It's definitely a compounding issue as you grow and shrink SLOC.
One bit of code I received was somewhere in the range of 5-10k SLOC when handed to me. I reduced it to around 1k SLOC.
The original included numerous duplications, had a function that was itself on the order of 1-2k SLOC, was miserable to extend (which path do I need to follow to insert this new conditional? which paths will be impacted if I remove this conditionals?). Fortunately it wasn't shipped code, but it was useful for testing the embedded system.
My refactoring involved, first, re-coding one of the larger, outer if-else-if sequences as a simple switch/case. This quickly revealed which variables were common to a large number of the branches and could be brought to a higher level of scope. Then common series of statements were parameterized and extracted to functions (preambles and postambles, setup and teardown, if you will). Several hundred lines were replaced with something like one 20-line function which took a single parameter and one call to it with the parameter that was previously evaluated through some hairy if-else-if sequence.
Once completed, new test sequences could easily be coded up or were available because there was already a path that led to it, you just had to feed it a different value or series of values to trigger that path. Then we could automate the whole thing because we knew what the parameters were that clearly led to each branch.
In the end the code was 5-10x smaller, but immensely more valuable.
One bit of code I received was somewhere in the range of 5-10k SLOC when handed to me. I reduced it to around 1k SLOC.
The original included numerous duplications, had a function that was itself on the order of 1-2k SLOC, was miserable to extend (which path do I need to follow to insert this new conditional? which paths will be impacted if I remove this conditionals?). Fortunately it wasn't shipped code, but it was useful for testing the embedded system.
My refactoring involved, first, re-coding one of the larger, outer if-else-if sequences as a simple switch/case. This quickly revealed which variables were common to a large number of the branches and could be brought to a higher level of scope. Then common series of statements were parameterized and extracted to functions (preambles and postambles, setup and teardown, if you will). Several hundred lines were replaced with something like one 20-line function which took a single parameter and one call to it with the parameter that was previously evaluated through some hairy if-else-if sequence.
Once completed, new test sequences could easily be coded up or were available because there was already a path that led to it, you just had to feed it a different value or series of values to trigger that path. Then we could automate the whole thing because we knew what the parameters were that clearly led to each branch.
In the end the code was 5-10x smaller, but immensely more valuable.