Added to/from string conversion functions, and testcases for them.

2 files changed, 127 insertions, 2 deletions

diff --git a/unittests/Makefile b/unittests/Makefile
index cb5dbb4..14dac10 100644
--- a/unittests/Makefile
+++ b/unittests/Makefile
@@ -5,10 +5,10 @@ CC = gcc
 CFLAGS = -g -O0 -I../libfixmath -Wall -Wextra -Werror
 
 # The files required for tests
-FIX16_SRC = ../libfixmath/fix16.c ../libfixmath/fix16_sqrt.c \
+FIX16_SRC = ../libfixmath/fix16.c ../libfixmath/fix16_sqrt.c ../libfixmath/fix16_str.c \
 	../libfixmath/fix16_exp.c ../libfixmath/fix16.h
 
-all: run_fix16_unittests run_fix16_exp_unittests
+all: run_fix16_unittests run_fix16_exp_unittests run_fix16_str_unittests
 
 clean:
 	rm -f fix16_unittests_????
@@ -55,3 +55,11 @@ run_fix16_exp_unittests: fix16_exp_unittests
 
 fix16_exp_unittests: fix16_exp_unittests.c $(FIX16_SRC)
 	$(CC) $(CFLAGS) $(DEFINES) -o $@ $^ -lm
+	
+# Tests for string conversion, run only in default config
+run_fix16_str_unittests: fix16_str_unittests
+	./fix16_str_unittests > /dev/null
+
+fix16_str_unittests: fix16_str_unittests.c $(FIX16_SRC)
+	$(CC) $(CFLAGS) $(DEFINES) -o $@ $^ -lm
+
diff --git a/unittests/fix16_str_unittests.c b/unittests/fix16_str_unittests.c
new file mode 100644
index 0000000..5a5bf94
--- /dev/null
+++ b/unittests/fix16_str_unittests.c
@@ -0,0 +1,117 @@
+#include <fix16.h>
+#include <stdio.h>
+#include <math.h>
+#include <string.h>
+#include <stdbool.h>
+#include "unittests.h"
+
+int main()
+{
+    int status = 0;
+
+    {
+        COMMENT("Testing fix16_to_str corner cases");
+        char buf[13];
+        
+        fix16_to_str(fix16_from_dbl(1234.5678), buf, 4);
+        printf("1234.5678 = %s\n", buf);
+        TEST(strcmp(buf, "1234.5678") == 0);
+        
+        fix16_to_str(fix16_from_dbl(-1234.5678), buf, 4);
+        printf("-1234.5678 = %s\n", buf);
+        TEST(strcmp(buf, "-1234.5678") == 0);
+     
+        fix16_to_str(0, buf, 0);
+        TEST(strcmp(buf, "0") == 0);
+     
+        fix16_to_str(fix16_from_dbl(0.9), buf, 0);
+        TEST(strcmp(buf, "1") == 0);
+     
+        fix16_to_str(1, buf, 5);
+        printf("(fix16_t)1 = %s\n", buf);
+        TEST(strcmp(buf, "0.00002") == 0);
+        
+        fix16_to_str(-1, buf, 5);
+        printf("(fix16_t)-1 = %s\n", buf);
+        TEST(strcmp(buf, "-0.00002") == 0);
+        
+        fix16_to_str(65535, buf, 5);
+        printf("(fix16_t)65535 = %s\n", buf);
+        TEST(strcmp(buf, "0.99998") == 0);
+
+        fix16_to_str(65535, buf, 4);
+        printf("(fix16_t)65535 = %s\n", buf);
+        TEST(strcmp(buf, "1.0000") == 0);
+        
+        fix16_to_str(fix16_maximum, buf, 5);
+        printf("fix16_maximum = %s\n", buf);
+        TEST(strcmp(buf, "32767.99998") == 0);
+        
+        fix16_to_str(fix16_minimum, buf, 5);
+        printf("fix16_minimum = %s\n", buf);
+        TEST(strcmp(buf, "-32768.00000") == 0);
+    }
+
+    {
+        COMMENT("Testing fix16_from_str corner cases");
+    
+        TEST(fix16_from_str("1234.5678") == fix16_from_dbl(1234.5678));
+        TEST(fix16_from_str("-1234.5678") == fix16_from_dbl(-1234.5678));
+        TEST(fix16_from_str("   +1234,56780   ") == fix16_from_dbl(1234.5678));
+    
+        TEST(fix16_from_str("0") == 0);
+        TEST(fix16_from_str("1") == fix16_one);
+        TEST(fix16_from_str("1.0") == fix16_one);
+        TEST(fix16_from_str("1.0000000000") == fix16_one);
+        
+        TEST(fix16_from_str("0.00002") == 1);
+        TEST(fix16_from_str("0.99998") == 65535);
+        
+        TEST(fix16_from_str("32767.99998") == fix16_maximum);
+        TEST(fix16_from_str("-32768.00000") == fix16_minimum);
+    }
+    
+    {
+        COMMENT("Extended testing for whole range");
+        fix16_t value = fix16_minimum;
+        char testbuf[13];
+        char goodbuf[13];
+        
+        bool ok = true;
+        while (value < fix16_maximum)
+        {
+            double fvalue = fix16_to_dbl(value);
+        
+            /* Turns out we have to jump through some hoops to round
+            doubles perfectly for printing: 
+            http://stackoverflow.com/questions/994764/rounding-doubles-5-sprintf
+            */
+            fvalue = round(fvalue * 100000.)/100000.;
+        
+            snprintf(goodbuf, 13, "%0.5lf", fvalue);
+            fix16_to_str(value, testbuf, 5);
+            
+            if (strcmp(goodbuf, testbuf) != 0)
+            {
+                printf("Value (fix16_t)%d gave %s, should be %s\n", value, testbuf, goodbuf);
+                ok = false;
+            }
+            
+            fix16_t roundtrip = fix16_from_str(testbuf);
+            if (roundtrip != value)
+            {
+                printf("Roundtrip failed: (fix16_t)%d -> %s -> (fix16_t)%d\n", value, testbuf, roundtrip);
+                ok = false;
+            }
+        
+            value += 0x10001;
+        }
+        
+        TEST(ok);
+    }
+
+    if (status != 0)
+        fprintf(stdout, "\n\nSome tests FAILED!\n");
+
+    return status;
+}