private static string ApplyRegex(FastaHeaderFieldRegex regex, string line)
{
string result = null;
if (regex != null)
{
var matches = regex.Regex.Matches(line);
if (matches.Count > regex.Match && matches[regex.Match].Groups.Count > regex.Group)
{
result = matches[regex.Match].Groups[regex.Group].Value;
}
}
return(result);
}
/// <summary>
/// Load a protein fasta database, using regular expressions to get various aspects of the headers. The first regex capture group is used as each field.
/// </summary>
public static List <Protein> LoadProteinFasta(string proteinDbLocation, bool generateTargets, DecoyType decoyType, bool isContaminant,
FastaHeaderFieldRegex accessionRegex, FastaHeaderFieldRegex fullNameRegex, FastaHeaderFieldRegex nameRegex,
FastaHeaderFieldRegex geneNameRegex, FastaHeaderFieldRegex organismRegex, out List <string> errors, int maxThreads = -1)
{
HashSet <string> unique_accessions = new HashSet <string>();
int unique_identifier = 1;
string accession = null;
string name = null;
string fullName = null;
string organism = null;
List <Tuple <string, string> > geneName = new List <Tuple <string, string> >();
errors = new List <string>();
Regex substituteWhitespace = new Regex(@"\s+");
List <Protein> targets = new List <Protein>();
using (var stream = new FileStream(proteinDbLocation, FileMode.Open, FileAccess.Read, FileShare.Read))
{
Stream fastaFileStream = proteinDbLocation.EndsWith("gz") ? // allow for .bgz and .tgz, which are (rarely) used
(Stream)(new GZipStream(stream, CompressionMode.Decompress)) :
stream;
StringBuilder sb = null;
StreamReader fasta = new StreamReader(fastaFileStream);
while (true)
{
string line = "";
line = fasta.ReadLine();
if (line == null)
{
break;
}
if (line.StartsWith(">"))
{
accession = ApplyRegex(accessionRegex, line);
fullName = ApplyRegex(fullNameRegex, line);
name = ApplyRegex(nameRegex, line);
organism = ApplyRegex(organismRegex, line);
string geneNameString = ApplyRegex(geneNameRegex, line);
if (geneNameString != null)
{
geneName.Add(new Tuple <string, string>("primary", geneNameString));
}
if (accession == null || accession == "")
{
accession = line.Substring(1).TrimEnd();
}
sb = new StringBuilder();
}
else if (sb != null)
{
sb.Append(line.Trim());
}
if ((fasta.Peek() == '>' || fasta.Peek() == -1) && accession != null && sb != null)
{
string sequence = substituteWhitespace.Replace(sb.ToString(), "");
while (unique_accessions.Contains(accession))
{
accession += "_" + unique_identifier.ToString();
unique_identifier++;
}
unique_accessions.Add(accession);
Protein protein = new Protein(sequence, accession, organism, geneName, name: name, fullName: fullName,
isContaminant: isContaminant, databaseFilePath: proteinDbLocation);
if (protein.Length == 0)
{
errors.Add("Line" + line + ", Protein Length of 0: " + protein.Name + " was skipped from database: " + proteinDbLocation);
}
else
{
targets.Add(protein);
}
accession = null;
name = null;
fullName = null;
organism = null;
geneName = new List <Tuple <string, string> >();
}
// no input left
if (fasta.Peek() == -1)
{
break;
}
}
}
if (!targets.Any())
{
errors.Add("Error: No proteins could be read from the database: " + proteinDbLocation);
}
List <Protein> decoys = DecoyProteinGenerator.GenerateDecoys(targets, decoyType, maxThreads);
return((generateTargets ? targets : new List <Protein>()).Concat(decoyType != DecoyType.None ? decoys : new List <Protein>()).ToList());
}
/// <summary>
/// Load a protein fasta database, using regular expressions to get various aspects of the headers. The first regex capture group is used as each field.
/// </summary>
public static List <Protein> LoadProteinFasta(string proteinDbLocation, bool generateTargets, DecoyType decoyType, bool isContaminant,
FastaHeaderFieldRegex accessionRegex, FastaHeaderFieldRegex fullNameRegex, FastaHeaderFieldRegex nameRegex,
FastaHeaderFieldRegex geneNameRegex, FastaHeaderFieldRegex organismRegex, out List <string> errors, int maxThreads = -1)
{
HashSet <string> unique_accessions = new HashSet <string>();
int unique_identifier = 2;//for isoforms. the first will be "accession", the next will be "accession_2"
string accession = null;
string name = null;
string fullName = null;
string organism = null;
List <Tuple <string, string> > geneName = new List <Tuple <string, string> >();
errors = new List <string>();
Regex substituteWhitespace = new Regex(@"\s+");
List <Protein> targets = new List <Protein>();
using (var stream = new FileStream(proteinDbLocation, FileMode.Open, FileAccess.Read, FileShare.Read))
{
Stream fastaFileStream = proteinDbLocation.EndsWith("gz") ? // allow for .bgz and .tgz, which are (rarely) used
(Stream)(new GZipStream(stream, CompressionMode.Decompress)) :
stream;
StringBuilder sb = null;
StreamReader fasta = new StreamReader(fastaFileStream);
while (true)
{
string line = "";
line = fasta.ReadLine();
if (line == null)
{
break;
}
if (line.StartsWith(">"))
{
accession = ApplyRegex(accessionRegex, line);
fullName = ApplyRegex(fullNameRegex, line);
name = ApplyRegex(nameRegex, line);
organism = ApplyRegex(organismRegex, line);
string geneNameString = ApplyRegex(geneNameRegex, line);
if (geneNameString != null)
{
geneName.Add(new Tuple <string, string>("primary", geneNameString));
}
if (accession == null || accession == "")
{
accession = line.Substring(1).TrimEnd();
}
sb = new StringBuilder();
}
else if (sb != null)
{
sb.Append(line.Trim());
}
if ((fasta.Peek() == '>' || fasta.Peek() == -1) && accession != null && sb != null)
{
string sequence = substituteWhitespace.Replace(sb.ToString(), "");
// sanitize the sequence to replace unexpected characters with X (unknown amino acid)
// sometimes strange characters get added by RNA sequencing software, etc.
sequence = SanitizeAminoAcidSequence(sequence, 'X');
if (unique_accessions.Contains(accession)) //this will happen for isoforms
{
string originalAccession = accession; //save the original
accession += "_" + unique_identifier.ToString(); //add a number onto it
while (unique_accessions.Contains(accession)) //if that number was already added
{
unique_identifier++; //keep increasing it
accession = originalAccession + "_" + unique_identifier.ToString(); //try the new number
}
unique_identifier = 2; //reset
}
unique_accessions.Add(accession);
Protein protein = new Protein(sequence, accession, organism, geneName, name: name, fullName: fullName,
isContaminant: isContaminant, databaseFilePath: proteinDbLocation);
if (protein.Length == 0)
{
errors.Add("Line" + line + ", Protein Length of 0: " + protein.Name + " was skipped from database: " + proteinDbLocation);
}
else
{
targets.Add(protein);
}
accession = null;
name = null;
fullName = null;
organism = null;
geneName = new List <Tuple <string, string> >();
}
// no input left
if (fasta.Peek() == -1)
{
break;
}
}
}
if (!targets.Any())
{
errors.Add("Error: No proteins could be read from the database: " + proteinDbLocation);
}
List <Protein> decoys = DecoyProteinGenerator.GenerateDecoys(targets, decoyType, maxThreads);
return(generateTargets ? targets.Concat(decoys).ToList() : decoys);
}
