X-Git-Url: https://plomlompom.com/repos/?a=blobdiff_plain;f=src%2Freadwrite.c;h=039dadea4a6855e1f2222241193897db4f987b4c;hb=4d9b6ac142740aa337fc3e622902c9595c36f6d0;hp=fd520685a935f978584851feaaf69a51878de802;hpb=f743c2cc4451192d645e726654a48bd58a636cef;p=plomrogue

diff --git a/src/readwrite.c b/src/readwrite.c
index fd52068..039dade 100644
--- a/src/readwrite.c
+++ b/src/readwrite.c
@@ -1,36 +1,103 @@
-#include <stdio.h>
-#include <limits.h>
-#include <stdint.h>
-#define UCHARSIZE (UCHAR_MAX + 1)
-
-uint16_t read_uint16_bigendian(FILE * file) {
-// Read uint16 from file in big-endian order.
-  unsigned char a = fgetc(file);
-  unsigned char b = fgetc(file);
-  return (a * UCHARSIZE) + b; }
-
-void write_uint16_bigendian(uint16_t x, FILE * file) {
-// Write uint16 to file in beg-endian order.
-  unsigned char a = x / UCHARSIZE;
-  unsigned char b = x % UCHARSIZE;
-  fputc(a, file);
-  fputc(b, file); }
-
-uint32_t read_uint32_bigendian(FILE * file) {
-// Read uint32 from file in big-endian order.
-  unsigned char a = fgetc(file);
-  unsigned char b = fgetc(file);
-  unsigned char c = fgetc(file);
-  unsigned char d = fgetc(file);
-  return (a * UCHARSIZE * UCHARSIZE * UCHARSIZE) + (b * UCHARSIZE * UCHARSIZE) + (c * UCHARSIZE) + d; }
-
-void write_uint32_bigendian(uint32_t x, FILE * file) {
-// Write uint32 to file in beg-endian order.
-  unsigned char a = x / (UCHARSIZE * UCHARSIZE * UCHARSIZE);
-  unsigned char b = (x - (a * UCHARSIZE * UCHARSIZE * UCHARSIZE)) / (UCHARSIZE * UCHARSIZE);
-  unsigned char c = (x - ((a * UCHARSIZE * UCHARSIZE * UCHARSIZE) + (b * UCHARSIZE * UCHARSIZE))) / UCHARSIZE;
-  unsigned char d = x % UCHARSIZE;
-  fputc(a, file);
-  fputc(b, file);
-  fputc(c, file);
-  fputc(d, file); }
+/* readwrite.c */
+
+#include "readwrite.h"
+#include <stdio.h> /* for FILE typedef*/
+#include <stdint.h> /* for uint16_t, uint32_t */
+
+
+
+/* Read/write "x" from/to "file" as bigendian representation of "size" bits. */
+static uint8_t read_uintX_bigendian(FILE * file, uint32_t * x, uint8_t size);
+static uint8_t write_uintX_bigendian(FILE * file, uint32_t x, uint8_t size);
+
+
+
+static uint8_t read_uintX_bigendian(FILE * file, uint32_t * x, uint8_t size)
+{
+    if (0 != size % 8)
+    {
+        return 1;
+    }
+    int16_t bitshift = size - 8;
+
+    * x = 0;
+    int test;
+    for (; bitshift >= 0; bitshift = bitshift - 8)
+    {
+        test = fgetc(file);
+        if (EOF == test)
+        {
+            return 1;
+        }
+        * x = * x + ((uint32_t) test << bitshift);
+    }
+    return 0;
+}
+
+
+
+static uint8_t write_uintX_bigendian(FILE * file, uint32_t x, uint8_t size)
+{
+    if (0 != size % 8)
+    {
+        return 1;
+    }
+    int16_t bitshift = size - 8;
+
+    for (; bitshift >= 0; bitshift = bitshift - 8)
+    {
+        if (EOF == fputc((x >> bitshift) & 0xFF, file))
+        {
+            return 1;
+        }
+    }
+    return 0;
+}
+
+
+
+extern uint8_t read_uint8(FILE * file, uint8_t * x)
+{
+    uint32_t y = * x;
+    uint8_t err = read_uintX_bigendian(file, &y, 8);
+    * x = (uint8_t) y;
+    return err;
+}
+
+
+
+extern uint8_t read_uint16_bigendian(FILE * file, uint16_t * x)
+{
+    uint32_t y = * x;
+    uint8_t err = read_uintX_bigendian(file, &y, 16);
+    * x = (uint16_t) y;
+    return err;
+}
+
+
+
+extern uint8_t read_uint32_bigendian(FILE * file, uint32_t * x)
+{
+    return read_uintX_bigendian(file, x, 32);
+}
+
+
+
+extern uint8_t write_uint8(uint8_t x, FILE * file)
+{
+    return write_uintX_bigendian(file, x, 8);
+}
+
+
+
+extern uint8_t write_uint16_bigendian(uint16_t x, FILE * file)
+{
+    return write_uintX_bigendian(file, x, 16);
+}
+
+
+
+extern uint8_t write_uint32_bigendian(uint32_t x, FILE * file)
+{
+    return write_uintX_bigendian(file, x, 32);
+}