version shell-V with commented out code

1 files changed, 214 insertions, 0 deletions

diff --git a/lexical_analysis.c b/lexical_analysis.c
new file mode 100644
index 0000000..f931118
--- /dev/null
+++ b/lexical_analysis.c
@@ -0,0 +1,214 @@
+#include "lexical_analysis.h"
+MAKE_QUEUE_PUSH(c_queue, cmdline, char**)
+
+int is_double_quotes_pair(struct param_type params)
+{
+    return !(params.double_quotes_counter % 2);
+}
+
+int escape_double_quotes_or_backslash(int ch, struct param_type params)
+{
+    return params.escape_sequences &&
+        (ch == double_quotes || ch == backslash);
+}
+
+int double_quotes_again(int ch, struct param_type params)
+{
+    return ch == double_quotes && !params.is_word &&
+        params.stored_symbol == '"';
+}
+
+int check_separation(int ch, struct param_type params)
+{
+    return (ch == whitespace || ch == tab) && params.is_word &&
+            !params.escape_sequences;
+}
+
+int ignore_spaces(int ch, struct param_type params)
+{
+    return (ch == whitespace || ch == tab) && !params.escape_sequences;
+}
+
+int change_mode(int ch, struct param_type params)
+{
+    return ch == '"' && !params.escape_sequences;
+}
+
+int start_escape_sequence(int ch, struct param_type params)
+{
+    return ch == backslash && !params.escape_sequences;
+}
+
+int is_empty_word(int ch, struct param_type params)
+{
+    return (ch == whitespace || ch == tab) && !params.is_word &&
+            params.empty_word_flag;
+}
+
+int command_execution_condition(struct param_type *params)
+{
+    return
+        (!filename_waiting(params) && !params->pipeline) ||
+        (params->pipeline && params->tokens == '&');
+}
+
+int is_special_token(int ch)
+{
+    return ch == and || ch == or || ch == '&' || ch == ';' || ch == '|';
+}
+
+int is_redirect_token(int ch, int next_ch)
+{
+    return ch == '<' || ch == '>' || (ch == '>' && next_ch == '>');
+}
+
+int excessive_words(int ch, struct param_type *params)
+{
+    int next_ch;
+
+    if(filename_waiting(params)) {
+        if(ch == new_line)
+            return 0;
+        while((next_ch = getchar()) != new_line) {
+            if(next_ch == ' ')
+                continue;
+            if(!is_special_token(next_ch) && next_ch != '<' && next_ch != '>')
+                return 1;
+            else
+                break;
+        }
+        ungetc(next_ch, stdin);
+    }
+    return 0;
+}
+
+void add_word_or_filename(struct w_queue *word_chain,
+                          struct dynamic_array *tmp_word,
+                          struct param_type *params)
+{
+    /* filenames */
+    if(filename_waiting(params) && !params->wrong_command)
+            add_filename(tmp_word, params);
+    /* execute command */
+    else if(params->is_word)
+        add_word(word_chain, tmp_word, params);
+}
+
+int validate_redirections(int ch, int next_ch, struct param_type *params)
+{
+    return (ch == '<' && params->streams.input_stream == NULL) ||
+            ((ch == '>' || (ch == '>' && next_ch == '>')) &&
+             params->streams.output_stream == NULL &&
+             params->streams.output_stream_to_append == NULL);
+}
+
+int is_double_token(struct param_type *params)
+{
+    return params->tokens == and || params->tokens == or ||
+            params->tokens == append;
+}
+
+/*
+ * redirection token verification
+ */
+int stream_redirect_tokens(struct w_queue *word_chain,
+                           struct dynamic_array *tmp_word, int ch,
+                           struct param_type *params)
+{
+    int next_ch;
+    next_ch = getchar();
+    ungetc(next_ch, stdin);
+
+    if(is_redirect_token(ch, next_ch)) {
+        add_word_or_filename(word_chain, tmp_word, params);
+
+        if(params->wrong_command)
+            return 0;
+
+        if(validate_redirections(ch, next_ch, params)) {
+            params->tokens = (ch == '>' && next_ch == '>') ? append : ch;
+            if(is_double_token(params))
+                getchar();
+            return 1;
+        } else {
+            fprintf(stderr, "syntax error\n");
+            params->wrong_command = 1;
+        }
+    }
+    return 0;
+}
+
+int wrong_streams_redirection(struct param_type *params)
+{
+    return
+        (!params->pipeline && (params->tokens == '>' ||
+                               params->tokens == append)) ||
+        (params->pipeline && (params->tokens == '>' ||
+                              params->tokens == append ||
+                              params->tokens == '<'));
+}
+
+int pipeline_token_processing(struct w_queue *word_chain,
+                              struct c_queue *cmdlines,
+                              struct dynamic_array *tmp_word,
+                              struct param_type *params)
+{
+    char **cmdline = NULL;
+    if(is_stream_redirection_set(params) &&
+            wrong_streams_redirection(params)) {
+        /* TODO: add error codes */
+        params->wrong_command = 1;
+        return 0;
+    }
+    params->tokens = '|';
+    params->pipeline = 1;
+    cmdline =
+        create_cmdline(word_chain, w_queue_get_word_count(word_chain));
+
+    c_queue_push(cmdlines, cmdline);
+    w_queue_clear(word_chain);
+    dynarr_drop_word(tmp_word);
+    return 1;
+}
+
+/*
+ * verification of special tokens (|, &, &&, ||), except redirection tokens
+ */
+int special_tokens(struct w_queue *word_chain, struct c_queue *cmdlines,
+                   struct dynamic_array *tmp_word, int ch,
+                   struct param_type *params)
+{
+    int next_ch;
+    next_ch = getchar();
+    ungetc(next_ch, stdin);
+
+    if(is_special_token(ch)) {
+        add_word_or_filename(word_chain, tmp_word, params);
+
+        if(params->wrong_command)
+            return 0;
+
+        if(ch == '|' && next_ch == '|')
+            params->tokens = or;
+        else if(ch == '|') {
+            if(!pipeline_token_processing(word_chain, cmdlines, tmp_word,
+                                          params))
+                return 0;
+        } else if(ch == '&' && next_ch == '&')
+            params->tokens = and;
+        else if(ch == '&') {
+            while((ch = getchar()) != new_line) {
+                if(ch != whitespace && ch != tab) {
+                    fprintf(stderr, "incorrect command\n");
+                    params->wrong_command = 1;
+                    return 0;
+                }
+            }
+            params->tokens = '&';
+        }
+        if(is_double_token(params))
+                getchar();
+        return 1;
+    }
+    return 0;
+}