Generic resizable array templates.

array.h

+#define DECLARE_SASS_ARRAY_OF(type) \
+typedef struct { \
+  size_t length; \
+  size_t capacity; \
+  type *contents; \
+} sass_ ## type ## _array; \
+sass_ ## type ## _array sass_make_ ## type ## _array(size_t cap); \
+void sass_ ## type ## _array_push(sass_ ## type ## _array *a, type elem); \
+void sass_ ## type ## _array_cat(sass_ ## type ## _array *a, sass_ ## type ## _array *b); \
+void sass_free_ ## type ## _array(sass_ ## type ## _array *a)
+
+#define DEFINE_SASS_ARRAY_OF(type) \
+sass_ ## type ## _array sass_make_ ## type ## _array(size_t cap) { \
+  sass_ ## type ## _array a; \
+  a.contents = (type *) malloc(cap * sizeof(type)); \
+  if (!a.contents) { \
+    printf("ERROR: unable to allocate array of %s\n", #type); \
+    abort(); \
+  } \
+  a.capacity = cap; \
+  a.length = 0; \
+  return a; \
+} \
+void sass_ ## type ## _array_push(sass_ ## type ## _array *a, type elem) { \
+  size_t len = a->length, cap = a->capacity; \
+  if (len < cap) { \
+    a->contents[len] = elem; \
+    a->length++; \
+  } \
+  else { \
+    type *new = (type *) realloc(a->contents, len * 2); \
+    if (!new) { \
+      printf("ERROR: unable to resize array of %s\n", #type); \
+      abort(); \
+    } \
+    else { \
+      new[len] = elem; \
+      a->contents = new; \
+      a->length++; \
+      a->capacity = len * 2; \
+    } \
+  } \
+} \
+void sass_ ## type ## _array_cat(sass_ ## type ## _array *a, sass_ ## type ## _array *b) { \
+  size_t b_len = b->length; \
+  type *b_cont = b->contents; \
+  int i; \
+  for (i = 0; i < b_len; i++) sass_ ## type ## _array_push(a, b_cont[i]); \
+}

test_array.c

+#include <stdio.h>
+#include <stdlib.h>
+#include "test_array.h"
+
+DEFINE_SASS_ARRAY_OF(char);
+
+int main() {
+  sass_char_array a = sass_make_char_array(4);
+  printf("%ld, %ld\n", a.length, a.capacity);
+  sass_char_array_push(&a, 'h');
+  sass_char_array_push(&a, 'e');
+  sass_char_array_push(&a, 'l');
+  sass_char_array_push(&a, 'l');
+  
+  printf("%ld, %ld\n", a.length, a.capacity);
+  
+  
+  int i;
+  for (i = 0; i < a.length; i++) putchar(a.contents[i]);
+  putchar('\n');
+  
+  sass_char_array_push(&a, 'o');
+  printf("%ld, %ld\n", a.length, a.capacity);
+  
+  for (i = 0; i < a.length; i++) putchar(a.contents[i]);
+  putchar('\n');
+  
+  sass_char_array b = sass_make_char_array(7);
+  sass_char_array_push(&a, ' ');
+  sass_char_array_push(&a, 'w');
+  sass_char_array_push(&a, 'o');
+  sass_char_array_push(&a, 'r');
+  sass_char_array_push(&a, 'l');
+  sass_char_array_push(&a, 'd');
+  
+  sass_char_array_cat(&a, &b);
+  
+  printf("%ld, %ld\n", a.length, a.capacity);
+  for (i = 0; i < a.length; i++) putchar(a.contents[i]);
+  putchar('\n');
+  
+  return 0;
+}
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test_array.h

+#include "array.h"
+
+DECLARE_SASS_ARRAY_OF(char);
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