In our TL, French King Charles X invaded Algeria (Algiers) shortly before he was overthrown. After his overthrow, the Algerian expedition was so popular that the new French King Louis Philippe continued it in spite of the fact that he was personally opposed to it.
Anyway, what if Charles X gets overthrown before he is able to give the order to invade Algeria? (Or, alternatively, you could have him delay this order until he gets overthrown, after which point he'll obviously lack the ability to issue such an order.) What would happen to Algeria in this scenario?
I strongly doubt that Louis Philippe would have been willing to invade Algeria without Charles actually laying the groundwork for this. Thus, how does Algeria fare if the French are not there starting from 1830?
In theory with no French invasion:
1. It will remain untouched for some period. Possibly the 1870s if they stop pissing off great powers.
3. By the late 1840s early 1850s the Ottomans will regain minimum authority in the region a la Tunis. Self rule but Ottomans are their superiors in name.
3. If things go OTL and the Ottomans lose in 1878, Algiers protectorship will go to the French anyway. Tunis will be Italian most likely.
4. If the Ottomans have a better time during the latter war Algiers will remain semi-independent with the French and Italians investing in the region.
There is a good chance it will end up French later in the 19th century. But personally I give the British and Italians a chance as well. Especially between 1830 and 1850 for the British. If ofcourse the Algerians decide piracy should be kept going on. The Italians might get it in a Berlin Treaty.