1 files changed, 249 insertions, 0 deletions
diff --git a/circuitpython/py/vstr.c b/circuitpython/py/vstr.c
new file mode 100644
index 0000000..acc957e
--- /dev/null
+++ b/circuitpython/py/vstr.c
@@ -0,0 +1,249 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * SPDX-FileCopyrightText: Copyright (c) 2013, 2014 Damien P. George
+ * SPDX-FileCopyrightText: Copyright (c) 2014 Paul Sokolovsky
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <assert.h>
+
+#include "py/mpconfig.h"
+#include "py/runtime.h"
+#include "py/mpprint.h"
+
+// returned value is always at least 1 greater than argument
+#define ROUND_ALLOC(a) (((a) & ((~0U) - 7)) + 8)
+
+// Init the vstr so it allocs exactly given number of bytes.  Set length to zero.
+void vstr_init(vstr_t *vstr, size_t alloc) {
+    if (alloc < 1) {
+        alloc = 1;
+    }
+    vstr->alloc = alloc;
+    vstr->len = 0;
+    vstr->buf = m_new(char, vstr->alloc);
+    vstr->fixed_buf = false;
+}
+
+// Init the vstr so it allocs exactly enough ram to hold a null-terminated
+// string of the given length, and set the length.
+void vstr_init_len(vstr_t *vstr, size_t len) {
+    if (len == SIZE_MAX) {
+        m_malloc_fail(len);
+    }
+    vstr_init(vstr, len + 1);
+    vstr->len = len;
+}
+
+void vstr_init_fixed_buf(vstr_t *vstr, size_t alloc, char *buf) {
+    vstr->alloc = alloc;
+    vstr->len = 0;
+    vstr->buf = buf;
+    vstr->fixed_buf = true;
+}
+
+void vstr_init_print(vstr_t *vstr, size_t alloc, mp_print_t *print) {
+    vstr_init(vstr, alloc);
+    print->data = vstr;
+    print->print_strn = (mp_print_strn_t)vstr_add_strn;
+}
+
+void vstr_clear(vstr_t *vstr) {
+    if (!vstr->fixed_buf) {
+        m_del(char, vstr->buf, vstr->alloc);
+    }
+    vstr->buf = NULL;
+}
+
+vstr_t *vstr_new(size_t alloc) {
+    vstr_t *vstr = m_new_obj(vstr_t);
+    vstr_init(vstr, alloc);
+    return vstr;
+}
+
+void vstr_free(vstr_t *vstr) {
+    if (vstr != NULL) {
+        if (!vstr->fixed_buf) {
+            m_del(char, vstr->buf, vstr->alloc);
+        }
+        m_del_obj(vstr_t, vstr);
+    }
+}
+
+// Extend vstr strictly by requested size, return pointer to newly added chunk.
+char *vstr_extend(vstr_t *vstr, size_t size) {
+    if (vstr->fixed_buf) {
+        // We can't reallocate, and the caller is expecting the space to
+        // be there, so the only safe option is to raise an exception.
+        mp_raise_msg(&mp_type_RuntimeError, NULL);
+    }
+    char *new_buf = m_renew(char, vstr->buf, vstr->alloc, vstr->alloc + size);
+    char *p = new_buf + vstr->alloc;
+    vstr->alloc += size;
+    vstr->buf = new_buf;
+    return p;
+}
+
+STATIC void vstr_ensure_extra(vstr_t *vstr, size_t size) {
+    if (vstr->len + size > vstr->alloc) {
+        if (vstr->fixed_buf) {
+            // We can't reallocate, and the caller is expecting the space to
+            // be there, so the only safe option is to raise an exception.
+            mp_raise_msg(&mp_type_RuntimeError, NULL);
+        }
+        size_t new_alloc = ROUND_ALLOC((vstr->len + size) + 16);
+        char *new_buf = m_renew(char, vstr->buf, vstr->alloc, new_alloc);
+        vstr->alloc = new_alloc;
+        vstr->buf = new_buf;
+    }
+}
+
+void vstr_hint_size(vstr_t *vstr, size_t size) {
+    vstr_ensure_extra(vstr, size);
+}
+
+char *vstr_add_len(vstr_t *vstr, size_t len) {
+    vstr_ensure_extra(vstr, len);
+    char *buf = vstr->buf + vstr->len;
+    vstr->len += len;
+    return buf;
+}
+
+// Doesn't increase len, just makes sure there is a null byte at the end
+char *vstr_null_terminated_str(vstr_t *vstr) {
+    // If there's no more room, add single byte
+    if (vstr->alloc == vstr->len) {
+        vstr_extend(vstr, 1);
+    }
+    vstr->buf[vstr->len] = '\0';
+    return vstr->buf;
+}
+
+void vstr_add_byte(vstr_t *vstr, byte b) {
+    byte *buf = (byte *)vstr_add_len(vstr, 1);
+    buf[0] = b;
+}
+
+void vstr_add_char(vstr_t *vstr, unichar c) {
+    #if MICROPY_PY_BUILTINS_STR_UNICODE
+    // TODO: Can this be simplified and deduplicated?
+    // Is it worth just calling vstr_add_len(vstr, 4)?
+    if (c < 0x80) {
+        byte *buf = (byte *)vstr_add_len(vstr, 1);
+        *buf = (byte)c;
+    } else if (c < 0x800) {
+        byte *buf = (byte *)vstr_add_len(vstr, 2);
+        buf[0] = (c >> 6) | 0xC0;
+        buf[1] = (c & 0x3F) | 0x80;
+    } else if (c < 0x10000) {
+        byte *buf = (byte *)vstr_add_len(vstr, 3);
+        buf[0] = (c >> 12) | 0xE0;
+        buf[1] = ((c >> 6) & 0x3F) | 0x80;
+        buf[2] = (c & 0x3F) | 0x80;
+    } else {
+        assert(c < 0x110000);
+        byte *buf = (byte *)vstr_add_len(vstr, 4);
+        buf[0] = (c >> 18) | 0xF0;
+        buf[1] = ((c >> 12) & 0x3F) | 0x80;
+        buf[2] = ((c >> 6) & 0x3F) | 0x80;
+        buf[3] = (c & 0x3F) | 0x80;
+    }
+    #else
+    vstr_add_byte(vstr, c);
+    #endif
+}
+
+void vstr_add_str(vstr_t *vstr, const char *str) {
+    vstr_add_strn(vstr, str, strlen(str));
+}
+
+void vstr_add_strn(vstr_t *vstr, const char *str, size_t len) {
+    vstr_ensure_extra(vstr, len);
+    memmove(vstr->buf + vstr->len, str, len);
+    vstr->len += len;
+}
+
+STATIC char *vstr_ins_blank_bytes(vstr_t *vstr, size_t byte_pos, size_t byte_len) {
+    size_t l = vstr->len;
+    if (byte_pos > l) {
+        byte_pos = l;
+    }
+    if (byte_len > 0) {
+        // ensure room for the new bytes
+        vstr_ensure_extra(vstr, byte_len);
+        // copy up the string to make room for the new bytes
+        memmove(vstr->buf + byte_pos + byte_len, vstr->buf + byte_pos, l - byte_pos);
+        // increase the length
+        vstr->len += byte_len;
+    }
+    return vstr->buf + byte_pos;
+}
+
+void vstr_ins_byte(vstr_t *vstr, size_t byte_pos, byte b) {
+    char *s = vstr_ins_blank_bytes(vstr, byte_pos, 1);
+    *s = b;
+}
+
+void vstr_ins_char(vstr_t *vstr, size_t char_pos, unichar chr) {
+    // TODO UNICODE
+    char *s = vstr_ins_blank_bytes(vstr, char_pos, 1);
+    *s = chr;
+}
+
+void vstr_cut_head_bytes(vstr_t *vstr, size_t bytes_to_cut) {
+    vstr_cut_out_bytes(vstr, 0, bytes_to_cut);
+}
+
+void vstr_cut_tail_bytes(vstr_t *vstr, size_t len) {
+    if (len > vstr->len) {
+        vstr->len = 0;
+    } else {
+        vstr->len -= len;
+    }
+}
+
+void vstr_cut_out_bytes(vstr_t *vstr, size_t byte_pos, size_t bytes_to_cut) {
+    if (byte_pos >= vstr->len) {
+        return;
+    } else if (byte_pos + bytes_to_cut >= vstr->len) {
+        vstr->len = byte_pos;
+    } else {
+        memmove(vstr->buf + byte_pos, vstr->buf + byte_pos + bytes_to_cut, vstr->len - byte_pos - bytes_to_cut);
+        vstr->len -= bytes_to_cut;
+    }
+}
+
+void vstr_printf(vstr_t *vstr, const char *fmt, ...) {
+    va_list ap;
+    va_start(ap, fmt);
+    vstr_vprintf(vstr, fmt, ap);
+    va_end(ap);
+}
+
+void vstr_vprintf(vstr_t *vstr, const char *fmt, va_list ap) {
+    mp_print_t print = {vstr, (mp_print_strn_t)vstr_add_strn};
+    mp_vprintf(&print, fmt, ap);
+}