summaryrefslogtreecommitdiff
path: root/src/sparkline.c
blob: 3355a598cda171bf41c7c57185361ff7369cd9e4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
/* sparkline.c -- ASCII Sparklines
 * This code is modified from http://github.com/antirez/aspark and adapted
 * in order to return SDS strings instead of outputting directly to
 * the terminal.
 *
 * ---------------------------------------------------------------------------
 *
 * Copyright(C) 2011-2014 Salvatore Sanfilippo <antirez@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "redis.h"

#include <math.h>

/* This is the charset used to display the graphs, but multiple rows are used
 * to increase the resolution. */
static char charset[] = "_-`";
static char charset_fill[] = "_o#";
static int charset_len = sizeof(charset)-1;
static int label_margin_top = 1;

/* ----------------------------------------------------------------------------
 * Sequences are arrays of samples we use to represent data to turn
 * into sparklines. This is the API in order to generate a sparkline:
 *
 * struct sequence *seq = createSparklineSequence();
 * sparklineSequenceAddSample(seq, 10, NULL);
 * sparklineSequenceAddSample(seq, 20, NULL);
 * sparklineSequenceAddSample(seq, 30, "last sample label");
 * sds output = sparklineRender(sdsempty(), seq, 80, 4, SPARKLINE_FILL);
 * freeSparklineSequence(seq);
 * ------------------------------------------------------------------------- */

/* Create a new sequence. */
struct sequence *createSparklineSequence(void) {
    struct sequence *seq = zmalloc(sizeof(*seq));
    seq->length = 0;
    seq->samples = NULL;
    return seq;
}

/* Add a new sample into a sequence. */
void sparklineSequenceAddSample(struct sequence *seq, double value, char *label) {
    label = label == NULL ? label : zstrdup(label);
    if (seq->length == 0) {
        seq->min = seq->max = value;
    } else {
        if (value < seq->min) seq->min = value;
        else if (value > seq->max) seq->max = value;
    }
    seq->samples = zrealloc(seq->samples,sizeof(struct sample)*(seq->length+1));
    seq->samples[seq->length].value = value;
    seq->samples[seq->length].label = label;
    seq->length++;
    if (label) seq->labels++;
}

/* Free a sequence. */
void freeSparklineSequence(struct sequence *seq) {
    int j;

    for (j = 0; j < seq->length; j++)
        zfree(seq->samples[j].label);
    zfree(seq->samples);
    zfree(seq);
}

/* ----------------------------------------------------------------------------
 * ASCII rendering of sequence
 * ------------------------------------------------------------------------- */

/* Render part of a sequence, so that render_sequence() call call this function
 * with differnent parts in order to create the full output without overflowing
 * the current terminal columns. */
sds sparklineRenderRange(sds output, struct sequence *seq, int rows, int offset, int len, int flags) {
    int j;
    double relmax = seq->max - seq->min;
    int steps = charset_len*rows;
    int row = 0;
    char *chars = zmalloc(len);
    int loop = 1;
    int opt_fill = flags & SPARKLINE_FILL;
    int opt_log = flags & SPARKLINE_LOG_SCALE;

    if (opt_log) {
        relmax = log(relmax+1);
    } else if (relmax == 0) {
        relmax = 1;
    }

    while(loop) {
        loop = 0;
        memset(chars,' ',len);
        for (j = 0; j < len; j++) {
            struct sample *s = &seq->samples[j+offset];
            double relval = s->value - seq->min;
            int step;

            if (opt_log) relval = log(relval+1);
            step = (int) (relval*steps)/relmax;
            if (step < 0) step = 0;
            if (step >= steps) step = steps-1;

            if (row < rows) {
                /* Print the character needed to create the sparkline */
                int charidx = step-((rows-row-1)*charset_len);
                loop = 1;
                if (charidx >= 0 && charidx < charset_len) {
                    chars[j] = opt_fill ? charset_fill[charidx] :
                                          charset[charidx];
                } else if(opt_fill && charidx >= charset_len) {
                    chars[j] = '|';
                }
            } else {
                /* Labels spacing */
                if (seq->labels && row-rows < label_margin_top) {
                    loop = 1;
                    break;
                }
                /* Print the label if needed. */
                if (s->label) {
                    int label_len = strlen(s->label);
                    int label_char = row - rows - label_margin_top;

                    if (label_len > label_char) {
                        loop = 1;
                        chars[j] = s->label[label_char];
                    }
                }
            }
        }
        if (loop) {
            row++;
            output = sdscatlen(output,chars,len);
            output = sdscatlen(output,"\n",1);
        }
    }
    zfree(chars);
    return output;
}

/* Turn a sequence into its ASCII representation */
sds sparklineRender(sds output, struct sequence *seq, int columns, int rows, int flags) {
    int j;

    for (j = 0; j < seq->length; j += columns) {
        int sublen = (seq->length-j) < columns ? (seq->length-j) : columns;

        if (j != 0) output = sdscatlen(output,"\n",1);
        output = sparklineRenderRange(output, seq, rows, j, sublen, flags);
    }
    return output;
}