Dynamic allocation of lines

Massive refactor including implementing my own read_line function

2 files changed, 78 insertions, 27 deletions

diff --git a/sort.c b/sort.c
index c2c55fb..f8a3dcc 100644
--- a/sort.c
+++ b/sort.c
@@ -1,43 +1,72 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
+#include "sort.h"
 
-#define MAX_LINE_LENGTH (2 << 8)
-#define LINES_VECTOR_SIZE_INITIAL (2 << 6)
-#define LINES_VECTOR_SIZE_INCREMENT (2 << 4)
+int main(void) {
+    vec *lines;
+    unsigned long i;
+    char *line;
 
-static int qsort_strcmp(const void *p1, const void *p2);
+    lines = vec_init();
 
-int main(void)
-{
-    char **lv;
-    unsigned long la, lc, li;
+    while ((line = read_line(stdin)) != NULL) {
+        vec_add(lines, line);
+    }
+
+    qsort(lines->data, lines->count, sizeof(char *), qsort_strcmp);
+
+    for (i = 0; i < lines->count; i++) {
+        fputs(lines->data[i], stdout);
+    }
+
+    exit(EXIT_SUCCESS);
+}
+
+char *read_line(FILE* stream) {
+    char *buf;
+    char *line;
+    unsigned long line_length;
+    unsigned long line_size;
 
-    la = LINES_VECTOR_SIZE_INITIAL;
-    lv = (char **) malloc(la * sizeof(char *));
+    line_size = BUF_SIZE;
+    line = malloc(line_size * sizeof(char *));
+    strncpy(line, "", 1);
 
-    for (lc = 0 ; ; lc++) {
-        if (lc == la) {
-            la += LINES_VECTOR_SIZE_INCREMENT;
-            lv = (char **) realloc(lv, la * sizeof(char *));
+    buf = malloc(BUF_SIZE);
+    for (;;) {
+        if (fgets(buf, BUF_SIZE, stream) == NULL) {
+            free(buf);
+            return NULL;
         }
-        lv[lc] = (char *) malloc(MAX_LINE_LENGTH * sizeof(char));
-        if ((fgets(lv[lc], MAX_LINE_LENGTH, stdin)) == NULL) {
-            break;
+        line = strncat(line, buf, BUF_SIZE);
+        line_length = strlen(line);
+        if (line[line_length - 1] == '\n') {
+            free(buf);
+            return line;
+        } else {
+            line_size <<= 1;
+            line = realloc(line, line_size * sizeof(char *));
         }
     }
+}
 
-    qsort(lv, lc, sizeof(char *), qsort_strcmp);
+vec *vec_init(void) {
+    vec *v;
+    v = malloc(sizeof(vec));
+    v->count = 0;
+    v->size = VEC_SIZE;
+    v->data = malloc(v->size * sizeof(char *));
+    return v;
+}
 
-    for (li = 0; li < lc; li++) {
-        fputs(lv[li], stdout);
+void vec_add(vec *v, char *s) {
+    if (v->count == v->size) {
+        v->size <<= 1;
+        v->data = realloc(v->data, v->size * sizeof(char *));
     }
-
-    exit(EXIT_SUCCESS);
+    v->data[v->count++] = s;
+    return;
 }
 
-static int qsort_strcmp(const void *p1, const void *p2)
-{
+static int qsort_strcmp(const void *p1, const void *p2) {
     return strcmp(* (char * const *) p1, * (char * const *) p2);
 }
 
diff --git a/sort.h b/sort.h
new file mode 100644
index 0000000..9b499c8
--- /dev/null
+++ b/sort.h
@@ -0,0 +1,22 @@
+#ifndef __SORT_H
+#define __SORT_H
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h> 
+
+#define VEC_SIZE 64
+#define BUF_SIZE 64
+
+typedef struct {
+    unsigned long count, size;
+    char **data;
+} vec;
+
+char *read_line(FILE* stream);
+vec *vec_init(void);
+void vec_add(vec *v, char *s);
+static int qsort_strcmp(const void *p1, const void *p2);
+
+#endif
+