initial commit

c/acronym/src/acronym.c

@@ -0,0 +1,69 @@
+#include <string.h>
+#include <malloc.h>
+#include <ctype.h>
+
+#include "acronym.h"
+
+/* See GNUmakefile in following link for explanation
+ * https://exercism.io/my/solutions/103b2f7d92db42309c1988030f5202c7
+ */
+#if defined UNIT_TEST || defined DEBUG
+#include <stdio.h>
+#include <stdlib.h>
+#endif
+
+#define SKIPWORD(p) { while (*(p) && (isalpha(*(p)) || *p=='\'')) (p)++;}
+#define NEXTWORD(p) { while (*(p) && !isalpha(*(p))) (p)++;}
+
+char *abbreviate(const char *phrase)
+{
+    /* Yet another approach (to avoid scanning phrase twice):
+     * We (re)allocate a ALLOCSIZE buffer when current one is not large
+     * enough to accept next character + 1 ('\0')
+     *
+     * Other solutions would be to scan phrase twice (for example an initial
+     * strlen() to find out a maximum length), or the (bad idea) using a fixed
+     * size buffer.
+     *
+     * The usual choices.
+     */
+    char *buf=NULL;
+    int c=0, size=0;
+
+    if (!phrase)
+        return NULL;
+
+    while (*phrase) {
+        NEXTWORD(phrase);
+        if (*phrase) {
+            /* buffer too small */
+            if (c>=size-1) {
+                size+=ALLOCSIZE;
+                if (!(buf=realloc(buf, size)))
+                    return NULL;
+            }
+            *(buf+c++)=toupper(*phrase++);
+            SKIPWORD(phrase);
+        }
+    }
+
+    /* at least one character */
+    if (c)
+        *(buf+c)=0;
+    return buf;
+}
+
+#ifdef UNIT_TEST
+int main(int ac, char **av)
+{
+    int arg=1;
+    char *p;
+
+    for (; arg<ac; ++arg) {
+        p=abbreviate(*(av+arg));
+        printf("acronym(%s)=[%s]\n", *(av+arg), p? p: "NULL");
+        if (p)
+            free(p);
+    }
+}
+#endif