From d2c5793516ad4bd2dd8f8c17575520e5affdd3e4 Mon Sep 17 00:00:00 2001
From: "Michael D. Lowis" <mike@mdlowis.com>
Date: Tue, 29 Apr 2014 20:33:02 -0400
Subject: [PATCH] CP: Reworking parser with string and char literals as well as
 different number literals

---
 source/slvm/parser.c | 160 +++++++++++++++++++++++++++++++++++++++++++
 source/slvm/parser.h |  25 +++++++
 2 files changed, 185 insertions(+)
 create mode 100644 source/slvm/parser.c
 create mode 100644 source/slvm/parser.h

diff --git a/source/slvm/parser.c b/source/slvm/parser.c
new file mode 100644
index 0000000..e6dce38
--- /dev/null
+++ b/source/slvm/parser.c
@@ -0,0 +1,160 @@
+/**
+  @file parser.c
+  @brief See header for details
+  $Revision$
+  $HeadURL$
+  */
+#include "parser.h"
+
+/* Fetching Tokens
+ *****************************************************************************/
+static void skip_whitespace(FILE* input);
+static void skip_comment(FILE* input);
+static void parse_string(FILE* input);
+static void parse_token(FILE* input);
+static void grow_token(size_t* p_size, size_t* p_index, char** p_p_str, char ch);
+static bool is_whitespace(FILE* input);
+static char fpeekc(FILE* input);
+
+char* fetch(FILE* input)
+{
+    char* result = NULL;
+    skip_whitespace();
+    switch(fpeekc(input))
+    {
+        case '#':  skip_comment();
+                   result = fetch(input);
+                   break;
+        case '"':  result = parse_string(input);
+                   break;
+        case EOF:  break;
+        default:   result = parse_token(input);
+                   break;
+
+    }
+    return result;
+}
+
+static char* parse_string(FILE* input)
+{
+    size_t strsize  = 8;
+    size_t strindex = 0;
+    char*  string   = (char*)malloc(strsize);
+    grow_token(&strsize, &strindex, &string, fgetc(input));
+    while('"' != fpeekc(input))
+    {
+        if(feof(input)) {
+            free(string);
+            return NULL;
+        }
+        grow_token(&strsize, &strindex, &string, fgetc(input));
+    }
+    grow_token(&strsize, &strindex, &string, fgetc(input));
+    return string;
+}
+
+static char* parse_token(FILE* input)
+{
+    size_t strsize  = 8;
+    size_t strindex = 0;
+    char*  string   = (char*)malloc(strsize);
+    while(!is_whitespace(input))
+    {
+        if(feof(input)) {
+            free(string);
+            return NULL;
+        }
+        grow_token(&strsize, &strindex, &string, fgetc(input));
+    }
+    return string;
+}
+
+static void grow_token(size_t* p_size, size_t* p_index, char** p_p_str, char ch)
+{
+    /* If we don't have enough room for the new char */
+    if( (*(p_index)+1) >= *p_size )
+    {
+        /* Double the string size */
+        *(p_size) *= 2;
+        *(p_p_str) = (char*)realloc( *(p_p_str), *(p_size) );
+    }
+    /* Add the new char and null terminate the string */
+    *(p_p_str)[*(p_index)++] = ch;
+    *(p_p_str)[*(p_index)]   = '\0';
+}
+
+static void skip_whitespace(FILE* input)
+{
+    while(!feof(input) && is_whitespace(input))
+    {
+        (void)fgetc(input);
+    }
+}
+
+static void skip_comment(FILE* input)
+{
+    while(!feof(input) && ('\n' != fgetc(input)))
+    {
+    }
+}
+
+static bool is_whitespace(FILE* input)
+{
+    char ch = peekc(input);
+    return ((ch == ' ')  || (ch == '\t') ||
+            (ch == '\r') || (ch == '\n'));
+}
+
+static char fpeekc(FILE* input)
+{
+    char ch = fgetc(input);
+    ungetc(ch,input);
+    return ch;
+}
+
+/* Parsing Tokens
+ *****************************************************************************/
+static bool is_float(val_t* p_val);
+static bool is_integer(val_t* p_val);
+static bool is_string(val_t* p_val);
+static bool is_char(val_t* p_val);
+
+ValueType_T parse(char* str, val_t* p_val)
+{
+    ValueType_T type = ERROR;
+    if(str != NULL)
+    {
+        if(!is_float(p_val) &&
+           !is_integer(p_val) &&
+           !is_string(p_val) &&
+           !is_char(p_val))
+        {
+            type = WORD;
+            *(p_val) = (val_t)str;
+        }
+    }
+    return type;
+}
+
+
+static bool is_float(val_t* p_val)
+{
+    return false;
+}
+
+static bool is_integer(val_t* p_val)
+{
+    return false;
+}
+
+static bool is_string(val_t* p_val)
+{
+    return false;
+}
+
+static bool is_char(val_t* p_val)
+{
+    return false;
+}
+
+
diff --git a/source/slvm/parser.h b/source/slvm/parser.h
new file mode 100644
index 0000000..099df11
--- /dev/null
+++ b/source/slvm/parser.h
@@ -0,0 +1,25 @@
+/**
+  @file parser.h
+  @brief TODO: Describe this file
+  $Revision$
+  $HeadURL$
+  */
+#ifndef PARSER_H
+#define PARSER_H
+
+#include "slvm.h"
+
+typedef enum {
+    WORD = 0,
+    STRING,
+    CHAR,
+    INTEGER,
+    FLOAT,
+    ERROR
+} TokenType_T;
+
+char* fetch(FILE* input);
+
+ValueType_T parse(char* str, val_t* p_val);
+
+#endif /* PARSER_H */
-- 
2.52.0