C solution for week 98, part 1

2 files changed, 221 insertions, 0 deletions

diff --git a/challenge-098/abigail/README.md b/challenge-098/abigail/README.md
index 3b8c4e5800..56e481bb08 100644
--- a/challenge-098/abigail/README.md
+++ b/challenge-098/abigail/README.md
@@ -55,6 +55,7 @@ Output:
 ### Solutions
 * [AWK](awk/ch-1.awk)
 * [Bash](bash/ch-1.sh)
+* [C](c/ch-1.ch)
 * [Perl](perl/ch-1.pl)
 
 ### Blog
diff --git a/challenge-098/abigail/c/ch-1.c b/challenge-098/abigail/c/ch-1.c
new file mode 100644
index 0000000000..8aee103290
--- /dev/null
+++ b/challenge-098/abigail/c/ch-1.c
@@ -0,0 +1,220 @@
+# include <stdlib.h>
+# include <stdio.h>
+# include <string.h>
+# include <ctype.h>
+# include <limits.h>
+
+/*
+ * See ../README.md
+ */
+
+/*
+ * Run as: cc -o ch-1.o ch-1.c; ./ch-1.o < input-file
+ */
+
+/*
+ * Copied from https://gist.github.com/w-vi/7e98342181776162b1a3
+ */
+char * slurpfile (char * filename) {
+    FILE * fp;
+    char * source;
+    long bufsize;
+    size_t len;
+    if ((fp = fopen (filename, "r")) == NULL) {
+        fprintf (stderr, "Failed to open %s\n", filename);
+        exit (1);
+    }
+    /*
+     * Get the size of the file:
+     *   - seek to the end of the file
+     *   - use ftell to get the offset from the start
+     *   - seek back to the beginning
+     */
+    if (fseek (fp, 0L, SEEK_END) != 0) {
+        fprintf (stderr, "seek() failed for %s\n", filename);
+        exit (1);
+    }
+    if ((bufsize = ftell (fp)) == -1) {
+        fprintf (stderr, "ftell() failed for %s\n", filename);
+        exit (1);
+    }
+    if (fseek (fp, 0L, SEEK_SET) != 0) {
+        fprintf (stderr, "seek() failed for %s\n", filename);
+        exit (1);
+    }
+
+    /*
+     * Allocate memory for content of the file
+     */
+    if ((source = (char *) malloc (sizeof (char) * (bufsize + 1))) == NULL) {
+        fprintf (stderr, "malloc() failed for %s\n", filename);
+        exit (1);
+    }
+
+    /*
+     * And read it in
+     */
+    if ((len = fread (source, sizeof (char), bufsize, fp)) == 0) {
+        fprintf (stderr, "fread() failed for %s\n", filename);
+        exit (1);
+    }
+    source [++ len] = '\0';
+
+    return source;
+}
+
+/*
+ * Use four arrays:
+ *   - filenames:    names of files read
+ *   - content:      pointers to content of files read
+ *   - content_ptr:  pointers to unreturned content
+ *   - content_size: number of characters not returned yet
+ */
+size_t   read_files   = 0;
+char  ** filenames    = NULL;
+char  ** content      = NULL;
+char  ** content_ptr  = NULL;
+size_t * content_size = NULL;
+
+char * readN (char * filename, int amount) {
+    ssize_t found = -1;
+    char * out;
+    /*
+     * Check whether we've already found the file --
+     * if so, set its position in "found".
+     */
+    for (size_t i = 0; i < read_files; i ++) {
+        if (strncmp (filename, filenames [i], PATH_MAX) == 0) {
+            /*
+             * Found the file
+             */
+            found = i;
+            break;
+        }
+    }
+
+    /*
+     * Not found; all filename, content of file, and size to
+     * the end of the arrays.
+     */
+    if (found < 0) {
+        found = read_files ++;
+        /*
+         * Allocate memory
+         */
+        if ((filenames = (char **)
+                realloc (filenames,    read_files * sizeof (char *))) == NULL) {
+            fprintf (stderr, "malloc() failed for %s\n", filename);
+            exit (1);
+        }
+        if ((content = (char **)
+                realloc (content,      read_files * sizeof (char *))) == NULL) {
+            fprintf (stderr, "malloc() failed for %s\n", filename);
+            exit (1);
+        }
+        if ((content_ptr = (char **)
+                realloc (content_ptr,  read_files * sizeof (char *))) == NULL) {
+            fprintf (stderr, "malloc() failed for %s\n", filename);
+            exit (1);
+        }
+        if ((content_size = (size_t *)
+                realloc (content_size, read_files * sizeof (size_t))) == NULL) {
+            fprintf (stderr, "malloc() failed for %s\n", filename);
+            exit (1);
+        }
+
+        /*
+         * Set data
+         */
+        if ((filenames [found] = (char *)
+                    malloc (sizeof (char) * (strlen (filename) + 1))) == NULL) {
+            fprintf (stderr, "malloc() failed for %s\n", filename);
+            exit (1);
+        }
+        stpncpy (filenames [found], filename, strlen (filename));
+        filenames [found] [strlen (filename)] = '\0';
+        content      [found] = slurpfile (filename);
+        content_ptr  [found] = content [found];
+        content_size [found] = strlen (content [found]);
+
+        /*
+         * Remove any trailing new lines
+         */
+        while (content [found] [content_size [found] - 1] == '\n') {
+            content [found] [-- content_size [found]] = '\0';
+        }
+    }
+    /*
+     * Now 'found' points to the place where the content
+     * of the file is.
+     */
+
+     /*
+      * Cannot return more than we have.
+      */
+     if (content_size [found] < amount) {
+        amount = content_size [found];
+     }
+     /*
+      * Allocate memory for the return value
+      */
+     if ((out = (char *) malloc (sizeof (char) * (amount + 1))) == NULL) {
+        fprintf (stderr, "malloc() failed for %s\n", filename);
+        exit (1);
+    }
+    /*
+     * Copy the amount of data, make sure it's NUL terminated.
+     */
+    stpncpy (out, content_ptr [found], amount);
+    out [amount] = '\0';
+
+    /*
+     * Adjust the pointer and size left
+     */
+    content_ptr  [found] += amount;
+    content_size [found] -= amount;
+
+    return out;
+}
+
+
+
+int main (void) {
+    char *  line    = NULL;
+    size_t  len     = 0;
+    size_t  strlen;
+
+    /*
+     * Iterate over the lines of input; parse each line into
+     * a file name and an amount. Call readN for each line.
+     */
+    while ((strlen = getline (&line, &len, stdin)) != -1) {
+        char * line_ptr = line;
+        char * filename;
+        int amount;
+        if ((filename = (char *) malloc (PATH_MAX * sizeof (char))) == NULL) {
+            fprintf (stderr, "malloc() failed\n");
+            exit (1);
+        }
+        if (sscanf (line_ptr, "%s %d", filename, &amount) != 2) {
+            fprintf (stderr, "Could not parse input\n");
+            exit (1);
+        }
+        printf ("%s\n", readN (filename, amount));
+        free (filename);
+    }
+    /*
+     * Release memory
+     */
+    free (line);
+    for (size_t i = 0; i < read_files; i ++) {
+        free (filenames [i]);
+        free (content   [i]);
+    }
+    free (filenames);
+    free (content);
+    free (content_ptr);
+    free (content_size);
+
+    return (0);
+}