First commit

libsvm-3.36/matlab/libsvmread.c

@@ -0,0 +1,212 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <errno.h>
+
+#include "mex.h"
+
+#ifdef MX_API_VER
+#if MX_API_VER < 0x07030000
+typedef int mwIndex;
+#endif
+#endif
+#ifndef max
+#define max(x,y) (((x)>(y))?(x):(y))
+#endif
+#ifndef min
+#define min(x,y) (((x)<(y))?(x):(y))
+#endif
+
+void exit_with_help()
+{
+	mexPrintf(
+	"Usage: [label_vector, instance_matrix] = libsvmread('filename');\n"
+	);
+}
+
+static void fake_answer(int nlhs, mxArray *plhs[])
+{
+	int i;
+	for(i=0;i<nlhs;i++)
+		plhs[i] = mxCreateDoubleMatrix(0, 0, mxREAL);
+}
+
+static char *line;
+static int max_line_len;
+
+static char* readline(FILE *input)
+{
+	int len;
+
+	if(fgets(line,max_line_len,input) == NULL)
+		return NULL;
+
+	while(strrchr(line,'\n') == NULL)
+	{
+		max_line_len *= 2;
+		line = (char *) realloc(line, max_line_len);
+		len = (int) strlen(line);
+		if(fgets(line+len,max_line_len-len,input) == NULL)
+			break;
+	}
+	return line;
+}
+
+// read in a problem (in libsvm format)
+void read_problem(const char *filename, int nlhs, mxArray *plhs[])
+{
+	int max_index, min_index, inst_max_index;
+	size_t elements, k, i, l=0;
+	FILE *fp = fopen(filename,"r");
+	char *endptr;
+	mwIndex *ir, *jc;
+	double *labels, *samples;
+
+	if(fp == NULL)
+	{
+		mexPrintf("can't open input file %s\n",filename);
+		fake_answer(nlhs, plhs);
+		return;
+	}
+
+	max_line_len = 1024;
+	line = (char *) malloc(max_line_len*sizeof(char));
+
+	max_index = 0;
+	min_index = 1; // our index starts from 1
+	elements = 0;
+	while(readline(fp) != NULL)
+	{
+		char *idx, *val;
+		// features
+		int index = 0;
+
+		inst_max_index = -1; // strtol gives 0 if wrong format, and precomputed kernel has <index> start from 0
+		strtok(line," \t"); // label
+		while (1)
+		{
+			idx = strtok(NULL,":"); // index:value
+			val = strtok(NULL," \t");
+			if(val == NULL)
+				break;
+
+			errno = 0;
+			index = (int) strtol(idx,&endptr,10);
+			if(endptr == idx || errno != 0 || *endptr != '\0' || index <= inst_max_index)
+			{
+				mexPrintf("Wrong input format at line %d\n",l+1);
+				fake_answer(nlhs, plhs);
+				return;
+			}
+			else
+				inst_max_index = index;
+
+			min_index = min(min_index, index);
+			elements++;
+		}
+		max_index = max(max_index, inst_max_index);
+		l++;
+	}
+	rewind(fp);
+
+	// y
+	plhs[0] = mxCreateDoubleMatrix(l, 1, mxREAL);
+	// x^T
+	if (min_index <= 0)
+		plhs[1] = mxCreateSparse(max_index-min_index+1, l, elements, mxREAL);
+	else
+		plhs[1] = mxCreateSparse(max_index, l, elements, mxREAL);
+
+	labels = mxGetPr(plhs[0]);
+	samples = mxGetPr(plhs[1]);
+	ir = mxGetIr(plhs[1]);
+	jc = mxGetJc(plhs[1]);
+
+	k=0;
+	for(i=0;i<l;i++)
+	{
+		char *idx, *val, *label;
+		jc[i] = k;
+
+		readline(fp);
+
+		label = strtok(line," \t\n");
+		if(label == NULL)
+		{
+			mexPrintf("Empty line at line %d\n",i+1);
+			fake_answer(nlhs, plhs);
+			return;
+		}
+		labels[i] = strtod(label,&endptr);
+		if(endptr == label || *endptr != '\0')
+		{
+			mexPrintf("Wrong input format at line %d\n",i+1);
+			fake_answer(nlhs, plhs);
+			return;
+		}
+
+		// features
+		while(1)
+		{
+			idx = strtok(NULL,":");
+			val = strtok(NULL," \t");
+			if(val == NULL)
+				break;
+
+			ir[k] = (mwIndex) (strtol(idx,&endptr,10) - min_index); // precomputed kernel has <index> start from 0
+
+			errno = 0;
+			samples[k] = strtod(val,&endptr);
+			if (endptr == val || errno != 0 || (*endptr != '\0' && !isspace(*endptr)))
+			{
+				mexPrintf("Wrong input format at line %d\n",i+1);
+				fake_answer(nlhs, plhs);
+				return;
+			}
+			++k;
+		}
+	}
+	jc[l] = k;
+
+	fclose(fp);
+	free(line);
+
+	{
+		mxArray *rhs[1], *lhs[1];
+		rhs[0] = plhs[1];
+		if(mexCallMATLAB(1, lhs, 1, rhs, "transpose"))
+		{
+			mexPrintf("Error: cannot transpose problem\n");
+			fake_answer(nlhs, plhs);
+			return;
+		}
+		plhs[1] = lhs[0];
+	}
+}
+
+void mexFunction( int nlhs, mxArray *plhs[],
+		int nrhs, const mxArray *prhs[] )
+{
+	#define filename_size 256
+
+	char filename[filename_size];
+
+	if(nrhs != 1 || nlhs != 2)
+	{
+		exit_with_help();
+		fake_answer(nlhs, plhs);
+		return;
+	}
+
+	if(mxGetString(prhs[0], filename, filename_size) == 1){
+		mexPrintf("Error: wrong or too long filename\n");
+		fake_answer(nlhs, plhs);
+		return;
+	}
+
+	read_problem(filename, nlhs, plhs);
+
+	return;
+}
+