[PATCH] cmd: test: Add operators to deal with hexadecimal numbers.

[Michal Simek]

On 12. 03. 20 10:52, Christoph Müllner wrote:
> Hi Michal,
> 
> On 3/12/20 8:38 AM, Michal Simek wrote:
>> On 11. 03. 20 23:46, Christoph Muellner wrote:
>>> The DLUG states the following:
>>>   Almost all U-Boot commands expect numbers to be entered in hexadecimal
>>>   input format.
>>>
>>> Besides this fact, also most commands output hex values.
>>>
>>> Given this facts, we need to be able to use the information provided
>>> by to/from commands in scripts. The test command does not support
>>> operating on hexadecimal input formats. This leads to very surprising
>>> tests like this (simple_strtol("ff", 10) == 0):
>>>
>>>   => if test "ff" -eq 0; then echo "equal"; fi
>>>   equal
>>>   =>
>>>
>>> This patch introduces comparison operators for the test command,
>>> that allow parameters in hexadecimal format. So the test above
>>> can be implemented as follows:
>>>
>>>   => if test "ff" -heq 0; then echo "equal"; fi
>>>   =>
>>>
>>> [1] https://www.denx.de/wiki/view/DULG/UBootCommandLineInterface
>>>
>>> Signed-off-by: Christoph Muellner <christoph.muellner at theobroma-systems.com>
>>>
>>> ---
>>>
>>>  cmd/test.c | 36 ++++++++++++++++++++++++++++++++++++
>>>  1 file changed, 36 insertions(+)
>>>
>>> diff --git a/cmd/test.c b/cmd/test.c
>>> index 258bfd8806..dbaf23596b 100644
>>> --- a/cmd/test.c
>>> +++ b/cmd/test.c
>>> @@ -25,6 +25,12 @@
>>>  #define OP_INT_GT	14
>>>  #define OP_INT_GE	15
>>>  #define OP_FILE_EXISTS	16
>>> +#define OP_HEX_EQ	17
>>> +#define OP_HEX_NEQ	18
>>> +#define OP_HEX_LT	19
>>> +#define OP_HEX_LE	20
>>> +#define OP_HEX_GT	21
>>> +#define OP_HEX_GE	22
>>>  
>>>  const struct {
>>>  	int arg;
>>> @@ -48,6 +54,12 @@ const struct {
>>>  	{0, "-z", OP_STR_EMPTY, 2},
>>>  	{0, "-n", OP_STR_NEMPTY, 2},
>>>  	{0, "-e", OP_FILE_EXISTS, 4},
>>> +	{1, "-heq", OP_HEX_EQ, 3},
>>> +	{1, "-hne", OP_HEX_NEQ, 3},
>>> +	{1, "-hlt", OP_HEX_LT, 3},
>>> +	{1, "-hle", OP_HEX_LE, 3},
>>> +	{1, "-hgt", OP_HEX_GT, 3},
>>> +	{1, "-hge", OP_HEX_GE, 3},
>>>  };
>>>  
>>>  static int do_test(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>>> @@ -139,6 +151,30 @@ static int do_test(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>>>  		case OP_FILE_EXISTS:
>>>  			expr = file_exists(ap[1], ap[2], ap[3], FS_TYPE_ANY);
>>>  			break;
>>> +		case OP_HEX_EQ:
>>> +			expr = simple_strtol(ap[0], NULL, 16) ==
>>> +					simple_strtol(ap[2], NULL, 16);
>>> +			break;
>>> +		case OP_HEX_NEQ:
>>> +			expr = simple_strtol(ap[0], NULL, 16) !=
>>> +					simple_strtol(ap[2], NULL, 16);
>>> +			break;
>>> +		case OP_HEX_LT:
>>> +			expr = simple_strtol(ap[0], NULL, 16) <
>>> +					simple_strtol(ap[2], NULL, 16);
>>> +			break;
>>> +		case OP_HEX_LE:
>>> +			expr = simple_strtol(ap[0], NULL, 16) <=
>>> +					simple_strtol(ap[2], NULL, 16);
>>> +			break;
>>> +		case OP_HEX_GT:
>>> +			expr = simple_strtol(ap[0], NULL, 16) >
>>> +					simple_strtol(ap[2], NULL, 16);
>>> +			break;
>>> +		case OP_HEX_GE:
>>> +			expr = simple_strtol(ap[0], NULL, 16) >=
>>> +					simple_strtol(ap[2], NULL, 16);
>>> +			break;
>>>  		}
>>>  
>>>  		switch (op) {
>>>
>>
>> We have been trying to improve this. Take a look at it.
>>
>> https://lists.denx.de/pipermail/u-boot/2020-March/401745.html
>>
>> It should cover your case.
>> But if you start to mix hex with dec then it will fail.
> 
> thanks for this input.
> 
> I would prefer to not "guess" the base based on the fact that the string contains [a-f].
> Reason is, that I cannot guarantee that all hex numbers contain [a-f].
> 
> I want to have something reliably compatible to other commands like setexpr
> (allowing operations like addition and subtraction, but all in hex format).
> So I want to strictly interpret all numbers as hex numbers (as stated in the DLUG).

Yes I am aware about it. Also someone mentioned to take a look at itest
which is using hex as base all the time.

M