gnuplot: Eliminate fixed-size header buffer based on max probes.

[libsigrok.git] / output / vcd.c

diff --git a/output/vcd.c b/output/vcd.c
index 829fcde7722e5d05b2b91a8d4590c72237d91ab4..27cc15336bf1422595ffce92be83ce4d99d7bbc7 100644 (file)
--- a/output/vcd.c
+++ b/output/vcd.c
@@ -1,5 +1,5 @@
 /*
- * This file is part of the sigrok project.
+ * This file is part of the libsigrok project.
  *
  * Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
  * Copyright (C) 2013 Bert Vermeulen <bert@biot.com>
@@ -38,11 +38,12 @@
 struct context {
        int num_enabled_probes;
        char *probelist[SR_MAX_NUM_PROBES + 1];
-       int *prevbits;
+       int probeindices[SR_MAX_NUM_PROBES + 1];
        GString *header;
-       uint64_t prevsample;
+       uint8_t *prevsample;
        int period;
        uint64_t samplerate;
+       unsigned int unitsize;
 };
 
 static const char *vcd_header_comment = "\
@@ -70,13 +71,16 @@ static int init(struct sr_output *o)
                probe = l->data;
                if (!probe->enabled)
                        continue;
-               ctx->probelist[ctx->num_enabled_probes++] = probe->name;
+               ctx->probelist[ctx->num_enabled_probes] = probe->name;
+               ctx->probeindices[ctx->num_enabled_probes] = probe->index;
+               ctx->num_enabled_probes++;
        }
        if (ctx->num_enabled_probes > 94) {
                sr_err("VCD only supports 94 probes.");
                return SR_ERR;
        }
 
+       ctx->unitsize = (ctx->num_enabled_probes + 7) / 8;
        ctx->probelist[ctx->num_enabled_probes] = 0;
        ctx->header = g_string_sized_new(512);
        num_probes = g_slist_length(o->sdi->probes);
@@ -135,10 +139,10 @@ static int init(struct sr_output *o)
        g_string_append(ctx->header, "$upscope $end\n"
                        "$enddefinitions $end\n$dumpvars\n");
 
-       if (!(ctx->prevbits = g_try_malloc0(sizeof(int) * num_probes))) {
+       if (!(ctx->prevsample = g_try_malloc0(ctx->unitsize))) {
                g_string_free(ctx->header, TRUE);
                g_free(ctx);
-               sr_err("%s: ctx->prevbits malloc failed", __func__);
+               sr_err("%s: ctx->prevsample malloc failed", __func__);
                return SR_ERR_MALLOC;
        }
 
@@ -152,10 +156,9 @@ static GString *receive(struct sr_output *o, const struct sr_dev_inst *sdi,
        struct context *ctx;
        GString *text;
        unsigned int i;
-       int p, curbit, prevbit;
-       uint64_t sample;
+       int p, curbit, prevbit, index;
+       uint8_t *sample;
        static uint64_t samplecount = 0;
-       gboolean first_sample;
 
        (void)sdi;
 
@@ -174,27 +177,20 @@ static GString *receive(struct sr_output *o, const struct sr_dev_inst *sdi,
                /* The header is still here, this must be the first packet. */
                text = ctx->header;
                ctx->header = NULL;
-               first_sample = TRUE;
        } else {
                text = g_string_sized_new(512);
-               first_sample = FALSE;
        }
 
        logic = packet->payload;
        for (i = 0; i <= logic->length - logic->unitsize; i += logic->unitsize) {
                samplecount++;
 
-               memcpy(&sample, logic->data + i, logic->unitsize);
-
-               if (first_sample) {
-                       /* First packet. We neg to make sure sample is stored. */
-                       ctx->prevsample = ~sample;
-                       first_sample = FALSE;
-               }
+               sample = logic->data + i;
 
                for (p = 0; p < ctx->num_enabled_probes; p++) {
-                       curbit = (sample & ((uint64_t) (1 << p))) >> p;
-                       prevbit = (ctx->prevsample & ((uint64_t) (1 << p))) >> p;
+                       index = ctx->probeindices[p % 8];
+                       curbit = (sample[p / 8] & (((uint8_t) 1) << index)) >> index;
+                       prevbit = (ctx->prevsample[p / 8] & (((uint64_t) 1) << index)) >> index;
 
                        /* VCD only contains deltas/changes of signals. */
                        if (prevbit == curbit)
@@ -206,7 +202,7 @@ static GString *receive(struct sr_output *o, const struct sr_dev_inst *sdi,
                                        * ctx->period), curbit, (char)('!' + p));
                }
 
-               ctx->prevsample = sample;
+               memcpy(ctx->prevsample, sample, ctx->unitsize);
        }
 
        return text;