mood.c: Move struct statistics into struct mood.

Because it's part of the state of an open mood. Expand and improve
the documentation of struct mood and current_mood while at it, and
kill the pointless return value of update_afs_statistics().

diff --git a/mood.c b/mood.c
index a2c3d099d1b5f25595e76ae843b1cf18d6a15f4f..398713437997ee30034f739404ee640b0e389281 100644 (file)
--- a/mood.c
+++ b/mood.c
@@ -47,18 +47,27 @@ struct afs_statistics {
        /** Number of admissible files */
        unsigned num;
 };
-static struct afs_statistics statistics = {.normalization_divisor = 1};
 
+/**
+ * Stores an instance of an open mood (parser and statistics).
+ *
+ * A structure of this type is allocated and initialized at mood open time.
+ */
 struct mood {
-       /** The name of this mood. */
+       /** NULL means that this is the "dummy" mood. */
        char *name;
-       /** Info for the bison parser. */
+       /** Bison's abstract syntax tree, used to determine admissibility. */
        struct mp_context *parser_context;
+       /** To compute the score. */
+       struct afs_statistics stats;
 };
 
 /*
  * If current_mood is NULL then no mood is currently open. If
  * current_mood->name is NULL, the dummy mood is currently open.
+ *
+ * The statistics are adjusted dynamically through this pointer as files are
+ * added, removed or played.
  */
 static struct mood *current_mood;
 
@@ -133,6 +142,7 @@ static struct mood *alloc_new_mood(const char *name)
        struct mood *m = zalloc(sizeof(struct mood));
        if (name)
                m->name = para_strdup(name);
+       m->stats.normalization_divisor = 1;
        return m;
 }
 
@@ -250,10 +260,11 @@ static int64_t normalized_value(int64_t x, int64_t n, int64_t sum, int64_t qd)
 
 static long compute_score(struct afs_info *afsi)
 {
-       long score = -normalized_value(afsi->num_played, statistics.num,
-               statistics.num_played_sum, statistics.num_played_qd);
-       score -= normalized_value(afsi->last_played, statistics.num,
-               statistics.last_played_sum, statistics.last_played_qd);
+       const struct afs_statistics *stats = &current_mood->stats;
+       long score = -normalized_value(afsi->num_played, stats->num,
+               stats->num_played_sum, stats->num_played_qd);
+       score -= normalized_value(afsi->last_played, stats->num,
+               stats->last_played_sum, stats->last_played_qd);
        return score / 2;
 }
 
@@ -262,63 +273,65 @@ static int add_afs_statistics(const struct osl_row *row)
        uint64_t n, x, s, q;
        struct afs_info afsi;
        int ret;
+       struct afs_statistics *stats = &current_mood->stats;
 
        ret = get_afsi_of_row(row, &afsi);
        if (ret < 0)
                return ret;
-       n = statistics.num;
+       n = stats->num;
        x = afsi.last_played;
-       s = statistics.last_played_sum;
+       s = stats->last_played_sum;
        if (n > 0) {
                q = (x > s / n)? x - s / n : s / n - x;
-               statistics.last_played_qd += q * q * n / (n + 1);
+               stats->last_played_qd += q * q * n / (n + 1);
        }
-       statistics.last_played_sum += x;
+       stats->last_played_sum += x;
 
        x = afsi.num_played;
-       s = statistics.num_played_sum;
+       s = stats->num_played_sum;
        if (n > 0) {
                q = (x > s / n)? x - s / n : s / n - x;
-               statistics.num_played_qd += q * q * n / (n + 1);
+               stats->num_played_qd += q * q * n / (n + 1);
        }
-       statistics.num_played_sum += x;
-       statistics.num++;
+       stats->num_played_sum += x;
+       stats->num++;
        return 1;
 }
 
 static int del_afs_statistics(const struct osl_row *row)
 {
+       struct afs_statistics *stats = &current_mood->stats;
        uint64_t n, s, q, a, new_s;
        struct afs_info afsi;
        int ret;
        ret = get_afsi_of_row(row, &afsi);
        if (ret < 0)
                return ret;
-       n = statistics.num;
+       n = stats->num;
        assert(n);
        if (n == 1) {
-               memset(&statistics, 0, sizeof(statistics));
-               statistics.normalization_divisor = 1;
+               memset(stats, 0, sizeof(*stats));
+               stats->normalization_divisor = 1;
                return 1;
        }
 
-       s = statistics.last_played_sum;
-       q = statistics.last_played_qd;
+       s = stats->last_played_sum;
+       q = stats->last_played_qd;
        a = afsi.last_played;
        new_s = s - a;
-       statistics.last_played_sum = new_s;
-       statistics.last_played_qd = q + s * s / n - a * a
+       stats->last_played_sum = new_s;
+       stats->last_played_qd = q + s * s / n - a * a
                - new_s * new_s / (n - 1);
 
-       s = statistics.num_played_sum;
-       q = statistics.num_played_qd;
+       s = stats->num_played_sum;
+       q = stats->num_played_qd;
        a = afsi.num_played;
        new_s = s - a;
-       statistics.num_played_sum = new_s;
-       statistics.num_played_qd = q + s * s / n - a * a
+       stats->num_played_sum = new_s;
+       stats->num_played_qd = q + s * s / n - a * a
                - new_s * new_s / (n - 1);
 
-       statistics.num--;
+       stats->num--;
        return 1;
 }
 
@@ -346,17 +359,18 @@ struct admissible_array {
  */
 static int add_if_admissible(struct osl_row *aft_row, void *data)
 {
+       const struct afs_statistics *stats = &current_mood->stats;
        struct admissible_array *aa = data;
 
        if (!mp_eval_row(aft_row, aa->m->parser_context))
                return 0;
-       if (statistics.num >= aa->size) {
+       if (stats->num >= aa->size) {
                aa->size *= 2;
                aa->size += 100;
                aa->array = arr_realloc(aa->array, aa->size,
                        sizeof(struct osl_row *));
        }
-       aa->array[statistics.num] = aft_row;
+       aa->array[stats->num] = aft_row;
        return add_afs_statistics(aft_row);
 }
 
@@ -402,22 +416,21 @@ _static_inline_ int64_t update_quadratic_deviation(int64_t n, int64_t old_qd,
        return old_qd + delta * (sigma - 2 * old_sum / n - delta / n);
 }
 
-static int update_afs_statistics(struct afs_info *old_afsi,
+static void update_afs_statistics(struct afs_info *old_afsi,
                struct afs_info *new_afsi)
 {
-       unsigned n = statistics.num;
-       assert(n);
-
-       statistics.last_played_qd = update_quadratic_deviation(n,
-               statistics.last_played_qd, old_afsi->last_played,
-               new_afsi->last_played, statistics.last_played_sum);
-       statistics.last_played_sum += new_afsi->last_played - old_afsi->last_played;
-
-       statistics.num_played_qd = update_quadratic_deviation(n,
-               statistics.num_played_qd, old_afsi->num_played,
-               new_afsi->num_played, statistics.num_played_sum);
-       statistics.num_played_sum += new_afsi->num_played - old_afsi->num_played;
-       return 1;
+       struct afs_statistics *stats = &current_mood->stats;
+
+       assert(stats->num > 0);
+       stats->last_played_qd = update_quadratic_deviation(stats->num,
+               stats->last_played_qd, old_afsi->last_played,
+               new_afsi->last_played, stats->last_played_sum);
+       stats->last_played_sum += new_afsi->last_played - old_afsi->last_played;
+
+       stats->num_played_qd = update_quadratic_deviation(stats->num,
+               stats->num_played_qd, old_afsi->num_played,
+               new_afsi->num_played, stats->num_played_sum);
+       stats->num_played_sum += new_afsi->num_played - old_afsi->num_played;
 }
 
 static int add_to_score_table(const struct osl_row *aft_row)
@@ -502,11 +515,8 @@ static int mood_update_audio_file(const struct osl_row *aft_row,
        ret = get_afsi_of_row(aft_row, &afsi);
        if (ret < 0)
                return ret;
-       if (old_afsi) {
-               ret = update_afs_statistics(old_afsi, &afsi);
-               if (ret < 0)
-                       return ret;
-       }
+       if (old_afsi)
+               update_afs_statistics(old_afsi, &afsi);
        score = compute_score(&afsi);
        PARA_DEBUG_LOG("score: %li\n", score);
        percent = (score + 100) / 3;
@@ -521,7 +531,8 @@ static int mood_update_audio_file(const struct osl_row *aft_row,
 /* sse: seconds since epoch. */
 static void log_statistics(int64_t sse)
 {
-       unsigned n = statistics.num;
+       const struct afs_statistics *stats = &current_mood->stats;
+       unsigned n = stats->num;
        int mean_days, sigma_days;
 
        assert(current_mood);
@@ -531,19 +542,19 @@ static void log_statistics(int64_t sse)
                PARA_WARNING_LOG("no admissible files\n");
                return;
        }
-       PARA_NOTICE_LOG("%u admissible files\n", statistics.num);
-       mean_days = (sse - statistics.last_played_sum / n) / 3600 / 24;
-       sigma_days = int_sqrt(statistics.last_played_qd / n) / 3600 / 24;
+       PARA_NOTICE_LOG("%u admissible files\n", stats->num);
+       mean_days = (sse - stats->last_played_sum / n) / 3600 / 24;
+       sigma_days = int_sqrt(stats->last_played_qd / n) / 3600 / 24;
        PARA_NOTICE_LOG("last_played mean/sigma: %d/%d days\n", mean_days, sigma_days);
        PARA_NOTICE_LOG("num_played mean/sigma: %" PRId64 "/%" PRIu64 "\n",
-               statistics.num_played_sum / n,
-               int_sqrt(statistics.num_played_qd / n));
+               stats->num_played_sum / n,
+               int_sqrt(stats->num_played_qd / n));
        PARA_NOTICE_LOG("num_played correction factor: %" PRId64 "\n",
-               statistics.num_played_correction);
+               stats->num_played_correction);
        PARA_NOTICE_LOG("last_played correction factor: %" PRId64 "\n",
-               statistics.last_played_correction);
+               stats->last_played_correction);
        PARA_NOTICE_LOG("normalization divisor: %" PRId64 "\n",
-               statistics.normalization_divisor);
+               stats->normalization_divisor);
 }
 
 /**
@@ -555,13 +566,11 @@ void close_current_mood(void)
 {
        destroy_mood(current_mood);
        current_mood = NULL;
-       memset(&statistics, 0, sizeof(statistics));
-       statistics.normalization_divisor = 1;
 }
 
 static void compute_correction_factors(int64_t sse)
 {
-       struct afs_statistics *s = &statistics;
+       struct afs_statistics *s = &current_mood->stats;
 
        if (s->num > 0) {
                s->normalization_divisor = int_sqrt(s->last_played_qd)
@@ -646,7 +655,7 @@ int change_current_mood(const char *mood_name, char **errmsg)
        clock_get_realtime(&rnow);
        compute_correction_factors(rnow.tv_sec);
        log_statistics(rnow.tv_sec);
-       for (i = 0; i < statistics.num; i++) {
+       for (i = 0; i < current_mood->stats.num; i++) {
                ret = add_to_score_table(aa.array[i]);
                if (ret < 0) {
                        if (errmsg)
@@ -655,7 +664,7 @@ int change_current_mood(const char *mood_name, char **errmsg)
                        goto out;
                }
        }
-       ret = statistics.num;
+       ret = current_mood->stats.num;
 out:
        free(aa.array);
        if (ret < 0)