URLENCODE vs RAWURLENCODE

Differences in ASCII:

URLENCODE:

Calculates a start/end length of the input string, allocates memory
Walks through a while-loop, increments until we reach the end of the string
Grabs the present character
If the character is equal to ASCII Char 0x20 (ie, a "space"), add a + sign to the output string.
If it's not a space, and it's also not alphanumeric (isalnum(c)), and also isn't and _, -, or .character, then we , output a % sign to array position 0, do an array look up to the hexcharsarray for a lookup for os_toascii array (an array from Apache that translates char to hex code) for the key of c (the present character), we then bitwise shift right by 4, assign that value to the character 1, and to position 2 we assign the same lookup, except we preform a logical and to see if the value is 15 (0xF), and return a 1 in that case, or a 0 otherwise. At the end, you'll end up with something encoded.
If it ends up it's not a space, it's alphanumeric or one of the _-. chars, it outputs exactly what it is.

RAWURLENCODE:

Allocates memory for the string
Iterates over it based on length provided in function call (not calculated in function as with URLENCODE).

Note: Many programmers have probably never seen a for loop iterate this way, it's somewhat hackish and not the standard convention used with most for-loops, pay attention, it assigns x and y, checks for exit on len reaching 0, and increments both x and y. I know, it's not what you'd expect, but it's valid code.

Assigns the present character to a matching character position in str.
It checks if the present character is alphanumeric, or one of the _-. chars, and if it isn't, we do almost the same assignment as with URLENCODE where it preforms lookups, however, we increment differently, using y++ rather than to[1], this is because the strings are being built in different ways, but reach the same goal at the end anyway.
When the loop's done and the length's gone, It actually terminates the string, assigning the \0byte.
It returns the encoded string.

Differences:

UrlEncode checks for space, assigns a + sign, RawURLEncode does not.
UrlEncode does not assign a \0 byte to the string, RawUrlEncode does (this may be a moot point)
They iterate differntly, one may be prone to overflow with malformed strings, I'm merely suggesting this and I haven't actually investigated.

They basically iterate differently, one assigns a + sign in the event of ASCII 20.

Differences in EBCDIC:

URLENCODE:

Same iteration setup as with ASCII
Still translating the "space" character to a + sign. Note-- I think this needs to be compiled in EBCDIC or you'll end up with a bug? Can someone edit and confirm this?
It checks if the present char is a char before 0, with the exception of being a . or -, OR less than A but greater than char 9, OR greater than Z and less than a but not a _. OR greater than z (yeah, EBCDIC is kinda messed up to work with). If it matches any of those, do a similar lookup as found in the ASCII version (it just doesn't require a lookup in os_toascii).

RAWURLENCODE:

Same iteration setup as with ASCII
Same check as described in the EBCDIC version of URL Encode, with the exception that if it's greater than z, it excludes ~ from the URL encode.
Same assignment as the ASCII RawUrlEncode
Still appending the \0 byte to the string before return.

Grand Summary

Both use the same hexchars lookup table
URIEncode doesn't terminate a string with \0, raw does.
If you're working in EBCDIC I'd suggest using RawUrlEncode, as it manages the ~ that UrlEncode does not (this is a reported issue). It's worth noting that ASCII and EBCDIC 0x20 are both spaces.
They iterate differently, one may be faster, one may be prone to memory or string based exploits.
URIEncode makes a space into +, RawUrlEncode makes a space into %20 via array lookups.

Disclaimer: I haven't touched C in years, and I haven't looked at EBCDIC in a really really long time. If I'm wrong somewhere, let me know.

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Sael

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