Add dynamically-sized strings.

1 files changed, 103 insertions, 0 deletions

diff --git a/cstring/src/cstring.c b/cstring/src/cstring.c
new file mode 100644
index 0000000..832cb85
--- /dev/null
+++ b/cstring/src/cstring.c
@@ -0,0 +1,103 @@
+#include <cstring.h>
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+string string_new(const char* cstr) {
+  const size_t length = strlen(cstr);
+  const size_t size   = length + 1;
+
+  char* data = calloc(size, sizeof(char));
+  ASSERT(data);
+  if (length > 0) {
+    memcpy(data, cstr, length);
+  }
+
+  return (string){
+      .data   = data,
+      .length = length,
+  };
+}
+
+void string_del(string* str) {
+  if (str->data) {
+    free((void*)str->data);
+    str->data   = 0;
+    str->length = 0;
+  }
+}
+
+string string_concat(string left, string right) {
+  const size_t length = left.length + right.length;
+  const size_t size   = length + 1;
+
+  char* data = calloc(size, sizeof(char));
+  ASSERT(data);
+  if (length > 0) {
+    memcpy(data, left.data, left.length);
+    memcpy(data + left.length, right.data, right.length);
+  }
+
+  return (string){
+      .data   = data,
+      .length = length,
+  };
+}
+
+string string_from_size(size_t size) {
+  const size_t length = snprintf(NULL, 0, "%zu", size) + 1;
+  char*        data   = calloc(length, sizeof(char));
+  ASSERT(data);
+  snprintf(data, length, "%zu", size);
+  return (string){
+      .data   = data,
+      .length = length,
+  };
+}
+
+string string_format_size(size_t size) {
+  const size_t multiples[] = {1073741824, 1048576, 1024, 1};
+  const char*  units[]     = {"G", "M", "K", "B"};
+
+  size_t integer    = 0;
+  size_t fractional = 0;
+
+  int i;
+  for (i = 0; i < 4; ++i) {
+    const size_t m = multiples[i];
+    if (size >= m) {
+      integer    = size / m;
+      fractional = size % m;
+      break;
+    }
+  }
+
+  double      s;
+  const char* unit;
+  const char* format;
+  if (i == 4) { // 0
+    s      = (double)size;
+    unit   = "";
+    format = "%f%s";
+  } else if (i == 3) { // Bytes
+    s      = (double)integer + (double)fractional / (double)multiples[i];
+    unit   = units[i];
+    format = "%.0f%s";
+  } else { // KB, MB, GB
+    assert(i >= 0);
+    assert(i < 3);
+    s      = (double)integer + (double)fractional / (double)multiples[i];
+    unit   = units[i];
+    format = "%.2f%s";
+  }
+
+  const size_t length = snprintf(NULL, 0, format, s, unit) + 1;
+  char*        data   = calloc(length, sizeof(char));
+  ASSERT(data);
+  snprintf(data, length, format, s, unit);
+  return (string){
+      .data   = data,
+      .length = length,
+  };
+}