[goffice] GOFormat: improve general rendering; add more tests.

[Morten Welinder <mortenw src gnome org>]

commit ffd71bca70abeea628e5388ef810221e67de2a54
Author: Morten Welinder <terra gnome org>
Date:   Wed Apr 2 16:50:55 2014 -0400

    GOFormat: improve general rendering; add more tests.
    
    Note, that tests still fail.

 goffice/utils/go-format.c |   45 +++++++++++++++++++++++++++++++--------------
 tests/test-format.c       |   29 +++++++++++++++++++++++++----
 2 files changed, 56 insertions(+), 18 deletions(-)
---
diff --git a/goffice/utils/go-format.c b/goffice/utils/go-format.c
index c176253..fe23330 100644
--- a/goffice/utils/go-format.c
+++ b/goffice/utils/go-format.c
@@ -4809,6 +4809,18 @@ drop_zeroes (GString *str, int *prec)
 }
 #endif
 
+static int
+SUFFIX(ilog10) (DOUBLE x)
+{
+       if (x >= 1000)
+               return (int)log10 (x);
+       if (x >= 100)
+               return 2;
+       if (x >= 10)
+               return 1;
+       return 0;
+}
+
 
 /**
  * go_render_general:
@@ -4854,8 +4866,8 @@ SUFFIX(go_render_general) (PangoLayout *layout, GString *str,
                           guint num_shape,
                           guint shape_flags)
 {
-       DOUBLE aval, l10;
-       int prec, safety, digs, maxdigits = PREFIX(DIG);
+       DOUBLE aval;
+       int prec, safety, digs, digs_as_int, maxdigits = PREFIX(DIG);
        size_t epos;
        gboolean rounds_to_0;
        int sign_width;
@@ -4871,15 +4883,18 @@ SUFFIX(go_render_general) (PangoLayout *layout, GString *str,
                col_width = INT_MAX;
                sign_width = 0;
        } else {
-               int w = col_width / min_digit_width;
+               int w;
+
+               sign_width = unicode_minus
+                       ? metrics->minus_width
+                       : metrics->hyphen_width;
+
+               w = (col_width - (val <= -0.5 ? sign_width : 0)) / min_digit_width;
                if (w <= maxdigits) {
                        /* We're limited by width.  */
                        maxdigits = w;
                        check_val = FALSE;
                }
-               sign_width = unicode_minus
-                       ? metrics->minus_width
-                       : metrics->hyphen_width;
        }
 
 #ifdef DEBUG_GENERAL
@@ -4892,25 +4907,24 @@ SUFFIX(go_render_general) (PangoLayout *layout, GString *str,
        aval = SUFFIX(fabs) (val);
        if (aval >= SUFFIX(1e15) || aval < SUFFIX(1e-4))
                goto e_notation;
-       l10 = SUFFIX(log10) (aval);
 
-       /* Number of digits in [aval].  */
-       digs = (aval >= 1 ? 1 + (int)l10 : 1);
+       /* Number of digits in round(aval).  */
+       digs_as_int = (aval >= 9.5 ? 1 + SUFFIX(ilog10) (aval + 0.5) : 1);
 
        /* Check if there is room for the whole part, including sign.  */
        safety = metrics->avg_digit_width / 2;
 
-       if (digs * min_digit_width > col_width) {
+       if (digs_as_int * min_digit_width > col_width) {
 #ifdef DEBUG_GENERAL
                g_print ("No room for whole part.\n");
 #endif
                goto e_notation;
-       } else if (digs * metrics->max_digit_width + safety <
+       } else if (digs_as_int * metrics->max_digit_width + safety <
                   col_width - (val > 0 ? 0 : sign_width)) {
 #ifdef DEBUG_GENERAL
                g_print ("Room for whole part.\n");
 #endif
-               if (val == SUFFIX(floor) (val) || digs == maxdigits) {
+               if (val == SUFFIX(floor) (val) || digs_as_int == maxdigits) {
                        g_string_printf (str, "%.0" FORMAT_f, val);
                        HANDLE_NUMERAL_SHAPE;
                        HANDLE_SIGN (0);
@@ -4931,10 +4945,13 @@ SUFFIX(go_render_general) (PangoLayout *layout, GString *str,
                if (w > col_width)
                        goto e_notation;
 
-               if (val == SUFFIX(floor) (val) || digs == maxdigits)
+               if (val == SUFFIX(floor) (val) || digs_as_int == maxdigits)
                        return;
        }
 
+       /* Number of digits in [aval].  */
+       digs = (aval >= 1 ? 1 + SUFFIX(ilog10) (aval) : 1);
+
        prec = maxdigits - digs;
        g_string_printf (str, "%.*" FORMAT_f, prec, val);
        if (check_val) {
@@ -4972,7 +4989,7 @@ SUFFIX(go_render_general) (PangoLayout *layout, GString *str,
  e_notation:
        rounds_to_0 = (aval < 0.5);
        prec = (col_width -
-               (val > 0 ? 0 : sign_width) -
+               (val >= 0 ? 0 : sign_width) -
                (aval < 1 ? sign_width : metrics->plus_width) -
                metrics->E_width) / min_digit_width - 3;
        if (prec <= 0) {
diff --git a/tests/test-format.c b/tests/test-format.c
index 0d34245..3ce2cd5 100644
--- a/tests/test-format.c
+++ b/tests/test-format.c
@@ -17,7 +17,10 @@ test_general_format_1 (double val, int width, const char *expected)
        g_printerr ("go_render_general: %.17g %d -> \"%s\"\n",
                    val, width, str->str);
 
-       g_assert (strcmp (str->str, expected) == 0);
+       if (expected && strcmp (str->str, expected) != 0) {
+               g_printerr ("Expected \"%s\"\n", expected);
+               g_assert (0);
+       }
 
        g_string_free (str, TRUE);
 }
@@ -25,13 +28,31 @@ test_general_format_1 (double val, int width, const char *expected)
 static void
 test_general_format (void)
 {
-       test_general_format_1 (-9.5, 5, "-9.5");
-       test_general_format_1 (-9.5, 4, "-9.5");
-       test_general_format_1 (-9.5, 3, "-10");
+       test_general_format_1 (0, 5, "0");
+       test_general_format_1 (0, 3, "0");
+       test_general_format_1 (0, 2, "0");
+       test_general_format_1 (0, 1, "0");
+
+       test_general_format_1 (9.25, 5, "9.25");
+       test_general_format_1 (9.25, 3, "9.3");
+       test_general_format_1 (9.25, 2, "9");
+       test_general_format_1 (9.25, 1, "9");
 
        test_general_format_1 (9.5, 5, "9.5");
        test_general_format_1 (9.5, 3, "9.5");
        test_general_format_1 (9.5, 2, "10");
+       test_general_format_1 (9.5, 1, NULL);
+
+       test_general_format_1 (-9.5, 5, "-9.5");
+       test_general_format_1 (-9.5, 4, "-9.5");
+       test_general_format_1 (-9.5, 3, "-10");
+       test_general_format_1 (-9.5, 2, NULL);
+
+       test_general_format_1 (-9.25, 5, "-9.25");
+       test_general_format_1 (-9.25, 4, "-9.3");
+       test_general_format_1 (-9.25, 2, "-9");
+       test_general_format_1 (-9.25, 1, NULL);
+
 }
 
 /* ------------------------------------------------------------------------- */