[graph] Simple sparse graph implementation, essentially a sparse matrix with no values array

src/graph.c

@@ -0,0 +1,183 @@
+#include "graph.h"
+
+graph_t *graph_new_dims(graph_type_t type, uint32_t m, uint32_t n, size_t nnz, bool fixed_rows) {
+    graph_t *graph = malloc(sizeof(graph_t));
+    graph->m = m;
+    graph->fixed_rows = fixed_rows;
+    graph->n = n;
+    graph->type = type;
+    graph->indptr = uint32_array_new_size(m + 1);
+    if (graph->indptr == NULL) {
+        graph_destroy(graph);
+        return NULL;
+    }
+
+    if (!fixed_rows) {
+        uint32_array_push(graph->indptr, 0);
+    }
+
+    if (nnz > 0) {
+        graph->indices = uint32_array_new_size(nnz);
+    } else {
+        graph->indices = uint32_array_new();
+    }
+
+    if (graph->indices == NULL) {
+        graph_destroy(graph);
+        return NULL;
+    }
+
+    return graph;
+}
+
+graph_t *graph_new(graph_type_t type) {
+    return graph_new_dims(type, 0, 0, 0, false);
+}
+
+void graph_destroy(graph_t *self) {
+    if (self == NULL) return;
+
+    if (self->indptr != NULL) {
+        uint32_array_destroy(self->indptr);
+    }
+
+    if (self->indices != NULL) {
+        uint32_array_destroy(self->indices);
+    }
+
+    free(self);
+}
+
+inline void graph_set_size(graph_t *self) {
+    if (self->type != GRAPH_BIPARTITE) {
+        uint32_t max = self->m > self->n ? self->m : self->n;
+        self->m = max;
+        self->n = max;
+    }
+}
+
+inline void graph_clear(graph_t *self) {
+    uint32_array_clear(self->indptr);
+    if (!self->fixed_rows) {
+        uint32_array_push(self->indptr, 0);
+    }
+
+    uint32_array_clear(self->indices);
+}
+
+inline void graph_finalize_vertex(graph_t *self) {
+    uint32_array_push(self->indptr, (uint32_t)self->indices->n);
+    if (!self->fixed_rows) {
+        self->m++;
+        graph_set_size(self);
+    }
+}
+
+inline void graph_append_edge(graph_t *self, uint32_t col) {
+    uint32_array_push(self->indices, col);
+    if (col >= self->n) self->n = col + 1;
+    graph_set_size(self);
+}
+
+inline void graph_append_edges(graph_t *self, uint32_t *col, size_t n) {
+    for (int i = 0; i < n; i++) {
+        graph_append_edge(self, col[i]);
+    }
+    graph_finalize_vertex(self);
+}
+
+graph_t *graph_read(FILE *f) {
+    graph_t *g = malloc(sizeof(graph_t));
+    if (g == NULL) return NULL;
+
+    g->indptr = NULL;
+    g->indices = NULL;
+
+    if (!file_read_uint32(f, &g->m) ||
+        !file_read_uint32(f, &g->n) ||
+        !file_read_uint8(f, (uint8_t *)&g->fixed_rows)) {
+        goto exit_graph_allocated;
+    }
+
+    uint64_t len_indptr;
+
+    if (!file_read_uint64(f, &len_indptr)) {
+        goto exit_graph_allocated;
+    }
+
+    uint32_array *indptr = uint32_array_new_size(len_indptr);
+    if (indptr == NULL) {
+        goto exit_graph_allocated;
+    }
+
+    g->indptr = indptr;
+
+    for (int i = 0; i < len_indptr; i++) {
+        if (!file_read_uint32(f, indptr->a + i)) {
+            goto exit_graph_allocated;
+        }
+    }
+
+    uint64_t len_indices;
+
+    if (!file_read_uint64(f, &len_indices)) {
+        goto exit_graph_allocated;
+    }
+
+    uint32_array *indices = uint32_array_new_size(len_indices);
+    if (indices == NULL) {
+        goto exit_graph_allocated;
+    }
+
+    g->indices = indices;
+
+    for (int i = 0; i < len_indices; i++) {
+        if (!file_read_uint32(f, indices->a + i)) {
+            goto exit_graph_allocated;
+        }
+    }
+    
+    return g;
+
+exit_graph_allocated:
+    graph_destroy(g);
+    return NULL;
+}
+
+bool graph_write(graph_t *self, FILE *f) {
+    if (self == NULL || self->indptr == NULL || self->indices == NULL) {
+        return false;
+    }
+
+    if (!file_write_uint32(f, self->m) ||
+        !file_write_uint32(f, self->n) ||
+        !file_write_uint8(f, (uint8_t)self->fixed_rows)) {
+        return false;
+    }
+
+    uint64_t len_indptr = self->indptr->n;
+
+    if (!file_write_uint64(f, len_indptr)) {
+        return false;
+    }
+
+    for (int i = 0; i < len_indptr; i++) {
+        if (!file_write_uint32(f, self->indptr->a[i])) {
+            return false;
+        }
+    }
+
+    uint64_t len_indices = (uint64_t)self->indices->n;
+
+    if (!file_write_uint64(f, len_indices)) {
+        return false;
+    }
+
+    for (int i = 0; i < len_indices; i++) {
+        if (!file_write_uint32(f, self->indices->a[i])) {
+            return false;
+        }
+    }
+
+    return true;
+}