X-Git-Url: https://plomlompom.com/repos/index.html?a=blobdiff_plain;f=src%2Freadwrite.c;h=039dadea4a6855e1f2222241193897db4f987b4c;hb=4d9b6ac142740aa337fc3e622902c9595c36f6d0;hp=34ec09beecb86d8ee1e06624163143ca8b71e617;hpb=47d7b87570ce3c79d3e0a6b8e765c74d065b6ba5;p=plomrogue
diff --git a/src/readwrite.c b/src/readwrite.c
index 34ec09b..039dade 100644
--- a/src/readwrite.c
+++ b/src/readwrite.c
@@ -1,38 +1,103 @@
+/* readwrite.c */
+
#include "readwrite.h"
-#include
-#include
-#include
-
-static const uint16_t uchar_s = UCHAR_MAX + 1;
-
-extern 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 * uchar_s) + b; }
-
-extern void write_uint16_bigendian(uint16_t x, FILE * file) {
-// Write uint16 to file in beg-endian order.
- unsigned char a = x / uchar_s;
- unsigned char b = x % uchar_s;
- fputc(a, file);
- fputc(b, file); }
-
-extern 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 * uchar_s * uchar_s * uchar_s) + (b * uchar_s * uchar_s) + (c * uchar_s) + d; }
-
-extern void write_uint32_bigendian(uint32_t x, FILE * file) {
-// Write uint32 to file in beg-endian order.
- unsigned char a = x / (uchar_s * uchar_s * uchar_s);
- unsigned char b = (x - (a * uchar_s * uchar_s * uchar_s)) / (uchar_s * uchar_s);
- unsigned char c = (x - ((a * uchar_s * uchar_s * uchar_s) + (b * uchar_s * uchar_s))) / uchar_s;
- unsigned char d = x % uchar_s;
- fputc(a, file);
- fputc(b, file);
- fputc(c, file);
- fputc(d, file); }
+#include /* for FILE typedef*/
+#include /* 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);
+}