added lina_loadMatrixFromStream
This commit is contained in:
Francesco Cozzuto
@@ -2,6 +2,9 @@
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#include <assert.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <errno.h>
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#include <ctype.h>
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#include "lina.h"
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#define check assert
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@@ -27,12 +30,9 @@ void lina_dot(double *A, double *B, double *C, int m, int n, int l){
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pos += A[i*n + j] * B[j*l + k];
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// The usage of a support variable 'pos'
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// is for safety purpose (non-zero C matrix)
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C[i*l + k] = pos;
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}
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}
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}
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void lina_add(double *A, double *B, double *C, int m, int n){
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@@ -97,4 +97,294 @@ void lina_transpose(double *A, double *B, int m, int n)
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B[1] = item;
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}
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}
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// Returns 0 if an error occurred, 1 if an integer
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// was scanned and -1 if a floating point was scanned.
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static int scanValue(FILE *fp, char *buffer, int max_length, char first, char *final, char **error)
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{
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assert(fp != NULL && buffer != NULL && error != NULL);
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assert(isdigit(first));
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int n = 0;
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char c = first;
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// Scan the integer portion of
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// the numeric value and copy it
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// into the buffer.
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do
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{
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if(n == max_length)
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// ERROR: Internal buffer is too small to hold
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// the representation of this item.
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return 0;
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buffer[n++] = c;
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c = getc(fp);
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}
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while(c != EOF && isdigit(c));
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// Did the integer part end with
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// a dot?
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_Bool dot = (c == '.');
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// Now scan and copy the decimal
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// part of the numeric value if
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// a dot was found.
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if(dot)
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{
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if(n == max_length)
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// ERROR: Internal buffer is too small to hold
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// the representation of this item.
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// (The dot doesn't fit.)
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return 0;
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buffer[n++] = '.';
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c = getc(fp);
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if(!isdigit(c))
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// ERROR: Got something other than a
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// digit after the dot.
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return 0;
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do
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{
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if(n == max_length)
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// ERROR: Internal buffer is too small
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// to hold the representation of
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// this item.
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return 0;
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buffer[n++] = c;
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c = getc(fp);
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}
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while(c != EOF && isdigit(c));
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}
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buffer[n] = '\0';
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if(final != NULL)
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*final = c;
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return dot ? -1 : 1;
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}
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double *lina_loadMatrixFromStream(FILE *fp, int *width, int *height, char **error)
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{
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assert(width != NULL && height != NULL);
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if(fp == NULL)
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fp = stdin;
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char *dummy;
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if(error == NULL)
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error = &dummy;
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else
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*error = NULL;
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char c = getc(fp);
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while(c != EOF && isspace(c))
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c = getc(fp);
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if(c == EOF)
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{
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// ERROR: Stream ended before a matrix was
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// found.
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*error = "Stream ended before a matrix was found";
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return NULL;
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}
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if(c != '[')
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{
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// ERROR: Was expected a '[' as the first
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// character of a matrix, but got
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// something else instead.
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*error = "Got something other than a matrix "
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"where one was expected";
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return NULL;
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}
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c = getc(fp);
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// Skip spaces before the first element.
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while(c != EOF && isspace(c))
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c = getc(fp);
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if(c == EOF)
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{
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// ERROR: Stream ended where a numeric value
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// was expected.
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*error = "Stream ended where a numeric value "
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"was expected";
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return NULL;
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}
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double *matrix = malloc(sizeof(matrix[0]) * 64);
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if(matrix == NULL)
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{
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// ERROR: Insufficient memory.
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*error = "Insufficient memory";
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return NULL;
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}
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int capacity = 64, size = 0,
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w = -1, i = 0, j = 0;
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if(c != ']')
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while(1)
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{
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if(!isdigit(c))
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{
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// ERROR: Got something other than a digit
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// where a numeric value was expected.
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*error = "Got something other than a numeric "
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"value where one was expected";
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return NULL;
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}
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// Numeric values can't be represented
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// in strings bigger than this buffer
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// since they need to be copied in it
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// to be converted to actual numeric
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// variables.
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char buffer[128];
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int res = scanValue(fp, buffer, sizeof(buffer), c, &c, error);
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if(res == 0)
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// Failed to scan the value, abort.
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// NOTE: The error was already reported.
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return NULL;
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assert(res == 1 || res == -1);
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// Make sure the matrix has enough space.
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if(size == capacity)
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{
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int new_capacity = capacity * 2;
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double *temp = realloc(matrix, sizeof(double) * new_capacity);
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if(temp == NULL)
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{
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// ERROR: Insufficient memory.
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*error = "Insufficient memory";
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free(matrix);
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return NULL;
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}
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matrix = temp;
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capacity = new_capacity;
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}
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errno = 0;
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double casted;
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if(res == 1)
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casted = (double) strtoll(buffer, NULL, 10);
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else
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casted = strtod(buffer, NULL);
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if(errno)
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{
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// ERROR: Failed to convert a numeric value
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// from it's string form to a numeric
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// variable.
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*error = "Failed to convert string to number";
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free(matrix);
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return NULL;
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}
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matrix[size++] = casted;
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i += 1;
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while(c != EOF && isspace(c))
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c = getc(fp);
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if(c == ']' || c == ',')
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{
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// The matrix's row just ended.
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if(w == -1)
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// This was the first row.
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w = i;
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else
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{
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// This wasn't the first row,
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// so it's possible that it's
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// length is different from the
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// previous ones.
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assert(w > -1);
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if(i != w)
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{
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// ERROR: The j-th row has the wrong
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// number of elements.
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if(i < w)
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*error = "Matrix row is too short";
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else
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*error = "Matrix row is too long";
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return NULL;
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}
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}
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i = 0;
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j += 1;
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if(c == ']')
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// The whole matrix ended!
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break;
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c = getc(fp);
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while(c != EOF && isspace(c))
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c = getc(fp);
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}
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if(c == EOF)
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{
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// ERROR: Stream ended inside a matrix, where
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// either ',', ']' or a numeric value was
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// expected.
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*error = "Stream ended inside a matrix, where either "
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"',', ']' or a numeric value was expected";
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return NULL;
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}
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}
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if(size == 0)
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{
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free(matrix);
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*error = "Empty matrix";
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return NULL;
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}
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// If the internal fragmentation is too much,
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// return a dynamic memory region with the
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// exact size instead of the buffer used to
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// build the matrix.
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int fragm_threshold = 30; // (It's a percentage)
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if(100.0 * size/capacity < fragm_threshold)
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{
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int new_capacity = (size == 0) ? 1 : size;
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double *temp = realloc(matrix, new_capacity * sizeof(double));
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if(temp != NULL)
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matrix = temp;
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}
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*width = w;
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*height = j;
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return matrix;
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}
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