first attempt at sort

2024/c/01.c

@@ -35,6 +35,8 @@ void DS_grow(struct DynSlice* slice, usize newcap) {
     usize cap = slice->capacity;
     usize size = slice->size;
 
+    if(cap >= newcap) return;
+
     void* dataptr = slice->data;
     
     if(cap == 0) cap = 1;
@@ -58,6 +60,10 @@ void DS_debugprint(const struct DynSlice* slice) {
     printf("dynslice, size %li, cap %li, size of %li\n", slice->size, slice->capacity, slice->size_of);
 }
 
+void* DS_iptr(struct DynSlice* slice, usize index) {
+    return slice->data + index * slice->size_of;
+}
+
 // Pushes a new object. Accepts a pointer to said object. Copies. 
 // returns index of pushed data
 // assumes size_of from slice. Take care of types lol.
@@ -67,15 +73,15 @@ usize DS_push(struct DynSlice* slice, void* ptr) {
     if(cap <= size) {
         DS_grow(slice, cap+1);
     }
-    memcpy(slice->data + slice->size * slice->size_of, ptr, slice->size_of);
+    memcpy(DS_iptr(slice, slice->size), ptr, slice->size_of);
     slice->size += 1;
     return size;
 }
 
 // Extends a slice from another array-like object
 void DS_extend(struct DynSlice* slice, void* ptr, usize count) {
-    if(slice->capacity < slice->size + count) DS_grow(slice, slice->size + count);
-    memcpy(slice->data + slice->size * slice->size_of, ptr, slice->size_of * count);
+    DS_grow(slice, slice->size + count);
+    memcpy(DS_iptr(slice, slice->size), ptr, slice->size_of * count);
     slice->size += count;
 }
 
@@ -103,7 +109,7 @@ void DS_drop(struct DynSlice* slice) {
 
 // Gets pointer to a single element, checking it's size
 void* DS_get(const struct DynSlice* slice, const usize i) {
-    if(slice->size >= i) {
+    if(slice->size <= i) {
         panic("DS Get out of bounds");
     }
     return slice->data + i * slice->size_of;
@@ -144,15 +150,102 @@ struct DynSlice DS_line_from_file(FILE* input) {
     }
 }
 
+// Swaps two indexes in place, using last element of vector (may grow the vector and cause alloc)
+void DS_swap(struct DynSlice* slice, usize i, usize j) {
+    DS_grow(slice, slice->size + 1);
+    memcpy(DS_iptr(slice, slice->size), DS_iptr(slice, i), slice->size_of);
+    memcpy(DS_iptr(slice, i), DS_iptr(slice, j), slice->size_of);
+    memcpy(DS_iptr(slice, j), DS_iptr(slice, slice->size), slice->size_of);
+}
+
+void DS_intdebugprint(struct DynSlice* slice) {
+    if(slice->size_of != sizeof(int)) panic("using int debug print on non-int");
+
+    DS_debugprint(slice);
+    printf("values: ");
+    for(usize i = 0; i < slice->size; i += 1) {
+        printf("%i ", *(int*)DS_get(slice, i));
+    }
+    printf("\n");
+}
+
+
+// Sorts the array between left and right
+// Uses a compare function. Returning -1 means the left number is smaller, 0 =, 1 left > right
+// quicksort impl based on https://www.youtube.com/watch?v=Hoixgm4-P4M
+void DS_sort_sliced(struct DynSlice* slice, int (*compare)(void*, void*), usize left, usize right) {
+    if(right <= left) return;
+
+    usize pivot = left;
+    usize len = right - left;
+
+    DS_swap(slice, pivot, right);
+    pivot = right;
+
+    while(1) {
+        usize itemFromLeft = left;
+        while(compare(DS_get(slice, itemFromLeft), DS_get(slice, pivot)) < 0)
+            itemFromLeft += 1;
+
+        usize itemFromRight = right - 1;
+        while(compare(DS_get(slice, itemFromRight), DS_get(slice, pivot)) > 0)
+            itemFromRight -= 1;
+
+        if(itemFromLeft < itemFromRight) {
+            DS_swap(slice, itemFromLeft, itemFromRight);
+        } else {
+            DS_swap(slice, itemFromLeft, pivot);
+            pivot = itemFromLeft;
+            DS_intdebugprint(slice);
+            break;
+        }
+    }
+}
+
+// Sort the array using Quicksort
+// Uses a compare function. Returning -1 means the left number is smaller, 0 =, 1 left > right
+void DS_sort(struct DynSlice* slice, int (*compare)(void*, void*)) {
+    DS_sort_sliced(slice, compare, 0, slice->size);
+}
+
+int intcompare(int* a, int* b) {
+    if(*a > *b) return 1;
+    if(*a == *b) return 0;
+    if(*a < *b) return -1;
+}
+
 int main(int argc, char *argv[]) {
     setvbuf(stdout, NULL, _IONBF, 0);
     const char* loc = argv[1];
     printf("file %s\n", loc);
     FILE* input = fopen(loc, "r");
+    
+    struct DynSlice left = DS_create(sizeof(int));
+    struct DynSlice right = DS_create(sizeof(int));
+
     while(!feof(input)) {
         struct DynSlice line = DS_line_from_file(input);
-        printf("%s\n", (char*)line.data);
+        
+        // line is in a format of int   int
+        // find space, add 2 to it. Then 0 - space is one int, space+3 - end is the other one.
+        // we do this by inserting a null byte to effectively split into two strings
+
+        char* spaceptr = strchr(line.data, ' ');
+        *spaceptr = '\0';
+        spaceptr += 3;
+
+        int first = atoi(line.data);
+        DS_push(&left, &first);
+        int second = atoi(spaceptr);
+        DS_push(&left, &first);
+
         DS_drop(&line);
     }
+
+    DS_intdebugprint(&left);
+    DS_sort(&left, intcompare);
+
     fclose(input);
+    DS_drop(&left);
+    DS_drop(&right);
 }