Data update

Task/Search-in-paragraphs-text/C/search-in-paragraphs-text.c

@@ -0,0 +1,112 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define INPUT_FILE_NAME     "Traceback.txt"
+#define KEYWORD_STRING      "SystemError"
+#define TRACEBACK_STRING    "Traceback (most recent call last):"
+#define END_OF_PARAGRAPH    "\n----------------\n"
+
+char *load_paragraph( FILE *f );
+
+int main() {
+    FILE *f   = fopen( INPUT_FILE_NAME, "r" );
+
+    if( f ) {
+        char *par = NULL;
+
+        while( (par=load_paragraph(f)) ) {
+            if( strstr(par,KEYWORD_STRING) ) {
+                char *p = strstr( par, TRACEBACK_STRING );
+
+                if( p ) printf( p );
+                else printf( "%s\n%s", TRACEBACK_STRING, par );
+
+                printf( END_OF_PARAGRAPH );
+            }
+
+            free( par ); par = NULL;
+        }
+
+        if( !feof(f) )
+            puts( "End of file not reached." );
+
+        fclose( f ); f = NULL;
+    }
+    else {
+        puts( "Input file not opened." );
+    }
+
+    return 0;
+}
+
+/*===========================================================================
+Starting from the current position, looks for the first occurrence of "\n\n"
+in the file f, counting the number of characters from the current position
+to "\n\n" itself (not included) or to the end of the file (whichever occurs
+first). Resets the file to its original position, then returns the number of
+characters.
+If the funtions fails, it returns ((size_t)-1).
+===========================================================================*/
+
+size_t get_paragraph_length( FILE *f ) {
+    size_t l = ((size_t)-1);
+
+    if( f && !feof(f) ) {
+        fpos_t ex_pos;
+
+        if( 0==fgetpos(f,&ex_pos) ) {
+            int c;
+
+            for( c=fgetc(f); c!=EOF; c=fgetc(f) ) {
+                if( '\n'==c ) {
+                    if( '\n'!=(c=fgetc(f)) ) {
+                        ungetc( c, f );
+                    }
+                    else {
+                        ++l;
+                        break;
+                    }
+                }
+
+                ++l;
+            }
+
+            l += EOF==c;
+
+            fsetpos( f, &ex_pos );
+        }
+    }
+
+    return l;
+}
+
+/*===========================================================================
+Loads a paragraph from the file f. Paragraphs are detected looking for the
+occurrences of "\n\n" separators. The loaded paragraph is put into a chunk of
+memory allocated with malloc(). The pointer to that memory is returned.
+If the function fails, no memory is allocated and NULL is returned.
+===========================================================================*/
+
+char *load_paragraph( FILE *f ) {
+    char *par = NULL;
+
+    if( !feof(f) ) {
+        size_t i, l = get_paragraph_length( f );
+
+        if( ((size_t)-1)!=l ) {
+            par = malloc( l+1 );
+
+            if( par ) {
+                for( i=0; i<l; ++i )
+                    par[i] = fgetc( f );
+                par[i] = '\0';
+
+                /* just jump beyond the paragraph delimiter */
+                fgetc( f ); fgetc( f );
+            }
+        }
+    }
+
+    return par;
+}