1 files changed, 78 insertions, 23 deletions

diff --git a/py/qstr.c b/py/qstr.c
index 0dd8a04b70..0ed7aa9a24 100644
--- a/py/qstr.c
+++ b/py/qstr.c
@@ -2,55 +2,110 @@
 #include <string.h>
 
 #include "misc.h"
+#include "mpqstr.h"
 
-static int qstrs_alloc;
-static int qstrs_len;
-static const char **qstrs;
+// NOTE: we are using linear arrays to store and search for qstr's (unique strings, interned strings)
+// ultimately we will replace this with a static hash table of some kind
+// also probably need to include the length in the string data, to allow null bytes in the string
+
+#if 0 // print debugging info
+#include <stdio.h>
+#define DEBUG_printf(args...) printf(args)
+#else // don't print debugging info
+#define DEBUG_printf(args...) (void)0
+#endif
+
+typedef struct _qstr_pool_t {
+    struct _qstr_pool_t *prev;
+    uint total_prev_len;
+    uint alloc;
+    uint len;
+    const char *qstrs[];
+} qstr_pool_t;
+
+const static qstr_pool_t const_pool = {
+    NULL,               // no previous pool
+    0,                  // no previous pool
+    10,                 // set so that the first dynamically allocated pool is twice this size; must be <= the len (just below)
+    MP_QSTR_number_of,  // corresponds to number of strings in array just below
+    {
+        "nil", // must be first, since 0 qstr is nil
+#define Q(id) #id,
+#include "mpqstrraw.h"
+#undef Q
+    },
+};
+
+static qstr_pool_t *last_pool = (qstr_pool_t*)&const_pool; // we won't modify the const_pool since it has no allocated room left
 
 void qstr_init(void) {
-    qstrs_alloc = 400;
-    qstrs_len = 1;
-    qstrs = m_new(const char*, qstrs_alloc);
-    qstrs[0] = "nil";
+    // nothing to do!
 }
 
 static qstr qstr_add(const char *str) {
-    if (qstrs_len >= qstrs_alloc) {
-        qstrs = m_renew(const char*, qstrs, qstrs_alloc, qstrs_alloc * 2);
-        qstrs_alloc *= 2;
+    DEBUG_printf("QSTR: add %s\n", str);
+
+    // make sure we have room in the pool for a new qstr
+    if (last_pool->len >= last_pool->alloc) {
+        qstr_pool_t *pool = m_new_obj_var(qstr_pool_t, const char*, last_pool->alloc * 2);
+        pool->prev = last_pool;
+        pool->total_prev_len = last_pool->total_prev_len + last_pool->len;
+        pool->alloc = last_pool->alloc * 2;
+        pool->len = 0;
+        last_pool = pool;
+        DEBUG_printf("QSTR: allocate new pool of size %d\n", last_pool->alloc);
     }
-    qstrs[qstrs_len++] = str;
-    return qstrs_len - 1;
+
+    // add the new qstr
+    last_pool->qstrs[last_pool->len++] = str;
+
+    // return id for the newly-added qstr
+    return last_pool->total_prev_len + last_pool->len - 1;
 }
 
 qstr qstr_from_str_static(const char *str) {
-    for (int i = 0; i < qstrs_len; i++) {
-        if (strcmp(qstrs[i], str) == 0) {
-            return i;
+    for (qstr_pool_t *pool = last_pool; pool != NULL; pool = pool->prev) {
+        for (const char **qstr = pool->qstrs, **qstr_top = pool->qstrs + pool->len; qstr < qstr_top; qstr++) {
+            if (strcmp(*qstr, str) == 0) {
+                return pool->total_prev_len + (qstr - pool->qstrs);
+            }
         }
     }
     return qstr_add(str);
 }
 
 qstr qstr_from_str_take(char *str, int alloc_len) {
-    for (int i = 0; i < qstrs_len; i++) {
-        if (strcmp(qstrs[i], str) == 0) {
-            m_del(char, str, alloc_len);
-            return i;
+    for (qstr_pool_t *pool = last_pool; pool != NULL; pool = pool->prev) {
+        for (const char **qstr = pool->qstrs, **qstr_top = pool->qstrs + pool->len; qstr < qstr_top; qstr++) {
+            if (strcmp(*qstr, str) == 0) {
+                m_del(char, str, alloc_len);
+                return pool->total_prev_len + (qstr - pool->qstrs);
+            }
         }
     }
     return qstr_add(str);
 }
 
 qstr qstr_from_strn_copy(const char *str, int len) {
-    for (int i = 0; i < qstrs_len; i++) {
-        if (strncmp(qstrs[i], str, len) == 0 && qstrs[i][len] == '\0') {
-            return i;
+    for (qstr_pool_t *pool = last_pool; pool != NULL; pool = pool->prev) {
+        for (const char **qstr = pool->qstrs, **qstr_top = pool->qstrs + pool->len; qstr < qstr_top; qstr++) {
+            if (strncmp(*qstr, str, len) == 0 && (*qstr)[len] == '\0') {
+                return pool->total_prev_len + (qstr - pool->qstrs);
+            }
         }
     }
     return qstr_add(strndup(str, len));
 }
 
+// convert qstr id to pointer to its string
 const char *qstr_str(qstr qstr) {
-    return qstrs[qstr];
+    // search
+    for (qstr_pool_t *pool = last_pool; pool != NULL; pool = pool->prev) {
+        if (qstr >= pool->total_prev_len) {
+            return pool->qstrs[qstr - pool->total_prev_len];
+        }
+    }
+
+    // not found, return nil
+    return const_pool.qstrs[0];
 }