[Bug 113] New: std.format.doFormat and small hex numbers

[d-bugmail at puremagic.com]

http://d.puremagic.com/bugzilla/show_bug.cgi?id=113

           Summary: std.format.doFormat and small hex numbers
           Product: D
           Version: 0.154
          Platform: PC
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: bugzilla at digitalmars.com
        ReportedBy: fvbommel at wxs.nl


There's a bug in std.format.doFormat regarding small hexadecimals, specifically
0xA to 0xF.

This small test program demonstrates the problem:

-----

D:\Temp>cat test.d
import std.stdio;

int main()
{
    for (int i = 10; i < 16; i++) writefln("%d - %x", i, i);
    return 0;
}

D:\Temp>dmd -run test.d
10 - :
11 - ;
12 - <
13 - =
14 - >
15 - ?

-----

As you can see, this program doesn't produce the expected output (which would
have the lines end in a-f instead of the various punctuation marks).
Similar behavior can be observed by using std.string.format and probably
anything else that relies on std.format.doFormat to perform such formatting.

>From a quick look at the code the bug seems to originate around line 875 of
src/phobos/std/format.d where for single-character numbers (vnumber < base) the
single-character output '0'+vnumber is produced. This "optimization" seems to
result in this bug when vnumber > 9 and base > 10.


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