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Diffstat (limited to 'db/examples_c/csv/query.c')
| -rw-r--r-- | db/examples_c/csv/query.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/db/examples_c/csv/query.c b/db/examples_c/csv/query.c new file mode 100644 index 000000000..bd11da9dd --- /dev/null +++ b/db/examples_c/csv/query.c @@ -0,0 +1,242 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 2005-2006 + * Oracle Corporation. All rights reserved. + * + * $Id: query.c,v 1.14 2006/08/24 14:45:43 bostic Exp $ + */ + +#include "csv.h" +#include "csv_local.h" +#include "csv_extern.h" + +static int query_by_field(char *); +static int query_fieldlist(char *); +static int query_help(char *); +static int query_usage(void); + +typedef struct _cmdtab { + char *cmd; /* Command name */ + int (*f)(char *); /* Underlying function. */ + char *help; /* Help message. */ +} CMDTAB; + +static CMDTAB cmdtab[] = { + { "?", + query_help, + "?\t\tDisplay help screen" }, + { "exit", + NULL, + "exit\t\tExit program" }, + { "fields", + query_fieldlist, + "fields\t\tDisplay list of field names" }, + { "help", + query_help, + "help\t\tDisplay help screen" }, + { "quit", + NULL, + "quit\t\tExit program" }, + { NULL, + query_by_field, + "field[op]value\tDisplay fields by value (=, !=, <, <=, >, >=, ~, !~)" }, + { NULL, NULL, NULL } +}; + +/* + * query_interactive -- + * Allow the user to interactively query the database. + */ +int +query_interactive() +{ + int done; + char *p, input[256]; + + for (;;) { + printf("Query: "); + (void)fflush(stdout); + if (fgets(input, sizeof(input), stdin) == NULL) { + printf("\n"); + if (ferror(stdin)) { + dbenv->err(dbenv, errno, + "error occurred reading from stdin"); + return (1); + } + break; + } + if ((p = strchr(input, '\n')) == NULL) { + dbenv->errx(dbenv, "input buffer too small"); + return (1); + } + *p = '\0'; + if (query(input, &done) != 0) + return (1); + if (done != 0) + break; + } + return (0); +} + +/* + * query -- + * Process a query. + */ +int +query(char *cmd, int *donep) +{ + CMDTAB *p; + + if (donep != NULL) + *donep = 0; + + for (p = cmdtab; p->cmd != NULL; ++p) + if (p->cmd != NULL && + strncasecmp(cmd, p->cmd, strlen(p->cmd)) == 0) + break; + + if (p->cmd == NULL) + return (query_by_field(cmd)); + + if (p->f == NULL) { + if (donep != NULL) + *donep = 1; + return (0); + } + + return (p->f(cmd)); +} + +/* + * query_by_field -- + * Query the primary database by field. + */ +static int +query_by_field(char *input) +{ + OPERATOR operator; + size_t len; + char *field, *op, *value; + + /* + * We expect to see "field [op] value" -- figure it out. + * + * Skip leading whitespace. + */ + while (isspace(*input)) + ++input; + + /* + * Find an operator, and it better not start the string. + */ + if ((len = strcspn(field = input, "<>!=~")) == 0) + return (query_usage()); + op = field + len; + + /* Figure out the operator, and find the start of the value. */ + switch (op[0]) { + case '~': + operator = WC; + value = op + 1; + break; + case '!': + if (op[1] == '=') { + operator = NEQ; + value = op + 2; + break; + } + if (op[1] == '~') { + operator = NWC; + value = op + 2; + break; + } + return (query_usage()); + case '<': + if (op[1] == '=') { + operator = LTEQ; + value = op + 2; + } else { + operator = LT; + value = op + 1; + } + break; + case '=': + operator = EQ; + if (op[1] == '=') + value = op + 2; + else + value = op + 1; + break; + case '>': + if (op[1] == '=') { + operator = GTEQ; + value = op + 2; + } else { + operator = GT; + value = op + 1; + } + break; + default: + return (query_usage()); + } + + /* Terminate the field name, and there better be a field name. */ + while (--op > input && isspace(*op)) + ; + if (op == input) + return (query_usage()); + op[1] = '\0'; + + /* Make sure there is a value field. */ + while (isspace(*value)) + ++value; + if (*value == '\0') + return (query_usage()); + + return (DbRecord_search_field_name(field, value, operator)); +} + +/* + * query_fieldlist -- + * Display list of field names. + */ +static int +query_fieldlist(char *input) +{ + DbField *f; + + input = input; /* Quiet compiler. */ + + for (f = fieldlist; f->name != NULL; ++f) + printf("field %3d: %s\n", f->fieldno, f->name); + return (0); +} + +/* + * query_help -- + * Query command list. + */ +static int +query_help(char *input) +{ + CMDTAB *p; + + input = input; /* Quiet compiler. */ + + printf("Query commands:\n"); + for (p = cmdtab; p->help != NULL; ++p) + printf("\t%s\n", p->help); + return (0); +} + +/* + * query_usage -- + * Query usage message. + */ +static int +query_usage(void) +{ + fprintf(stderr, "%s: query syntax error\n", progname); + return (query_help(NULL)); +} |