Changeset 180 for libyaml/trunk/src/reader.c

Timestamp:

05/29/06 16:08:09 (7 years ago)

Author:

xi

Message:

Working on the decoding code.

File:

• libyaml/trunk/src/reader.c (modified) (3 diffs)

libyaml/trunk/src/reader.c

@@ -1 +1 @@
 
-#define RAW_BUFFER_SIZE 16384
-#define BUFFER_SIZE (RAW_BUFFER_SIZE*2) /* Should be enough for decoding 
-                                           the whole raw buffer. */
+#if HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <yaml/yaml.h>
+
+#include <assert.h>
+
+/* Check for the UTF-16-BE BOM. */
+#define IS_UTF16BE_BOM(pointer) ((pointer)[0] == 0xFE && (pointer)[1] == 0xFF)
+
+/* Check for the UTF-16-LE BOM. */
+#define IS_UTF16LE_BOM(pointer) ((pointer)[0] == 0xFF && (pointer)[1] == 0xFE)
+
+/* Get a UTF-16-BE character. */
+#define UTF16BE_CHAR(pointer)   ((pointer)[0] << 8 + (pointer)[1])
+
+/* Get a UTF-16-LE character. */
+#define UTF16LE_CHAR(pointer)   ((pointer)[0] + (pointer)[1] << 8)
+
+/*
+ * From http://www.ietf.org/rfc/rfc3629.txt:
+ *
+ *    Char. number range  |        UTF-8 octet sequence
+ *      (hexadecimal)    |              (binary)
+ *   --------------------+---------------------------------------------
+ *   0000 0000-0000 007F | 0xxxxxxx
+ *   0000 0080-0000 07FF | 110xxxxx 10xxxxxx
+ *   0000 0800-0000 FFFF | 1110xxxx 10xxxxxx 10xxxxxx
+ *   0001 0000-0010 FFFF | 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+ */
+
+/* Get the length of a UTF-8 character (0 on error). */
+#define UTF8_LENGTH(pointer)    \
+    ((pointer)[0] < 0x80 ? 1 :  \
+    (pointer)[0] < 0xC0 ? 0 :   \
+    (pointer)[0] < 0xE0 ? 2 :   \
+    (pointer)[0] < 0xF0 ? 3 :   \
+    (pointer)[0] < 0xF8 ? 4 : 0)
+
+/* Get the value of the first byte of a UTF-8 sequence (0xFF on error). */
+#define UTF8_FIRST_CHUNK(pointer)   \
+    ((pointer)[0] < 0x80 ? (pointer)[0] & 0x7F :    \
+    (pointer)[0] < 0xC0 ? 0xFF :    \
+    (pointer)[0] < 0xE0 ? (pointer)[0] & 0x1F : \
+    (pointer)[0] < 0xF0 ? (pointer)[0] & 0x0F : \
+    (pointer)[0] < 0xF8 ? (pointer)[0] & 0x07 : 0xFF)
+
+/* Get the value of a non-first byte of a UTF-8 sequence (0xFF on error). */
+#define UTF8_NEXT_CHUNK(pointer)    \
+    ((pointer)[0] >= 0x80 && (pointer)[0] < 0xC0 ? (pointer)[0] & 0x3F : 0xFF)
+
+/* Determine the length of a UTF-8 character. */
 
 /*
  * Ensure that the buffer contains at least length characters.
  * Return 1 on success, 0 on failure.
+ *
+ * The length is supposed to be significantly less that the buffer size.
  */
 
 int
-yaml_parser_update_reader(yaml_parser_t *parser, size_t length)
+yaml_parser_update_buffer(yaml_parser_t *parser, size_t length)
 {
     /* If the EOF flag is set, do nothing. */
@@ -17 +69 @@
         return 1;
 
-    /* First, let us check that the buffers are allocated. */
-
-    if (!parser->buffer) {
-        parser->buffer = yaml_malloc(BUFFER_SIZE);
-        if (!parser->buffer) {
-            parser->error = YAML_MEMORY_ERROR;
-            return 0;
-        }
-        parser->buffer_size = BUFFER_SIZE;
-        parser->buffer_pointer = parser->buffer;
-        parser->buffer_length = 0;
-    }
-
-    if (!parser->raw_buffer) {
-        parser->raw_buffer = yaml_malloc(RAW_BUFFER_SIZE);
-        if (!parser->raw_buffer) {
-            parser->error = YAML_MEMORY_ERROR;
-            return 0;
-        }
-        parser->raw_buffer_size = RAW_BUFFER_SIZE;
-    }
-
-    /* Next, determine the input encoding. */
+    /* Return if the buffer contains enough characters. */
+
+    if (parser->unread >= length)
+        return 1;
+
+    /* Determine the input encoding if it is not known yet. */
 
     if (!parser->encoding) {
@@ -46 +81 @@
     }
 
-    /* more... */
+    /* Move the unread characters to the beginning of the buffer. */
+
+    if (parser->buffer < parser->pointer
+            && parser->pointer < parser->buffer_end) {
+        size_t size = parser->buffer_end - parser->pointer;
+        memmove(parser->buffer, parser->pointer, size);
+        parser->pointer = parser->buffer;
+        parser->buffer_end -= size;
+    }
+    else if (parser->pointer == parser->buffer_end) {
+        parser->pointer = parser->buffer;
+        parser->buffer_end = parser->buffer;
+    }
+
+    /* Fill the buffer until it has enough characters. */
+
+    while (parser->unread < length)
+    {
+        /* Fill the raw buffer. */
+
+        if (!yaml_parser_update_raw_buffer(parser)) return 0;
+
+        /* Decode the raw buffer. */
+
+        while (parser->raw_unread)
+        {
+            unsigned int ch;
+            int incomplete = 0;
+
+            /* Decode the next character. */
+
+            switch (parser->encoding)
+            {
+                case YAML_UTF8_ENCODING:
+
+                    unsigned int utf8_length = UTF8_LENGTH(parser->raw_pointer);
+                    unsigned int utf8_chunk;
+
+                    /* Check if the raw buffer contains an incomplete character. */
+
+                    if (utf8_length > parser->raw_unread) {
+                        if (parser->eof) {
+                            parser->error = YAML_READER_ERROR;
+                            return 0;
+                        }
+                        incomplete = 1;
+                    }
+
+                    /* Get the character checking it for validity. */
+
+                    utf8_chunk = UTF8_FIRST_CHUNK(parser->raw_pointer ++);
+                    if (utf8_chunk == 0xFF) {
+                        parser->error = YAML_READER_ERROR;
+                        return 0;
+                    }
+                    ch = utf8_chunk;
+                    parser->raw_unread --;
+                    while (-- utf8_length) {
+                        utf8_chunk = UTF8_NEXT_CHUNK(parser->raw_pointer ++);
+                        if (utf8_chunk == 0xFF) {
+                            parser->error = YAML_READER_ERROR;
+                            return 0;
+                        }
+                        ch = ch << 6 + utf8_chunk;
+                        parser->raw_unread --;
+                    }
+
+                    break;
+                
+                case YAML_UTF16LE_ENCODING:
+
+                    /* Check if the raw buffer contains an incomplete character. */
+
+                    if (parser->raw_unread < 2) {
+                        if (parser->eof) {
+                            parser->error = YAML_READER_ERROR;
+                            return 0;
+                        }
+                        incomplete = 1;
+                    }
+
+                    /* Get the current character. */
+
+                    ch = UTF16LE_CHAR(parser->raw_pointer);
+                    parser->raw_pointer += 2;
+                    parser->raw_unread -= 2;
+
+                    break;
+
+                case YAML_UTF16BE_ENCODING:
+
+                    /* Check if the raw buffer contains an incomplete character. */
+
+                    if (parser->raw_unread < 2) {
+                        if (parser->eof) {
+                            parser->error = YAML_READER_ERROR;
+                            return 0;
+                        }
+                        incomplete = 1;
+                    }
+
+                    /* Get the current character. */
+
+                    ch = UTF16BE_CHAR(parser->raw_pointer);
+                    parser->raw_pointer += 2;
+                    parser->raw_unread -= 2;
+
+                    break;
+            }
+
+            /*
+             * Check if the character is in the allowed range:
+             *      #x9 | #xA | #xD | [#x20-#x7E]               (8 bit)
+             *      | #x85 | [#xA0-#xD7FF] | [#xE000-#xFFFD]    (16 bit)
+             *      | [#x10000-#x10FFFF]                        (32 bit)
+             */
+
+            if (! (ch == 0x09 || ch == 0x0A || ch == 0x0D
+                        || (ch >= 0x20 && ch <= 0x7E)
+                        || (ch == 0x85) || (ch >= 0xA0 && ch <= 0xD7FF)
+                        || (ch >= 0xE000 && ch <= 0xFFFD)
+                        || (ch >= 0x10000 && ch <= 0x10FFFF))) {
+                parser->error = YAML_READER_ERROR;
+                return 0;
+            }
+
+            /* Finally put the character into the buffer. */
+
+            /* 0000 0000-0000 007F -> 0xxxxxxx */
+            if (ch <= 0x7F) {
+                *(parser->buffer_end++) = ch;
+            }
+            /* 0000 0080-0000 07FF -> 110xxxxx 10xxxxxx */
+            else if (ch <= 0x7FF) {
+                *(parser->buffer_end++) = 0xC0 + (ch >> 6) & 0x1F;
+                *(parser->buffer_end++) = 0x80 + ch & 0x3F;
+            }
+            /* 0000 0800-0000 FFFF -> 1110xxxx 10xxxxxx 10xxxxxx */
+            else if (ch <= 0xFFFF) {
+                *(parser->buffer_end++) = 0x80 + ch & 0x3F;
+                *(parser->buffer_end++) = 0xC0 + (ch >> 6) & 0x1F;
+                
+            }
+            /* 0001 0000-0010 FFFF -> 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */
+            else {
+            }
+        }
+        
+    }
 
 }
 
-
-
+/*
+ * Determine the input stream encoding by checking the BOM symbol. If no BOM is
+ * found, the UTF-8 encoding is assumed. Return 1 on success, 0 on failure.
+ */
+
+int
+yaml_parser_determine_encoding(yaml_parser_t *parser)
+{
+    /* Ensure that we had enough bytes in the raw buffer. */
+
+    while (!parser->eof && parser->raw_unread < 2) {
+        if (!yaml_parser_update_raw_buffer(parser)) {
+            return 0;
+        }
+    }
+
+    /* Determine the encoding. */
+
+    if (parser->raw_unread >= 2 && IS_UTF16BE_BOM(parser->raw_pointer)) {
+        parser->encoding = YAML_UTF16BE_ENCODING;
+    }
+    else if (parser->raw_unread >= 2 && IS_UTF16LE_BOM(parser->raw_pointer)) {
+        parser->encoding = YAML_UTF16LE_ENCODING;
+    }
+    else {
+        parser->encoding = YAML_UTF8_ENCODING;
+    }
+}
+
+/*
+ * Update the raw buffer.
+ */
+
+int
+yaml_parser_update_raw_buffer(yaml_parser_t *parser)
+{
+    size_t size_read = 0;
+
+    /* Return if the raw buffer is full. */
+
+    if (parser->raw_unread == YAML_RAW_BUFFER_SIZE) return 1;
+
+    /* Return on EOF. */
+
+    if (parser->eof) return 1;
+
+    /* Move the remaining bytes in the raw buffer to the beginning. */
+
+    if (parser->raw_unread && parser->raw_buffer < parser->raw_pointer) {
+        memmove(parser->raw_buffer, parser->raw_pointer, parser->raw_unread);
+    }
+    parser->raw_pointer = parser->raw_buffer;
+
+    /* Call the read handler to fill the buffer. */
+
+    if (!parser->read_handler(parser->read_handler_data,
+                parser->raw_buffer + parser->raw_unread,
+                YAML_RAW_BUFFER_SIZE - parser->raw_unread,
+                &size_read)) {
+        parser->error = YAML_READER_ERROR;
+        return 0;
+    }
+    parser->raw_unread += size_read;
+    if (!size_read) {
+        parser->eof = 1;
+    }
+
+    return 1;
+}
+