]> sigrok.org Git - libsigrok.git/blobdiff - src/input/vcd.c
input/vcd: abort VCD import when timestamp counts backwards
[libsigrok.git] / src / input / vcd.c
index fe9375672d80048e39fb1de6ded1342da45df20a..b9e9497dc8baf07b65370329179a615d2c175531 100644 (file)
@@ -2,6 +2,7 @@
  * This file is part of the libsigrok project.
  *
  * Copyright (C) 2012 Petteri Aimonen <jpa@sr.mail.kapsi.fi>
+ * 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
@@ -25,7 +26,7 @@
  *
  * skip:        Allows skipping until given timestamp in the file.
  *              This can speed up analyzing of long captures.
- *            
+ *
  *              Value < 0: Skip until first timestamp listed in
  *              the file. (default)
  *
  * - more than 64 channels
  */
 
+#include <config.h>
 #include <stdlib.h>
 #include <glib.h>
 #include <stdio.h>
 #include <string.h>
-#include "libsigrok.h"
+#include <libsigrok/libsigrok.h>
 #include "libsigrok-internal.h"
 
 #define LOG_PREFIX "input/vcd"
 
-#define DEFAULT_NUM_CHANNELS 8
-#define CHUNKSIZE 1024
+#define CHUNK_SIZE (4 * 1024 * 1024)
 
 struct context {
+       gboolean started;
+       gboolean got_header;
+       uint64_t prev_timestamp;
        uint64_t samplerate;
-       int maxchannels;
-       int channelcount;
+       unsigned int maxchannels;
+       unsigned int channelcount;
        int downsample;
        unsigned compress;
        int64_t skip;
+       gboolean skip_until_end;
        GSList *channels;
+       size_t bytes_per_sample;
+       size_t samples_in_buffer;
+       uint8_t *buffer;
+       uint8_t *current_levels;
 };
 
 struct vcd_channel {
@@ -83,82 +92,60 @@ struct vcd_channel {
        gchar *identifier;
 };
 
-
-/* Read until specific type of character occurs in file.
- * Skip input if dest is NULL.
- * Modes:
- * 'W' read until whitespace
- * 'N' read until non-whitespace, and ungetc() the character
- * '$' read until $end
- */
-static gboolean read_until(FILE *file, GString *dest, char mode)
-{
-       int  c;
-       char prev[4] = "";
-
-       for(;;) {
-               c = fgetc(file);
-
-               if (c == EOF) {
-                       if (mode == '$')
-                               sr_err("Unexpected EOF.");
-                       return FALSE;
-               }
-
-               if (mode == 'W' && g_ascii_isspace(c))
-                       return TRUE;
-
-               if (mode == 'N' && !g_ascii_isspace(c)) {
-                       ungetc(c, file);
-                       return TRUE;
-               }
-
-               if (mode == '$') {
-                       prev[0] = prev[1]; prev[1] = prev[2]; prev[2] = prev[3]; prev[3] = c;
-                       if (prev[0] == '$' && prev[1] == 'e' && prev[2] == 'n' && prev[3] == 'd') {
-                               if (dest != NULL)
-                                       g_string_truncate(dest, dest->len - 3);
-
-                               return TRUE;
-                       }
-               }
-
-               if (dest != NULL)
-                       g_string_append_c(dest, c);
-       }
-}
-
 /*
- * Reads a single VCD section from input file and parses it to structure.
- * e.g. $timescale 1ps $end  => "timescale" "1ps"
+ * Reads a single VCD section from input file and parses it to name/contents.
+ * e.g. $timescale 1ps $end => "timescale" "1ps"
  */
-static gboolean parse_section(FILE *file, gchar **name, gchar **contents)
+static gboolean parse_section(GString *buf, gchar **name, gchar **contents)
 {
+       GString *sname, *scontent;
        gboolean status;
-       GString *sname, *scontents;
+       unsigned int pos;
+
+       *name = *contents = NULL;
+       status = FALSE;
+       pos = 0;
 
-       /* Skip any initial white-space */
-       if (!read_until(file, NULL, 'N')) return FALSE;
+       /* Skip UTF8 BOM */
+       if (buf->len >= 3 && !strncmp(buf->str, "\xef\xbb\xbf", 3))
+               pos = 3;
+
+       /* Skip any initial white-space. */
+       while (pos < buf->len && g_ascii_isspace(buf->str[pos]))
+               pos++;
 
        /* Section tag should start with $. */
-       if (fgetc(file) != '$')
+       if (buf->str[pos++] != '$')
                return FALSE;
 
-       /* Read the section tag */
        sname = g_string_sized_new(32);
-       status = read_until(file, sname, 'W');
-
-       /* Skip whitespace before content */
-       status = status && read_until(file, NULL, 'N');
-
-       /* Read the content */
-       scontents = g_string_sized_new(128);
-       status = status && read_until(file, scontents, '$');
-       g_strchomp(scontents->str);
+       scontent = g_string_sized_new(128);
+
+       /* Read the section tag. */
+       while (pos < buf->len && !g_ascii_isspace(buf->str[pos]))
+               g_string_append_c(sname, buf->str[pos++]);
+
+       /* Skip whitespace before content. */
+       while (pos < buf->len && g_ascii_isspace(buf->str[pos]))
+               pos++;
+
+       /* Read the content. */
+       while (pos < buf->len - 4 && strncmp(buf->str + pos, "$end", 4))
+               g_string_append_c(scontent, buf->str[pos++]);
+
+       if (sname->len && pos < buf->len - 4 && !strncmp(buf->str + pos, "$end", 4)) {
+               status = TRUE;
+               pos += 4;
+               while (pos < buf->len && g_ascii_isspace(buf->str[pos]))
+                       pos++;
+               g_string_erase(buf, 0, pos);
+       }
 
-       /* Release strings if status is FALSE, return them if status is TRUE */
        *name = g_string_free(sname, !status);
-       *contents = g_string_free(scontents, !status);
+       *contents = g_string_free(scontent, !status);
+       if (*contents)
+               g_strchomp(*contents);
+
        return status;
 }
 
@@ -170,12 +157,6 @@ static void free_channel(void *data)
        g_free(vcd_ch);
 }
 
-static void release_context(struct context *ctx)
-{
-       g_slist_free_full(ctx->channels, free_channel);
-       g_free(ctx);
-}
-
 /* Remove empty parts from an array returned by g_strsplit. */
 static void remove_empty_parts(gchar **parts)
 {
@@ -194,14 +175,18 @@ static void remove_empty_parts(gchar **parts)
  * Parse VCD header to get values for context structure.
  * The context structure should be zeroed before calling this.
  */
-static gboolean parse_header(FILE *file, struct context *ctx)
+static gboolean parse_header(const struct sr_input *in, GString *buf)
 {
-       uint64_t p, q;
-       gchar *name = NULL, *contents = NULL;
-       gboolean status = FALSE;
        struct vcd_channel *vcd_ch;
+       uint64_t p, q;
+       struct context *inc;
+       gboolean status;
+       gchar *name, *contents, **parts;
 
-       while (parse_section(file, &name, &contents)) {
+       inc = in->priv;
+       name = contents = NULL;
+       status = FALSE;
+       while (parse_section(buf, &name, &contents)) {
                sr_dbg("Section '%s', contents '%s'.", name, contents);
 
                if (g_strcmp0(name, "enddefinitions") == 0) {
@@ -211,334 +196,474 @@ static gboolean parse_header(FILE *file, struct context *ctx)
                        /*
                         * The standard allows for values 1, 10 or 100
                         * and units s, ms, us, ns, ps and fs.
-                        * */
+                        */
                        if (sr_parse_period(contents, &p, &q) == SR_OK) {
-                               ctx->samplerate = q / p;
+                               inc->samplerate = q / p;
                                if (q % p != 0) {
                                        /* Does not happen unless time value is non-standard */
                                        sr_warn("Inexact rounding of samplerate, %" PRIu64 " / %" PRIu64 " to %" PRIu64 " Hz.",
-                                               q, p, ctx->samplerate);
+                                               q, p, inc->samplerate);
                                }
 
-                               sr_dbg("Samplerate: %" PRIu64, ctx->samplerate);
+                               sr_dbg("Samplerate: %" PRIu64, inc->samplerate);
                        } else {
                                sr_err("Parsing timescale failed.");
                        }
                } else if (g_strcmp0(name, "var") == 0) {
-                       /* Format: $var type size identifier reference $end */
-                       gchar **parts = g_strsplit_set(contents, " \r\n\t", 0);
+                       /* Format: $var type size identifier reference [opt. index] $end */
+                       unsigned int length;
+
+                       parts = g_strsplit_set(contents, " \r\n\t", 0);
                        remove_empty_parts(parts);
+                       length = g_strv_length(parts);
 
-                       if (g_strv_length(parts) != 4)
-                               sr_warn("$var section should have 4 items");
+                       if (length != 4 && length != 5)
+                               sr_warn("$var section should have 4 or 5 items");
                        else if (g_strcmp0(parts[0], "reg") != 0 && g_strcmp0(parts[0], "wire") != 0)
                                sr_info("Unsupported signal type: '%s'", parts[0]);
                        else if (strtol(parts[1], NULL, 10) != 1)
                                sr_info("Unsupported signal size: '%s'", parts[1]);
-                       else if (ctx->channelcount >= ctx->maxchannels)
-                               sr_warn("Skipping '%s' because only %d channels requested.", parts[3], ctx->maxchannels);
+                       else if (inc->maxchannels && inc->channelcount >= inc->maxchannels)
+                               sr_warn("Skipping '%s%s' because only %d channels requested.",
+                                       parts[3], parts[4] ? : "", inc->maxchannels);
                        else {
-                               sr_info("Channel %d is '%s' identified by '%s'.", ctx->channelcount, parts[3], parts[2]);
                                vcd_ch = g_malloc(sizeof(struct vcd_channel));
                                vcd_ch->identifier = g_strdup(parts[2]);
-                               vcd_ch->name = g_strdup(parts[3]);
-                               ctx->channels = g_slist_append(ctx->channels, vcd_ch);
-                               ctx->channelcount++;
+                               if (length == 4)
+                                       vcd_ch->name = g_strdup(parts[3]);
+                               else
+                                       vcd_ch->name = g_strconcat(parts[3], parts[4], NULL);
+
+                               sr_info("Channel %d is '%s' identified by '%s'.",
+                                               inc->channelcount, vcd_ch->name, vcd_ch->identifier);
+
+                               sr_channel_new(in->sdi, inc->channelcount++, SR_CHANNEL_LOGIC, TRUE, vcd_ch->name);
+                               inc->channels = g_slist_append(inc->channels, vcd_ch);
                        }
 
                        g_strfreev(parts);
                }
 
-               g_free(name); name = NULL;
-               g_free(contents); contents = NULL;
+               g_free(name);
+               name = NULL;
+               g_free(contents);
+               contents = NULL;
        }
-
        g_free(name);
        g_free(contents);
 
+       /*
+        * Compute how many bytes each sample will have and initialize the
+        * current levels. The current levels will be updated whenever VCD
+        * has changes.
+        */
+       inc->bytes_per_sample = (inc->channelcount + 7) / 8;
+       inc->current_levels = g_malloc0(inc->bytes_per_sample);
+
+       inc->got_header = status;
+
        return status;
 }
 
-static int format_match(const char *filename)
+static int format_match(GHashTable *metadata, unsigned int *confidence)
 {
-       FILE *file;
-       gchar *name = NULL, *contents = NULL;
+       GString *buf, *tmpbuf;
        gboolean status;
+       gchar *name, *contents;
 
-       file = fopen(filename, "r");
-       if (file == NULL)
-               return FALSE;
+       buf = g_hash_table_lookup(metadata, GINT_TO_POINTER(SR_INPUT_META_HEADER));
+       tmpbuf = g_string_new_len(buf->str, buf->len);
 
        /*
         * If we can parse the first section correctly,
         * then it is assumed to be a VCD file.
         */
-       status = parse_section(file, &name, &contents);
-       status = status && (*name != '\0');
-
+       status = parse_section(tmpbuf, &name, &contents);
+       g_string_free(tmpbuf, TRUE);
        g_free(name);
        g_free(contents);
-       fclose(file);
 
-       return status;
+       if (!status)
+               return SR_ERR;
+       *confidence = 1;
+
+       return SR_OK;
 }
 
-static int init(struct sr_input *in, const char *filename)
+/* Send all accumulated bytes from inc->buffer. */
+static void send_buffer(const struct sr_input *in)
 {
-       struct sr_channel *ch;
-       int num_channels, i;
-       char name[SR_MAX_CHANNELNAME_LEN + 1];
-       char *param;
-       struct context *ctx;
-
-       (void)filename;
+       struct context *inc;
+       struct sr_datafeed_packet packet;
+       struct sr_datafeed_logic logic;
 
-       if (!(ctx = g_try_malloc0(sizeof(*ctx)))) {
-               sr_err("Input format context malloc failed.");
-               return SR_ERR_MALLOC;
-       }
+       inc = in->priv;
 
-       num_channels = DEFAULT_NUM_CHANNELS;
-       ctx->samplerate = 0;
-       ctx->downsample = 1;
-       ctx->skip = -1;
-
-       if (in->param) {
-               param = g_hash_table_lookup(in->param, "numchannels");
-               if (param) {
-                       num_channels = strtoul(param, NULL, 10);
-                       if (num_channels < 1) {
-                               release_context(ctx);
-                               return SR_ERR;
-                       } else if (num_channels > 64) {
-                               sr_err("No more than 64 channels supported.");
-                               return SR_ERR;
-                       }
-               }
+       if (inc->samples_in_buffer == 0)
+               return;
 
-               param = g_hash_table_lookup(in->param, "downsample");
-               if (param) {
-                       ctx->downsample = strtoul(param, NULL, 10);
-                       if (ctx->downsample < 1)
-                               ctx->downsample = 1;
-               }
-
-               param = g_hash_table_lookup(in->param, "compress");
-               if (param)
-                       ctx->compress = strtoul(param, NULL, 10);
+       packet.type = SR_DF_LOGIC;
+       packet.payload = &logic;
+       logic.unitsize = inc->bytes_per_sample;
+       logic.data = inc->buffer;
+       logic.length = inc->bytes_per_sample * inc->samples_in_buffer;
+       sr_session_send(in->sdi, &packet);
+       inc->samples_in_buffer = 0;
+}
 
-               param = g_hash_table_lookup(in->param, "skip");
-               if (param)
-                       ctx->skip = strtoul(param, NULL, 10) / ctx->downsample;
-       }
+/*
+ * Add N copies of the current sample to buffer.
+ * When the buffer fills up, automatically send it.
+ */
+static void add_samples(const struct sr_input *in, size_t count)
+{
+       struct context *inc;
+       size_t samples_per_chunk;
+       size_t space_left, i;
+       uint8_t *p;
 
-       /* Maximum number of channels to parse from the VCD */
-       ctx->maxchannels = num_channels;
+       inc = in->priv;
+       samples_per_chunk = CHUNK_SIZE / inc->bytes_per_sample;
 
-       /* Create a virtual device. */
-       in->sdi = sr_dev_inst_new(0, SR_ST_ACTIVE, NULL, NULL, NULL);
-       in->internal = ctx;
+       while (count) {
+               space_left = samples_per_chunk - inc->samples_in_buffer;
 
-       for (i = 0; i < num_channels; i++) {
-               snprintf(name, SR_MAX_CHANNELNAME_LEN, "%d", i);
+               if (space_left > count)
+                       space_left = count;
 
-               if (!(ch = sr_channel_new(i, SR_CHANNEL_LOGIC, TRUE, name))) {
-                       release_context(ctx);
-                       return SR_ERR;
+               p = inc->buffer + inc->samples_in_buffer * inc->bytes_per_sample;
+               for (i = 0; i < space_left; i++) {
+                       memcpy(p, inc->current_levels, inc->bytes_per_sample);
+                       p += inc->bytes_per_sample;
+                       inc->samples_in_buffer++;
+                       count--;
                }
 
-               in->sdi->channels = g_slist_append(in->sdi->channels, ch);
+               if (inc->samples_in_buffer == samples_per_chunk)
+                       send_buffer(in);
        }
-
-       return SR_OK;
 }
 
-/* Send N samples of the given value. */
-static void send_samples(const struct sr_dev_inst *sdi, uint64_t sample, uint64_t count)
+/* Set the channel level depending on the identifier and parsed value. */
+static void process_bit(struct context *inc, char *identifier, unsigned int bit)
 {
-       struct sr_datafeed_packet packet;
-       struct sr_datafeed_logic logic;
-       uint64_t buffer[CHUNKSIZE];
-       uint64_t i;
-       unsigned chunksize = CHUNKSIZE;
-
-       if (count < chunksize)
-               chunksize = count;
-
-       for (i = 0; i < chunksize; i++)
-               buffer[i] = sample;
-
-       packet.type = SR_DF_LOGIC;
-       packet.payload = &logic;
-       logic.unitsize = sizeof(uint64_t);
-       logic.data = buffer;
-
-       while (count) {
-               if (count < chunksize)
-                       chunksize = count;
-
-               logic.length = sizeof(uint64_t) * chunksize;
-
-               sr_session_send(sdi, &packet);
-               count -= chunksize;
+       GSList *l;
+       struct vcd_channel *vcd_ch;
+       unsigned int j;
+
+       for (j = 0, l = inc->channels; j < inc->channelcount && l; j++, l = l->next) {
+               vcd_ch = l->data;
+               if (g_strcmp0(identifier, vcd_ch->identifier) == 0) {
+                       /* Found our channel. */
+                       size_t byte_idx = (j / 8);
+                       size_t bit_idx = j - 8 * byte_idx;
+                       if (bit)
+                               inc->current_levels[byte_idx] |= (uint8_t)1 << bit_idx;
+                       else
+                               inc->current_levels[byte_idx] &= ~((uint8_t)1 << bit_idx);
+                       break;
+               }
        }
+       if (j == inc->channelcount)
+               sr_dbg("Did not find channel for identifier '%s'.", identifier);
 }
 
-/* Parse the data section of VCD */
-static void parse_contents(FILE *file, const struct sr_dev_inst *sdi, struct context *ctx)
+/* Parse a set of lines from the data section. */
+static void parse_contents(const struct sr_input *in, char *data)
 {
-       GString *token = g_string_sized_new(32);
+       struct context *inc;
+       uint64_t timestamp;
+       unsigned int bit, i;
+       char **tokens;
 
-       uint64_t prev_timestamp = 0;
-       uint64_t prev_values = 0;
+       inc = in->priv;
 
        /* Read one space-delimited token at a time. */
-       while (read_until(file, NULL, 'N') && read_until(file, token, 'W')) {
-               if (token->str[0] == '#' && g_ascii_isdigit(token->str[1])) {
+       tokens = g_strsplit_set(data, " \t\r\n", 0);
+       remove_empty_parts(tokens);
+       for (i = 0; tokens[i]; i++) {
+               if (inc->skip_until_end) {
+                       if (!strcmp(tokens[i], "$end")) {
+                               /* Done with unhandled/unknown section. */
+                               inc->skip_until_end = FALSE;
+                               break;
+                       }
+               }
+               if (tokens[i][0] == '#' && g_ascii_isdigit(tokens[i][1])) {
                        /* Numeric value beginning with # is a new timestamp value */
-                       uint64_t timestamp;
-                       timestamp = strtoull(token->str + 1, NULL, 10);
+                       timestamp = strtoull(tokens[i] + 1, NULL, 10);
 
-                       if (ctx->downsample > 1)
-                               timestamp /= ctx->downsample;
+                       if (inc->downsample > 1)
+                               timestamp /= inc->downsample;
 
                        /*
                         * Skip < 0 => skip until first timestamp.
                         * Skip = 0 => don't skip
                         * Skip > 0 => skip until timestamp >= skip.
                         */
-                       if (ctx->skip < 0) {
-                               ctx->skip = timestamp;
-                               prev_timestamp = timestamp;
-                       } else if (ctx->skip > 0 && timestamp < (uint64_t)ctx->skip) {
-                               prev_timestamp = ctx->skip;
-                       }
-                       else if (timestamp == prev_timestamp) {
+                       if (inc->skip < 0) {
+                               inc->skip = timestamp;
+                               inc->prev_timestamp = timestamp;
+                       } else if (inc->skip > 0 && timestamp < (uint64_t)inc->skip) {
+                               inc->prev_timestamp = inc->skip;
+                       } else if (timestamp == inc->prev_timestamp) {
                                /* Ignore repeated timestamps (e.g. sigrok outputs these) */
-                       }
-                       else {
-                               if (ctx->compress != 0 && timestamp - prev_timestamp > ctx->compress)
-                               {
+                       } else if (timestamp < inc->prev_timestamp) {
+                               sr_err("Invalid timestamp: %" PRIu64 " (smaller than previous timestamp).", timestamp);
+                               inc->skip_until_end = TRUE;
+                               break;
+                       } else {
+                               if (inc->compress != 0 && timestamp - inc->prev_timestamp > inc->compress) {
                                        /* Compress long idle periods */
-                                       prev_timestamp = timestamp - ctx->compress;
+                                       inc->prev_timestamp = timestamp - inc->compress;
                                }
 
                                sr_dbg("New timestamp: %" PRIu64, timestamp);
 
                                /* Generate samples from prev_timestamp up to timestamp - 1. */
-                               send_samples(sdi, prev_values, timestamp - prev_timestamp);
-                               prev_timestamp = timestamp;
+                               add_samples(in, timestamp - inc->prev_timestamp);
+                               inc->prev_timestamp = timestamp;
                        }
-               } else if (token->str[0] == '$' && token->len > 1) {
-                       /* This is probably a $dumpvars, $comment or similar.
-                        * $dump* contain useful data, but other tags will be skipped until $end. */
-                       if (g_strcmp0(token->str, "$dumpvars") == 0
-                                       || g_strcmp0(token->str, "$dumpon") == 0
-                                       || g_strcmp0(token->str, "$dumpoff") == 0
-                                       || g_strcmp0(token->str, "$end") == 0) {
+               } else if (tokens[i][0] == '$' && tokens[i][1] != '\0') {
+                       /*
+                        * This is probably a $dumpvars, $comment or similar.
+                        * $dump* contain useful data.
+                        */
+                       if (g_strcmp0(tokens[i], "$dumpvars") == 0
+                                       || g_strcmp0(tokens[i], "$dumpon") == 0
+                                       || g_strcmp0(tokens[i], "$dumpoff") == 0
+                                       || g_strcmp0(tokens[i], "$end") == 0) {
                                /* Ignore, parse contents as normally. */
                        } else {
-                               /* Skip until $end */
-                               read_until(file, NULL, '$');
+                               /* Ignore this and future lines until $end. */
+                               inc->skip_until_end = TRUE;
+                               break;
                        }
-               }
-               else if (strchr("bBrR", token->str[0]) != NULL) {
-                       /* A vector value. Skip it and also the following identifier. */
-                       read_until(file, NULL, 'N');
-                       read_until(file, NULL, 'W');
-               } else if (strchr("01xXzZ", token->str[0]) != NULL) {
-                       /* A new 1-bit sample value */
-                       int i, bit;
-                       GSList *l;
-                       struct vcd_channel *vcd_ch;
-
-                       bit = (token->str[0] == '1');
-
-                       g_string_erase(token, 0, 1);
-                       if (token->len == 0) {
-                               /* There was a space between value and identifier.
-                                * Read in the rest.
-                                */
-                               read_until(file, NULL, 'N');
-                               read_until(file, token, 'W');
+               } else if (strchr("rR", tokens[i][0]) != NULL) {
+                       sr_dbg("Real type vector values not supported yet!");
+                       if (!tokens[++i])
+                               /* No tokens left, bail out */
+                               break;
+                       else
+                               /* Process next token */
+                               continue;
+               } else if (strchr("bB", tokens[i][0]) != NULL) {
+                       bit = (tokens[i][1] == '1');
+
+                       /*
+                        * Bail out if a) char after 'b' is NUL, or b) there is
+                        * a second character after 'b', or c) there is no
+                        * identifier.
+                        */
+                       if (!tokens[i][1] || tokens[i][2] || !tokens[++i]) {
+                               sr_dbg("Unexpected vector format!");
+                               break;
                        }
 
-                       for (i = 0, l = ctx->channels; i < ctx->channelcount && l; i++, l = l->next) {
-                               vcd_ch = l->data;
+                       process_bit(inc, tokens[i], bit);
+               } else if (strchr("01xXzZ", tokens[i][0]) != NULL) {
+                       char *identifier;
 
-                               if (g_strcmp0(token->str, vcd_ch->identifier) == 0) {
-                                       /* Found our channel */
-                                       if (bit)
-                                               prev_values |= (uint64_t)1 << i;
-                                       else
-                                               prev_values &= ~((uint64_t)1 << i);
+                       /* A new 1-bit sample value */
+                       bit = (tokens[i][0] == '1');
 
+                       /*
+                        * The identifier is either the next character, or, if
+                        * there was whitespace after the bit, the next token.
+                        */
+                       if (tokens[i][1] == '\0') {
+                               if (!tokens[++i]) {
+                                       sr_dbg("Identifier missing!");
                                        break;
                                }
+                               identifier = tokens[i];
+                       } else {
+                               identifier = tokens[i] + 1;
                        }
-
-                       if (i == ctx->channelcount)
-                               sr_dbg("Did not find channel for identifier '%s'.", token->str);
+                       process_bit(inc, identifier, bit);
                } else {
-                       sr_warn("Skipping unknown token '%s'.", token->str);
+                       sr_warn("Skipping unknown token '%s'.", tokens[i]);
                }
-
-               g_string_truncate(token, 0);
        }
+       g_strfreev(tokens);
+}
+
+static int init(struct sr_input *in, GHashTable *options)
+{
+       struct context *inc;
+
+       inc = in->priv = g_malloc0(sizeof(struct context));
+
+       inc->maxchannels = g_variant_get_int32(g_hash_table_lookup(options, "numchannels"));
+       inc->downsample = g_variant_get_int32(g_hash_table_lookup(options, "downsample"));
+       if (inc->downsample < 1)
+               inc->downsample = 1;
+
+       inc->compress = g_variant_get_int32(g_hash_table_lookup(options, "compress"));
+       inc->skip = g_variant_get_int32(g_hash_table_lookup(options, "skip"));
+       inc->skip /= inc->downsample;
+
+       in->sdi = g_malloc0(sizeof(struct sr_dev_inst));
+       in->priv = inc;
+
+       inc->buffer = g_malloc(CHUNK_SIZE);
+
+       return SR_OK;
+}
 
-       g_string_free(token, TRUE);
+static gboolean have_header(GString *buf)
+{
+       unsigned int pos;
+       char *p;
+
+       if (!(p = g_strstr_len(buf->str, buf->len, "$enddefinitions")))
+               return FALSE;
+       pos = p - buf->str + 15;
+       while (pos < buf->len - 4 && g_ascii_isspace(buf->str[pos]))
+               pos++;
+       if (!strncmp(buf->str + pos, "$end", 4))
+               return TRUE;
+
+       return FALSE;
 }
 
-static int loadfile(struct sr_input *in, const char *filename)
+static int process_buffer(struct sr_input *in)
 {
        struct sr_datafeed_packet packet;
        struct sr_datafeed_meta meta;
        struct sr_config *src;
-       FILE *file;
-       struct context *ctx;
+       struct context *inc;
        uint64_t samplerate;
+       char *p;
+
+       inc = in->priv;
+       if (!inc->started) {
+               std_session_send_df_header(in->sdi);
+
+               packet.type = SR_DF_META;
+               packet.payload = &meta;
+               samplerate = inc->samplerate / inc->downsample;
+               src = sr_config_new(SR_CONF_SAMPLERATE, g_variant_new_uint64(samplerate));
+               meta.config = g_slist_append(NULL, src);
+               sr_session_send(in->sdi, &packet);
+               g_slist_free(meta.config);
+               sr_config_free(src);
+
+               inc->started = TRUE;
+       }
 
-       ctx = in->internal;
+       while ((p = g_strrstr_len(in->buf->str, in->buf->len, "\n"))) {
+               *p = '\0';
+               g_strstrip(in->buf->str);
+               if (in->buf->str[0] != '\0')
+                       parse_contents(in, in->buf->str);
+               g_string_erase(in->buf, 0, p - in->buf->str + 1);
+       }
 
-       if ((file = fopen(filename, "r")) == NULL)
-               return SR_ERR;
+       return SR_OK;
+}
 
-       if (!parse_header(file, ctx)) {
-               sr_err("VCD parsing failed");
-               fclose(file);
-               return SR_ERR;
+static int receive(struct sr_input *in, GString *buf)
+{
+       struct context *inc;
+       int ret;
+
+       g_string_append_len(in->buf, buf->str, buf->len);
+
+       inc = in->priv;
+       if (!inc->got_header) {
+               if (!have_header(in->buf))
+                       return SR_OK;
+               if (!parse_header(in, in->buf))
+                       /* There was a header in there, but it was malformed. */
+                       return SR_ERR;
+
+               in->sdi_ready = TRUE;
+               /* sdi is ready, notify frontend. */
+               return SR_OK;
        }
 
-       /* Send header packet to the session bus. */
-       std_session_send_df_header(in->sdi, LOG_PREFIX);
+       ret = process_buffer(in);
 
-       /* Send metadata about the SR_DF_LOGIC packets to come. */
-       packet.type = SR_DF_META;
-       packet.payload = &meta;
-       samplerate = ctx->samplerate / ctx->downsample;
-       src = sr_config_new(SR_CONF_SAMPLERATE, g_variant_new_uint64(samplerate));
-       meta.config = g_slist_append(NULL, src);
-       sr_session_send(in->sdi, &packet);
-       sr_config_free(src);
+       return ret;
+}
+
+static int end(struct sr_input *in)
+{
+       struct context *inc;
+       int ret;
 
-       /* Parse the contents of the VCD file */
-       parse_contents(file, in->sdi, ctx);
+       inc = in->priv;
 
-       /* Send end packet to the session bus. */
-       packet.type = SR_DF_END;
-       sr_session_send(in->sdi, &packet);
+       if (in->sdi_ready)
+               ret = process_buffer(in);
+       else
+               ret = SR_OK;
+
+       /* Send any samples that haven't been sent yet. */
+       send_buffer(in);
+
+       if (inc->started)
+               std_session_send_df_end(in->sdi);
+
+       return ret;
+}
+
+static void cleanup(struct sr_input *in)
+{
+       struct context *inc;
+
+       inc = in->priv;
+       g_slist_free_full(inc->channels, free_channel);
+       g_free(inc->buffer);
+       inc->buffer = NULL;
+       g_free(inc->current_levels);
+       inc->current_levels = NULL;
+}
 
-       fclose(file);
-       release_context(ctx);
-       in->internal = NULL;
+static int reset(struct sr_input *in)
+{
+       struct context *inc = in->priv;
+
+       cleanup(in);
+       inc->started = FALSE;
+       g_string_truncate(in->buf, 0);
 
        return SR_OK;
 }
 
+static struct sr_option options[] = {
+       { "numchannels", "Number of logic channels", "The number of (logic) channels in the data", NULL, NULL },
+       { "skip", "Skip samples until timestamp", "Skip samples until the specified timestamp; "
+               "< 0: Skip until first timestamp listed; 0: Don't skip", NULL, NULL },
+       { "downsample", "Downsampling factor", "Downsample, i.e. divide the samplerate by the specified factor", NULL, NULL },
+       { "compress", "Compress idle periods", "Compress idle periods longer than the specified value", NULL, NULL },
+       ALL_ZERO
+};
+
+static const struct sr_option *get_options(void)
+{
+       if (!options[0].def) {
+               options[0].def = g_variant_ref_sink(g_variant_new_int32(0));
+               options[1].def = g_variant_ref_sink(g_variant_new_int32(-1));
+               options[2].def = g_variant_ref_sink(g_variant_new_int32(1));
+               options[3].def = g_variant_ref_sink(g_variant_new_int32(0));
+       }
+
+       return options;
+}
+
 SR_PRIV struct sr_input_module input_vcd = {
        .id = "vcd",
-       .description = "Value Change Dump",
+       .name = "VCD",
+       .desc = "Value Change Dump data",
+       .exts = (const char*[]){"vcd", NULL},
+       .metadata = { SR_INPUT_META_HEADER | SR_INPUT_META_REQUIRED },
+       .options = get_options,
        .format_match = format_match,
        .init = init,
-       .loadfile = loadfile,
+       .receive = receive,
+       .end = end,
+       .cleanup = cleanup,
+       .reset = reset,
 };