %s",
                        filename, g_strerror(errno));
                fclose(stream);
                return SR_ERR;
        }
        header = g_string_sized_new(CHUNK_SIZE);
        count = fread(header->str, 1, header->allocated_len - 1, stream);
        if (count < 1 || ferror(stream)) {
                sr_err("Failed to read %s: %s", filename, g_strerror(errno));
                fclose(stream);
                g_string_free(header, TRUE);
                return SR_ERR;
        }
        fclose(stream);
        g_string_set_size(header, count);

        meta = g_hash_table_new(NULL, NULL);
        g_hash_table_insert(meta, GINT_TO_POINTER(SR_INPUT_META_FILENAME),
                        (char *)filename);
        g_hash_table_insert(meta, GINT_TO_POINTER(SR_INPUT_META_FILESIZE),
                        GSIZE_TO_POINTER(MIN(filesize, G_MAXSSIZE)));
        g_hash_table_insert(meta, GINT_TO_POINTER(SR_INPUT_META_HEADER),
                        header);
        midx = 0;
        avail_metadata[midx++] = SR_INPUT_META_FILENAME;
        avail_metadata[midx++] = SR_INPUT_META_FILESIZE;
        avail_metadata[midx++] = SR_INPUT_META_HEADER;
        avail_metadata[midx] = 0;
        /* TODO: MIME type */

        best_imod = NULL;
        best_conf = ~0;
        for (i = 0; input_module_list[i]; i++) {
                imod = input_module_list[i];
                if (!imod->metadata[0]) {
                        /* Module has no metadata for matching so will take
                         * any input. No point in letting it try to match. */
                        continue;
                }
                if (!check_required_metadata(imod->metadata, avail_metadata))
                        /* Cannot satisfy this module's requirements. */
                        continue;

                sr_dbg("Trying module %s.", imod->id);

                ret = imod->format_match(meta, &conf);
                if (ret == SR_ERR) {
                        /* Module didn't recognize this buffer. */
                        continue;
                } else if (ret != SR_OK) {
                        /* Module recognized this buffer, but cannot handle it. */
                        continue;
                }
                /* Found a matching module. */
                sr_dbg("Module %s matched, confidence %u.", imod->id, conf);
                if (conf >= best_conf)
                        continue;
                best_imod = imod;
                best_conf = conf;
        }
        g_hash_table_destroy(meta);
        g_string_free(header, TRUE);

        if (best_imod) {
                *in = sr_input_new(best_imod, NULL);
                return SR_OK;
        }

        return SR_ERR;
}

/**
 * Return the input instance's module "class". This can be used to find out
 * which input module handles a specific input file. This is especially
 * useful when an application did not create the input stream by specifying
 * an input module, but instead some shortcut or convenience wrapper did.
 *
 * @since 0.6.0
 */
SR_API const struct sr_input_module *sr_input_module_get(const struct sr_input *in)
{
        if (!in)
                return NULL;

        return in->module;
}

/**
 * Return the input instance's (virtual) device instance. This can be
 * used to find out the number of channels and other information.
 *
 * If the device instance has not yet been fully populated by the input
 * module, NULL is returned. This indicates the module needs more data
 * to identify the number of channels and so on.
 *
 * @since 0.4.0
 */
SR_API struct sr_dev_inst *sr_input_dev_inst_get(const struct sr_input *in)
{
        if (in->sdi_ready)
                return in->sdi;
        else
                return NULL;
}

/**
 * Send data to the specified input instance.
 *
 * When an input module instance is created with sr_input_new(), this
 * function is used to feed data to the instance.
 *
 * As enough data gets fed into this function to completely populate
 * the device instance associated with this input instance, this is
 * guaranteed to return the moment it's ready. This gives the caller
 * the chance to examine the device instance, attach session callbacks
 * and so on.
 *
 * @since 0.4.0
 */
SR_API int sr_input_send(const struct sr_input *in, GString *buf)
{
        size_t len;

        len = buf ? buf->len : 0;
        sr_spew("Sending %zu bytes to %s module.", len, in->module->id);
        return in->module->receive((struct sr_input *)in, buf);
}

/**
 * Signal the input module no more data will come.
 *
 * This will cause the module to process any data it may have buffered.
 * The SR_DF_END packet will also typically be sent at this time.
 *
 * @since 0.4.0
 */
SR_API int sr_input_end(const struct sr_input *in)
{
        sr_spew("Calling end() on %s module.", in->module->id);
        return in->module->end((struct sr_input *)in);
}

/**
 * Reset the input module's input handling structures.
 *
 * Causes the input module to reset its internal state so that we can re-send
 * the input data from the beginning without having to re-create the entire
 * input module.
 *
 * @since 0.5.0
 */
SR_API int sr_input_reset(const struct sr_input *in_ro)
{
        struct sr_input *in;
        int rc;

        in = (struct sr_input *)in_ro;  /* "un-const" */
        if (!in || !in->module)
                return SR_ERR_ARG;

        /*
         * Run the optional input module's .reset() method. This shall
         * take care of the context (kept in the 'inc' variable).
         */
        if (in->module->reset) {
                sr_spew("Resetting %s module.", in->module->id);
                rc = in->module->reset(in);
        } else {
                sr_spew("Tried to reset %s module but no reset handler found.",
                        in->module->id);
                rc = SR_OK;
        }

        /*
         * Handle input module status (kept in the 'in' variable) here
         * in common logic. This agrees with how input module's receive()
         * and end() routines "amend but never seed" the 'in' information.
         *
         * Void potentially accumulated receive() buffer content, and
         * clear the sdi_ready flag. This makes sure that subsequent
         * processing will scan the header again before sample data gets
         * interpreted, and stale content from previous calls won't affect
         * the result.
         *
         * This common logic does not harm when the input module implements
         * .reset() and contains identical assignments. In the absence of
         * an individual .reset() method, simple input modules can completely
         * rely on common code and keep working across resets.
         */
        if (in->buf)
                g_string_truncate(in->buf, 0);
        in->sdi_ready = FALSE;

        return rc;
}

/**
 * Free the specified input instance and all associated resources.
 *
 * @since 0.4.0
 */
SR_API void sr_input_free(const struct sr_input *in)
{
        if (!in)
                return;

        /*
         * Run the input module's optional .cleanup() routine. This
         * takes care of the context (kept in the 'inc' variable).
         */
        if (in->module->cleanup)
                in->module->cleanup((struct sr_input *)in);

        /*
         * Common code releases the input module's state (kept in the
         * 'in' variable). Release the device instance, the receive()
         * buffer, the shallow 'in->priv' block which is 'inc' (after
         * .cleanup() released potentially nested resources under 'inc').
         */
        sr_dev_inst_free(in->sdi);
        if (in->buf->len > 64) {
                /* That seems more than just some sub-unitsize leftover... */
                sr_warn("Found %" G_GSIZE_FORMAT
                        " unprocessed bytes at free time.", in->buf->len);
        }
        g_string_free(in->buf, TRUE);
        g_free(in->priv);
        g_free((gpointer)in);
}

/** @} */