1 files changed, 72 insertions, 1 deletions
diff --git a/src/encoder.c b/src/encoder.c
index b45e3b9..a670a11 100644
--- a/src/encoder.c
+++ b/src/encoder.c
@@ -8,15 +8,86 @@
 #include "sstv.h"
 #include "libsstv.h"
 
+/*
+ * Encoder context
+ */
+typedef struct {
+    /* common encoder stuff */
+    sstv_mode_t mode;
+} sstv_encoder_context_t;
+
+/* default encoder contexts, for when no allocation/deallocation routines are provided */
+static sstv_encoder_context_t default_encoder_context[SSTV_DEFAULT_ENCODER_CONTEXT_COUNT];
+static uint64_t default_encoder_context_usage = 0x0;
+
+
 sstv_error_t
 sstv_create_encoder(sstv_mode_t mode, uint8_t *image, size_t sample_rate, void **out_ctx)
 {
-    /* Check input */
+    sstv_encoder_context_t *ctx = NULL;
+
+    /* check input */
+    if (!out_ctx) {
+        return SSTV_BAD_PARAMETER;
+    }
+
+    /* create context */
+    if (sstv_malloc_user) {
+        /* user allocator */
+        ctx = (sstv_encoder_context_t *) sstv_malloc_user(sizeof(sstv_encoder_context_t));
+        if (!ctx) {
+            return SSTV_BAD_USER_ALLOC;
+        }
+    } else {
+        size_t i;
+        /* use default contexts */
+        for (i = 0; i < SSTV_DEFAULT_ENCODER_CONTEXT_COUNT; i++) {
+            if ((default_encoder_context_usage & (0x1 << i)) == 0) {
+                default_encoder_context_usage |= (0x1 << i);
+                ctx = &default_encoder_context[i];
+                break;
+            }
+        }
+    }
+
+    if (!ctx) {
+        return SSTV_INTERNAL_ERROR;
+    }
+
+    /* initialize context */
+    ctx->mode = mode;
+
+    /* set output */
+    *out_ctx = ctx;
+
+    /* all ok */
+    return SSTV_OK;
 }
 
 sstv_error_t
 sstv_delete_encoder(void *ctx)
 {
+    size_t i;
+
+    /* check default contexts */
+    for (i = 0; i < SSTV_DEFAULT_ENCODER_CONTEXT_COUNT; i++) {
+        if (ctx == default_encoder_context+i) {
+            default_encoder_context_usage &= ~(0x1 << i);
+            ctx = NULL;
+            break;
+        }
+    }
+
+    /* deallocate context */
+    if (ctx) {
+        if (!sstv_free_user) {
+            return SSTV_BAD_USER_DEALLOC;
+        }
+        sstv_free_user(ctx);
+    }
+    
+    /* all ok */
+    return SSTV_OK;
 }
 
 sstv_error_t