Implement missing 'space' formatting flag

This flag causes space (padding) to be reserved for the sign even if the
number is positive. It is basically the same as the 'plus' flag except that
a space is displayed instead of a plus sign. The 'plus' flag takes precedence.

4 files changed, 25 insertions, 4 deletions

diff --git a/src/library.js b/src/library.js
index 995fa2ab..2faa40d7 100644
--- a/src/library.js
+++ b/src/library.js
@@ -1974,6 +1974,7 @@ LibraryManager.library = {
         var flagLeftAlign = false;
         var flagAlternative = false;
         var flagZeroPad = false;
+        var flagPadSign = false;
         flagsLoop: while (1) {
           switch (next) {
             case {{{ charCode('+') }}}:
@@ -1992,6 +1993,9 @@ LibraryManager.library = {
                 flagZeroPad = true;
                 break;
               }
+            case {{{ charCode(' ') }}}:
+              flagPadSign = true;
+              break;
             default:
               break flagsLoop;
           }
@@ -2158,8 +2162,12 @@ LibraryManager.library = {
             }
 
             // Add sign if needed
-            if (flagAlwaysSigned && currArg >= 0) {
-              prefix = '+' + prefix;
+            if (currArg >= 0) {
+              if (flagAlwaysSigned) {
+                prefix = '+' + prefix;
+              } else if (flagPadSign) {
+                prefix = ' ' + prefix;
+              }
             }
 
             // Move sign to prefix so we zero-pad after the sign
@@ -2250,8 +2258,12 @@ LibraryManager.library = {
               if (next == {{{ charCode('E') }}}) argText = argText.toUpperCase();
 
               // Add sign.
-              if (flagAlwaysSigned && currArg >= 0) {
-                argText = '+' + argText;
+              if (currArg >= 0) {
+                if (flagAlwaysSigned) {
+                  argText = '+' + argText;
+                } else if (flagPadSign) {
+                  argText = ' ' + argText;
+                }
               }
             }
 
diff --git a/tests/printf/output.txt b/tests/printf/output.txt
index 7ca4d88c..0155f0da 100644
--- a/tests/printf/output.txt
+++ b/tests/printf/output.txt
@@ -6,9 +6,12 @@ Decimals: 1977 650000 12 4
 Preceding with blanks:       1977      -1977
 Preceding with zeros: 0000001977 -000001977
 Force sign: +1977 -1977  +1977  -1977
+Force sign or space:  1977 -1977   1977  -1977
+Sign overrides space: +1977 -1977  +1977  -1977
 Some different radixes: 100 64 144 0x64 0144
 floats: 3.14 +3e+00 3.141600E+00 00003.14
 negative floats: -3.14 -3e+00 -3.141600E+00 -0003.14
+Force sign or space:  3.14 -3.14   3.14  -3.14
 Width trick:    10
 A string %
 Null string:  (null)
diff --git a/tests/printf/output_i64_1.txt b/tests/printf/output_i64_1.txt
index 9cd8ed98..e38fb78f 100644
--- a/tests/printf/output_i64_1.txt
+++ b/tests/printf/output_i64_1.txt
@@ -6,9 +6,12 @@ Decimals: 1977 650000 12 4
 Preceding with blanks:       1977      -1977
 Preceding with zeros: 0000001977 -000001977
 Force sign: +1977 -1977  +1977  -1977
+Force sign or space:  1977 -1977   1977  -1977
+Sign overrides space: +1977 -1977  +1977  -1977
 Some different radixes: 100 64 144 0x64 0144
 floats: 3.14 +3e+00 3.141600E+00 00003.14
 negative floats: -3.14 -3e+00 -3.141600E+00 -0003.14
+Force sign or space:  3.14 -3.14   3.14  -3.14
 Width trick:    10
 A string %
 Null string:  (null)
diff --git a/tests/printf/test.c b/tests/printf/test.c
index b01a99db..1c8ad9f7 100644
--- a/tests/printf/test.c
+++ b/tests/printf/test.c
@@ -11,9 +11,12 @@ int main() {
   printf("Preceding with blanks: %10d %10d\n", 1977, -1977);
   printf("Preceding with zeros: %010d %010d\n", 1977, -1977);
   printf("Force sign: %+d %+d %+6d %+6d\n", 1977, -1977, 1977, -1977);
+  printf("Force sign or space: % d % d % 6d % 6d\n", 1977, -1977, 1977, -1977);
+  printf("Sign overrides space: % +d % +d % +6d % +6d\n", 1977, -1977, 1977, -1977);
   printf("Some different radixes: %d %x %o %#x %#o\n", 100, 100, 100, 100, 100);
   printf("floats: %4.2f %+.0e %E %08.2f\n", 3.1416, 3.1416, 3.1416, 3.1416);
   printf("negative floats: %4.2f %+.0e %E %08.2f\n", -3.1416, -3.1416, -3.1416, -3.1416);
+  printf("Force sign or space: % .2f % .2f % 6.2f % 6.2f\n", 3.1416, -3.1416, 3.1416, -3.1416);
   printf("Width trick: %*d\n", 5, 10);
   printf("%s %%\n", "A string");
   printf("Null string: %7s\n", NULL);