I have one charater pointer array which points to the some stirngs
every element points to some strings one thing in mind strings have only 1 and 0 .
for example
i have character pointer that stores string like "100110" so its takes 6 bytes to store but i want to store this in bits so i reduce memory occpuied.
In C style, something like this should work:
char* str = "100101";
unsigned out = 0;
for (int i = 0; str[i]; i++) {
out = (out << 1);
if (str[i] == '1')
out++;
}
(I cannot test this for now, so please correct me if I'm wrong)
Explanation:
str = "100101"
out = 0000 0000 0000 0000
i = 0:
out = 0000 0000 0000 0000 (out << 1)
out = 0000 0000 0000 0001 (out++ because str[0] == '1')
i = 1:
out = 0000 0000 0000 0010 (out << 1)
[...]
i = 5:
out = 0000 0000 0010 0100 (out << 1)
out = 0000 0000 0010 0101 (out++ because str[5] == '1')
unsigned is for unsigned int, use the type you want, depending of your string lengthunsigned char is 1 byte (8 bits)Why not use 'strtol'? It's a standard lib function. Or you're writing low-level code for memory shortage hardware?
char *str = "010101";
int i = strtol(str ,(char**)NULL ,2);
==> i=21
One way is to, define that char* [] as a global and use its indices for accessing it:
char stringLiterals [] = { "0101010", "10010010", "111", "010100100", ... };
Usage: Instead of
char *p = stringLiteral[3];
use
unsigned int idx = 3;
Rationale: If you are compacting this string into bits for serialization purpose than it's ok. But otherwise I don't see any use case of compacting them. In my above solution, it doesn't use any extra memory. You already have an array of string literals; I am just asking to declare in global scope and use its index.
Also, if the string size is > 32 bytes then, you won't be able to store it in a single 32-bit int.
"010101" somewhere and then for using it you again covert it back to "010101". Instead of that, you can simply store that string literal into an array and just get its index. It's equivalent to converting "010101" into a single int. If you are not dealing with serializing your data then this technique is helpful. I assume that you want to covert the string literals and not the content of some variable, in the later case u have to use vector instead of array> 32 bytes and the OP will not be able to store it in a single 32-bit int. :)
<<operator should help you.