[pacman-dev] [PATCH] Created hex_representation() in lib/libalpm/util.c which is used in alpm_compute_md5sum() and alpm_compute_sha256sum().

[Diogo Sousa]

On 12/21/2011 10:54 PM, Dan McGee wrote:
> On Wed, Dec 21, 2011 at 4:48 PM, Diogo Sousa <diogogsousa at gmail.com> wrote:
>> Created hex_representation() in lib/libalpm/util.c which is
>> used in alpm_compute_md5sum() and alpm_compute_sha256sum().
>>
>> Signed-off-by: Diogo Sousa <diogogsousa at gmail.com>
>> ---
>>  lib/libalpm/util.c |   56 ++++++++++++++++++++++++++--------------------------
>>  1 files changed, 28 insertions(+), 28 deletions(-)
>>
>> diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c
>> index 4eeb0cd..2fe6087 100644
>> --- a/lib/libalpm/util.c
>> +++ b/lib/libalpm/util.c
>> @@ -917,7 +917,30 @@ static int sha2_file(const char *path, unsigned char output[32], int is224)
>>  }
>>  #endif
>>
>> -static const char *hex_digits = "0123456789abcdef";
>> +/** Create a string representing bytes in hexadecimal.
>> + *
>> + * @param bytes the bytes to represent in hexadecimal.
>> + * @param size number of bytes to consider.
>> + * @return a nul terminated string with the hexadecimal representation
>> + *         of bytes or NULL on error. This string must be freed.
>> + */
>> +static char *hex_representation(unsigned char *bytes, size_t size)
>> +{
>> +       static const char *hex_digits = "0123456789abcdef";
> static not needed with const now that this is local to the function,
> not a big deal though.
> 
>> +       char *str;
>> +       int i;
>> +
>> +       MALLOC(str, 2*size+1, return NULL);
> Man, this happens too much ,time to update HACKING.
> Bad:
>     2*size+1
> Good:
>     2 * size + 1
> 
> We like spaces around here, so please use them in all places in this
> patch you are using operators- this should have been clear from the
> code you removed (e.g., "pos + 1").
>> +
>> +       for (i=0; i < size; i++) {
>> +               str[2*i] = hex_digits[bytes[i] >> 4];
>> +               str[2*i+1] = hex_digits[bytes[i] & 0x0f];
>> +       }
>> +
>> +       str[2*size] = '\0';
>> +
>> +       return str;
>> +}
>>
>>  /** Get the md5 sum of file.
>>  * @param filename name of the file
>> @@ -927,29 +950,17 @@ static const char *hex_digits = "0123456789abcdef";
>>  char SYMEXPORT *alpm_compute_md5sum(const char *filename)
>>  {
>>        unsigned char output[16];
>> -       char *md5sum;
>> -       int ret, i;
>> +       int ret;
>>
>>        ASSERT(filename != NULL, return NULL);
>>
>> -       MALLOC(md5sum, (size_t)33, return NULL);
>> -       /* defined above for OpenSSL, otherwise defined in md5.h */
>>        ret = md5_file(filename, output);
>>
>>        if(ret > 0) {
>> -               free(md5sum);
>>                return NULL;
>>        }
>>
>> -       /* Convert the result to something readable */
>> -       for(i = 0; i < 16; i++) {
>> -               int pos = i * 2;
>> -               /* high 4 bits are first digit, low 4 are second */
>> -               md5sum[pos] = hex_digits[output[i] >> 4];
>> -               md5sum[pos + 1] = hex_digits[output[i] & 0x0f];
>> -       }
>> -       md5sum[32] = '\0';
>> -       return md5sum;
>> +       return hex_representation(output,16);
> Space after comma too...
>>  }
>>
>>  /** Get the sha256 sum of file.
>> @@ -960,29 +971,18 @@ char SYMEXPORT *alpm_compute_md5sum(const char *filename)
>>  char SYMEXPORT *alpm_compute_sha256sum(const char *filename)
>>  {
>>        unsigned char output[32];
>> -       char *sha256sum;
>> -       int ret, i;
>> +       int ret;
>>
>>        ASSERT(filename != NULL, return NULL);
>>
>> -       MALLOC(sha256sum, (size_t)65, return NULL);
>>        /* defined above for OpenSSL, otherwise defined in sha2.h */
>>        ret = sha2_file(filename, output, 0);
>>
>>        if(ret > 0) {
>> -               free(sha256sum);
>>                return NULL;
>>        }
>>
>> -       /* Convert the result to something readable */
>> -       for(i = 0; i < 32; i++) {
>> -               int pos = i * 2;
>> -               /* high 4 bits are first digit, low 4 are second */
>> -               sha256sum[pos] = hex_digits[output[i] >> 4];
>> -               sha256sum[pos + 1] = hex_digits[output[i] & 0x0f];
>> -       }
>> -       sha256sum[64] = '\0';
>> -       return sha256sum;
>> +       return hex_representation(output,32);
>>  }
>>
>>  /** Calculates a file's MD5 or SHA2 digest  and compares it to an expected value.
>> --
>> 1.7.8
> 

Sorry,

will submit in a few minutes.

Thanks,
Diogo Sousa