Rolling read in a loop, instead of recurse calls.

1 files changed, 48 insertions, 39 deletions

diff --git a/mpq-file.c b/mpq-file.c
index 2088335..ad5d51b 100644
--- a/mpq-file.c
+++ b/mpq-file.c
@@ -153,56 +153,65 @@ static int cache_sector(struct mpq_file_t * mpq_f, int sector) {
 }
 
 /*
- * The read function will call itself recursively, in order to split the calls across the sectors.
+ * The read function will iterate several times, in order to split the calls across the sectors.
  */
 
 uint32_t mpqlib_read(struct mpq_file_t * mpq_f, void * _buffer, uint32_t size) {
-    char * buffer = (char *) _buffer;
-    int sector_begin, sector_end;
-    uint32_t cl_size;
-    uint32_t offset_begin, offset_end;
+    int return_size = 0;
+
+    while (1) {
+        char * buffer = (char *) _buffer;
+        int sector_begin, sector_end;
+        uint32_t cl_size;
+        uint32_t offset_begin, offset_end;
     
-    uint32_t first_sector_begins;
+        uint32_t first_sector_begins;
 	uint32_t last_sector_ends;
 
 	__mpqlib_errno = MPQLIB_ERROR_NO_ERROR;
         
-    /* Computing various cursors and stuff. */
-    if ((size + mpq_f->cursor) >= mpq_f->file_size)
-	size = mpq_f->file_size - mpq_f->cursor;
+        /* Computing various cursors and stuff. */
+        if ((size + mpq_f->cursor) >= mpq_f->file_size)
+    	    size = mpq_f->file_size - mpq_f->cursor;
 
-    offset_begin = mpq_f->cursor;
-    sector_begin = offset_begin / mpq_f->sector_size;
-    first_sector_begins = offset_begin % mpq_f->sector_size;
-    
-    offset_end = size + mpq_f->cursor;
-    sector_end = offset_end / mpq_f->sector_size;
-    last_sector_ends = offset_end % mpq_f->sector_size;
-    
-    if (!(offset_end % mpq_f->sector_size)) {
-	sector_end--;
-	last_sector_ends = mpq_f->sector_size;
-    }
-    
-    /* Let's ask for the first sector */
-    if (!cache_sector(mpq_f, sector_begin)) {
-        __mpqlib_errno = MPQLIB_ERROR_COMPRESSION;
-        return 0;
-    }
-    
-    /* If we've hit the end sector, let's just copy that over and exit. */
-    if (sector_begin == sector_end) {
-	memcpy(buffer, mpq_f->buffer + first_sector_begins, size);
-        mpq_f->cursor += size;
-	return size;
+        offset_begin = mpq_f->cursor;
+        sector_begin = offset_begin / mpq_f->sector_size;
+        first_sector_begins = offset_begin % mpq_f->sector_size;
+    
+        offset_end = size + mpq_f->cursor;
+        sector_end = offset_end / mpq_f->sector_size;
+        last_sector_ends = offset_end % mpq_f->sector_size;
+    
+        if (!(offset_end % mpq_f->sector_size)) {
+	    sector_end--;
+	    last_sector_ends = mpq_f->sector_size;
+        }
+    
+        /* Let's ask for the first sector */
+        if (!cache_sector(mpq_f, sector_begin)) {
+            __mpqlib_errno = MPQLIB_ERROR_COMPRESSION;
+            return 0;
+        }
+    
+        /* If we've hit the end sector, let's just copy that over and exit. */
+        if (sector_begin == sector_end) {
+    	    memcpy(buffer, mpq_f->buffer + first_sector_begins, size);
+            mpq_f->cursor += size;
+            return_size = size;
+            break;
+        }
+    
+        /* Else, let's compute the cluster size, copy that chunk, and reiterate. */
+        cl_size = mpq_f->sector_size - first_sector_begins;
+        memcpy(buffer, mpq_f->buffer + first_sector_begins, cl_size);
+        mpq_f->cursor += cl_size;
+        
+        return_size += cl_size;
+        _buffer = buffer + cl_size;
+        size  = size - cl_size;
     }
     
-    /* Else, let's compute the cluster size, copy that chunk, and recurse. */
-    cl_size = mpq_f->sector_size - first_sector_begins;
-    memcpy(buffer, mpq_f->buffer + first_sector_begins, cl_size);
-    mpq_f->cursor += cl_size;
-    
-    return mpqlib_read(mpq_f, buffer + cl_size, size - cl_size) + cl_size;
+    return return_size;
 }
 
 uint32_t mpqlib_seek(struct mpq_file_t * mpq_f, int32_t offset, enum mpqlib_file_seek_t wheel) {