From 2f66e8678971ba0340a96d811ced405d75dbb114 Mon Sep 17 00:00:00 2001
From: "@syxhe" <https://t.me/syxhe>
Date: Sun, 19 Jan 2025 17:58:45 -0600
Subject: Write example code for generating, storing, and verifying a password

---
 src/shared.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 55 insertions(+), 2 deletions(-)

(limited to 'src/shared.c')

diff --git a/src/shared.c b/src/shared.c
index b154391..e5f0f13 100644
--- a/src/shared.c
+++ b/src/shared.c
@@ -2,6 +2,8 @@
 
 #include <stdarg.h>
 #include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
 #include <errno.h>
 #include <error.h>
 #include <stdio.h>
@@ -9,7 +11,7 @@
 void* xcalloc(size_t nmemb, size_t size) {
     void *mem = calloc(nmemb, size);
 
-    if(mem == NULL) {
+    if(!mem) {
         #if defined ___VXGG___XALLOC_EXIT_ON_ERROR___ && ___VXGG___XALLOC_EXIT_ON_ERROR___ > 0
             error(1, errno, "<xcalloc> Could not allocate memory");
         #endif
@@ -33,4 +35,55 @@ void* xreallocarray(void *ptr, size_t nmemb, size_t size) {
     }
 
     return mem;
-}
\ No newline at end of file
+}
+
+int readwholebuffer(char **str, unsigned long int initsize, int fd) {
+	// Try to read bytes from fd into str
+		// Bytes read == 0, return 0
+		// Bytes read < 0, free string, return -1;
+	// When string hits capacity, double the capacity, and reallocate the string
+
+	char *lstr = NULL, *tmp = NULL;
+	ssize_t bytesread = -1;
+	int csize = initsize, ccap = initsize;
+
+	lstr = xcalloc(initsize, sizeof(char));
+	while((bytesread = read(fd, lstr + (csize - ccap), ccap)) > 0) {
+		ccap -= bytesread;
+		if(ccap <= 0) {
+			csize *= 2;
+			ccap = csize / 2;
+
+			tmp = realloc(lstr, csize * sizeof(char));
+			if(!tmp) {
+				error(0, errno, "Could not reallocate enough space for lstr");
+				free(lstr);
+				bytesread = -100;
+				break;
+			}
+			lstr = tmp;
+		}
+	}
+	if(bytesread < 0 && bytesread != -100) {
+		error(0, errno, "Ran into a read() error");
+		free(lstr);
+		lstr = NULL;
+	}
+
+	if(lstr) {
+		tmp = realloc(lstr, csize - ccap + 1);
+		if(!tmp) {
+			error(0, errno, "Could not shrink lstr after reading buffer");
+			free(lstr);
+			bytesread = -100;
+		}
+		lstr = tmp;
+	}
+
+    if(lstr) {
+        lstr[csize - ccap - 1] = '\0'; // Don't include the newline
+    }
+
+	*str = lstr;
+	return ((bytesread == 0) ? (csize - ccap) : -1);
+}
-- 
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