Navigation Menu

Skip to content

Instantly share code, notes, and snippets.

@lavoy

lavoy/Base58Encoder.h

Created February 10, 2011 01:22
Show Gist options
  • Star 2 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save lavoy/819739 to your computer and use it in GitHub Desktop.
Save lavoy/819739 to your computer and use it in GitHub Desktop.
Download ZIP
Raw
Base58Encoder.h
@interface Base58Encoder : NSObject {
}
+ (NSString *)base58EncodedValue:(long long)num;
+ (NSString *)base58DecodedValue:(NSString *)strNum;
@end
Raw
Base58Encoder.m
@implementation Base58Encoder
// Based on Kellan Elliot-McCrea's PHP code:
// http://www.flickr.com/groups/api/discuss/72157616713786392
//
+ (NSString *)base58EncodedValue:(long long)num {
NSString *alphabet = @"123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";
int baseCount = [alphabet length];
NSString *encoded = @"";
while(num >= baseCount) {
double div = num/baseCount;
long long mod = (num - (baseCount * (long long)div));
NSString *alphabetChar = [alphabet substringWithRange: NSMakeRange(mod, 1)];
encoded = [NSString stringWithFormat: @"%@%@", alphabetChar, encoded];
num = (long long)div;
}
if(num) {
encoded = [NSString stringWithFormat: @"%@%@", [alphabet substringWithRange: NSMakeRange(num, 1)], encoded];
}
return encoded;
}
+ (NSString *)base58DecodedValue:(NSString *)strNum {
NSString *alphabet = @"123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";
unsigned long long lDecoded = 0;
unsigned long long lMulti = 1;
NSString *lastCharOfNum;
while ([strNum length] > 0) {
lastCharOfNum = [strNum substringFromIndex:([strNum length] - 1)];
lDecoded += lMulti * [alphabet rangeOfString:lastCharOfNum].location;
lMulti = lMulti * [alphabet length];
strNum = [strNum substringToIndex:[strNum length] - 1];
}
return [NSString stringWithFormat:@"%llu", lDecoded];
}
@end
Raw
EncoderUnitTest.m
- (void)testShortURL {
NSDictionary *testData = [NSDictionary dictionaryWithObjectsAndKeys:
@"6hKMCS", @"3471391110",
@"6hDrmR", @"3470152229",
@"6hHHZB", @"3470988633",
@"6hHKum", @"3470993664",
@"6hLgFW", @"3471485480",
@"6hBRKR", @"3469844075",
@"6hGRTd", @"3470820062",
@"6hCuie", @"3469966999",
@"6hJuXN", @"3471139908",
@"6hJsyS", @"3471131850",
@"6hFWFb", @"3470641072",
@"6hENdZ", @"3470417529",
@"6hEJqg", @"3470404727",
@"6hGNaq", @"3470807546",
@"6hDRoZ", @"3470233089",
@"6hKkP9", @"3471304242",
@"6hHVZ3", @"3471028968",
@"6hNcfE", @"3471860782",
@"6hJBqs", @"3471161638",
@"6hCPyc", @"3470031783",
@"6hJNrC", @"3471198710",
@"6hKmkd", @"3471305986",
@"6hFUYs", @"3470635346",
@"6hK6UC", @"3471257464",
@"6hBmiv", @"3469744991",
@"6hKex1", @"3471283122",
@"6hFHQj", @"3470597870",
@"6hCA2n", @"3469986263",
@"6hBTgt", @"3469849157",
@"6hHEss", @"3470976734",
@"6hLows", @"3471508478",
@"6hD95z", @"3470094097",
@"6hKjcq", @"3471298806",
@"6hGEbd", @"3470780680",
@"6hKSNS", @"3471408510",
@"6hG8hv", @"3470676761",
@"6hEmj6", @"3470330361",
@"6hGjpn", @"3470714163",
@"6hEsUr", @"3470352537",
@"6hJEhy", @"3471171272",
@"6hKBHn", @"3471357731",
@"6hG3gi", @"3470659871",
@"6hFJTT", @"3470601441",
@"6hLZDs", @"3471626624",
@"6hGdL7", @"3470695182",
@"6hBpi4", @"3469755057",
@"6hEuFV", @"3470358539",
@"6hGVw1", @"3470832288",
@"6hLdm1", @"3471474232",
@"6hFcCK", @"3470496279",
@"6hDZmR", @"3470259877",
@"6hG8iX", @"3470676845",
@"6hFZZL", @"3470652242",
@"6hJ79u", @"3471063156",
@"6hMsrS", @"3471716780",
@"6hGH3G", @"3470790336",
@"6hKqD3", @"3471320476",
@"6hKxEY", @"3471344136",
@"6hHVF1", @"3471027922",
@"6hKDSQ", @"3471365008",
@"6hKwHs", @"3471340916",
@"6hH4s6", @"3470858973",
@"6hGmKB", @"3470722065",
@"6hEzdi", @"3470373757",
@"6hJQwJ", @"3471205734",
@"6hHd6a", @"3470888035",
@"6hH1j3", @"3470848414",
@"6hNP1u", @"3471981064",
@"6hFWge", @"3470639683",
@"6hFpmP", @"3470535723",
@"6hCgQZ", @"3469925109",
@"6hFJSm", @"3470601352",
@"6hEd9v", @"3470302893",
@"6hDwuF", @"3470169503",
@"6hCVSX", @"3470053055",
@"6hCUgr", @"3470047631",
@"6hEsqR", @"3470350937",
@"6hBmKg", @"3469746485",
@"6hDvUx", @"3470167523",
@"6hJUi7", @"3471218400",
@"6hF39e", @"3470464349",
@"6hH43K", @"3470857619",
@"6hGSC5", @"3470822548",
@"6hFz1s", @"3470568182",
@"6hFaKZ", @"3470489971",
@"6hD65K", @"3470084015",
@"6hBAVk", @"3469794165",
@"6hLkWA", @"3471499786",
@"6hHi7q", @"3470904928",
@"6hHdDF", @"3470889921",
@"6hHcCo", @"3470886482",
@"6hGQQf", @"3470816526",
@"6hLAfo", @"3471547914",
@"6hBDEV", @"3469803421",
@"6hL4BE", @"3471444864",
@"6hL2TT", @"3471439077",
@"6hKcxb", @"3471276404",
@"6hD1vg", @"3470068617",
@"6hLtTT", @"3471526541",
@"6hHXtw", @"3471033984",
@"6hHCQj", @"3470971274",
@"6hFrXx", @"3470544465",
@"6hMVkJ", @"3471807252",
@"6hDv6V", @"3470164819",
@"6hD1gR", @"3470067839",
@"6hShWW", @"3472660386",
@"6hK4tb", @"3471249260",
@"6hLzrQ", @"3471545214",
@"6hBTAe", @"3469850245",
@"6hLABq", @"3471549134",
@"6hGbN7", @"3470688570",
@"6hFtro", @"3470549444",
@"6hRRAQ", @"3472575120",
@"6hFViL", @"3470636466",
@"6hFkLP", @"3470523659",
@"6hNAKc", @"3471939809",
@"6hLLNE", @"3471583426",
@"6hJstp", @"3471131533",
@"6hHxv3", @"3470953336",
@"6hLToQ", @"3471605592",
@"6hJ74F", @"3471062877",
@"6hGjCA", @"3470714930",
@"6hCQoD", @"3470034593",
@"6hCqxX", @"3469954397",
@"6hCbg8", @"3469906325",
@"6hJwGw", @"3471145750",
@"6hP2Tt", @"3472024389",
@"6hHDuy", @"3470973492",
@"6hGRpq", @"3470818450",
@"6hDx8F", @"3470171649",
@"6hLhxU", @"3471488378",
@"6hFrkd", @"3470542358",
@"6hPc3D", @"3472055197",
@"6hJV29", @"3471220838",
@"6hCc3c", @"3469908939",
@"6hLycA", @"3471541024",
@"6hLd75", @"3471473424",
@"6hKJ1m", @"3471378900",
@"6hHgEG", @"3470900072",
@"6hFNfm", @"3470612720",
@"6hFsaF", @"3470545169",
@"6hERqV", @"3470428313",
@"6hEnYK", @"3470335967",
@"6hDGeT", @"3470202285",
@"6hFDZo", @"3470584940",
@"6hMvPE", @"3471728136",
@"6hKTro", @"3471410628",
@"6hKfXG", @"3471287918",
@"6hKeuU", @"3471283000",
@"6hHFYj", @"3470981830",
@"6hHDzj", @"3470973768",
@"6hCozt", @"3469947757",
@"6hKB8D", @"3471355775",
@"6hCtrc", @"3469964097",
@"6hDXcx", @"3470252609",
@"6hCxSR", @"3469979041",
@"6hC1Vk", @"3469874901",
@"6hKmaS", @"3471305444",
@"6hK9fn", @"3471265337",
@"6hFDH6", @"3470583995",
@"6hEB7c", @"3470380131",
@"6hC1E2", @"3469874013",
@"6hBZnx", @"3469869693",
@"6hBXNz", @"3469864417",
@"6hQKjm", @"3472358868",
@"6hHn4j", @"3470918204",
@"6hHiQ2", @"3470907341",
@"6hHhHb", @"3470903580",
@"6hGnBc", @"3470724941",
@"6hG6Ht", @"3470671481",
@"6hDvh6", @"3470165409",
@"6hCGtp", @"3470007957",
@"6hCnzi", @"3469944383",
@"6hMxEY", @"3471734360",
@"6hG9sL", @"3470680720",
@"6hCarn", @"3469903555",
@"6hLsdE", @"3471520902",
@"6hKnDa", @"3471310391",
@"6hKn2L", @"3471308338",
@"6hGpfH", @"3470730481",
@"6hRkJS", @"3472474666",
@"6hFEV3", @"3470588052",
@"6hE7VV", @"3470285343",
@"6hSSAq", @"3472773572",
@"6hNTtQ", @"3471996106",
@"6hMAuK", @"3471743859",
@"6hJ95H", @"3471069665",
@"6hHZ39", @"3471039240",
@"6hByNi", @"3469787029",
@"6hLLnb", @"3471581948",
@"6hHYoQ", @"3471037076",
@"6hHCLm", @"3470971044",
@"6hFHkC", @"3470596206",
@"6hDKq4", @"3470212967",
@"6hRapC", @"3472439910",
@"6hKJBs", @"3471380936",
@"6hHids", @"3470905278",
@"6hEJ8R", @"3470403775",
@"6hMY3L", @"3471816360",
@"6hFRAC", @"3470623988",
@"6hEP9c", @"3470420615",
@"6hEqVR", @"3470345891",
@"6hHGBX", @"3470984013",
@"6hEzFB", @"3470375341",
@"6hDnRp", @"3470140429",
@"6hDdQH", @"3470110113",
@"6hCK7B", @"3470016843",
@"6hCxvH", @"3469977815",
@"6hC4v4", @"3469883585",
@"6hC15g", @"3469872055",
@"6hGHRA", @"3470793056",
@"6hGCGL", @"3470775724",
@"6hGbuW", @"3470687574",
@"6hT7FY", @"3472820990",
@"6hMFHs", @"3471761416",
@"6hJybH", @"3471150749",
@"6hGEFs", @"3470782376",
@"6hCBnX", @"3469990821",
@"6hNJZt", @"3471967549",
@"6hMxUV", @"3471735169",
@"6hLoGG", @"3471509072",
@"6hJdy5", @"3471084708",
@"6hGnwp", @"3470724663",
@"6hGkhZ", @"3470717157",
@"6hG7yd", @"3470674308",
@"6hDAqF", @"3470182727",
@"6hPQVJ", @"3472182628",
@"6hHyqy", @"3470956440",
@"6hFG6k", @"3470592013",
@"6hTavC", @"3472830482",
@"6hJjzU", @"3471104998",
@"6hFE7r", @"3470585349",
@"6hNQU7", @"3471987422",
@"6hJYSj", @"3471233782",
@"6hFVRB", @"3470638313",
@"6hEeQt", @"3470308575",
@"6hBmnK", @"3469745237",
@"6hP9VU", @"3472048078",
@"6hJeDp", @"3471088381",
@"6hHV4d", @"3471025846",
@"6hFXmS", @"3470643374",
@"6hBgEn", @"3469729381",
@"6hNDjB", @"3471948475",
@"6hKEkd", @"3471366538",
@"6hJDq6", @"3471168345",
@"6hHbCG", @"3470883136",
@"6hCgN2", @"3469924937",
@"6hQa3S", @"3472243594",
@"6hLphv", @"3471511033",
@"6hHoqd", @"3470922780",
@"6hGT2W", @"3470823932",
@"6hEd6V", @"3470302743",
@"6hNac3", @"3471853844",
@"6hHzYe", @"3470961641",
@"6hRDAC", @"3472534740",
@"6hJ2bu", @"3471046452",
@"6hGRPN", @"3470819864",
@"6hFS6P", @"3470625681",
@"6hG8Yn", @"3470679073",
@"6hFSGB", @"3470627699",
@"6hFQhL", @"3470619588",
@"6hF4VT", @"3470470361",
@"6hE7vD", @"3470283935",
@"6hBeKa", @"3469722931",
@"6hPLs1", @"3472167564",
@"6hHcKm", @"3470886886",
@"6hG9KW", @"3470681716",
@"6hE8E4", @"3470287787",
@"6hNp1U", @"3471900352",
@"6hJ29T", @"3471046359",
@"6hHPLb", @"3471008038",
@"6hGWGq", @"3470836256",
@"6hEipV", @"3470320607",
@"6hMB8U", @"3471746014",
@"6hKWyr", @"3471421129",
@"6hKLxb", @"3471387416",
@"6hJstE", @"3471131548",
@"6hHk3k", @"3470911419",
@"6hPSdE", @"3472186974",
@"6hPfEY", @"3472067396",
@"6hGVSS", @"3470833498",
@"6hFVX4", @"3470638629",
@"6hFQRa", @"3470621467",
@"6hCsKK", @"3469961809",
@"6hJbdY", @"3471076872",
@"6hE2ok", @"3470266691",
@"6hCrc8", @"3469956553",
@"6hRgwS", @"3472460514",
@"6hPhLY", @"3472074472",
@"6hLTK1", @"3471606762",
@"6hHh5u", @"3470901452",
@"6hDiBB", @"3470126173",
@"6hD678", @"3470084095",
@"6hKMXC", @"3471392198",
@"6hBohi", @"3469751649",
@"6hJXRV", @"3471230395",
@"6hFzad", @"3470568690",
@"6hCCbH", @"3469993533",
@"6hLpoA", @"3471511386",
@"6hKZQN", @"3471432170",
@"6hG3Ax", @"3470660987",
@"6hT7kf", @"3472819788",
@"6hKrzq", @"3471323630",
@"6hHMHM", @"3471001171",
@"6hHL9q", @"3470995872",
@"6hBUkR", @"3469852775",
@"6hRRLf", @"3472575666",
@"6hJFUg", @"3471176707",
@"6hBML2", @"3469830629",
@"6hS9eE", @"3472631080",
@"6hPD3o", @"3472142646",
@"6hKWhL", @"3471420220",
@"6hJMpr", @"3471195219",
@"6hHzVA", @"3470961488",
@"6hGvu9", @"3470751444",
@"6hGkTu", @"3470719158",
@"6hF7bv", @"3470477937",
@"6hDzQp", @"3470180739",
@"6hQ2Mo", @"3472219148",
@"6hM7Tn", @"3471650979",
@"6hJWDp", @"3471226305",
@"6hJpX5", @"3471123046",
@"6hNLTn", @"3471973923",
@"6hGuRu", @"3470749318",
@"6hG1CM", @"3470654389",
@"6hEMDx", @"3470415589",
@"6hCYpx", @"3470061557",
@"6hCSTr", @"3470042991",
@"6hBnJr", @"3469749801",
@"6hRZSh", @"3472602928",
@"6hRtVW", @"3472502220",
@"6hDzc2", @"3470178571",
@"6hCMan", @"3470023731",
@"6hRfUj", @"3472458394",
@"6hLdME", @"3471475720",
@"6hE69P", @"3470279363",
@"6hDgaa", @"3470117911",
@"6hDeKg", @"3470113161",
@"6hKSis", @"3471406804",
@"6hKwYj", @"3471341778",
@"6hJ4Ro", @"3471055436",
@"6hHTug", @"3471020571",
@"6hHSH2", @"3471017947",
@"6hHCE6", @"3470970681",
@"6hG5R5", @"3470668558",
@"6hFaBX", @"3470489505",
@"6hL13o", @"3471432842",
@"6hJtQr", @"3471136117",
@"6hHpg3", @"3470925612",
@"6hGinv", @"3470710691",
@"6hFQXR", @"3470621855",
@"6hCKN6", @"3470019133",
@"6hJme9", @"3471110522",
@"6hGUY8", @"3470830439",
@"6hEDPM", @"3470389271",
@"6hBg1c", @"3469727167",
@"6hNyoj", @"3471931870",
@"6hNdQu", @"3471866108",
@"6hMNAK", @"3471784575",
@"6hHkvV", @"3470913019",
@"6hDHLi", @"3470207413",
@"6hCwUk", @"3469975763",
@"6hCd2a", @"3469912243",
@"6hPeRd", @"3472064626",
@"6hP4SL", @"3472031076",
@"6hJQFC", @"3471206250",
@"6hJLVJ", @"3471193612",
@"6hJAJT", @"3471159343",
@"6hJ8Mi", @"3471068655",
@"6hJ6o5", @"3471060580",
@"6hH667", @"3470864484",
@"6hH5RU", @"3470863718",
@"6hC2jx", @"3469876247",
@"6hPm75", @"3472085672",
@"6hN8ud", @"3471848112",
@"6hLD4g", @"3471557361",
@"6hGAr2", @"3470768083",
@"6hFVQH", @"3470638261",
@"6hDxtV", @"3470172823",
@"6hPNwj", @"3472174542",
@"6hKTB7", @"3471411192",
@"6hJdfQ", @"3471083708",
@"6hRvdq", @"3472506540",
@"6hNpN9", @"3471902976",
@"6hMd75", @"3471668536",
@"6hLkks", @"3471497748",
@"6hHkYn", @"3470914553",
@"6hGZgY", @"3470844930",
@"6hGorv", @"3470727743",
@"6hG941", @"3470679342",
@"6hC6xK", @"3469890469",
@"6hTA5N", @"3472913142",
@"6hNzGE", @"3471936298",
@"6hN3F1", @"3471831918",
@"6hLdgN", @"3471473988",
@"6hFyvS", @"3470566524",
@"6hCxUM", @"3469979153",
@"6hCmje", @"3469940145",
@"6hC87z", @"3469895737",
@"6hC4mV", @"3469883113",
@"6hQXaJ", @"3472398736",
@"6hP6Tw", @"3472037848",
@"6hLx7r", @"3471537361",
@"6hFvYh", @"3470557964",
@"6hEPWM", @"3470423317",
@"6hDKDT", @"3470213769",
@"6hBrcn", @"3469761455",
@"6hBkh4", @"3469741543",
@"6hMdbq", @"3471668788",
@"6hK3cE", @"3471244996",
@"6hJSUj", @"3471213714",
@"6hJvFs", @"3471142324",
@"6hHVMu", @"3471028298",
@"6hHUZG", @"3471025642",
@"6hHeVT", @"3470894225",
@"6hFqjr", @"3470538949",
@"6hETNt", @"3470436291",
@"6hEPkX", @"3470421297",
@"6hCVrB", @"3470051585",
@"6hCE2V", @"3469999751",
@"6hNe3j", @"3471866794",
@"6hKjmA", @"3471299338",
@"6hHbMp", @"3470883641",
@"6hGWJ7", @"3470836354",
@"6hGn3F", @"3470723055",
@"6hFoKL", @"3470533690",
@"6hETWx", @"3470436759",
@"6hPaH5", @"3472050698",
@"6hNFFf", @"3471956400",
@"6hNnyp", @"3471895451",
@"6hM7ra", @"3471649459",
@"6hHof7", @"3470922194",
@"6hH8KM", @"3470873455",
@"6hGbCG", @"3470688024",
@"6hDXaB", @"3470252497",
@"6hDSF2", @"3470237383",
@"6hDfq8", @"3470115415",
@"6hCqqR", @"3469953985",
@"6hPpj7", @"3472096462",
@"6hMSHG", @"3471798434",
@"6hKyF6", @"3471347507",
@"6hK33v", @"3471244465",
@"6hJwva", @"3471145091",
@"6hGX9e", @"3470837753",
@"6hFWeR", @"3470639603",
@"6hD8oF", @"3470091783",
@"6hCopg", @"3469947165",
@"6hC9L8", @"3469901279",
@"6hBhS4", @"3469733423",
@"6hMQXy", @"3471792510",
@"6hLoRU", @"3471509606",
@"6hKCib", @"3471359692",
@"6hKder", @"3471278739",
@"6hHYPy", @"3471038510",
@"6hD4hz", @"3470077973",
@"6hPgTS", @"3472071508",
@"6hNXii", @"3472008951",
@"6hKYzE", @"3471427928",
@"6hKSr2", @"3471407243",
@"6hG4fB", @"3470663195",
@"6hFyz2", @"3470566707",
@"6hFoMT", @"3470533813",
@"6hC5V4", @"3469888341",
@"6hBZmZ", @"3469869661",
@"6hPXKU", @"3472205606",
@"6hHVwm", @"3471027420",
@"6hCzFH", @"3469985123",
@"6hCvsM", @"3469970917",
@"6hChKr", @"3469928151",
@"6hBv6F", @"3469774581",
@"6hPf62", @"3472065427",
@"6hNS4s", @"3471991328",
@"6hNPXe", @"3471984239",
@"6hLguh", @"3471484804",
@"6hJ5zB", @"3471057885",
@"6hHr6j", @"3470931776",
@"6hLBUx", @"3471553491",
@"6hLi1P", @"3471489939",
@"6hKQ35", @"3471399184",
@"6hKK67", @"3471382540",
@"6hHUcT", @"3471022985",
@"6hGPjm", @"3470811428",
@"6hF5ti", @"3470472183",
@"6hDZPz", @"3470261427",
@"6hC17D", @"3469872193",
@"6hR7R3", @"3472431292",
@"6hN7hS", @"3471844090",
@"6hHqoC", @"3470929416",
@"6hFDdx", @"3470582339",
@"6hFzdL", @"3470568896",
@"6hDuEH", @"3470163357",
@"6hCaZk", @"3469905409",
@"6hT2Hw", @"3472804260",
@"6hPhJY", @"3472074356",
@"6hKNBy", @"3471394398",
@"6hJPEq", @"3471202816",
@"6hGMH7", @"3470806020",
@"6hGp5L", @"3470729904",
@"6hFfRV", @"3470507135",
@"6hESHt", @"3470432637", nil];
Base58Encoder *encoder = [[Base58Encoder alloc] init];
for(NSString *nsid in testData) {
NSString *expectedEncoding = [testData objectForKey: nsid];
NSString *expectedShortURL = [NSString stringWithFormat: @"http://flic.kr/p/%@", expectedEncoding];
NSLog(@"NSID: %@, expectedEncoding: %@", nsid, expectedEncoding);
NSString *encodedID = [encoder base58EncodedValue: [nsid longLongValue]];
STAssertTrue([encodedID compare: expectedEncoding] == NSOrderedSame, @"Encodings don't match. Expected %@. Got %@.", expectedEncoding, encodedID);
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment