Initial commit

1 files changed, 82 insertions, 0 deletions

diff --git a/readall.c b/readall.c
new file mode 100644
index 0000000..9f55697
--- /dev/null
+++ b/readall.c
@@ -0,0 +1,82 @@
+/* by Nominal Animal, 2017: https://stackoverflow.com/a/44894946 */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+
+#include "readall.h"
+
+/* Size of each input chunk to be
+   read and allocate for. */
+#ifndef  READALL_CHUNK
+#define  READALL_CHUNK  262144
+#endif
+
+/* This function returns one of the READALL_ constants above.
+   If the return value is zero == READALL_OK, then:
+     (*dataptr) points to a dynamically allocated buffer, with
+     (*sizeptr) chars read from the file.
+     The buffer is allocated for one extra char, which is NUL,
+     and automatically appended after the data.
+   Initial values of (*dataptr) and (*sizeptr) are ignored.
+*/
+int readall(FILE *in, char **dataptr, size_t *sizeptr)
+{
+    char  *data = NULL, *temp;
+    size_t size = 0;
+    size_t used = 0;
+    size_t n;
+
+    /* None of the parameters can be NULL. */
+    if (in == NULL || dataptr == NULL || sizeptr == NULL)
+        return READALL_INVALID;
+
+    /* A read error already occurred? */
+    if (ferror(in))
+        return READALL_ERROR;
+
+    while (1) {
+
+        if (used + READALL_CHUNK + 1 > size) {
+            size = used + READALL_CHUNK + 1;
+
+            /* Overflow check. Some ANSI C compilers
+               may optimize this away, though. */
+            if (size <= used) {
+                free(data);
+                return READALL_TOOMUCH;
+            }
+
+            temp = realloc(data, size);
+            if (temp == NULL) {
+                free(data);
+                return READALL_NOMEM;
+            }
+            data = temp;
+        }
+
+        n = fread(data + used, 1, READALL_CHUNK, in);
+        if (n == 0)
+            break;
+
+        used += n;
+    }
+
+    if (ferror(in)) {
+        free(data);
+        return READALL_ERROR;
+    }
+
+    temp = realloc(data, used + 1);
+    if (temp == NULL) {
+        free(data);
+        return READALL_NOMEM;
+    }
+    data = temp;
+    data[used] = '\0';
+
+    *dataptr = data;
+    *sizeptr = used;
+
+    return READALL_OK;
+}