X-Git-Url: https://plomlompom.com/repos/?a=blobdiff_plain;f=src%2Freadwrite.c;h=96505adf4387cc52f4a83241f03098869b0a67d9;hb=0e6c855b67e0cd3def7196396f3d1f45ff85b692;hp=039dadea4a6855e1f2222241193897db4f987b4c;hpb=4d9b6ac142740aa337fc3e622902c9595c36f6d0;p=plomrogue

diff --git a/src/readwrite.c b/src/readwrite.c
index 039dade..96505ad 100644
--- a/src/readwrite.c
+++ b/src/readwrite.c
@@ -1,26 +1,82 @@
 /* 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. */
+#include <stdio.h> /* for FILE typedef, fgetc(), fputc(), fseek() */
+#include <stdint.h> /* for uint8_t, uint16_t, uint32_t */
+
+
+
+/* Read/write "x" from/to "file" as bigendian representation of "size" bits. On
+ * failure, return 1, else 0. (As of of now, all extern read/write functions
+ * build on top of these.)
+ *
+ * Only use multiples of 8 greater or equal 32 for "size", so that storage
+ * inside uint32_t is possible. Originally a bit number check prefaced the code
+ * of both functions. It was removed as redundant due to all possible "size"
+ * values being hardcoded into the library (i.e. in all extern functions calling
+ * / wrapping around either function). If this ever changes, (re-)insert:
+ *
+ *    if (0 == size || size > 32 || 0 != size % 8)
+ *    {
+ *        return 1;
+ *    }
+ */
 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)
+extern uint8_t textfile_sizes(FILE * file, uint16_t * linemax_p,
+                              uint16_t * n_lines_p)
 {
-    if (0 != size % 8)
+    int c = 0;
+    uint16_t c_count = 0;
+    uint16_t n_lines = 0;
+    uint16_t linemax = 0;
+    while (1)
+    {
+        c = fgetc(file);
+        if (EOF == c)
+        {
+            break;
+        }
+        c_count++;
+        if ('\n' == c)
+        {
+            if (c_count > linemax)
+            {
+                linemax = c_count;
+            }
+            c_count = 0;
+            if (n_lines_p)
+            {
+                n_lines++;
+            }
+        }
+    }
+    if (0 == linemax && 0 < c_count) /* Handle files that consist of only one */
+    {                                /* line / lack newline chars.            */
+        linemax = c_count;
+    }
+
+    if (-1 == fseek(file, 0, SEEK_SET))
     {
         return 1;
     }
-    int16_t bitshift = size - 8;
+    * linemax_p = linemax;
+    if (n_lines_p)
+    {
+        * n_lines_p = n_lines;
+    }
+    return 0;
+}
 
+
+
+static uint8_t read_uintX_bigendian(FILE * file, uint32_t * x, uint8_t size)
+{
     * x = 0;
+    int16_t bitshift = size - 8;
     int test;
     for (; bitshift >= 0; bitshift = bitshift - 8)
     {
@@ -38,12 +94,7 @@ 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)
 {
-    if (0 != size % 8)
-    {
-        return 1;
-    }
     int16_t bitshift = size - 8;
-
     for (; bitshift >= 0; bitshift = bitshift - 8)
     {
         if (EOF == fputc((x >> bitshift) & 0xFF, file))
@@ -58,6 +109,9 @@ static uint8_t write_uintX_bigendian(FILE * file, uint32_t x, uint8_t size)
 
 extern uint8_t read_uint8(FILE * file, uint8_t * x)
 {
+    /* Since read_uintX_bigendian() works on -- and zeroes -- four bytes, direct
+     * work on values of fewer bytes would corrupt immediate neighbor values.
+     */
     uint32_t y = * x;
     uint8_t err = read_uintX_bigendian(file, &y, 8);
     * x = (uint8_t) y;
@@ -68,6 +122,7 @@ extern uint8_t read_uint8(FILE * file, uint8_t * x)
 
 extern uint8_t read_uint16_bigendian(FILE * file, uint16_t * x)
 {
+    /* See read_uint8() introductory code comment for rationale. */
     uint32_t y = * x;
     uint8_t err = read_uintX_bigendian(file, &y, 16);
     * x = (uint16_t) y;